cleaner production & energy efficiency manual

UNEP

Cleaner Production~

Energy Efficiency

MANUAL

United Nations Environment ProgrammeDivision of Technology, Industry and Economics

Guidelines for the Integration of Cleaner Production and Energy Efficiency

Contents listing

About the CP-EE Manual

Part 1 CP-EE methodology

Part 2 Technical modules

Part 3 Tools and resources

Cleaner Production – Energy Efficiency Manual page b

Cleaner Production–Energy Efficiency (CP-EE) Manual

© Copyright 2004 UNEP

This publication may be reproduced in whole or in part and in anyform for educational or non-profit purposes without special permissionfrom the copyright holder, provided acknowledgement of the sourceis made. UNEP would appreciate receiving a copy of any publicationthat uses this publication as a source.

No use of this publication may be made for resale or for any othercommercial purpose whatsoever without prior permission in writingfrom UNEP.

First edition 2004

The designations employed and the presentation of the material in thispublication do not imply the expression of any opinion whatsoever onthe part of the United Nations Environment Programme concerningthe legal status of any country, territory, city or area or of itsauthorities, or concerning delimitation of its frontiers or boundaries.Moreover, the views expressed do not necessarily represent thedecision or the stated policy of the United Nations EnvironmentProgramme, nor does citing of individual companies, trade names orcommercial processes constitute endorsement.

UNITED NATIONS PUBLICATIONISBN: 92-807-2444-4

Designed and produced by Words and Publications, Oxford, UK

Cover photographs courtesy of Photodisc Inc.

These Guidelines for the Integration of Cleaner Production and Energy Efficiency are part of a UNEP

effort to link the professional disciplines of Cleaner Production and Energy Efficiency in a more

systematic manner. They were developed during a project that saw National Cleaner Production

Centres (NCPCs) in six countries pull energy management principles into the resource efficiency

approach that lies at the heart of Cleaner Production.

The National Productivity Council of India prepared the draft manual, which was then used by NCPC

staff in China, the Czech Republic, Hungary, India, the Slovak Republic and Vietnam. Together these

NCPCs then tested the Cleaner Production–Energy Efficiency methodology in almost 100 companies.

Their experiences in applying the Guidelines helped improve the working draft, as did the editorial

skill of Geoffrey Bird.

The manual has also benefited from comments and suggestions provided by external reviewers, most

notably Thomas Bürki.

Preparation of the manual was coordinated at UNEP by Amr Abdel Hai. Surya Chandak and Mark

Radka also contributed to the effort, which was conducted as a joint activity between UNEP’s Cleaner

Production and Energy programmes.

Cleaner Production – Energy Efficiency Manual page i

Preface

Objectives of the ManualThis electronic manual is part of UNEP DTIE's broad effort to strengthen the energy component of

Cleaner Production (CP) assessments carried out by National Cleaner Production Centres (NCPC).

The Manual presents an integrated Cleaner Production–Energy Efficiency (CP-EE) methodology

based on the proven CP methodology and combines this with factual information, technical data,

worksheets, and tools and resources that will allow both technical specialists and managers to take

direct and effective action.

The guidance provided in the manual can be used by facility personnel conducting in-house

assessments and by consultants interested in providing industrial assessments. CP professionals (who

are not energy specialists) will find guidance on how to better incorporate energy issues into their CP

assessments at industrial or other facilities. Managers will gain insight into the role they can play in

instigating and supporting an ongoing, cost-effective process that has both economic and

environmental advantages.

Structure of the ManualThe CP-EE Manual makes full use of the advantages of its electronic format, providing readers with

‘hyperlinks’ to the sections that are most relevant to their needs. This aspect is explained further in

‘Navigating the Manual’ on the following page.

The first two chapters lay the foundations of the CP-EE assessment methodology for all readers.

Chapter 1 introduces the benefits of integrating CP and EE and of producing a CP-EE methodology.

This is followed, in Chapter 2, by a full explanation of the five steps that make up the methodology.

Readers are then ‘walked through’ the tasks that comprise each step. These simple and easy to follow

explanations are accompanied by a ‘Running Example’ in the form of Completed Worksheets taken

from the actual CP-EE assessment of a textile processing house in India.

Worksheets are an important tool for CP-EE assessment and blank versions of those used for the

Running Example are provided on the CP-EE CD-ROM in editable, printable form, allowing users to

adapt them to their own purposes (see Navigating the Manual on the following page).

The third and final chapter of Part 1 presents the full Case Study of the textile firm used for the

Running Example in Chapter 2.

Cleaner Production – Energy Efficiency Manual page ii

About the CP-EE Manual


Cleaner Production – Energy Efficiency Manual page iii

… About the CP-EE Manual (continued)

Module 1 provides background information on different energy-using systems (thermal and

electrical), information that will be helpful in identifying areas of focus for CP-EE assessments.

Module 2 presents Energy Efficient Technologies. Module 1 includes further worksheets that can be

used during assessment.

Part 3 provides tools and resources for everyday use, including: checklists (of procedures that improve

energy efficiency and safety in energy-using equipment); thumb rules (for rapid assessment of the

efficiency of major energy systems); a summary of different types of measuring instruments; links to

sources of information on the Internet; conversion tables (equating SI, metric and other units); and a

summary of acronyms and abbreviations used throughout the Manual.

An additional feature of Part 3 is UNEP’s ‘GHG Indicator’—a spreadsheet based calculator that

allows users to compute the greenhouse gas (GHG) emissions from their facilities. Hyperlinks provide

access to the GHG Indicator either on UNEP’s website or on the CP-EE CD-ROM.

Navigating the ManualHyperlinks are provided throughout the three Parts of the Manual, allowing readers to navigate within

the document and to access Internet based and additional resources with ease. For example:

• Hyperlinks in the contents pages and at the beginning of each main Part enable readers to jump

directly to the topics of their choice.

• Blank versions of the sample Worksheets presented in Parts 1 and 2 are included on the CP-EE CD-ROM

in editable (Microsoft® Word™) format. These can be opened individually by clicking on the

‘Open File’ button at the top right hand corner of the Worksheets displayed in the Manual.

• UNEP’s GHG Indicator is included on the CD-ROM and can be opened directly via the hyperlinks

on the contents page and in Part 3 of the Manual.

• Part 3 includes a comprehensive list of information resources on the Internet. Hyperlinks are

included to provide the reader with direct access to the Internet sites listed. (Note: please read

the disclaimer at the beginning of this section of the Manual before using these resources).



Cleaner Production – Energy Efficiency Manual page iv

Cleaner Production ~ Energy Efficiency (CP-EE)Guidelines for the Integration of Cleaner Production and Energy Efficiency

MANUAL

Contents

Preface i

About the CP-EE manual ii

Part 1 CP-EE methodology 1

Chapter 1: Introduction 2

1.0 Building on established strategies 2

1.1 Cleaner Production (CP)—a focus on material flows 2

1.2 Energy Efficiency (EE)—a focus on cost reduction 2

1.3 Integrating CP and EE 3

1.4 Areas requiring particular attention when integrating CP-EE 4

Chapter 2: CP-EE assessment methodology 7

2.1 Introduction 7

2.2 CP assessment—an established methodology 8

2.3 EE assessment—towards a methodology 10

2.4 Integrated CP-EE assessment methodology—combining for synergy 10

2.5 Description of a CP-EE methodology 12

2.6 The CP-EE process (incorporating the Running Example) 14

2.7 Worksheets for a CP-EE assessment methodology 61

Chapter 3: Case study 87

3.1 About the company 87

3.2 Process description and process flow chart 88

3.3 Baseline information 91

3.4 Identification of waste streams, cause analysis and CP-EE opportunities 95

3.5 Feasibility analysis of CP-EE options 98

3.6 Benefits and achievements 105

3.7 CP-EE assessment barriers 108

3.8 Conclusions 109

… Contents (continued)

Cleaner Production – Energy Efficiency Manual page v

Part 2 Technical modules 111

Module 1: Energy use in industrial production 112

Thermal systems 112

M1.1 Fuels—storage, preparation and handling 112

M1.2 Combustion 116

M1.3 Boilers 121

M1.4 Thermic fluid heaters 135

M1.5 Steam distribution and utilization 137

M1.6 Furnaces 154

M1.7 Waste heat recovery 163

Electrical systems 176

M1.8 Electricity management systems 176

M1.9 Electric drives and electrical end-use equipment 189

M1.10 Cooling towers 222

M1.11 Refrigeration and air-conditioning 227

M1.12 Lighting systems basics 234

Module 2: Energy efficient technologies 240

M2.1 New electrical technologies 240

M2.2 Boiler and furnace technologies 242

M2.3 Heat upgrading systems 244

M2.4 Other utilities 245

Part 3 Tools and resources 247

A: Checklists for enhancing efficiency and safety 248

B: Thumb rules for quick efficiency assessment 260

C: List of energy measuring instruments 262

D: Greenhouse Gas Emissions Indicator 267

E: Information resources 276

F: Conversion tables 287

G: Acronyms and abbreviations 293

Cleaner Production – Energy Efficiency Manual page vi

ENERGYEFFICIENCY

Cleaner Production – Energy Efficiency Manual page 1

Contents listing




Cleaner Production (CP) and Energy Efficiency (EE)

are established and powerful strategies that reduce costs

and generate profits by reducing waste. Their integration

can provide synergies that broaden the scope of their

application and give more effective results—both

environmental and economic. Integration of these two

powerful strategies is the subject of this manual.

1.0 Building on established strategiesBoth Cleaner Production (CP) and Energy Efficiency (EE) are established and powerful

strategies that reduce costs and generate profits by reducing waste. They are, however,

generally practiced separately, with little or no search for common ground. This is

unfortunate, since CP and EE are often highly complementary and their integration can

provide synergies that broaden the scope of their application and give more effective

results—both environmental and economic. Integration of these two powerful

strategies is the subject of this manual.

1.1 Cleaner Production—a focus on material flowsCP was developed as a preventive strategy to reduce environmental pollution and

simultaneously reduce consumption of material resources. Its main focus is on

processes and on reduction of the resources they use. CP is a new and creative way of

thinking about products and processes that implies continuous application of strategies

to prevent and/or reduce the occurrence of waste. Practitioners of CP call on an

established CP methodology to identify and implement solutions.

As the example below right illustrates, the CP concept can combine real opportunities

for growth with maximum efficiency in use of materials. However, because CP evolved

from environmental concerns about physical pollution arising from material waste

streams and emissions, its proponents and practitioners have focused on material

resource conservation. CP does not, generally, address issues of total resource

productivity holistically, and other avenues of productivity—such as energy

conservation, industrial engineering, value engineering, etc.—have not been well

integrated into the concept. In addition, CP—by definition—does not cover ‘end-of-

pipe’ solutions.

1.2 Energy Efficiency—a focus on cost reduction Efforts to improve energy efficiency in industry began in the early 1970s, driven

primarily by the need to reduce production costs. Although energy is a vital input to

many processes, it is not necessarily a critical cost component. This may explain why

EE practitioners have tended to focus on energy conversion equipment (involving less

risk in terms of process disruption) and have avoided process-related EE options (a

riskier proposition).

There is no universal, systematic methodology characterizing an EE approach and to

which EE practitioners can refer. Individual countries have accordingly adopted their

own strategies to address energy efficiency and energy input costs. Currently, EE is



Chapter 1: Introduction

snapshot

CP-EE

A small-scale textile-processing unit used

winches (heated by directfiring of solid fuel) for

bleaching and dyeing ofcotton fabric. A CP studyrevealed that the unit waswasting large amounts of

water, dyes and otherchemicals. CP solutions,including reducing thematerial-to-liquor ratiofrom 1:20 to 1:15 and

optimizing the chemicalsand dyes, reduced the

consumption of water andchemicals used and

resulted in annual savingsof US$3 600.

A seasoned CP practitioner,was asked to look into a

large educational institution’spumping system to improvewater use. Having recently

acquired EE skills, he was notonly able to reduce wastefulwater consumption by 30per cent but also to reduce

the energy used forpumping by 37 per cent(through reduced use,

optimum pipe size,simplified distribution

network and reduced headrequirements).

snapshot

CP-EE


Part 1 CP-EE methodology Chapter 1: Introduction

viewed as being highly compartmentalized and, in the absence of an established

methodology, is generally prescriptive and sporadic.

Very few EE practitioners are concerned about the environmental results of

implementation of EE and—even though a fair proportion of EE options lead to benefits

for the environment—these are almost never highlighted. For EE practitioners, cost

reduction is the overriding concern and they will favour economically attractive options

even when these may have negative environmental impacts.

1.3 Integrating CP and EE 1.3.1 Benefits of integrating CP and EE

The numerous, tangible benefits of an integrated CP-EE approach, illustrated succinctly

by the snapshots, are outlined below. Once the benefits have been described, some

consideration is given to important aspects of integration, highlighting differences in

assessing material and energy flows and identifying skills needed for successful CP-EE

integration.

An integrated CP-EE approach offers the following benefits:

I. Expanded service package with greater benefits (synergy)

When resources are low priced (or perhaps subsidized) and/or environmental issues are

not considered significant, a CP solution alone may not be attractive. By combining it

with EE benefits, a more attractive package can be proposed. Similarly, the

attractiveness of reduced energy consumption in a situation where energy prices are

not significant may be enhanced by combining it with CP. An integrated CP-EE

approach draws from a much wider repertoire of best practices, yielding

comprehensive business solutions and more attractive cost benefits.

II. Greater market share for products

CP-EE can lead to products that can genuinely be described as ‘eco-friendly’. ‘Green’

products that warrant both eco and energy rating labels have an additional

competitive edge—they can gain a better market share.

III. Integration ensures sustainability of EE options

To date, the prevailing approach to EE has been task oriented and prescriptive in nature

and EE has not been viewed as part of day-to-day management. EE improvement

programmes have therefore often ended as soon as advisors have left the plants,

resulting in programmes that are sporadic and short-lived.

snapshot

EE

A small-scale textile-processing unit used an

open winch for bleachingand dyeing of cottonfabric. The winch was

heated by direct firing ofsolid fuel under the tank.An energy audit indicatedinefficiency in the heatingsystem resulting in heavyfuel consumption and less

than optimum bathtemperatures. When, on

the EE professional's advice,changes were made to thedesign of the furnace, the

bath temperature wasincreased from 55 °C to

60 °C, and fuelconsumption was reduced.

This brought an annualsaving of US$1 200.

An acclaimed EE expert,was asked by the managersof a Vietnamese steel plantto help reduce energy bills.

Using integrated CP-EEtechniques, he not only

brought down oilconsumption and costs by20 per cent (by fine tuningexcess air in burners of heattreatment furnaces) but alsoreduced scale losses (due tooxidation) from 3 per centto less than 0.5 per cent—equivalent to an additional10 per cent of oil savings.

snapshot

CP-EE



Conversely, continuous application is a key aspect of CP. When CP and EE are

integrated, the notion of continuity becomes extended to EE thereby ensuring its long

term sustainability.

IV. Facilitating implementation of global agreements and protocols

In recent years a number of global and regional agreements and protocols have been

developed covering both environmental and energy issues.

CP-EE can help to mainstream these more easily than CP or EE alone. Some countries

have introduced laws on CP others on EE; a combination of both can help to enforce

material and energy conservation measures simultaneously. A CP-EE group could play

a pivotal role in helping a country’s government towards this end.

V. Less duplication of tasks and synergy between CP and EE objectives

CP and EE professionals spend a lot of time collecting and analysing data separately,

and then generating material and energy savings options, once again separately. An

integrated and simultaneous effort would save a lot of collection and analysis time and

would also lead to simpler ways of addressing interdependent issues of material and

energy waste.

VI. Improving access to a wider range of funding sources

There are global and regional sources of funds available exclusively for CP or exclusively

for EE. These could be accessed jointly by CP-EE.

VII. CP-EE paves the way for implementation of Environmental Management Systems (EMS)

An integrated CP-EE approach, by virtue of its methodology, makes it easier to implement

and sustain a more comprehensive Environmental Management System (EMS).

1.4 Areas requiring particular attention when integratingCP-EE: hidden wastes and inefficiencies in energy systemsBecause CP is generally applied to visible (i.e. material) resource wastes, it leaves little to

chance. Material inputs to a given operation can generally be traced through to

perceivable and quantifiable outputs. This is not always the case when considering

energy streams. While the same basic rule must hold true for energy inputs (i.e. amount

of energy ‘in’ must, ultimately, be equal to the amount of energy ‘out’) output energy

streams are often less easy to perceive than material ones. Identification and evaluation

of hidden waste streams and inefficiencies can therefore be a difficult proposition.



This is particularly true for electrically driven equipment such as pumps, fans, air

compressors, etc. where input energy, in the form of electricity, is easily measurable but

the degree to which this is efficiently converted into useful output (e.g. pumped water,

compressed air, etc.) is not directly quantifiable.

The following are examples of typical situations where only looking for visible/perceivable

energy streams can lead to overlooking of energy loss in output streams:

• Loss due to part load operation of energy-using equipment.

• Loss due to (low-efficiency) banking/idling operations of energy using equipment.

• Losses due to resistance to flow (high but avoidable resistance in electricity

conductors and fluid pipelines).

• Loss due to equipment degradation (pump impellers, pump bearings, etc.)

leading to increased losses.

1.4.1 Additional parameters and skills

In order to ascertain the outputs (both perceivable and non-perceivable) from energy

systems, some EE parameters have to be measured/monitored during a CP assessment

in addition to the essential ones—such as temperature, flow, humidity, concentration,

percentage compositions, etc.—already measured as part of CP.

Additional EE parameters that need to be measured/monitored could include:

kW (kilowatt power input); kV (kilovolts—impressed voltage); I (amperes—electrical

current); PF (power factor of induction electric equipment); Hz (frequency of

alternating current); N (rpm or speed of rotating equipment); P (pressure of

liquid/gaseous streams); DP (pressure drops in input/output liquid and gaseous

streams); Lux (light intensity); GCV, NCV (gross and net calorific value of fuels); etc.

CP professionals will need some additional skills to be able to integrate EE during

assessments effectively. They should:

• have a basic understanding of electrical circuits, to be able to measure input

power to motor drives correctly;

• be able to evaluate enthalpy (heat content) in each stream by measuring

temperature, pressure and flow;

• be able to quantify non-perceivable (invisible) streams using known streams. For

example, given pump output parameters (such as pressure developed, flow and

density) they should be able to evaluate work done and thus estimate energy output;



• be familiar with and able to convert between various energy, pressure and heat

content units;

• be able to control waste energy streams and learn to correlate the effect of

control measures with conversion efficiency of equipment.

Differences between material and energy flows are considered further when the

methodology for carrying out a CP-EE assessment is presented in Chapter 2.

1.4.2 Possible contradictions

CP and EE are highly complementary, with synergies between the individual benefits

of each delivering a more effective overall outcome. However, there are some situations

where the beneficial results of one methodology (say CP) can be perceived as being in

contradiction with the other methodology (EE). A few simple examples will illustrate

this:

• Recycling is a very profitable CP technique, but recycling of oils, and lubricants,

and reuse of reconditioned bearings or rewinding of burned out motors

(especially when not done properly) often lead to higher energy consumption.

• Refrigeration by vapour absorption is an eco friendly and pro-CP option in

comparison with the prevalent vapour compression machines. However, in terms

of energy use, vapour absorption systems are less efficient.

• Slim fluorescent tube lights are far more energy efficient than incandescent lamps,

but from the environmental (CP) point of view, their mercury coating makes them

less eco-friendly.

snapshot

CP-EE

‘EA’, a medium scale edibleoil processing unit in India,

was experiencing highhexane losses of 4.93 litresper ton of seeds processed.CP-EE studies in the plantrevealed that the losseswere primarily due to

inadequate steam supply atthe desired pressure,

inadequate heating surfacearea of the reactor vessel,

low vacuum, andinadequate condenser size.Further detailed studies ofthe boiler revealed that itdid not have the capacity

to supply the requiredquantity of steam at

optimum pressure. Thecompany changed the

boiler and—after necessarymodification of the reactor

vessel to increase theheating surface area—

reduced hexane losses by12.2 per cent. Besides

improving itsenvironmental

performance, the companyimproved the quality of the

de-oiled cake. A totalinvestment of US$255 500resulted in annual savings

of US$270 000.



Chapter 2:

CP-EE assessment methodology

2.1 IntroductionFrom the arguments presented in Chapter 1, the benefits, and the possible

importance, of integrating CP and EE should now be clear. This second section looks

at methodology, and shows how the proven method of carrying out a CP assessment

can be expanded to ensure a systematic approach to EE.

Traditionally, EE assessments have been driven by a need for quick solutions, to be

implemented quickly, and for quick profits. EE assessments and projects have therefore

tended to be needs-based, arising from situational demands, and have generally relied

on external EE expertise. There has been no perceived need to develop in-house

capacities to foster continuous improvement programmes. As a consequence, EE

assessments and implementation of the resulting projects have tended to be ad hoc,

piecemeal, and less logically structured than CP assessments.

If CP-EE coverage is to be comprehensive, a CP-EE assessment—like a CP assessment—

must be conducted systematically. A structured approach is essential to get the best

results and to ensure that the outcomes are consistent with those identified in the

enterprise's broader planning process. A step-by-step procedure based on a sound

methodology will ensure maximum benefit from CP-EE opportunities.

The assessment method should be flexible enough to accommodate unforeseen

circumstances and problems, and to allow solutions to be identified. How formal the

method needs to be will depend on the size and composition of the company, on its

material and energy use, and on specific aspects of its waste production.

The CP-EE assessment method should also ensure better use of available resources

(manpower, machinery, material, money) and should foster logical and sequential

thinking.

A CP-EE assessment is an excellent way of building a waste avoidance culture and of

creating competence within the company that is crucial for long-term sustainability.

And finally, if the CP-EE programme is to be effective and continuous, it is essential to

involve people from the different sectors of the company in its implementation.

Part 1 CP-EE methodology Chapter 2: CP-EE assessment methodology

2.2 CP assessment—an established methodologyAssessment, involving analysis of the material and energy flows entering and leaving a

process, is a central element of CP. Conducting a CP style assessment relies on a logical

and methodical approach that makes it possible to identify opportunities for CP, to

solve waste and emission problems at source, and to ensure continuity of CP activities

in a company. This analytical assessment approach is embedded in the CP

methodology, shown in Figure 1.1.

The basic CP methodology consists of the following principal elements:

• Planning and Organization

• Pre-assessment

• Assessment

• Feasibility Analysis

• Implementation and Continuation.


Planning andOrganization

obtain commitment of top management

involve employees

organize a team

identify barriers and solutions to the CPA process

decide the focus of the CPA

compile and prepare basic information

conduct a walkthrough

prepare an eco-mapprepare a preliminary material and energy balance

prepare a detailed materialand energy balance

conduct cause diagnosis

generate options

screen options

conduct economic andenvironmental evaluation

select feasible options

prepare a cleaner production implementation plan sustain cleaner production assessments

Pre-assessment

Assessment

FeasibilityAnalysis

Implementationand Continuation

compile existing basic information

Figure 1.1 CP methodology


Figure 1.1 shows the generic CP methodology. However, in practice, different

institutions and practitioners have expanded and/or modified the steps in this basic

methodology and have developed specific tasks at each step that suit local conditions

and specific requirements. A typical empirical CP methodology is presented in Figure

1.2. This is used later (in Section 2.5) to develop a CP-EE assessment methodology that

adheres strictly to the steps presented here but also includes specific features that need

to be covered to integrate energy efficiency aspects.


STEP 1: Planning and Organization

Task 1: Obtaining commitment and involvement of top managementTask 2: Involving employeesTask 3: Organizing a CP teamTask 4: Compiling existing basic informationTask 5: Identifying barriers and solutions to the CP assessment processTask 6: Deciding the focus of the CP assessment

Task 7: Preparing a process flow diagramTask 8: Conducting a walkthroughTask 9: Preparing material input-output quantification and characterizationTask 10: Generating and finalizing base data

Task 11: Preparing a detailed material balance with lossesTask 12: Conducting cause diagnosisTask 13: Generating optionsTask 14: Screening options

Task 15: Conducting technical, economic and environmental evaluationTask 16: Selecting feasible options

Task 17: Preparing CP implementation planTask 18: Sustaining CP assessments

STEP 2: Pre-assessment

STEP 3: Assessment

STEP 4: Feasibility Analysis

STEP 5: Implementation and Continuation

Figure 1.2 Steps of the CP methodology


2.3 EE assessment—towards a methodologyFor most companies, it is the absence or disruption of energy supply that is perceived

as having a dramatic impact on the process, not day-to-day energy consumption.

Energy is viewed as a crucial input but not always as an important cost intensive one.

There has therefore been little motivation and incentive to develop riskier but more

rewarding energy reduction initiatives in manufacturing process.

EE improvements have generally been made to standard energy converting

equipment—such as boilers, furnaces, heaters, dryers, ovens and kilns, and electrically

driven equipment such as pumps, fans, air compressors, refrigeration compressors,

etc.—with little effort on process and production related equipment and technology.

All industrial and commercial facilities have some energy conversion equipment, and

nearly all of this has well standardized performance assessment procedures and

reference performance indicators. The existence of these procedures and indicators is

seen as making a logical, structured and comprehensive methodology unnecessary and

gives little incentive for innovation and creativity in approach and methodology.

Over a period of time, this has led to development of very mature, proven, cost-

effective and standardized prescriptive solutions, with very little effort going into the

development of creative alternatives.

2.4 Integrated CP-EE assessment methodology—combining for synergySection 1.4 outlined important differences between CP and EE assessments,

underscoring the differences between material and energy flows and some of the

difficulties of quantifying the latter. The material below builds on that information,

going into greater detail on how energy flows can be quantified.

a) In a CP assessment, material streams are identifiable and quantifiable at both input

and output stages, since the material streams do not generally change form. In a

CP-EE assessment, however, care must be exercised when accounting for energy,

since energy is largely invisible at input and changes form within the process.

Electricity, for example, is used to drive motors but also to compress air as well as

for lighting, heating, etc. It may be identifiable and quantifiable at the input stage,

but it is much more difficult to identify and quantify at output.



b) Whenever energy changes form there are some inevitable losses. For CP, these

losses are not considered as important because they do not have a significant direct

impact on the environment. For EE, on the other hand, identification of the areas

where these losses occur is of great importance.

c) To identify losses, CP-EE studies have to include measurement of parameters not

measured for CP (e.g. temperature, tension in belts, lumens for lighting, etc.).

There are also parameters such as friction, surface tension, etc. which cannot be

perceived directly and which cannot therefore be measured directly. In these

cases estimates have to be made using empirical equations.

d) CP does not identify waste streams unless they are in the form of material waste.

For instance, in a combustion process, a CP study will measure the airflow before

and after combustion (in stack). If the quantities match, little or no further

attention will be paid to this stream. For EE studies, however, excess air levels in

the flue gas (in stack) are of great importance. Similarly a stream of hot

wastewater is a material waste for CP, for EE it is a heat loss.

e) In a CP assessment it is relatively easy to produce a material and mass balance for

a process because, as already explained, material streams do not generally change form1.

It is more difficult for a CP-EE assessment to produce an exact energy balance right across

a process since energy is invisible and changes its form. Even perceivable losses, such

as iron or copper losses, eddy current loss in motors, friction losses etc., are difficult to

measure and quantify. A different approach has to be adopted to obtain energy balances.

Some options for producing an energy balance are:

i) System efficiency based on measurable energy input and work output

For example, fan delivery air can be measured (in m3) against power consumed (in

kW), giving an indication of efficiency as kW/m3. A similar indication could be given for

a refrigeration system, as kW/TR.

ii) Measurement of major loss only

Sometimes input and output energy streams are difficult to measure. This would be the

case, for example, for steam flowing in a pipeline over a long distance and where it is

possible to measure neither input steam, owing to lack of flow meters, nor output heat

effect, because of the very narrow temperature difference. However, parameters such

as surface losses or radiation losses can be measured.


1 Even when some of the materials do change form (e.g. vapour loss from water duringheating) the changes are usually very small.


iii) Single parameter measurement and benchmark comparison

For systems like agitators, where even measuring of losses is not practicable,

comparative efficiency levels can be obtained by measuring the electricity input and

comparing it with input for similar systems elsewhere.

The causes of energy waste are well known, relatively uniform and standard and, at

times, making an exhaustive cause analysis may seem superfluous (e.g. Waste = excess

air in flue gas. Cause = air fan supplying too much air or air ingress). However, until the

CP-EE team becomes fully conversant with the normal/standard causes, it may still be

advisable to conduct an exhaustive cause analysis, to avoid overlooking possible causes.

2.5 Description of a CP-EE methodologyThe CP-EE methodology (shown in Figure 1.3) follows the same generic, systematic

and step-by-step approach as the CP methodology, and is characterized by the same

five steps. For a CP practitioner, the basic assessment methodology remains the same,

the difference lying in some of the specific tasks, in particular those in Step 2, and in

the details of the material and energy balance, in Step 3.


Planning andOrganization

STEP 1

Pre-assessmentSTEP 2

AssessmentSTEP 3

Implementationand Continuation

STEP 5

FeasibilityAnalysisSTEP 4

START HERE

Figure 1.3 CP-EE methodology


STEP 1: Planning and Organization

Task 1: Obtaining commitment and involvement of top managementTask 2: Involving employeesTask 3: Organizing a CP-EE teamTask 4: Compiling existing basic informationTask 5: Identifying barriers and solutions to the CP-EE assessment processTask 6: Deciding the focus of the CP-EE assessment

Task 7: Preparing a process flow diagramTask 8: Conducting a walkthroughTask 9: Preparing material and energy input-output quantification

and characterizationTask 10: Generating and finalizing base data

Task 11: Preparing a detailed material and energy balance with lossesTask 12: Conducting cause diagnosisTask 13: Generating optionsTask 14: Screening options

Task 15: Conducting technical, economic and environmental evaluationTask 16: Selecting feasible options

Task 17: Preparing CP-EE implementation planTask 18: Sustaining CP-EE assessments

STEP 2: Pre-assessment

STEP 3: Assessment

STEP 4: Feasibility Analysis

STEP 5: Implementation and Continuation

!

!

!

!

!

!

!

!

!


Figure 1.4 CP-EE assessment methodology

Note: the next to the

Tasks in Figure 1.4 indicate

Tasks which require additional

skills, expertise, data

collection and work; these

Tasks are similarly indicated

where they occur in the text.

!


2.6 The CP-EE process

Introduction

This section describes the CP-EE process. It gives detailed comments on each of the 18

tasks that make up the 5 steps of the process, and presents a set of Worksheets—the

tools for conducting an assessment—at the end of the section*.

To better illustrate the steps of the CP-EE assessment methodology, a ‘Running

Example’ is presented in this section of the manual. It is described as a ‘running’

example because it recurs throughout the section presenting relevant data and values,

in the form of Completed Worksheets, as each task of the five steps of the CP-EE

methodology is explained.

The data and values used in the Completed Worksheets are taken from an actual CP-EE

assessment carried out in 2002 at M/s Luthra Dyeing and Printing Mills (LDPM), Surat,

India. LDPM is a well-equipped textile processing house that is representative of the

synthetic fabric processing sector in India. A full description of the step by step CP-EE

assessment of LDPM is presented as a ‘Case Study’ contained in Chapter 3.

STEP 1 Planning and Organization

The planning and organization step is one of the most important for a successful CP-EE

assessment. It consists of the following six tasks:

• Obtaining commitment and involvement of top management

• Involving employees

• Organizing a CP-EE team

• Compiling existing basic information

• Identifying barriers and solutions to the CP-EE assessment process

• Deciding the focus of the CP-EE assessment.

Planning can begin once the members of the CP-EE team are identified and once the

interest of management in CP-EE has been obtained—often as a result of awareness

raising. However, a CP-EE assessment can only be initiated after a decision has been

made by the management to take action.


* The Worksheets

presented in Section 2.7

are included on the

CD-ROM in Microsoft®

Word™ format. These

editable files can be

opened by clicking on the

‘Open File’ button in the

top right corner of each

Worksheet displayed in the

Manual.



The CP-EE assessment may be conducted by an internal company team or by hiring

external CP-EE professionals.

Task 1 Obtaining commitment and involvement

of top management

If the company decides to involve external CP-EE professionals (consultants) a

meeting is generally organized between the consultants and top management

to formalize this decision.

Typically, a memorandum of understanding (MoU) is drawn up between the

consultants and the company to define the CP-EE objectives; establish a work

plan that will indicate a time frame, sharing of responsibilities and outcomes;

and to set fees.

The management of the company has to set the stage for the CP-EE assessment

in order to ensure cooperation and participation of the staff members. In addition

to signing the MoU, top management's commitment should take the form of:

• management of formation of a CP-EE team;

• ensuring availability of required resources;

• provision of necessary training, awareness-raising meetings for employees;

and

• responsiveness to the CP-EE results.

It is also important to assess the following:

• Where does the company stand in relation to environmental and energy

policies and to what extent have these been implemented?

• What is the status of environmental and energy management in the

company?

• What is the status of internal communications at different levels in the

company, of information flow, and of initiatives to raise awareness of energy

and environmental management issues amongst employees?

The Completed Worksheet 1 in the Running Example on the following page

shows how a matrix can facilitate assessment of managerial aspects.



Running Example: Task 1

Obtaining commitment and involvement of top management

CP-EE is not just a matter of finding technical solutions, numerous other factors influence

energy management and the identification and implementation of CP-EE options both

directly and indirectly. Commitment and involvement of a firm's top management are

therefore essential—CP-EE can only be initiated after management has made the

decision to act.

An Environmental Management Matrix like the one shown below2 (as the first

Completed Worksheet) can be used to foster management involvement and assist in

making decisions and identifying potential CP-EE solutions. Completing the matrix

indicates where the company stands in relation to six energy/environmental

management areas: policy and systems, organization, motivation, information systems,

awareness and investment.

The matrix presented below is the one used at M/s Luthra Dyeing and Printing Mills

(LDPM), Surat, India, the information being based on interviews with management and

presentations during an initial meeting on energy and environmental management

activities.

Based on interview outcomes, bullet points are inserted in the matrix, and these are

connected to give a curve (as shown in the matrix below). The peaks indicate where

current efforts are most advanced; the troughs indicate where the company is least

advanced. It is not unusual for the 'curve' to be uneven, this is the case for most

organizations.

The matrix helps to identify aspects where further attention is required to ensure energy

and environmental management is developed in a rounded and effective way. It will also

assist in organizing an energy and environmental management system.

How to use the matrix• Senior management staff and the CP-EE Team Leader are given a blank version of

the matrix. Ask them to indicate on it what they believe to be their company’spresent situation. A score of ‘4’ for a specific category means that all initiativesmentioned in categories 0 to 4 must be present.

• Hold a 1-hour interview with senior management to check the real position.• Based on interview outcomes, insert the bullets in the matrix and connect them up.

2 Modified from the Energy Management Matrix provided by the Sustainable Energy Authorityof Victoria, Australia, www.seav.vic.gov.au

http://www.seav.vic.gov.au



Motivation

Formal and informalchannels ofcommunicationregularly used byenergy/environmentalmanager and staff at alllevels

Energy/environmentcommittee used asmain channel togetherwith direct contact withmajor users

Contact with majorusers through ad hoccommittee chaired bysenior departmentalmanager

Informal contactsbetween engineer anda few users

No contact with users

Organization

Energy/environmentalmanagement fullyintegrated intomanagement structure.Clear delegation ofresponsibility for energyuse

Energy/environmentalmanager accountableto energy committee,chaired by a member ofthe management board

Energy/environmentalmanager in postreporting to ad hoccommittee but linemanagement andauthority unclear

Energy and environmentalmanagement are part-time responsibility ofsomeone with onlylimited influence or authority

No energy/env.manager or formaldelegation ofresponsibility forenv./energy use

Policy and systems

Formal energy/environmental policyand managementsystem, action plan andregular review withcommitment of seniormanagement or part ofcorporate strategy

Formal energy/environmental policybut no formalmanagement system,and with no activecommitment from topmanagement

Unadopted/informalenergy/environmentalpolicy set byenergy/environmentalmanager

Unwritten guidelines

No explicit policy

Information systems

Comprehensive systemsets targets; monitorsmaterials and energyconsumption, wastesand emissions;identifies faults;quantifies costs andsavings; and providesbudget tracking

Monitoring andtargeting reports forindividual premisesbased on sub-metering/monitoring,but savings not reportedeffectively to users

Monitoring andtargeting reports basedon supplymeter/measurementdata and invoices.Env./energy staff havead hoc involvement inbudget setting

Cost reporting basedon invoice data.Engineer compilesreports for internal usewithin technicaldepartment

No information system.No accounting formaterials and energyconsumption and waste

Awareness

Marketing the value ofmaterial and energyefficiency and theperformance ofenergy/environmentalmanagement

Programme of staffawareness and training

Some ad hoc staffawareness and training

Informal contacts usedto promote energyefficiency and resourceconservation

No promotion ofenergy efficiency andresource conservation

Investment

Positive discriminationin favour of energy/environmental savingschemes with detailedinvestment appraisalof all new buildingand plantimprovementopportunities

Same pay-back criteriaas for all otherinvestments. Cursoryappraisal of newbuilding and plantimprovementopportunities.

Investment usingmostly short-termpay-back critera

Only low-costmeasures taken

No investment inincreasingenvironmental/energyefficiency in premises

Level

4

3

2

1

0

Completed Worksheet 1

… Running Example: Task 1 (continued)


!


Task 2 Involving employees

Success of a CP-EE assessment depends heavily on staff involvement. It isimportant to remember that successful CP-EE assessments are not carried outby people external to the company, such as consultants, but by the staff of thecompany itself supported, if and where necessary, by people from outside.

Staff in this context means everyone, from senior management to employees onthe shop-floor. In fact, shop-floor staff often have a better understanding ofprocesses and are able to suggest improvements. Other departments such aspurchasing, marketing, finance, and administration can also play an important role.

Staff members provide useful data, especially on process ‘inputs’ and ‘outputs’, andassist with assessment of the economic and financial feasibility of CP-EE options.Group meetings should be organized to involve them. Well managed meetings willgain the goodwill and confidence of employees and also inform them about thebenefits of a CP-EE assessment. This rapport with employees will help to motivatethem and ensure their involvement in the studies. Completed Worksheet 2 showsa checklist of various activities that can be undertaken to involve employees.

Task 3 Organizing a CP-EE Team

Setting up one or more CP-EE teams is an important aspect of the initiation,coordination and supervision of the CP-EE studies. Teams should consist of companystaff supported and assisted where necessary by CP-EE professionals. Getting theright mix of team members is crucial, otherwise teams may face hindrance fromwithin (e.g. from other company staff members) as well as from outside.

For large organizations, teams could comprise a core group ensuring afavourable response to CP-EE options (made up of representatives of differentdepartments, especially finance/accounts and projects departments) and sub-groups addressing specific tasks.

For small and medium size firms, a single team comprising the owner or proprietorand supervisors or managers overseeing day-to-day operations may well besufficient. To be effective, the team should have enough collective knowledge toanalyse and review current production practices and energy systems and toexplore, develop and evaluate CP-EE measures. (See Completed Worksheet 3).



No ✗

✗

✗

✗

✗

✗

✗

Yes ✓

✓

✓

✓

✓

✓

✓

Tasks

CP-EE introduction

Workshop

• Middle manager

• Shop floor workers

• Utilities workers

• Administration staff

Group meetings

• Administration staff

• Various sections in the process house

• Utilities staff

• Maintenance staff

• Purchase department staff

Display of CP-EE posters

Showing of short films on CP-EE success stories

Organizing of slogan campaign on environmental and energy themes

Section no.

1)

2)

3)

4)

5)


LDPM employees were given formal training and were informed about CP-EE


Designation

Director

Operation In-charge

Maintenance Engineer

Dyeing In-charge

External Consultant

Department

Overall

Equipment and utilities

Plant maintenance

Dyeing section

–

Role

Team leader

Team member

Team member

Team member

Team member

Name

Girish Luthra

Bimal Kumar

Nikun Nanavati

Dadaram Gohdsware

Rajiv Garg

Section no.

1)

2)

3)

4)

5)


A CP-EE Team was organized in consultation with the management


!Task 4 Compiling existing basic information

In this task, the CP-EE team generates four important outputs:

General company information

This involves obtaining general details about the company including details of

key contact people, main products, turnover, employees, working hours and

production days in a year. (See Completed Worksheet 4a).

General production flow chart

A general production flow chart includes major energy conversion equipment

supplying utilities such as steam (boilers), compressed air (air compressors),

chilled water (refrigeration compressors), etc. (See Completed Worksheet 4b).

Data on consumption and cost of input raw materials, chemicals and energy

resources (electricity and fuels) must be collected and compiled, together with

data on consumption by utilities and details of production for both the entire

plant and for each process department. These data should be compiled in three

forms, namely: daily or batch average; monthly average (daily data over a

period of three to four representative months); and yearly average (twelve-

month data for preceding three years) (see Completed Worksheets 4c and 4d).

Graphical representation of the data will help the team to analyse work

practices and trends within the facility and may also highlight unusual practices

that are worthy of investigation.

Details of technical specifications

Details of technical specifications for equipment used in the production process and

supply of process utilities must also be collected. (See Completed Worksheet 4e).

A status list of readily available information

A status list of readily available information about the plant should be made. This

will include process flow diagrams, plant layouts, inventory and dispatch data

sheets, raw material consumption and cost data, production data, production

log sheets, material balance, water balance and conservation details, energy

consumption details, emissions records, waste analysis records, waste

generation and disposal records, maintenance log sheets and other relevant

data. (See Completed Worksheet 4f).



snapshot

CP-EE

A typical textile processingunit in Thailand processes

cloth which can bedivided into two

categories: dyed cloth andprinted cloth. The cloththat is printed is initially

dyed or whitened.Total production from the

unit was normalized interms of the total clothprocessed, the resources

used during theproduction forming thebasis for normalization.

Total (normalized)production =

total cloth printed + total cloth dyed.

snapshot

CP-EE

Information obtainedduring the first meetings

with top management andstaff, prior to the

assessment, will allow theteam to analyse and review

the information and bebetter prepared for the

‘conducting a walkthrough’task. Such informationcould be obtained, for

example, from an analysisof electricity bills. It may

lead to recommendations,before assessment, on

things like energy demandrescheduling and power

factor penalties.



Name and address of company

Contact person• designation• telephone/e-mail

Employee strength

No. of working hours per year

No. of batches per year

Luthra Dyeing and Printing Mills, 252/2, Luthra Mill Compound, GIDC, Pandersara, India

Girish LuthraDirector+91 261 28690606 8 / [email protected]

550

3 shifts/day, 300 days/yr

Approximately 300–400 batches

Section no.

1)

2)

4)

5)

6)

Completed Worksheet 4a


General information about the company was collected, presented in Completed Worksheets 4a to 4f

Completed Worksheet 4b: General production flowchart

coal

fines

waste gases

blowdown

steam

water

chemicals

coal yard

crusherhouse

boilerhouse

pre-treatment

bleachingand dyeing

product

grey cloth

wastewater

wastewater

wastewater

emissions

watersteam

chemicals

Utilities• DG sets• gas storage and handling

treated waterto drain + recycling

ETP

sludge

fines

watersteam

chemicals

printing

watersteam

chemicals

finishing

gassteam

chemicals

Completed Worksheet 4c: Monthly variation

cloth dyed (tons)

cloth printed (tons)

total dyed + printed (tons)

total cloth normalized (tons)

0

50

100

150

200

250

300

month

prod

ucti

on

1 2 3 4 5 6 7 8 9 10 11 12

51 30 65 48 62 44 42 63 80 126 83 104

87 108 112 155 157 92 148 168 162 148 101 151

138 138 177 203 219 136 191 231 242 274 184 256

112 123 145 179 188 114 170 199 202 211 143 203



MonthsUnit

1

115

201

3

772

698

247

827

1 525

61

82

2

122

208

846

663

256

858

1 521

65.4

80

3

136

222

4

697

345

363

1 216

1 561

60.5

88

4

148

234

4

625

1 587

0

0

1 587

65.1

93

5

136

222

3

611

234

608

2 037

2 272

60.1

85

6

172

258

3

804

294

417

1 395

1 690

74.2

110

7

143

229

4

629

225

421

1 410

1 636

61

100

8

133

219

4

656

234

366

1 227

1 461

61.4

93

9

123

209

4

582

208

361

1 209

1 417

61.8

87

10

136

222

4

576

1 469

0

0

1 469

61.3

90

11

135

221

4

623

1 641

0

0

1 641

64

99

12

125

211

3

553

1 356

0

0

1 356

63.5

85

Total average

135

221

3

664

746

253

848

1 595

63.2

91

Resources

Purchased water

Total water

Coal

Gas

Grid electricity

Diesel

Eqivalentelectricityfrom diesel

Total kWhelectricity

Dyes

Gums

m3/ton cloth

m3/ton cloth

t/ton cloth

m3/ton cloth

kWh/ton cloth

litre/ton cloth

kWh/ton cloth

kWh/ton cloth

kgs/ton cloth

kWh/ton cloth

Completed Worksheet 4d: Resource consumption


On average, the unit processes 8.0 tons of cloth per day. As is typical of textile processing units, the process requires steam, water,gas, compressed air, dyes and printing chemicals, etc. Consumption of major resources per ton of cloth processed in the year 2002 istabulated below.

Name of utility Capacity Quantity Specifications

6 t/hr

-

380 kVA125 kVA

>50 HP50 – 10

<10

3 280 m3/hr

5 m3/hr

1

2

21

81636

11

2

Make

IBL

-

KirloskarCummins

several

--

-

Type

Smoke tube

Screw compressor

3-phase

IDFD

Specific design parameters

6 t/hr, 10.98 kg/cm2,at 75% eff.

250 cfm at 6 kg/cm2

3 280 m3 hr at 600 mm WC

4 kg/cm2 at 30°, 5 m3/hr

Section no.

1)

2)

3)

4)

5)

6)

Boiler

Compressed air system

DG set

Motors

Fans

Pumps

Completed Worksheet 4e: Existing utilities and energy-intensive equipment



Completed Worksheet 4f: Information available within the unit


Section no. Information required Available Not available Remarks

1)

2)

3)

4)

5)

6)

7)

8)

9)

10)

11)

_

_

_

_

_

_

_

_

_

_

_

_

_

Partially

Partially

Partially

Partially

Partially

Layout

• Factory

• Steam and condensate distribution network

• Compressed air distribution network

Production details

Process flow diagram

Material balance

Energy balance

Design specification of utilities

Raw material consumption and cost

Energy, water consumption and cost

Waste generation and disposal records

Waste treatment records

Maintenance records

Task 5 Identifying barriers and solutions to the CP-EE

assessment process

In order to develop workable solutions, the CP-EE team must identify

impediments to the CP-EE process—for example difficulties in obtaining

information from certain departments. The team should highlight such

difficulties right away, so that corrective measures can be taken by

management to resolve the issue before the start of the CP-EE assessment itself.

Lack of measuring instruments and lack of provision for measurements could

also be a major barrier. Adequate steps must be taken to overcome such

barriers (e.g. purchasing or hiring of measuring equipment and making of

provision for measurement).

Lack of awareness of CP-EE on the part of staff and lack of relevant skills are

further possible barriers. These barriers are typically overcome by conducting

in-plant awareness-raising sessions, through training activities or through

provision and explanation of relevant case studies and similar measures. (See

Completed Worksheet 5).




Barrier Enabling measures suggestedNo.

1

2

3

4

5

6

Attitude barriers

Lack of awareness of energy and environmental issues

Emphasis on maximum production rather thanproductivity

Complacent attitude towards existingprocess/production conditions

Hesitant about risks involved

Low participation of workers in CP-EE programme

Belief that ‘I am doing the best’

Organizational barriers

One man show; middle (supervisory) level missing

Loose management structure

Production on ad-hoc basis

Labour intensive: workers employed on contract basis

Inadequate documentation of inventory andproduction data

Trade barriers

Production on job-order basis

Poor quality of input raw material

Industry mainly catering to local markets

Technical barriers

Lack of: • proper guidance on CP-EE• technically sound professionals• skilled workers• laboratory analysis facility• adequate in-plant waste usage

opportunities

Erratic power supply

Relevant technical literature not readily available

Highly water-intensive process steps

Technology developed abroad not applicable in Indian conditions

Economic barriers

Adequate funds not available

Low financial returns on certain CP-EE measures

Availability of cheap un-skilled labour, makingautomation less attractive

Changing excise and tax liabilities

Other barriers

Abundant supply of resources such as water, makingwater conservation less financially attractive

Lack of available space

Lack of regulation on environmental and energymanagement systems

Increase awareness

Involve workers in decision making

Acknowledge workers’ efforts

Formulate incentive schemes for workers

Encourage experimentation for CP-EE options

Review CP-EE measures on regular basis using simple indicators

Increase interaction among similar kinds of industries

Delegation of authority

Induction of technically sound person

Right wage for the right person

Recruitment of permanent skilled workforce

Setting up of integrated plants

Ensuring good quality of raw materials from supplier

Standardization of product

Promotion of marketing in the international market

Training and awareness workshops on CP-EE

Setting up of laboratory with basic facilities

Provision of regular power supply through captivepower generation

Promotion of relevant technical literature through in-house circulation

Development of indigenous CP-EE measures

Encouraging waste exchange among industrial units

Soft loans

Planned investment

Incentive schemes for industries going in for CP-EE

Training of workforce for specific job and formulation oflong-term industrial policy

Imposition of water levy on industries to restrict wateruse and encouraging of modernization of existing plants

Completed Worksheet 5: Barriers and solutions

No ✗Yes ✓ No ✗Yes ✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✗

✗

✗

✗

✗

✗

✗

✗

✗

✗

✗

✗


!Task 6 Deciding the focus of the CP-EE assessment

Deciding the focus of the CP-EE involves making decisions in two areas:

• scope: deciding whether to include the entire plant or limit CP-EE to certain

units/departments/processes; and

• emphasis: deciding which materials and energy resources to include (e.g.

raw material, products, fuel, electricity, steam, compressed air and

refrigeration, etc.).

The focus of the CP-EE assessment can be decided by using a set of weighted

criteria applied to the different sections and allocating a score to those sections

of a plant or facility that could be the focus of assessment. An example is given

in Completed Worksheet 6. The weight given to any particular criterion

depends on many factors and will probably need to be adapted to suit the

nature of the particular industry, location, etc.


In the textile industry, thegarment section is oftenoverlooked, as it is not a

major consumer ofresources or generator ofwastes or emissions. Inthe cement industry,

water is not given muchemphasis for CP-EE, asthe focus is on energy

and materials.Focus areas need to be

fixed on the basis ofinformation on

departments, utilitiesand/or sections, takingaccount of barriers and

the solutions toovercome them.

snapshot

CP-EE

Weight Scores obtainedCriteriaSection no.

1

2

3

4

5

6

7

10

5

5

5

5

10

10

7

2

2

3

3

8

8

4

3

1

3

1

3

4

5

3

2

3

3

5

6

5

4

1

2

2

4

5

Probability of pay-back for CP-EE options from section

Section/area consuming maximum resources

Multiplier effects

Increase in product quality/production rate

Barriers

Management preference

External pressure (govt. NGO, etc.)

SECTION Boiler house Dye house Printing Pre-treatment

Completed Worksheet 6: Audit focus for detailed CP-EE assessment

Different sections of the plant were analysed in accordance with the matrix and the boiler house was chosen asan audit focus for detailed CP-EE assessment.



!

STEP 2 Pre-assessment

Pre-assessment, Step 2 in the CP-EE assessment methodology, gives the CP-EE

practitioner an initial ‘hands on’ feel for the company’s operations. It consists of the

following four important tasks:

• Preparing process flow diagrams of CP-EE focus areas, using available information

and data

• Conducting a walkthrough

• Preparing material and energy input and output quantification and

characterization

• Generating and finalizing baseline data

Task 7 Preparing process flow diagrams

Preparing a process flow diagram (PFD) is an important step in the CP-EE

assessment. PFDs are prepared on the basis of discussions with plant personnel,

using readily available data, and for the audit focus areas only.

The best way for the CP-EE team to start is by listing the important process/unit

operations and the associated utility supply equipment/systems. At each

operation the team should list: (a) major input resources i.e. energy (electricity,

fuels, etc.), raw materials and chemicals, and utilities (water, steam, etc.); (b)

intermediate and final products; and (c) waste streams (wastewater, exhaust

air, exhaust gases, heat radiation emissions, solid wastes, etc.).


Figure 1.5: Process block diagram

Input resources

product

PROCESS 1

or

UNIT OPERATION 1

Waste stream

material resource 1energy resource 1

catalystmaterial resource 2energy resource 2

material resource 1material resource 2

catalystenergy resource 1energy resource 2

PROCESS 2

or

UNIT OPERATION 2

main raw material

gaseous wasteliquid wastesolid wasteenergy waste

gaseous wasteliquid wastesolid wasteenergy wastereusable waste



Completed Worksheet 7: An example of a process flow diagram (PFD)


Next, each of the process/unit operations can be presented as a block diagram

showing relevant material and energy inputs, resources, intermediate products,

products, by-products, and output waste material and waste energy streams.

Operating process parameters (flow rates, pressures, temperatures,

water/moisture content, humidity, etc.) should also be indicated in so far as

possible. An example of a block diagram is given in Figure 1.5. The way in

which this is expanded into the PFD is illustrated by Completed Worksheet 7

and explained in the accompanying text.

continued over page …

coal (lignite)

water spraycoal fines(carpet loss)fugitive emissions

coal yard

coal (lignite)

manual screeningand crushing

coal (lignite) 1.1 t/hr

steam generation boiler

Pr.

rating

Standard Operating

12 kg/cm2

6 t/hr 6 t/hr

10 kg/cm2

wet stream

steam separation

dry stream (97%)

radiation loss

ID fan

standard parameters:20 kW at250 mmWC; 200° C

electricity

flue gas

hot condensate (3%)

BFW pump

standard parameters:8 t/hr at 12 kg/cm2

waterconditioningchemical

FD fan

15 kW at100 mmWC; 30°C

electricity9 kW (actual)

air

electricity

The process flow diagram (PFD) is constructed by connecting the block diagrams of individual unit operations.

Sometimes, the best way to create and refine a PFD is to conduct a number of walkthroughs. While preparing a

PFD, the team should keep the following points in mind:

• Use blocks to denote the operations. For each block, write the name of the operation and any special



snapshot

CP-EE

The CP-EE team shouldnot conduct a

walkthrough when theoperations are closed (e.g.at weekends, during low

production cycles, orduring night shifts).


operating conditions that need to be highlighted (e.g. for a dyeing operation, it may be pertinent to

indicate a temperature of 90° C and pressure of 12 kg/cm2).

• All data should be based on the same time unit (e.g. annual, quarterly etc.).

• Wherever required, supplement the process flow diagram with chemical equations to facilitate

understanding of the process.

• The PFD may use symbols to add more information about the process. For instance, indicate clearly whether

the operations are batch or continuous. Also, solid and dotted lines can be used to show continuous or

intermittent release of emissions, respectively. Colour codes may also be useful (e.g. green lines to indicate

recycled streams and red lines to indicate release of wastes).

• Wherever data is easily available, characterize the input and output streams.

Task 8 Conducting a walkthrough

A walkthrough is one of the most effective techniques for getting first-hand

information on production and processes. A walkthrough usually follows the

PFD. This task generates two important outputs for the CP-EE team:

• A record of obvious housekeeping lapses and observations, in the form of a

table (see Completed Worksheet 8) or Eco-map (explained below).

• Simple line diagrams of major utilities (see Completed Worksheet 8).

Recording obvious housekeeping lapses

While conducting a walkthrough in the different sections of a plant, the CP-EE

team will record housekeeping lapses such as leaks of steam or water, leaks

from processes or of condensate, fuel oil leaks, compressed air leaks or any

obvious wastage going to the drain. These housekeeping lapses must be

recorded.

Notes should be taken relating to process operations, recording things like

specific duty conditions, problems faced by the operators and operators' views

on existing process conditions and parameters. Points picked up from the shop

floor often lead to potential energy and material saving measures.



Name of section Area Obvious lapses Categorization of lapse

1)

2)

3)

4)

Coal handling

Crusher house

Boiler house

ETP

Coal storage

Manual crushing

Coal

Feed water

Boiler

Boiler

Boiler

Boiler

Boiler

Boiler

Boiler

Boiler

Boiler

Boiler

Boiler

Steam distribution

Steam distribution

Steam distribution

Steam distribution

ETP

Carpet losses

Spontaneous combustion

Unsuitable water spray

Dusty atmosphere

Coal quantity use measurementnot provided

Water flow measurement

Radiation loss high

Manual fuel firing

Fuel firing door open regularly

Ash cleaning done manually

High unburned coal in ash

Cold air + water supplied toboiler drum

Major instrument absent1) Steam temp.2) Flue gas temp.3) O2 in flue gas analyser

Continuous blowdown withoutany B/D WHR system

No WHR from flue gases

Frequent boiler steam loadfluctuation

No damper control of FD and IDfan at any load

Steam pipe line flanges andvalves not insulated

Main steam line steam trapsblowing steam

Traps in process equipment notworking properly

Condensate from processequipment traps being drained

Average ETP inlet feed watertemp. high (45 °C)

Completed Worksheet 8: Obvious housekeeping lapses


OthersElectricalFuelGasLiquidSolid

✓

✓

✓

✓

✓✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

Section no.



Preparing and collecting simple line diagrams

Simple line diagrams should be collected or prepared for the following:

• Water supply and drainage networks

• Electricity distribution

• Refrigeration circuit

• Steam and condensate distribution

• Compressed air distribution system

These are simple single line diagrams depicting the supply and distribution

network of the above utilities. They may also contain helpful information on

operational parameters.

Eco-mapping

Eco-mapping is a simple and practical tool providing visual representation of

areas of concern as well as indicating instances of good practice.

Eco-maps can be developed for specific themes. They are made using the

layout maps of the site. Themes for which eco-maps can be made include:

• Water consumption and wastewater discharge

• Energy use

• Solid waste generation

• Odours, noise and dust

• Safety and environmental risks

For each eco-map, the team must be sure to include everything related to the

particular problem being studied. For instance, an eco-map for water

consumption and wastewater discharge must pinpoint the location of

overflows, spills or excessive use of water, etc. These areas can be highlighted

using colour codes or distinct symbols to distinguish between areas that should

be monitored or areas where problems need to be dealt with as soon as

possible. Figure 1.6 shows a typical eco-map.



Figure 1.6: Eco-map for water in the printing section of a textile factory

energy

solid waste

water

nodrains

drains

spillage

drain piping

bad practice

high waterconsumption

bad practice

processed ETPfinished

products storage

dyeing

printing

officeMC panel

raw materialstorage solutions,

metal

Dos and don’ts for housekeeping lapse identification

• Don’t find faults—this is not a fault-finding mission. The purpose is to better understand material and

energy flows and to generate ideas for efficiency gains, higher profitability and overall environmental

improvement. It is also to ‘make friends’ for future contacts and possible partnerships. So, don’t be critical—

be constructive and make suggestions.

• Don’t dominate the conversation. Give the responsible staff the opportunity to speak and explain—be a

good listener.

• Don’t ask questions to show your knowledge about the process and don’t digress by sharing information

that you have but that is not relevant.

• Ask questions only when you must but, if you don’t understand explanations and feel that they are critical,

do ask for further explanation. Don’t be shy about admitting what you don’t understand.

• Don’t leave the group—it can appear impolite.

• Do ensure that you meet timelines agreed earlier.

• Do always keep track of the outputs you are expected to produce. Observations should be made to allow

for corrective action and notes should be taken to allow for computation of preliminary material balances. It

is also important to obtain information on individual operations and key /major operational sequences.

• Do take along a camera—photographs can be very helpful. Don’t forget that, if outsiders are involved in the

team, it is essential to get permission from the management to use the camera.


!Task 9 Preparing material and energy input-output

quantification and characterization

Each input and output (including wastes)—whether resources, materials or

energy—must be quantified, characterized and noted on the PFD prepared in

Task 7.

Measurements or estimates of quantities will have to be made in the field when

relevant data are not readily available.

Data on other parameters necessary to characterize these streams must also be

compiled. Involving operating staff in data collection and verification is

strongly recommended.

Material and energy inputs and outputs will often not balance as many of the

loss streams—especially energy streams—have not yet been identified and

quantified. This will require further field visits and measurements.


CharacteristicsOutput QuantityProcess steps or unitoperations

Boiler

179 oC

200 oC

–

–

10 kg/ cm2

–

–

–

61.3 kg

–

–

–

_

O2 =8.5%

_

_

Temperature Pressure Totalsolids

Others

Completed Worksheet 9: Input-output quantification and characterization


CharacteristicsInputs Quantity

30 oC

30 oC

–

Water

Air

Coal

106.56 m3/d

302.6 t/d

26.4 t/d

12 kg/cm2

–

–

85.24 kg

–

–

_

_

GCV = 15 459.8 kJ/kg

Blow downlosses

Flue gas

Ash

Unburnt

10.56 m3

329 t/d

1.67 t/d

1.28 t/d

Temperature Pressure Totalsolids

Others


!


Completed Worksheet 10: Baseline data


Section/utility

equipment

Resource used/parameters

Quantity Specificconsumption/ton of cloth

Savingspotential

Targets

Boiler House

Boiler efficiency = 65 %

Evaporation ratio of boiler—3.63 ton of steam/ton of coal

3.33 t

13.6 m3

75 kWh

12 t

High

High

Medium

High

High

2.0 tons/ton of cloth

6.0 m3/ton of cloth

65 kWh/ton of cloth

75%

Coal

Water

Electricity

Cloth production

Steam

26.712 t

108.86 m3

600 kWh

8 t/d

96 t

Task 10 Generating and finalizing baseline data

Baseline information comprises historical consumption and cost data for all

input material and energy resources and output products (see Completed

Worksheet 10). The CP-EE team will need to collect all this information using

different time frames, i.e.:

• Annual: monthly average data for each year over the past three years.

• Monthly: daily average data for 30 days for three representative seasonal

months of the year.

• Daily: average batch data or hourly average data for a day.

The types of information to be gathered are:

• Material and energy resource inputs, consumption and cost (electricity use, energy

charges, peak demand charges, electricity unit cost, penalties and other costs).

• Products, actual production, capacity utilization.

• Energy conversion equipment, specifications and actual average parameters

for each piece of equipment.


!


Performance indicators need to be developed based on this information. For

example for:

• Specific material consumption for each material input, or at least for

important input materials (tons of input material/ton of product).

• Specific energy consumption for electricity and fuels (kWh per ton of product,

kg or litre of fuel per ton of product).

• Specific energy utility consumption (TR/ton product, steam/ton product).

• Equipment-related energy performance indicators (ton steam/ton coal,

kW/cfm of fan air).

• Production cost (per ton of product).

• Electricity, fuel, water, chemicals, transport, manpower as a percentage ofproduction cost.

These performance indicators need to be compared with targets or

benchmarks to assess improvement potential. These targets could be based on:

own best performance norms; local/national/regional/international industry best

performance norms

STEP 3 Assessment

Assessment comprises four critical tasks constituting the CP-EE assessment process.

Much of the entire CP-EE process depends on these four tasks:

• Preparing a detailed material and energy balance including losses

• Cause diagnosis

• Generating options

• Screening options

Task 11 Preparing a detailed material and energy

balance including losses

The physical laws of conservation of energy and mass tell us that, in any

process/unit operation in a steady state, the sum of all of the inputs must

equal the sum of all of the outputs (including losses and wastes). When


making a material and energy (M&E) balance an essential objective is

therefore to check that ‘what goes in, comes out’. All inputs, whether

material or energy, should have related outputs.

Input and output streams were quantified and characterized in Task 10, when

a balance was drawn up of material and energy inputs and outputs.

Only one or two of the output streams will constitute ‘useful’ output. It is the

proportion of input that can be traced through to useful output that reflects the

efficiency of the process. There are non-useful output streams in addition to the

useful output.

Unlike material streams, energy streams are characterized by a single useful output

stream, all of the others constituting ‘loss’ streams which need to be minimized.


As explained earlier, in energy streams, both the ‘useful’ and the ‘loss’ output

streams are quite often invisible or, at least, not easily detectable. Methods

other than direct measurement have to be employed to evaluate and quantify

energy content in these streams. The typical components of a material and

energy balance are shown in Figure 1.7. Completed Worksheets 11a, 11b and

11c give empirical examples.

M&E balances are normally prepared using proxy data supported by information

recorded during the walkthrough. For instance, monthly or annual water and

energy bills give an idea of consumption levels. On the output side, production

figures or orders filled (monthly or annual) can provide an estimate of average

production. Obtaining figures on wastes and emissions is generally more difficult.

Sometimes, concentration data for water pollutants and air pollutants exist and

Figure 1.7: Typical components of a material and energy balance

water/air

power

catalyst

PROCESS

or

UNIT OPERATION

product

wastewater

reusable waste inanother operation

gaseous emissions

liquid wastes for storage and/or disposal

solid wastes for storage and/or disposal




Completed Worksheet 11a: Boiler material balance

1.113 t/hr (actual)

water spray (50 l/hr)coal fines (carpet loss)

fugitive emissions

coal (lignite)

coal yard

coal (lignite)


coal (lignite) 1.1 t/hr

PROCESS STEP REFERENCE

processparameter

rating

Standard Operating

12 kg/cm2

6 t/hr 6 t/hr

10 kg/cm2

wet stream

steam separation

dry steam (97%)3.88 t/hr (actual)

blow down loss: 0.44 t/hr

ID fan

standard parameters:250 mmWC;head developed200° C & 20 kW

electricity

hot flue gases

hot condensate (3%)0.12 t/hr (actual)

BFW pump


water: 4.44 t/hr

conditioningchemical

FD fan

standard parameters:100 mmWC;30°C & 15 kW

electricity air: 12.61 t/hr (actual)

1.102 t/hr

losses:0.011 t/hr

rejects:0.002 t/hr

steam generation boilerprocess

step

pressure

unburnts: 0.05333 t/hrash: 0.0695 t/hr

4 t/hr (actual)

6 t/hr (standard)

4.44 t/h

electricity




Completed Worksheet 11b: Boiler energy balance

water spraycoal fines (carpet loss)

fugitive emissions

coal (lignite)

coal yard

coal (lignite)


coal (lignite) 1.1 t/hr (actual)

PROCESS STEP REFERENCE

processparameter

rating

Standard Operating

12 kg/cm2

6 t/hr 4 t/hr

10 kg/cm2

wet stream

steam separation

dry steam (97%)11.31 MkJ/hr (actual)

blow down loss: 1.4%0.24 MkJ/hr (actual)

ID fan

standard parameters:250 mmWChead developed200° C & 20 kW

electricity

flue gasesBFW pump


water

conditioningchemical

FD fan

standard parameters:100 mmWC;30°C & 15 kW at

electricity9 kW (actual)

air:12.61 t/hr (actual)14.34 t/hr (standard)

steam generationprocess

step

pressure

unburnt in ash: 4.85%0.83 MkJ/hr (actual)

11.40 MkJ/hr (actual)

electricity

17.0 MkJ/hr (actual)

hot condensate (3%)0.09 MkJ/hr (actual)

Hidden losses:

• H2 & moisture:2.5 MkJ/hour (actual) 14.4%

• Radiation:0.17 MkJ/hr (actual) 1%

• Moisture in air:0.03 MkJ/hr (actual) 0.15%

equipment boiler

0.5 MkJ/hr(actual)

loss: 13.2% (actual)2.25 MkJ/hr (actual)


these can be used to estimate (back calculate) mass emissions. Data on mass or

volumes of solid waste are also sometimes available. Often, approximate

calculations will need to be used, based on ‘typical’ values available locally.

The following guidelines will help:

• For extensive and complex production systems, it is better to start by

drawing up the M&E balance for the whole system.

• When dividing up a system, choose the simplest sub-systems. Division could

be along the lines of the material and energy flow. The PFD should come in

handy here.

• Choose the material and energy flows envelope in such a way that the

number of streams entering and leaving the process is the smallest possible.

• Always choose recycle streams within the envelope to start with.

• When determining the time factor, always choose a minimum but

representative time span.

• For batch production, consider one full batch. It is important to include start

up and cleaning operations.



Completed Worksheet 11c: Cost of waste stream

Section no. Section/process

Wastestream

Componentsof

waste stream

* Equivalentcoal quantity

(t/day)

* Total costof waste

component

1)

2)

3)

Coal yard

Manualcrushing

Boiler

Coal

Reject

Thermal

Coal

Stones

Flue gas

Blow down

Unburnt

H2 andmoisture

Radiation

Moisture in air

0.264

0.048

3.492

0.373

1.288

3.881

0.264

0.46

418.97

76.176

5 541.804

551.95

2 044.05

6 159.15

418.97

73.00

* The unit rate is fixed at

US$35 per tonne. The total

cost of the waste component is

the product of the unit rate and

the equivalent coal quantity.


Energy balances are usually more difficult to make because energy waste is

relatively difficult to identify and quantify. Alternative options for drawing up

energy balances are:

• System efficiency based on measurable output work and input energy.

• Measurement of major losses only.

• Single parameter measurement and benchmark comparison.

The CP-EE team will very probably find substantial discrepancies in the M&E

balance. This may require further discussion of the assumptions behind the data,

making of more measurements and revision of the input and output data, as

necessary. The next task for the team is therefore to prepare detailed M&E balances

for certain parts of the PFD. However, developing a detailed material balance for

every operation is neither practical nor relevant. Instead, critical operations are

usually chosen, based on the focus of the CP-EE study and results of the M&E

balance arrived at in the earlier steps, and on the types of materials and processes

used and energy use intensity. This means selecting operations where hazardous

materials are used or where material and energy losses are obvious. Detailed M&E

balances are often made when processes have long operational sequences.

To conclude the M&E balance, it can be extremely useful to assign costs to the

material and energy loss streams (the waste streams) identified in the balance.

Experience has shown that this is the type of information that can have the

greatest weight in convincing company management of the value of CP-EE and

in securing management commitment to the subsequent steps. When assigning

monetary values to materials and energy waste streams, the CP-EE team should

consider the following:

• The cost of raw materials, input energy, intermediate products, and final

products lost in waste streams (e.g. the costs of unexhausted dye in waste

dye liquor or unburned fuel in exhaust gases).

• The cost of energy in waste streams, in terms of heat content exhausted.

• The cost of treatment, handling and disposal of waste material streams

including tipping or discharge fees, if any.

• Costs, if any, incurred in protecting workers and maintaining safe working

conditions (e.g. exhaust system venting shop floor air).

• The potential liability costs of an accidental spill or discharge or penalties

and fines for leakages.


Note:A material balance

normally requires a tiecompound*, which forms

the basis for measuring theefficiency of the processes.

The selection of the tiecompound is a function of

several possibleparameters; it could be:

• A parameter which iseasy to measure/record

• An expensive resource• A toxic or hazardous

compound• A resource common to

most of the processes

(* E.g. nickel or zinc in

electroplating shops

or chromium in

leather tanning.)


!

Costs should be determined for at least each major waste stream and energy

source. Specific costs (i.e. cost per kWh, per unit mass/volume of a waste

material or energy stream) should also be determined, in order to be able to

calculate the savings that would be made by reducing or avoiding waste

streams. Obviously, the high-cost waste streams are the most interesting to

focus on from the economic point of view.

A detailed M&E balance provides the team with information to identify causes

of waste generation or low productivity. Cause diagnosis is dealt with in the

next sub-section.

Task 12 Cause diagnosis

Having identified, quantified and characterized various streams, and having

drawn up an M&E balance, the CP-EE team must now carry out cause diagnosis

to find out why waste is being generated. The cause diagnosis exercise involves

asking the question: ‘Why did such a problem or outcome occur?’ Essentially,

cause diagnosis is an exercise in finding the root causes of a problem.

The fishbone diagram (see Figure 1.8) is an excellent tool for cause diagnosis

in complex situations where a number of factors are involved. Once the

diagram has been prepared, the team can use it to help generate CP-EE

options. Below, we present an example from the textile dyeing process to

illustrate the technique used to prepare a fishbone diagram.

To construct the diagram in Figure 1.8, we took the example of a winch used in

the dyeing process. The winch is an open-top machine with a drum around

which a ‘rope’ of fabric is wound, pulling the fabric through a dye liquor over a

fixed period. It is one of the cheapest pieces of equipment used in dyeing and

is therefore used extensively by SMEs.

The first step is to define the principal problem to be diagnosed, and to write

it next to the ‘head’ of the fish (right-hand side). Our example has identified

low ‘Right First Time’ (RFT), a common problem encountered in textile dyeing:

the shade of the dyed fabric does not match the shade specified by the client.

This causes excessive product reject, lowering productivity and generating

waste (improperly dyed cloth).


Remember!

Don’t get ‘bogged

down’ in trying to

make a perfect M&E

balance. Do the best

you can. You’ll soon

see that even a

preliminary M&E

balance can open

opportunities for

material and energy

savings which can be

profitably exploited.


The next step is to identify the primary causes of the problem. Once identified,

these are placed in generic categories: ‘Man’, ‘Method’, ‘Material’ and

‘Energy/Energy Eqpt.’ For instance, primary causes of the low RFT problem

could be:

a) Lack of supervision (category = Man).

b) Dyeing operation not properly carried out (category = Method).

c) Poor quality of input materials (category = Material).

d) Optimum temperature of dye bath liquor not maintained (category = Energy).

As can be seen from our specimen diagram, these primary causes are listed on

the ‘primary fish bones’. Primary causes can then be further broken down into

one or more secondary causes. For example, pursuing point b) above, the

dyeing operation may not have been properly carried out due to:

• excessive use of salt in the dyeing operation; or

• incorrect procedure followed while dosing the chemicals.


Figure 1.8: Fishbone diagram to facilitate cause diagnosis in the dyeing process

MAN

MATERIAL ENERGY/ENERGY EQUIPMENT

METHOD

lack of supervision

absence of clearwork instructions

lack of training

dyeing operation notcarried out properly

excessive use ofsalt in dosing

incorrect procedure followedwhile dosing chemicals

poor water quality

high impuritiesin dyes

dyeing input materialsof poor quality improper storage

of fabric

shelf life of auxiliariesexceeded

poor contact betweenfabric and dye liquor

poor process controlresulting in inconsistent

performance

optimum temperaturenot maintained in dyebath liquor

Right First Time (RFT)in dyeing is low

Primary causes in bold typeSecondary causes in normal type


Similarly, for point c), the poor quality of input materials may be the result of:

• impurities in the dyes used for the dyeing operation;

• auxiliaries for the dyeing operation having exceeded their shelf-life;

• improper storage of fabric used in the dyeing operation; or

• poor quality of water used in the dyeing operation.

These secondary causes are listed on the ‘secondary fish bones’. Certain causes

appear several times in the diagnosis of primary (or perhaps even secondary)

causes. Common examples of this include ‘poor water quality used in the

dyeing operation’ and ‘lack of clear and concise work instructions’. This makes

it possible to identify common causes which, when corrected, could resolve

several productivity- and environment-related problems. Options that allow

correction of common causes naturally become priority options when drawing

up the implementation plan.

It is possible to pursue this logic (i.e. to continue to ask ‘Why?’)—secondary

causes may break down further into tertiary causes.

The causes identified in the fishbone diagram are only ‘probable’ causes and

the next step is to ascertain the extent to which each of them contributes to

the principal problem. In our example, the CP-EE team has to analyse the

extent to which each probable cause contributes to the unsatisfactory dyeing

operation. This analysis can be carried out on the basis of observations, record

keeping, and by setting up well-planned, controlled experiments to isolate a

specific secondary cause. These efforts will assist the team in validating the

primary and secondary causes and in prioritizing cause elimination.

Tools such as Pareto analysis may also be used if several primary and secondary

causes are to be analysed. Pareto analysis separates the most important causes

of a problem from trivial ones, and thereby indicates the most important

problems on which the team should concentrate.

Completed Worksheet 12 presents cause diagnosis in table form.




Completed Worksheet 12: Cause analysis


Section no. Section Waste stream Probable cause

1)

2)

3)

4)

5)

6)

7)

Coal yard

Screening and crushing

ID and FD fan motors

Boiler

Loss of coal

Stones as rejects

Electrical energy loss

Flue gases

Unburnts in ash

Blow down

Radiation loss

Unsuitable storage area

Manual handling of coal

Excessive air circulation

Spontaneous combustion of coal

Soil is soft

Poor quality of incoming lignite (coal)with extraneous material

Varying load on motors but power draw isnearly same

Oversize motors

Air-fuel ratio is not maintained

No monitoring of relevant parameters (O2 or CO2)

No device/method for heat recovery

Air ingress at various points

Air quantity and pressure is not sufficient

Distribution of primary air through grate

Sizing of coal not correct

Design of grate not appropriate

Firing rate is not uniform

Manual ash removal

Poor fuel quality and incorrect combustion

Bad boiler feed water quality

Condensate not recovered

Boiler drum TDS is not maintained asrequired

Un-insulated portions of boiler

Openings


!Task 13 Generating options

Generating options is a creative process. Like cause diagnosis, it is best

performed by the team in collaboration with other associated members of staff.

Involving colleagues in this activity will help them to develop a sense of

ownership of the options generated and to gain insight into why a particular

option is recommended for implementation.

Options are generated by brainstorming, a commonly used tool for generating

ideas. Faced with a particular problem, the team and relevant company staff

have to think their way through to a solution—they have to ask the question

‘How?’, i.e. ‘How do we solve this problem effectively?’. The cause diagnosis

described above (where we asked ‘Why?’) will provide a starting framework for

the brainstorming exercise.

In a typical brainstorming session, one person will propose an idea which

may be supported and/or expanded on by others. Further discussion then

yields new, transformed, opposing and/or supporting ideas, paving the way

for the generation of CP-EE options. This process is illustrated in Figure 1.9.

Examples of options generated are shown in Completed Worksheet 13 of the

Running Example.


idea 1

supportingidea 1

opposingidea 1

idea 4

idea 2

supportingidea 3

idea 3based on

1 and 2

supportingidea 3

extensionto idea 1

Figure 1.9: Generating options through brainstorming


CP-EE options may fall into one of the following categories:

• Housekeeping: improvements to work practices and methods, proper

maintenance of equipment, etc., come into this category. Good

housekeeping can provide significant benefits in terms of resource savings.

These options are typically low cost and provide low to moderate benefits.

• Management and personnel practices: management and personnel

practices include effective supervision, employee training, enhancing

operator skills, and the provision of incentives and bonuses to encourage

employees to strive conscientiously to reduce material and energy wastes

and emissions. These options are typically low cost; they can provide

moderate to high benefits.

• Process optimization: process optimization involves rationalization of the

process sequences, combining or modifying process operations to save on

material and energy resources and time, and improving process efficiency.

For instance, some washing operations may be made unnecessary by

changes in raw materials or product specifications.

• New technology: new technologies are often more resource efficient and

help in reducing energy and material wastes, as well as increasing

throughput or productivity. These options are often capital intensive but

can lead to potentially high benefits. Modifications in equipment design

may be another option. They tend to be less capital intensive and can lead

to potentially high benefits.

• Raw material substitution: there may be better options for primary and

auxiliary raw materials in terms of cost, process efficiency or reduced health

and safety related hazards, and these options can be substituted for the

current materials. Substitution may be necessary if materials become difficult

to source or become expensive, or if they come under new environmental or

health and safety regulations. Whenever materials are substituted, it is crucial

to test the appropriateness of the new material in terms of environmental and

economic benefits, optimum concentration, product quality, productivity,

and improved working conditions. An example of raw material substitution is

the replacement of chemical dyes with natural ones. Where energy is

concerned, it may be useful to evaluate the use of cleaner/renewable sources.

Use of renewable or non conventional energy sources is beneficial because it

has the global benefit of reducing greenhouse gas (GHG) emissions.

• New product design: changing product design can have impacts on both

the ‘upstream’ and ‘downstream’ sides of the product life-cycle. For


snapshot

CP-EE

A simple example of goodhousekeeping in a dyeingoperation is to clean thefloors and machines ofdirt, grease, rust, etc.

regularly. This will reducethe possibility of

accidentally soiling thefabric, and thus minimize

the need for extrawashing.

snapshot

CP-EE

In the case of a textiledyeing unit, instead of

draining off the last coldwashes, they can be

collected in anunderground tank,

adjusted for pH, and thenfiltered prior to reuse in

subsequent washingoperations. These options

are typically low tomedium cost and can

provide moderate to highbenefits.


example, re-designing a product may reduce the quantity or toxicity of

materials in the product; reduce the use of energy, water and other

materials consumed during the product's use; reduce packaging

requirements; or increase the ‘recyclability’ of used components. Benefits of

this can include reduced consumption of natural resources, increased

productivity, and reduced environmental risks. Product re-design can also

help to establish new markets or expand existing ones. It is, however, a

major business strategy decision, and may require feasibility studies and

market surveys, especially if the supply-chain for the product is already

established and is complex.

• Recovery of useful by-products, materials and energy: this category of CP-

EE option entails recovery of wastes (in the form of by-products from the

process or from resources) which may have useful applications within the

industry itself or outside of it. As the wastes or by-products are produced

anyway, this type of option can generate additional revenue with little or no

extra effort.

• On-site recycling and reuse: on-site recycling and reuse involves returning

of waste energy or material to the original process or using these as inputs

to another process. It should, however, be borne in mind that it is better not

to generate waste in the first place, rather than to generate it and then

recycle, recover or reuse it. The team should therefore only consider the

latter type of options once all options that could prevent generation of

waste have been examined. It is also important to remember that some of

the chosen options may require major changes in the processes or

equipment or product. While these may well dramatically reduce waste

generation or increase productivity, they also often imply considerable

investment.

Finally, it is important to bear in mind that certain options may require

laboratory, bench-scale or pilot studies to ensure that product quality is not lost

as a result of their application, and that they are acceptable to the market.

We round off this section by combining our example of cause diagnosis using

the fishbone diagram with the identification of possible options for cleaner

production. This is presented in Table 1.1.


A textile-processing unit inThailand used sodiumsulphide and acidifieddichromate as auxiliaryagents in the sulphurblack, textile dyeing

process. However, both ofthese agents are toxic andhazardous to handle andtheir use leaves harmfulresidues in the finishedfabric and generates

effluents that are difficultto treat and damaging to

the environment. CP-EE studies conducted at

the unit indicated thatboth of these agents couldsafely be replaced with noloss of fabric quality, thuseliminating adverse health

and environmentalimpacts. Glucose or

dextrose can be substitutedfor sodium sulphide andacidified dichromate canbe replaced by sodium

perborate or ammoniumpersulphate.

snapshot

CP-EE

snapshot

CP-EE

A common example ofrecovery from a waste

stream for many industriesis heat recovery through

the use of heatexchangers. Such optionsare typically medium costand can provide moderate

to high benefits.



Wastestream

CP-EE OptionsOptionref. no.

RMSPOOPGHK

Coal yard

ID and FDfan motors

Boiler

Steamdistribution

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

Store the coal on a concrete/brick lined level floor

Optimize the stack height and width of coalheaps

Use FIFO basis for coal usage

Construction of shed for coal storage

Optimize the use of water by installingefficient showers/sprinklers/spray/nozzles

Procure better quality coal from differentsources

Install mechanical coal crusher

Installation of variable speed drives in ID andFD fan motors

Installation of damper to control air flow

Install on-line O2 measuring sensor

Install economizer for recovery of waste heat

Install air heater for recovery of waste heat

Plug all the air leakages into boiler furnace

Conversion of existing boiler to FBC boiler

Replace existing boiler with FBC Boiler

Optimize coal sizing by proper crushing andsieving

Modify existing grate by reducing gapsbetween rods

Optimize the firing rate by use of stokerfiring

Install water treatment system (RO) plant

Change the water used in the boiler fromtanker water to municipal supply water

Install conductivity meter to check boilerdrum water quality and therefore optimizeblow down rate

Recover flash steam from boiler blow down

Re-circulate condensate from steamseparator wherever possible

Insulate all the bare and damaged portions

Insulate flanges (125 flanges)

Installation of steam traps (thermodynamictraps) of rated capacity to be provided inthe steam main pipe within a gap of 25 m

Loss of coal

Electricalenergy loss

Heat loss dueto flue gas

Heat loss dueto flue gas

Unburnt in ash

Blow down loss

Radiation loss

Radiation loss

Completed Worksheet 13: CP-EE options


EMORRNPDNT

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

Section

GHK: Good House Keeping OP: Operational Practices PO: Process Optimization RMS: Raw Material Substitution NT: New Technology NPD: New Product Design ORR: On-site Recycle & Reuse EM: Equipment Modification



Primary causes Secondary causes Possible CP-EE options Category of CP-EE option

Man

Method

Material

Energy and energyequipment

Lack ofsupervision

Dyeing operation notcarried outproperly

Input materialsare of poorquality

Poor process control resulting ininconsistentperformance

Absence of clear workinstructions

Lack of training

Excessive use of salt indosing

Incorrect procedurewhile dosing chemicals

High impurities in dyes

Shelf-life of auxiliariesexceeded

Improper storage of fabric

Poor water quality

Optimumtemperature notmaintained in the dyebath liquor

Poor contact betweenfabric and dye liquor

Management and personnelpractices


Management and personnelpractices, process optimization,raw material substitution


Raw material substitution


Management and personnelpractices, housekeeping

Raw material substitution

Process optimization, newtechnology

New equipment

Develop work instructions as Standard OperatingPractices (SOPs). Have the SOPs reviewed by externalexperts. Closely monitor improvements or identifyproblems faced, if any, in the implementation of theSOPs. Build a record keeping system to monitor SOPrelated compliance.

Organize shop floor based training programmes forworkers and supervisors.

Improve worker instruction and supervision.Redesign the dyeing recipe by changingcomposition and materials e.g. use of low salt dyes.

Improve worker instruction and supervision.

Have the dye purity checked by independentinstitutions over a number of samples and acrosscommonly used shades; change the supplier ifnecessary.

Improve the inspection at the receiving unit. Checkthe container labelling, storage and supply systems.

Ensure proper storage of scoured/bleached materialse.g. on wooden blocks, wrapping to avoid soiling

Analyse the water for hardness, total dissolvedsolids, pH and iron/manganese content, etc. andcompare the measured levels with recommendedstandards. Treat water to ensure that theparameters are within the recommended standards.

Check the steam inlet position and steam pressureto ensure that heating is optimum. Take readings oftemperature of the liquor before and after requisitemodifications.

Explore changing from a winch to a jet dyeingmachine that is enclosed, operates under pressureand gives better contact between fabric and dyeliquor.

Table 1.1: Matching the problems diagnosed using the fishbone diagram with possible CP–EE options

Categories


Task 14 Screening options

Preliminary screening of options

Once brainstorming has helped to identify CP-EE options, preliminary and

rapid screening should be carried out to decide on implementation priorities.

This screening exercise will place options in two categories:

• Options that can be implemented directly Simple and obvious options can be implemented straightaway. In general,

housekeeping (e.g. plugging leaks and avoiding spills) or simple process

optimization (e.g. control of excess air in combustion systems) options fall into

this category. No further detailed feasibility analysis is required for these

options. Moreover, their immediate implementation results in real and tangible

benefits in a short period, increasing management’s confidence in the CP-EE

assessment process.

• Options requiring further analysisSome options are technically and/or economically more complex and a

decision to implement them would require examination of their techno-

economic and environmental feasibility. Most management improvement, raw

material substitution, and equipment or technology change options fall into

this category.

Decision on options that require much more information collection or are

difficult to implement (e.g. for reasons of very high costs or lack of technology)

can be considered at a later time. Completed Worksheet 14 on the following

page shows how this works in practice.




Completed Worksheet 14: Screeening of CP-EE options


CP-EE optionref. no.

Directlyimplementable

Require furtheranalysis

Pending laterconsideration

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓


STEP 4 Feasibility analysis

• Technical, economic and environmental evaluation• Selecting feasible options

Task 15 Technical, economic and environmental evaluation

Detailed screening of options

The team can now undertake detailed screening of those options that require

further analysis, to determine which options are technically feasible and

ascertain both the economic and environmental benefits of their

implementation. These aspects are described below.

Technical evaluation

Technical evaluation should cover the following aspects (see also Completed

Worksheet 15a):

• Consumption of materials and energy: it is important to establish M&E

balances for each option before and after implementation conditions, in

order to quantify the materials and energy savings that would result.

• Product/by-product quality: quality of the product should be assessed before

and after implementation of the option.

• Right First Time (RFT): estimate must be made of the possible improvement

in RFT that would result from implementation of the option.

It is important to examine the following aspects when considering implementation:

• Human resources required: a decision must be made as to whether the option

can be implemented by in-house staff or whether external expertise or

collaboration with partner organization is required.

• Risks in implementing the option: some options may not be fully proven and

may require laboratory-scale experiments or pilot studies to assess their

outcomes before full-scale implementation. When options affect key

production processes or product features, the potential impact on business

if they do not work as planned can be very high.

• Ease of implementation: the ease with which an option can be implemented

will depend on such things as the layout of the production processes and of

the auxiliary services (e.g. steam lines, water lines, inert gas lines, etc.); the



physical space available; the maintenance requirements; training

requirements; etc. In addition, when options require work on key production

processes, the timing of their implementation becomes critical. If major

changes or interruptions to production patterns are required, any loss in

production needs to be factored into the economic analysis of the option.

• Time required for implementation: the time which implementation of an

option may require for procurement, installation or commissioning of

equipment or material must be considered. This must include consideration

of any shut-down time necessary for implementation.

• Cross-linkages with other options: a particular option may be linked to

implementation of other options; the decision must be made as to whether

it should be implemented on its own or with other options.

Environmental evaluation

Whenever practically possible, the environmental evaluation of an option

should take account of its impacts throughout the entire life cycle of a product

or service. In practice, however, evaluation is often restricted to on-site and off-

site (neighbourhood) environmental improvements.

The environmental evaluation should include estimates of the following

benefits that each option may bring about (where relevant):

• Likely reduction in the quantity of waste or emissions generated (expressed

as mass).

• Likely reduction in GHG emissions.

• Likely reduction in the release of hazardous, toxic, or non-biodegradable

wastes or emissions (expressed as mass).

• Likely reduction in consumption of non-renewable natural resources, e.g.

fossil fuels consumed (expressed as mass).

• Likely reduction in noise levels.

• Likely reduction in odour nuisance (by elimination of a substance causing

odour).

• Likely reduction in on-site risk levels (from the point of view of process

safety).

• Likely reduction in release of globally important pollutants, e.g. ozone-

depleting substances, persistent pollutants, etc.

Completed Worksheet 15b gives an example of environmental evaluation in practice.




Impact (+/0/-)Option ref. no.

1

5

8

9

10

11

12

15

17

19

20

23

26

Technologyavailability

Productionrate

Productionquality

Operationflexibility

Maintenance Safety

Completed Worksheet 15a: Technical feasibility analysis


Technical requirement

-

-

-

-

Electricalfittings

-

-

Watertreatment

facility

-

-

-

Piping work

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

-

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

0

0

0

0

+

+

+

+

+

0

0

+

+

0

+

+

+

+

+

+

+

+

+

+

0

+

+

+

+

+

+

+

+

0

0

0

+

+

0

+

-

-

-

0

-

-

-

0

+

+

-

-

+

+

+

+

+

+

+

+

+

+

+

0

+

Floor to be made

Water efficientnozzles

Variable speeddrive

Damper

O2 sensor

Economizer

Air preheater

FBC boiler

Modification ofexisting grate

Reverse osmosisplant

Change of waterfrom tankers tomunicipal supply

Recovercondensate

Thermodynamicsteam traps

Equipment requirement

Instrument oraccessories

Manpower Spaceavailability

Option ref. no.

1

5

8

9

10

11

12

15

17

19

20

23

26

Completed Worksheet 15b: Environmental aspect analysis

Impact (+/0/-)

-

Reduced

-

-

Reduced

Reduced

Reduced

Reduced

-

-

-

Reduced

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Water conserved

-

-

-

-

-

-

-

-

-

Water conserved

Water conserved

Resource conserved

-

-

-

-

-

-

-

Reduced

-

-

Reduced

-

L

L

L

L

M

M

M

H

L

M

M

H

L

-

-

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Air

gaseous emission including GHG

particulates others othersorganics(COD)

Totalsolids

Water Solid waste Overall impact*

* H = heavy M = medium L = light N = negligible


Economic evaluation

The team must evaluate the economic benefits of all reductions in waste generated and

in consumption of resources that would be brought about by each option (see

Completed Worksheet 15c). It must estimate the immediately obvious savings in

purchase of materials and fuels, the costs of treatment and disposal avoided, and

material and waste stream costs (identified in M&E balance).

However, the team must also estimate less obvious financial benefits such as reduced

sick days for workers or generally higher worker productivity; lower personnel costs

from reducing the burden of special management and reporting of hazardous

materials, wastes and pollution; reduced worker and environmental liability; and

potential profits from sale of waste as a by-product or from carbon credits; etc.

Experience has shown that expanding financial assessments to the less obvious benefits

often helps considerably by throwing additional light on the economic feasibility of an

option. The team must also estimate the economic costs of each option, in terms of

investments in new technology or equipment as well as in terms of training and other

costs associated with implementation.

Benefits and costs are then analysed and calculated using various evaluation criteria

(e.g. pay back period, Net Present Value (NPV) or Internal Rate of Return (IRR),etc.). These terms are explained in the box on the following page.



Completed Worksheet 15c: Economic viability analysis

CP-EE option no. Investment (US$) Annual savings (US$) Payback period

1

5

8,9

10

11,12

15

17

19

20

23

26

1 063.8

425.5

7 446.8

1 063.8

17 021.2

170 212.7

1 063.8

2 127.6

Nil

6 382.9

851.0

204 042

3 191.5

NQ†

6 382.9

NQ†

26 595.7

143 404.2

NQ†

NQ†

11 489.36

4 255.3

NQ

196 318.96

4 months

-

10 months

-

8 months

15 months

-

-

Immediate

18 months

-

† NQ = not quantified



Payback period

A simple payback period is evaluated from comparison of the annual savings resulting from implementation and

initial investment. This simply indicates the time needed to recoup the initial investment. It is calculated as:

Payback period (in years) = (Capital Investment/Annual Net Savings)

NPV and IRR

The simple payback period should, generally, be considered as an approximate or ‘ballpark’ assessment, as it

ignores depreciation of the investment made and the time value of money. Investment decisions are usually made

solely on the basis of payback period when the investment required is low and/or the returns are high enough for

the payback period to be less than two years.

If these conditions are not met, it is advisable to consider NPV or IRR. These take account of the time value of cash

inflows and outflows during the useful life of the investment made. This kind of economic evaluation requires

information on:

• The capital costs associated with any investments required.

• Net revenue, calculated as the difference between total revenue (could be higher than without

implementation) and operating costs (typically lower after implementation).

• Rates of interest and depreciation, to allow calculation of the present value.

NPV can be calculated using the following equation:

• CF0 = cash outflow in the first year (capital investment)

• r = opportunity cost of capital (for a rate of 10 per cent, ‘r’ would be 0.1)

• n = useful life of the investment in years

For an investment to be financially viable NPV must be greater than zero. Another indicator commonly used along

with NPV is the Profitability Index (PI). PI is the ratio of the present value of the total cash inflows to the present

value of the total cash outflows. For an investment to be financially viable, PI must be greater than 1.

IRR

IRR is essentially the rate of return on an investment that ensures that, during the investment’s lifetime, the net

cash flows (i.e. inflows – outflows) are equal to zero. In other words, IRR is the value of ‘r ’ that gives an NPV of

zero. It can be calculated using:

This problem is solved by assuming a value for ‘r’, and then interpolating. The IRR obtained is then compared with

the rate of interest the market would demand for any borrowing that may be needed. Typically, if IRR is lower

than the market-borrowing rate, the investment is not considered financially viable. Completed Worksheet 15C

shows some actual data for economic viability analysis.

NPV = - (CF0 ) + ∑ i=n Net Cashflow i_____________i=0 (1 + r) i

NPV = - (CF0 ) + ∑ i=n Net Cashflow i = 0_____________i=0 (1 + r) i


Task 16 Selecting feasible options

The evaluations described above help to eliminate options that are not viable.

The remaining options now need to be prioritized and a few will then be

selected for implementation.

Prioritizing CP-EE options

In most cases, the feasibility analyses will indicate that different options have

differing levels of technical feasibility, economic viability, and environmental

performance. Since it may well not be possible to implement all options at the

same time, the team will have to prioritize the options. A common evaluation

framework will be necessary to assist with prioritization. A weighted-sum

method could be considered for this purpose (see Completed Worksheet 16).

Using this method, the team assigns a weight to each of the three aspects of the

feasibility analysis (technical feasibility, economical viability and environmental

performance). Weighting could be decided in a brainstorming session involving

top management. The weights will vary from company to company depending

on technical competence, financial conditions, environmental sensitivity, etc.

For example, a financially healthy, small company facing considerable

environmental pressures may decide to give the greatest weight to

environmental performance (say 50 per cent), less to technical feasibility (say 30

per cent) and least to financial viability (the remaining 20 per cent). This

indicates that the company is most keen to reduce the pollution load but does

not have high levels of capability to undertake technically complex options.

Once weights are assigned, simple indicators such as ‘scores’ can be developed

to assess the relative performance of each option. For example, economic

viability could be assessed based on payback period, NPV or IRR. Environmental

performance could be assessed based on a percentage reduction in pollution

load. Technical feasibility could be assessed based on technical complexity, new

equipment or technology required, or additional technical skills needed, etc.

Each option is then evaluated subjectively and scores are assigned for each of the

three aspects. Scores could range from 0 to 10, with the lower score implying

poor performance. For example, if two options have IRRs of 15 per cent and 33

per cent respectively, they could be assigned scores of 8 and 5 for this aspect of

economic viability.




Completed Worksheet 16: Selection of CP-EE measures for implementation


Option ref. no.

Options

Weight (%)

Technicalfeasibility

Environmentalimpact

Economicfeasibility

Total Rank

1

5

8

9

10

11

12

15

17

19

20

23

26

Storing of coal on a concrete/ bricklined, level floor

Optimize the use of water byinstalling efficient showers /sprinklers/spray/nozzles

Installation of variable speed drivesin ID and FD fan motors

Installation of damper to control airflow


Install economizer for waste heatrecovery

Install air preheater for recovery ofwaste heat

Replace existing boiler with FBCboiler

Modify the existing grate byreducing the gaps between the rods

Install water treatment (RO) plant

Change the water used in theboiler from tanker water tomunicipal supply water


Installation of steam taps (TD traps)of rated capacity to be provided inthe steam main pipe within a gapof 25 m

30

7

5

7

7

3

3

2

2

6

2

8

5

3

25

5

7

2

4

5

3

3

5

5

3

8

4

3

45

5

5

6

6

5

4

4

2

5

3

9

6

5

10

5.6

5.5

5.3

5.8

4.4

3.45

3.15

2.75

4.25

2.7

8.45

5.2

3.9

3

4

5

2

7

10

11

12

8

13

1

6

9

The weighted sum of the scores gives an index for each option and this can be used as

a basis to rank options in terms of their level of priority. The intention is not to prioritize

each option individually but to group options into categories such as ‘top’, ‘medium’

and ‘low’ priority. Prioritizing options in this way provides a basis for preparation of the

implementation plan.


STEP 5 Implementation and continuation

• Preparing the CP-EE implementation plan• Sustaining the CP-EE assessment

Task 17 Preparing the CP-EE implementation plan

A completed CP-EE implementation plan indicates how the projects required to

implement the options are to be organized, as well as the necessary funds and

human resources to be mobilized, and the associated logistics. Training,

monitoring and establishment of a management system such as EMS are also

often important components of an implementation plan (see Completed

Worksheet 17).

The implementation plan should clearly define the timing, tasks and

responsibilities. This involves:

• prioritizing implementation of options in accordance with available

resources;

• preparing the required technical specifications; site preparation; preparing

bidding documentation; short-listing submissions; etc.;

• allocating responsibilities and drawing up monitoring and review schedules.

The CP-EE team should give top priority to implementing options that are low

in cost, that are easy to implement and/or a pre-requisite for the

implementation of other options. This should be followed by options that

require further investment, laboratory or pilot trials, or interruption in

production schedules.

Options are often implemented during or immediately after the CP-EE studies.

In such cases, the very fact of conducting CP-EE according to this methodology

provides an example for others to follow.




Completed Worksheet 17: Implementation plan for CP-EE measures


Option no.

Selected CP-EE measure

Classification(S/M/L)

Proposed dateof start

Personresponsible

1

2

3

5

8

9

10

11

12

13

15

16

17

19

20

21

23

24

25

26

Storing the coal on a concrete/bricklined level floor

Optimize the stack height and widthof coal heaps

Use FIFO basis for coal usage

Optimize the use of water by installingefficient showers/sprinklers/spray/nozzles

Installation of Variable speed drives inID and FD fan motors

Installation of damper to control airflow


Install economizer for waste heatrecovery

Install air preheater for recovery ofwaste heat

Plug all the air leaks into boiler furnace

Replace existing boiler withFBC boiler

Optimize the coal sizing by propercrushing and sieving

Modify the existing grate by reducingthe gaps between the rods

Install water treatment (RO) plant

Change the water used in the boilerfrom tanker water to municipal supplywater

Install conductivity meter to checkboiler drum


Insulate all bare and damagedportions

Insulate the flanges (125 flanges)

Installation of steam traps (TD traps)of rated capacity to be provided in thesteam main pipe within a gap of 25 m

S

S

S

S

M

S

S

S

S

S

M

S

S

M

S

S

M

S

S

S

23-9-2002

30-9-2002

23-9-2002

7-10-2002

3-4-2003

14-10-2002

14-10-2002

28-10-2002

4-11-2002

21-10-2002

16-5-2003

11-11-2002

28-10-2002

3-4-2003

18-11-2002

25-11-2002

4-11-2002

11-11-2002

18-11-2002

2-12-2002

Nikun NanavatiMaintenance Engineer




Bimal KumarOperation In-Charge
















S = small M = medium L = large


Task 18 Sustaining the CP-EE assessment

The application of CP-EE and implementation of CP options often requires

changes in the organization and management system of the company.

The key aspects that may require change are: integration of new technical

knowledge; understanding new operating practices; revising of procedures;

installing and operating new equipment; or changing the packaging and

marketing of products/by-products. Changes will include modified preventive

maintenance schedules, waste segregation and recycling practices, etc. It is

therefore important to integrate the concept of CP into the company’s

management system in order to ensure that CP-EE is implemented as an on-

going activity.



2.7 Worksheets for a CP-EE assessment methodology

This section contains worksheets that will be helpful to CP-EE professionals conducting

CP-EE assessments. These worksheets are also included on the CD-ROM in editable,

printable format (Microsoft® Word™) allowing adaptation to any particular facility.

Click on the button in the top right corner of each worksheet to open the individual files.

List of worksheets (click to jump directly to any of the examples in this section):

• Worksheet 1: CP-EE matrix

• Worksheet 2: Involving employees

• Worksheet 3: CP-EE team

• Worksheet 4a: General information about the unit

• Worksheet 4b: Department/section process flow

• Worksheet 4c: Production details

• Worksheet 4d: Inputs for production

• Worksheet 4e: Existing utilities and energy intensive equipment

• Worksheet 4f: Information available within the unit

• Worksheet 5: Barriers and solutions

• Worksheet 6: Weighting chart

• Worksheet 7: Process flow diagram

• Worksheet 8: Obvious housekeeping lapses

• Worksheet 9: Input-output quantification and characterization

• Worksheet 10: Baseline data

• Worksheet 11a: Material and energy balance

• Worksheet 11b: Cost of waste stream

• Worksheet 12: Cause analysis

• Worksheet 13: CP-EE options, generation and categorization

• Worksheet 14: Screening of CP-EE options

• Worksheet 15a: Technical feasibility analysis

• Worksheet 15b: Environmental analysis

• Worksheet 15c: Economic viability analysis

• Worksheet 16: Selection of CP-EE measures for implementation

• Worksheet 17: Implementation plan for CP-EE measures




Worksheet 1: CP-EE matrix

Polic

y an

d sy

stem

sO

rgan

izin

gM

otiv

atio

nIn

form

atio

n sy

stem

sA

war

enes

sIn

vest

men

t

Form

al e

nerg

y/en

viro

nmen

tal p

olic

yan

d m

anag

emen

tsy

stem

, act

ion

plan

and

regu

lar

revi

ew w

ithco

mm

itmen

t of

sen

ior

man

agem

ent

or p

art

ofco

rpor

ate

stra

tegy

Form

al e

nerg

y/en

viro

nmen

tal p

olic

ybu

t no

form

alm

anag

emen

t sy

stem

,an

d w

ith n

o ac

tive

com

mitm

ent

from

top

man

agem

ent

Una

dopt

ed/in

form

alen

ergy

/env

ironm

enta

lpo

licy

set

byen

ergy

/env

ironm

enta

lm

anag

er

Unw

ritte

n gu

idel

ines

No

expl

icit

polic

y

Ener

gy/e

nviro

nmen

tal

man

agem

ent

fully

inte

grat

ed in

tom

anag

emen

t st

ruct

ure.

Cle

ar d

eleg

atio

n of

resp

onsib

ility

for

ener

gyus

e

Ener

gy/e

nviro

nmen

tal

man

ager

acc

ount

able

to

ener

gy c

omm

ittee

,ch

aire

d by

a m

embe

r of

the

man

agem

ent

boar

d

Ener

gy/e

nviro

nmen

tal

man

ager

in p

ost

repo

rtin

g to

ad

hoc

com

mitt

ee b

ut li

nem

anag

emen

t an

dau

thor

ity u

ncle

ar

Ener

gy a

nd e

nviro

nmen

tal

man

agem

ent

are

part

-tim

e re

spon

sibili

ty o

fso

meo

ne w

ith o

nly

limite

d in

fluen

ce

or a

utho

rity

No

ener

gy/e

nv.

man

ager

or

form

alde

lega

tion

ofre

spon

sibili

ty fo

ren

v./e

nerg

y us

e

Form

al a

nd in

form

alch

anne

ls of

com

mun

icat

ion

regu

larly

use

d by

ener

gy/e

nviro

nmen

tal

man

ager

and

sta

ff at

all

leve

ls

Ener

gy/e

nviro

nmen

tco

mm

ittee

use

d as

mai

nch

anne

l tog

ethe

r w

ithdi

rect

con

tact

with

maj

or u

sers

Con

tact

with

maj

orus

ers

thro

ugh

ad h

occo

mm

ittee

cha

ired

byse

nior

dep

artm

enta

lm

anag

er

Info

rmal

con

tact

sbe

twee

n en

gine

er a

nd a

few

use

rs

No

cont

act

with

use

rs

Com

preh

ensiv

e sy

stem

sets

tar

gets

; mon

itors

mat

eria

ls an

d en

ergy

cons

umpt

ion,

was

tes

and

emiss

ions

; ide

ntifi

esfa

ults

; qua

ntifi

es c

osts

and

savi

ngs;

and

prov

ides

bud

get

trac

king

Mon

itorin

g an

dta

rget

ing

repo

rts

for

indi

vidu

al p

rem

ises

base

d on

sub

-met

erin

g/m

onito

ring,

but

sav

ings

not

repo

rted

effe

ctiv

ely

to u

sers

Mon

itorin

g an

dta

rget

ing

repo

rts

base

don

sup

ply

met

er/m

easu

rem

ent

data

and

invo

ices

.En

v./e

nerg

y st

aff h

ave

ad h

oc in

volv

emen

t in

budg

et s

ettin

g

Cos

t re

port

ing

base

d on

invo

ice

data

. Eng

inee

rco

mpi

les

repo

rts

for

inte

rnal

use

with

inte

chni

cal d

epar

tmen

t

No

info

rmat

ion

syst

em.

No

acco

untin

g fo

rm

ater

ials

and

ener

gyco

nsum

ptio

n an

d w

aste

Mar

ketin

g th

e va

lue

ofm

ater

ial a

nd e

nerg

yef

ficie

ncy

and

the

perf

orm

ance

of

ener

gy/e

nviro

nmen

tal

man

agem

ent

Prog

ram

me

of s

taff

awar

enes

s an

d tr

aini

ng

Som

e ad

hoc

sta

ffaw

aren

ess

and

trai

ning

Info

rmal

con

tact

s us

edto

pro

mot

e en

ergy

effic

ienc

y an

d re

sour

ceco

nser

vatio

n

No

prom

otio

n of

ener

gy e

ffici

ency

and

reso

urce

con

serv

atio

n

Posi

tive

disc

rimin

atio

nin

favo

ur o

f ene

rgy/

envi

ronm

enta

l sav

ing

sche

mes

with

det

aile

din

vest

men

t ap

prai

sal o

fal

l new

bui

ldin

g an

dpl

ant

impr

ovem

ent

oppo

rtun

ities

Sam

e pa

y-ba

ck c

riter

iaas

for

all o

ther

inve

stm

ents

. Cur

sory

appr

aisa

l of n

ewbu

ildin

g an

d pl

ant

impr

ovem

ent

oppo

rtun

ities

Inve

stm

ent

usin

gm

ostly

sho

rt-t

erm

pay-

back

crit

era

Onl

y lo

w-c

ost

mea

sure

sta

ken

No

inve

stm

ent

inin

crea

sing

envi

ronm

enta

l/en

ergy

effic

ienc

y in

pre

mis

es

OPEN FILE



Worksheet 2: Involving employees

Section no. Tasks Yes (✓ ) No (✗ )

1

2

3

4

5

CP-EE introduction

Workshop

• Middle manager

• Shop floor workers

• Utilities workers

• Adminstration staff

• Any other

Group meetings

Adminstration staff

Various sections in the process house

Utilities staff

Maintenance staff

Purchase department staff

Any other

Display of CP-EE posters

Display of short films on CP-EE success stories

Organizing of slogan campaign on environmental and energy themes

OPEN FILE



Worksheet 3: CP-EE Team

Section no. Name Designation Department Role

1

2

3

4

5

6

Mr XYZ MD/GM/ Operation/eng./utility Team leader

Worksheet 4a: General information about the unit

Section no.

1

2

3

4

5

6

Name and address of company

Contact Person

• Designation:

• Phone/e-mail:

Annual turnover

• 2001–02:

• 2002–03:

Employee strength

No. of working hours/year

No. of batches/year

OPEN FILE

OPEN FILE



Worksheet 4b: Department/section process flow

Major inputs Department / Section Major outputs

raw materials

product

Utilities Section

water treatment refrigeration and a/c

boiler system wastewater treatment

compressed air systems

OPEN FILE



Worksheet 4c: Production details

Section no. Product name Installed capacity Actual production Comparision

1

2

3

XYZ

a) Bleached cloth

b) Cotton

c) Rayon

d) Polyester

Printed cloth

tons/yr

tons/yr

tons/yr

tons/yr

%

OPEN FILE



Worksheet 4d: Inputs for production

Reso

urce

sU

nit

mon

ths

12

34

56

78

910

1112

Tota

l ave

rage

Purc

hase

d w

ater

Tota

l wat

er

Coa

l

Gas

Grid

ele

ctric

ity

Die

sel

Eqiv

alen

t el

ectr

icity

from

die

sel

Tota

l kW

h el

ectr

icity

OPEN FILE



Worksheet 4e: Existing utilities and energy intensive equipment

Section Name of Capacity Nos. Specifications

no. utility (TPH)

1

2

3

4

5

6

7

8

9

10

11

Boiler

Compressed air system

Thermic fluid heater

Furnaces

Cooling towers

DG set

R & A/C plants

Transformers

Motors

Fans

Pumps

Make Type Specific Specific operatingdesign parameters parameters

OPEN FILE



Worksheet 4f: Information available within the unit

Section Information required Available/ Available Remarksno. not available since

1

2

3

4

5

6

7

8

9

10

11

12

Layout

• Factory

• Steam and condensate distribution network

• Compressed air distributionnetwork

• Refrigeration system network

• Cooling water circuit

Production details

Process flow diagram

Material balance

Energy balance

Design specification of utilities

Raw material consumption and cost

Energy, water consumption and cost

Waste generation and disposal records

Waste treatment records

Maintenance records

Any other

OPEN FILE



Worksheet 5: Barriers and solutions

Section Barriers Yes No Enabling measures Yes No Remarksno. (✓ ) (✗ ) suggested (✓ ) (✗ )

1

2

3

Increase awareness

Involve workers in decisionmaking

Acknowledge workers efforts

Formulate incentive schemes forworkers

Encourage experimentation forCP-EE options

Review CP-EE measures on regularbasis using simple indicators

Increase interaction among similarkind of industries

Delegation of authority

Induction of technically soundperson

Right wage for the right person

Recruitment of permanent skilledworkforce

Setting up of integrated plants

Ensuring good quality of rawmaterials from supplier

Standardization of product

Promotion of marketing in theinternational market

Attitude barriers

Lack of awareness on energyand environment issues

Emphasis on maximumproduction rather thanproductivity

Complacent attitude towardsexisting process/productionconditions

Hesitant about risks involved

Low participation of workersin CP-EE programme

Belief that ‘I am doing the best’

Organizational barriers

One-man show; middle(supervisory) level missing

Loose management structure

Production on ad-hoc basis

Labour intensive: workersemployed on contract basis

Inappropriate: profit sharing

Inadequate documentation ofinventory and production data

Trade barriers

Production on job-order basis

Poor quality of input rawmaterial

Industry mainly catering tolocal markets

OPEN FILE



Worksheet 5: Barriers and solutions (continued)

Section Barriers Yes No Enabling measures Yes No Remarksno. (✓ ) (✗ ) suggested (✓ ) (✗ )

4

5

6

Training and awarenessworkshops on CP-EE

Setting up of laboratory withbasic facilities

Provision of regular power supplythrough captive powergeneration

Promotion of relevant technicalliterature through in-housecirculation

Development of indigenous CP-EEmeasures

Encouraging waste exchangeamong industrial units

Soft loans

Planned investment

Incentive schemes for industriesgoing in for CP-EE

Training of workforce for specificjob and formulation of long-termindustrial policy

Imposition of water levy onindustries to restrict use, andencourage modernization ofexisting plants

Technical barriers

Lack of:• proper guidance on CP-EE• technically sound professionals• skilled workers• laboratory analysis facility• adequate in-plant waste usage

opportunities not available

Erratic power supply

Relevant technical literature notreadily available

Highly water-intensive processsteps

Technology developed abroadnot applicable in Indianconditions

Economic barriers

Adequate funds not available

Low financial returns on certainCP-EE measures

Availability of cheap unskilledlabour making automation lessattractive

Changing excise and taxliabilities

Other barriers

Abundant supply of resources(e.g. water, making waterconservation less financiallyattractive)

Lack of available space

Lack of regulation onenvironmental and energymanagement systems

OPEN FILE



Worksheet 6: Weighting chart

Section no. Criteria Weight Scores obtained

1

2

3

4

5

6

7

Probability of payback CP-EE options fromsection

Section/area consuming maximumresources

Multiplier effects

Increase in product quality/production rate

Barriers

Management preference

External pressure (government, NGO, etc.)

TOTAL

10

5

5

5

5

10

10

50

OPEN FILE



Worksheet 7: Process flow diagram

Input Input Process step reference Output Outputstream stream Input raw stream stream Remarks

parameters reference materials reference parameters

Process step

Proc

ess

para

met

er

Equipment

Standard Actual

Process step

Proc

ess

para

met

er

Equipment

Standard Actual

Process step

Proc

ess

para

met

er

Equipment

Product

Standard Actual

OPEN FILE



Worksheet 8: Obvious housekeeping lapses

Section

No.

Name of

section

Area Obvious

lapses

Categorization of lapse Remarks

1

2

3

4

5

6

Solid Liquid Gas Fuel Electricity Other

OPEN FILE



Worksheet 9: Input-output quantification and characterization

S.N

oPr

oces

s In

puts

Qua

ntit

yC

hara

cter

isti

csO

utpu

tsQ

uant

ity

Cha

ract

eris

tics

step

s or

un

it

oper

atio

ns

Others

Moisturecontent

Total solids

Pressure

Temperature

Others

BOD

COD

pH

Total solids

Pressure

Temperature

OPEN FILE



Worksheet 10: Baseline data

Section Section/utility Resource Quantity Potential of CP-EE Targets

no. equipment used Low Medium High

OPEN FILE



Worksheet 11a: Material and energy balance

Section Input Unit operation/ Output Waste stream

no. unit process Name Quantity Liquid Solid/gas EnergyName Quantity

OPEN FILE



Worksheet 11b: Cost of waste stream

Section Section/process Waste Components of Quantity Unit rate Total cost ofno. stream of waste stream waste component

OPEN FILE



Worksheet 12: Cause analysis

Section no. Section Waste stream Probable cause

OPEN FILE



Worksheet 13: CP-EE options, generation and categorization

Sect

ion

Sect

ion

Was

teC

P-EE

Goo

dO

pera

ting

Proc

ess

Raw

N

ewN

ew

Reco

very

On-

site

no.

stre

amop

tion

sho

use-

prac

tice

s/op

timiz

atio

nm

ater

ial

tech

nolo

gypr

oduc

tof

use

ful

recy

cle

keep

ing

man

agem

ent

subs

titu

tion

desi

gnby

-pro

duct

san

d re

use

OPEN FILE



Worksheet 14: Screening of CP-EE options

Section CP-EE options Directly Require further Pending later no. implementable analysis consideration

OPEN FILE


Part 1 CP-EE methodology Chapter 2: CP-EE assessment methodologyO

ptio

nC

P-EE

Tech

nica

l req

uire

men

tIm

pact

(+/

0/-)

No.

mea

sure

Equi

pmen

tIn

stru

men

t or

M

anpo

wer

Spac

eTe

chno

logy

Pr

oduc

tion

Prod

uct

Ope

rati

onM

aint

enan

ceSa

fety

requ

irem

ent

acce

ssor

ies

avai

labi

lity

avai

labi

lity

rate

qual

ity

flexi

bilit

y

Worksheet 15a: Technical feasibility analysis

Not

e: P

repa

re d

etai

led

eval

uatio

n of

indi

vidu

al w

orka

ble

optio

n

OPEN FILE



Worksheet 15b: Environmental analysis

* N

ote:

Whe

reve

r po

ssib

le q

uant

itativ

e im

pact

is t

o be

rec

orde

d

H

= H

igh,

M =

Med

ium

, L =

Low

, N =

Neg

ativ

e

Opt

ion

CP-

EEIm

pact

(+/

0/-)

No.

mea

sure

Air

Wat

er

Gas

eous

em

issi

on

Part

icul

ates

Oth

ers

Org

anic

sTo

tal

Oth

ers

Solid

Ove

rall

impa

ct*

incl

udin

g G

HG

(CO

D)

solid

sw

aste

(H, M

, L, N

)OPEN FILE



Worksheet 15c: Economic viability analysis

Option CP-EE Investment Operational Annual Payback Remarksno. options (US$) (US$) saving (US$) period

OPEN FILE



Worksheet 16: Selection of CP-EE measures for implementation

Options Options Technical Environmental Economic Total Rank

ref. no. feasibility impact feasibility

Weighting (%) 30 25 45 10

OPEN FILE



Worksheet 17: Implementation plan for CP-EE measures

Opt

ion

Sele

cted

Cla

ssifi

cati

onD

ate

Pers

onRe

sult

s

no.

CP-

EE(s

hort

, med

ium

resp

onsi

ble

Econ

omic

Envi

ronm

enta

l

mea

sure

or lo

ng t

erm

)pr

opos

edac

tual

expe

cted

actu

alex

pect

edac

tual

OPEN FILE

3.1 About the companyM/s Luthra Dyeing and Printing Mills (LDPM)—located in Surat, a city which accounts

for 40 per cent of textile dyeing and processing houses in India—is a leading and well

equipped textile processing house. The company started operations in 1980 and has

grown continuously since. It processes various types of synthetic polyester cloths from

grey to finished stage, with an installed processing capacity of around 3 200 tons of

fabric per year. By 2002, the company was processing around 2 400 tons of fabric per

year with a workforce of around 550 people. LDPM operates around 300 days per year,

on three shifts a day.

The company has recently acquired ISO 14001 certification. In order to continue on its

path to excellence in resource and energy conservation, it volunteered to undertake

CP-EE studies implemented by India's National Cleaner Production Centre. LDPM was

also selected for CP-EE studies for the following reasons:

• It is representative of the synthetic fabric processing sector in India.

• It has significant potential for CP-EE interventions, especially regarding water and

energy conservation.

• There is potential for technology upgrade.

• There is a possible multiplier effect.

• Management was committed to CP-EE studies and ready to cooperate.



Chapter 3: Case study

Cleaner Production and Energy Efficiency Assessment

at

Luthra Dyeing and Printing Mills

Gidc, Pandesera, Surat, India (July 2002)


Part 1 CP-EE methodology Chapter 3: Case study

3.2 Process description and process flow chartAs for any typical textile firm, the demand for fabric processing at LDPM is largely

dependent on customer requirements which are basically governed by existing market

trends and fashion. There are variations in the use of chemicals, in process operating

sequences and even in the equipment used for processing. A general description of the

process is given below, and the process is summarized in Figures 1.10 and 1.11.

The main activities carried out at LDPM for textile processing are as follows:

• Pre-treatment, which comprises drumming and scouring, weight reduction

and bleaching

• Dyeing• Printing• Finishing• Ageing• Washing (washing is carried out after every operation)

Pre-treatment

The pre-treatment process prepares the textile material for subsequent processing.

a) Drumming

The grey fabric received is treated in the drumming machine to obtain the desired grain

texture. The cloth is wetted and rotated in drums, both clockwise and anti-clockwise.

The operation is done four times—with plain water, then with swelling chemicals,

followed by two washes. The drummed fabric is dewatered in a hydro extractor.

b) Scouring, weight reduction and bleaching

Scouring is the main operation carried out to remove foreign substances such as oils,

fats and other impurities. It is an alkaline extraction process involving heat (80–130 °C)

and pressure (2–3 kg/cm2). Additional swelling of fibres takes place during scouring,

improving the dye-uptake rate.

If necessary, the fabric is treated in the same bath to reduce its weight to give it a light

feel. Whiteness of the fabric needs to be improved and bleaching is also carried out in

this bath (by oxidative or reductive decomposition).

The scoured fabric is subjected to hot wash, followed by neutralization of residual alkali.



Dyeing

Fabric is dyed to give it its desired colour. The fabric to be dyed is treated with dyes

and auxiliary chemicals at 120–130 °C and under pressure. Polyester fibre is usually

dyed by an exhaustion process. A dispersing agent is added and the pH is adjusted.

Accelerants and other auxiliaries (wetting agents, levelling agent, etc.) are also added

as required. Vat dyes are also occasionally used for dyeing.

In the post-dyeing stage, the material is rinsed thoroughly or soaped. For dark finishes,

the fabric is subjected to reductive alkaline cleaning after dyeing. It is then subjected

to pH balance and, if no printing is required, is subjected to a heat setting operation.

Figure 1.10: Process sequence

GREY FABRIC

DYED FINISHED FABRIC PRINTED FINISHED FABRIC

hydro extraction

cold washing

chemical treatment

wetting (in drums)

washings

neutralization

scouring

stentoring

cold washing

hot washing

dyeing

reduction clearing

washings

dyeing

printing

colour developing

drying

stentoring

shrinking

• Operations in the

orange shaded area are

carried out in drums.

• Operations in the blue

area are carried out in

jet dyeing machines.



Figure 1.11: Pretreatment operations—inputs and outputs

GREY OR DRUM TREATED FABRIC

PRE-TREATED FABRIC

hot washing

heat setting

caustic washing

washing

scouring

washing

neutralization

water

watersoda

watersteam

scouring chemicals

watersteam

waterHCI

water

heat by steam

wastewater

wastewater

wastewater

wastewater

wastewater

wastewater

fumes

Printing

Printing is the process by which coloured patterns are produced on the fabric. The fabric

is printed on programmed, flat-bed or rotary screen-printing machines. It is then passed

through an attached dryer to remove moisture. Temperature in the dryer is varied

depending on the nature of fabric processed and the types of dyes used for printing. For

pigment printing, the temperature is maintained in the 160–170 °C range.

After printing, the printing screens are washed with water.

Finishing

Finishing comprises the final processes that make the fabric into an end-product. It

improves the feel and volume of the fabric.

Ageing

After printing the colours are not permanently fixed in the fabric. The ageing treatment

fixes the colour in the fabric permanently. This treatment is done in a Steam Ager or a

Loop Ager machine, at a temperature of 180–190 °C.

Washing

The fabric is washed to remove excess chemicals and dyes after every operation, or as

required. It is washed in several cold and hot washes, either in machines or in a series

of baths called washing ‘kundis’ (tanks). Excess wash water is removed by centrifuging.



3.3 Baseline informationThe CP-EE team observed wide variations in the production process and the product

at LDPM. Initially, it was planned to study one complete batch to provide the basis for

a detailed material and energy balance, and to extrapolate from this to obtain an

overall scenario for the year. However, when values were compared it was found that,

for this type of industry, using just one batch as a unit is neither representative nor

useful in obtaining the desired information for a CP-EE assessment.

Data was collected for the year 2002, which was then considered as the baseline for

further comparison.

Production

The unit's products divide easily into two categories: dyed cloth and printed cloth, with

printed cloth being initially dyed or whitened. The total production is normalized in

terms of the total cloth produced on the basis of the resources used during the

production of the cloth. As inferred from production data (see Figure 1.12), the total

output from the unit is equal to the total cloth printed plus half of the total dyed

production. On average, the unit produces 100–210 tons of cloth per month

(normalized basis), depending on orders and market situation.

Figure 1.12: Production data

cloth dyed (tons)

cloth printed (tons)

total dyed + printed (tons)

total cloth normalized (tons)

0

50

100

150

200

250

300

month

prod

ucti

on

1 2 3 4 5 6 7 8 9 10 11 12

51 30 65 48 62 44 42 63 80 126 83 104

87 108 112 155 157 92 148 168 162 148 101 151

138 138 177 203 219 136 191 231 242 274 184 256

112 123 145 179 188 114 170 199 202 211 143 203

Quantifying and characterizing wastewater

Monitoring in order to quantify and characterize wastewater in pre-treatment and

dyeing operations was carried out for a single batch of 2 400 metres of polyester fabric,

equivalent to 168 kg of fabric. Values were extrapolated for the day, assuming 48

batches per day, equivalent to 8.0 tons of cloth processed per day. For printing and

post-printing operations, monitoring was carried out for a 24-hour cycle.

The composite wastewater sample collected during the monitoring gave the results

shown in Table 1.3.



Resource consumption

On average, the unit processes 8.0 tons of cloth per day. Like any textile processing

unit, the process requires steam, water, gas, compressed air, dyes and printing

chemicals, etc. The consumption of major resources for the year 2002 per ton of cloth

processed is shown in Table 1.2

Unit/ton fabric

Months

Average

Purchasedwater(tanker ormunicipalsupply)

Bore wellwater

Recycledwater(from ETP)

Total water

Coal (lignite)

Gas

Gridelectricity

Diesel

Equivalentelectricityfrom diesel

Total kWhelectricity

Dyes

Gums

m3

m3

m3

m3

ton

m3

kWh

litre

kWh

kWh

kg

kg

115

36

50

201

3

772

698

247

827

1 525

61

82

122

30

56

208

4

846

663

256

858

1 521

65.4

80

136

2 4

62

222

4

697

345

363

1 216

1 561

60.5

88

148

20

66

234

4

625

1 587

0

0

1 587

65.1

93

136

40

46

222

3

611

234

608

2 037

2 272

60.1

85

172

48

38

258

3

804

294

417

1 395

1 690

74.2

110

143

42

44

229

4

629

225

421

1 410

1 636

61

100

133

50

36

219

4

656

234

366

1 227

1 461

61.4

93

123

46

40

209

4

582

208

361

1 209

1 417

61.8

87

136

30

56

222

4

576

1 469

0

0

1 469

61.3

90

135

34

52

221

4

623

1 641

0

0

1 641

64

99

125

32

54

211

3

553

1 356

0

0

1 356

63.5

85

135

36

50

221

3

664

746

253

848

1 595

63.2

91

Table 1.2: Major resource consumption at LDPM in 2002

Resources



Waste stream Quantity(litres/batch)

Quantity (litres/day)

pH TS (mg/l) COD (mg/l) BOD (mg/l)

Characteristics

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

Wastewater from drum wash

Wastewater from washing of grey fabric

Wastewater from scouring

Wastewater after cold wash of scouring

Wastewater from bleaching(bleaching liquor)

Wastewater from cold wash of bleaching

Wastewater from dyeing only(exhausted dye bath).

Wastewater from dyeing wash

Wastewater from neutralization

Wastewater from neutralization wash

Wastewater from washing of stirrerblades in print paste cooking

Wastewater from washing of bucketsand drums used for print pastepreparation and storage

Wastewater from screen washing

Wastewater from squeeze wash

Wastewater from screen preparation

Wastewater from print blanket washing

Wastewater from washing of printedfabric

Steam condensate from dyeing

Cooling water (not to ETP)

800

700

700

900

700

720

800

770

720

720

30 kl/d

715 kl/d

1.1 l/s

3.0 kl/d

94 kl/d

100 kl/d

600

38 400

33 600

33 600

43 200

33 600

34 560

38 400

36 960

34 560

34 560

30 000

71 500

31 680

3 000

94 000

100 000

28 800

150 000

8.11

7.7

9.5

7.12

7.27

8.35

4

8.85

7.59

-

-

-

5.81

-

5.69

8.48

20 608

14 923

13 856

4 500

6 500

4 300

4 480

4 350

4 840

4 800

8 000

8 500

27 048

8 000

25 688

11 712

1 362

1 515

2 210

1 532

1 224

890

2 020

800

1 510

980

1 600

770

1 980

1 700

745

1 750

654

353

380

243

308

150

1 216

250

389

316

450

230

204

170

238

360

0

Table 1.4: Wastewater quantification and characterization for individual streams

Section no.

Parameter Range of values

1

2

3

4

5

Volume

pH

Total solids (TS)*

COD

BOD

130 m3/d to 140 m3/d

6.75–8.5

9 000–11 500 mg/l

900–1 200 mg/l

275–325 mg/l

Table 1.3: Composite wastewater characteristics

Section no.

* TS values are relativelyhigh in relation to thosefor typical textileprocessing companiesbecause the groundwater(bore well) used forprocessing had a veryhigh total dissolved solidsconcentration.

Table 1.4 shows quantification and characterization data for individual wastewater

streams.



CP-EE potential, targets and selection of audit focus

Based on the resource consumption and waste water generation data, it was surmised

that there was wide scope for resource reduction at LDPM, including energy and water.

Table 1.5 indicates the existing conditions, the potential for improvements and

probable targets to be achieved in the future.

Audit focus

It can be seen from Table 1.5, that the company has great potential for reduction of all

resources used. After discussions between the CP-EE team and management, it was

decided that the CP-EE studies should cover the entire plant and utilities. The aim was

to minimize resource wastage as far as possible so as to maximize reductions in GHG

emissions and increase profits.

Parameter Existing values Cost (US$) Potential Target 2004

1

2

3

4

5

Water (m3/t fabric)PurchasedBore wellRecycledTotal

Electrical power(kWh/t fabric)

ThermalLignite (t/t fabric)Natural gas (m3/t fabric)

ChemicalsDyes (kg/t fabric)Gum (kg/t fabric)

Pollution loadCOD (kg/t fabric)GHG (t/t fabric)Wastewater (m3/t fabric)

1353650

221

1 595

3.0664

63.291

1507.6

161

0.45/m3

0.02/m3

0.11

35.48/t0.20/m3

9.03/kg0.41/kg

HighLowLowModerate

High

HighModerate

LowModerate

HighHighHigh

903045

165

1 220

2.0500

57.170

1206.0

120

Table 1.5: Potential for resource reduction at LDPM

Section no.



3.4 Identification of waste streams, cause analysis and CP-EE opportunitiesBased on the information collected and compiled by the CP-EE team, a detailed cause

analysis was made of the various waste streams. Cause analysis and the observations

made during company visits were used as a basis to identify CP-EE options to reduce

resource consumption. Some of the major CP-EE options are given in Table 1.6.

Probable cause CP-EE options

Wastewater from washingof grey cloth in drumsbefore pre-treatmentoperations

Low power factor in drummotors

Wastewater from scouringand weight reductionoperations andsubsequent washings

Wastewater from(bleaching) whiteningoperations andsubsequent washings

Wastewater from dyeingoperations

• Presence of foreign material (e.g. dust sticking tofabric, inks, markings, etc.)

• Removal of sizing material, oils and additionalimpurities, etc. used during weaving operations

• Use of excess water for drum soaking and washingdue to less than optimum capacity utilization

• Use of large quantities of water for direct cooling ofthe fabric (when the drum is opened, the fabric iscooled before removal; this is done by placing ahose into the drum and allowing the excess water toflow out continuously)

• Use of swelling agents during drum washingoperations

• Variable loading of drums and sudden load duringstart up operations

• Use of excess scouring chemicals (caustic) in theoperation

• Numerous steps for every small operation, withwashing after every operation.

• Use of high cloth to liquor ratio• Unexhausted dyes in the wastewater• Use of direct steam injection in jet machine to

maintain temperature and increase production rate• Small batches for dyeing in large jet dyeing machine

(i.e. unoptimized capacity utilization)

1 Optimization of cloth to liquor ratio from 1:6 to1:4, by installation of water measurement deviceor drum calibration and proper worker training

2 Installation of large capacity drum washer withindirect cooling mechanism for improvedproductivity and quality

3 Optimization of production planning for highercapacity utilization of the existing drum washers

4 Installation of soft starter and variablespeed/frequency drives in motors

5 Reuse of wastewater from scouring by addingmake up chemicals

6 Recovery of caustic by installing caustic recoverysystem

7 Combining weight reduction, scouring andwhitening operations into a single operation

8 Markings on the jet machine so as to ensureproper cloth to liquor ratio

9 Reduction in dye consumption from 5.5% to4.25% by change in process parameters, e.g.temperature from 130 °C to 135 °C andretention time from 30 minutes to 60 minutes

Table 1.6: Cause analysis and generating CP-EE options

Waste streams

continued …




Low power factor fordyeing machine motor

Wastewater fromneutralization operationand subsequent washing

Wastewater from washingof stirrer blades aftercooking, print pastepreparation buckets anddrums

Wastewater from washingof screens after printing

Wastewater and solventwaste from blanket of flatbed printing machine

• Use of organic acids causing high COD load

• Variable load pattern due to different batch sizesand weight of cloth

• Increase in peak demand • Improper removal of dyeing chemicals in washing

after dyeing

• Excess print paste sticking to the stirrer blades,buckets and drums

• Excess print paste sticking to the screens and on theedges of the screen frames

• Excess print paste seeping from screen throughcloth and onto the blanket

• Printing on portions of blanket not covered by cloth

10 Use of indirect steam instead of direct steam forheating and recovery of condensate for reuse asboiler feed water

11 Optimizing capacity utilization of jet dyeingmachine by production planning andprocurement of new, small jet dyeing machine

12 Replace acetic acid by tartaric acid13 Eliminate usage of Citric W14 Reduce usage of levelling agents by 10%15 Use inorganic mineral acids in place of organic

acids16 Replace the bottom basket in jet dyeing machine

by Teflon rods so as to increase the area andenhance the capacity of the machine by 70 kg

17 Enhance capacity of the jet machines byincreasing the height of the machine

18 Use of spent dye bath from polyester dyeingby adding make-up chemicals

19 Replacing ordinary water used for dyeing byRO/DM water for higher dye exhaustion rate

20 Install soft starters and variable speed drives onjet machine motors

21 Optimizing the washing operations after dyeing22 Reuse of neutralization waste liquor after adding

make up chemicals

23 Scraping of print paste before washing24 Use of dedicated buckets/drums and stirrer for

print paste preparation25 Wiping of print paste from buckets with waste

tissue paper, rags, etc. before washing

26 Scraping and reuse of print paste from thescreens before washing

27 Washing of screens by high pressure, manuallyactuated showers

28 Dipping of screens in a tank full of water beforefinal washing with fresh water

29 Reduce mesh size of the printing screens30 Cover un-used side strip of blanket by waste

cloth strip31 Provision of scraping mechanism using doctor

blade and squeeze end brush half dipped inwater to recover and reuse print paste from theblanket

32 Recovery of solvent used for blanket washing byinstalling solvent recovery plant

33 Use of non-organic liquid in place of solvent

Table 1.6: Cause analysis and generating CP-EE options (continued)

Waste streams

continued …




Waste thermal energy(gas) in printing machine

Waste thermal energy(gas) in padding mangle

Wastewater from postprint washing in tanks(kundi)

Wastewater from cookingpan, ageing machine andzero-zero machine

Electrical and thermalenergy loss in loop agermachine

Thermal energy loss insanforizing drum

Thermal energy loss inexisting boiler

Thermal energy losses insteam distribution system

Electrical energy loss incompressed air supplysystem

Electrical energy loss inmotors

Energy loss in electricallighting system

• Idle running of burner on printing machine

• Idle running of dryer even if there is no fabric

• Unoptimized water usage in washing

• Condensate from steam drained to ETP

• Low efficiency of heat transfer from steam heatedtubes in loop ager machine

• Feeding of single layer of cloth in loop ager even forlighter quality of cloth

• Inefficient heat transfer from steam to the drum

• No Excess air control• No waste heat recovery system from the boiler flue

gases• Higher blow down from boiler drum due to high

TDS in feed water• High level of unburnts in ash• Old and obsolete technology with efficiency of

around 65%

• Uninsulated flanges• Condensation of steam forming pools of water in

the steam carrying pipes

• Leakages in the compressed air supply lines• Compressed air used at a higher pressure than

required

• Unoptimized motor loading

• Use of old, energy-inefficient lighting fixtures

34 Operating the machine on continuous drive byinstalling auto cut off photovoltaic cell

35 Installing photovoltaic cut off switch in paddingmangle

36 Use of counter-current washing technique37 Passing the cloth through roller squeezes

between each wash

38 Reuse condensate to boiler

39 REPLACEMENT OF EXISTING LOOP AGER WITHDIRECT GAS FIRED LOOP AGER SYSTEM (ANINNOVATIVE SYSTEM DEVELOPED AT THEPLANT AND NOW PATENTED)

40 Two end overlapped feeding of cloth to the loopager for light weight fabric

41 Direct gas firing in sanforizing drum by slit typeburner

42 Installation of damper and variable speed drivesfor ID and FD fans

43 Preheat the feed water to boiler by exit flue gases44 Use low TDS municipal water in place of tanker

water45 Reduce the coal size (lower mesh size) to be

used in boiler46 Replace existing boiler system with a new FBC

boiler of 32 kg/cm2 pressure, coupled with backpressure turbine for cogeneration of 2 MWelectrical power

47 Insulate all 125 existing flanges48 Install thermodynamic steam traps in the main

header with a gap of 25 metres

49 Conduct regular air leak detection tests50 Reduce the air pressure to optimum limit

51 Conduct load analysis on motors andreshuffle/replace optimum rating motors

52 Replace 40 W tube light fixtures with energyefficient 30 W fixtures

53 Provision of skylight windows overhead toreduce lighting required during day time

Table 1.6: Cause analysis and generating CP-EE options (continued)

Waste streams



3.5 Feasibility analysis of CP-EE options To decide on implementation priorities, the CP-EE options developed were divided, by

preliminary screening, into ‘Directly Implementable’, ‘Requiring Further Analysis’ and

‘Pending, for Later Consideration’. Table 1.7 gives the detailed analysis.

CP-EE options Requiringfurther analysis


1

2

3

4

5

6

7

8

9

Optimization of cloth to liquor ratio from 1:6 to1:4, by installation of water measurement deviceor drum calibration and proper worker training

Installation of large capacity drum washer withindirect cooling mechanism for improvedproductivity and quality

Optimization of production planning forcapacity utilization of the existing drum washers

Installation of soft starter and variablespeed/frequency drives in motors

Reuse of wastewater from scouring by addingmake-up chemicals

Recovery of caustic by installing caustic recoverysystem

Combining weight reduction, scouring andwhitening operations into a single operation

Markings on the jet machine so as to ensureproper cloth to liquor ratio

Reduction in dye consumption from 5.5% to4.25% by change in process parameters (e.g.temperature from 130 °C to 135 °C andretention time from 30 minutes to 60 minutes)

✓

✓

✓

✓

✓

✓

✓

✓

✓

Change in operatingpractice—workers fill drumsbased on their experience,and generally overfill them

Discharged wastewater withvery high impurities, hencecannot be reused

Change in operatingpractice—workers fill drumsbased on their experience,and generally overfill them

Table 1.7: Prioritizing CP-EE options

CP-EEoption no.

continued …

Pending, for laterconsideration

Remarks



CP-EE options Requiringfurther analysis


10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

Use of indirect steam to direct steam for heatingand recovery of condensate for reuse as boilerfeed water

Optimizing the capacity utilization of jet dyeingmachine by production planning andprocurement of new, small jet dyeing machine

Replace acetic acid by tartaric acid

Eliminate usage of Citric W

Reduce usage of levelling agents by 10%

Use inorganic mineral acids in place of organicacids

Replace the bottom basket in jet dyeingmachine by Teflon rods so as to increase thearea and enhance the capacity of the machineby 70 kg

Enhance capacity of the jet machines byincreasing the height of the machine

Use of spent dye bath from polyester dyeing byadding make-up chemicals

Replacing ordinary water used for dyeing byRO/ DM water for increase dye exhaustion rate

Install soft starters and variable speed drives onjet machine motors

Optimizing the washing operations after dyeing

Reuse of neutralization waste liquor after addingmake up chemicals

Scraping of print paste from buckets /drumsbefore washing

Use of dedicated buckets/drums and stirrer forprint paste preparation

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

Will cause quality problemswith the fabric and is difficultto handle and use in smallquantities

Will effect the quality of thefabric as the dischargedwastewater will be coloured

Change in operating practiceleading to recovery of printpaste

Number of variations andkeeping dedicated bucketsetc. is not feasible

Table 1.7: Prioritizing CP-EE options (continued)

CP-EEoption no.

continued …


Remarks



CP-EE options Requiresfurther analysis


25

26

27

28

29

30

31

32

33

34

35

36

37

38

Wiping of print paste from buckets with wastetissue paper, rags etc before washing

Scraping and reuse of print paste from thescreens before washing

Washing of screens by high pressure, manuallyactuated showers

Dipping of screens in a tank full of water beforefinal washing with fresh water

Reduce mesh size of the printing screens

Cover unused side strip of blanket by wastecloth strip

Provision for scraping mechanism using doctorblade and squeeze end brush half dipped inwater to recover and reuse print paste from theblanket

Recovery of solvent used for blanket washing byinstalling solvent recovery plant

Use of non-organic liquid in place of solvent

Operating the machine on continuous drive byinstalling auto cut off photovoltaic cell

Installing photovoltaic cut off switch in paddingmangle

Use of counter-current washing technique

Passing the cloth through roller squeezesbetween each wash

Reuse condensate to boiler

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

Will lead to increase ofsolid/hazardous waste

Change in operating practiceleading to recovery of printpaste

Very low-investment solutionleading to water savings andincreased washing efficiency

Change in operating practicewith very small investment

Reducing mesh size meansthat consistency of the printpaste will have to bereduced, making dyes spreadon the cloth

Small investment resulting insavings of print paste

Small investment leading tovery high recovery of printpaste

The quantity of solvent is toosmall to be recovered

Blanket washing efficiencywill reduce and may lead tocolour sticking on theblanket causing problems forfurther printing of fabric

Obvious option resulting invery high energy savings


CP-EEoption no.

continued …


Remarks



CP-EE options Requiresfurther analysis


39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

REPLACEMENT OF EXISTING LOOP AGER WITHDIRECT GAS FIRED LOOP AGER SYSTEM (ANINNOVATIVE SYSTEM DEVELOPED AT THEPLANT ITSELF AND NOW PATENTED)

Two end overlapped feeding of cloth to theloop ager for light weight fabric

Direct gas firing in sanforizing drum by slit typeof burner

Installation of damper and variable speed drivesfor ID and FD fans

Preheat the feed water to boiler by exit flue gases

Use low TDS municipal water in place of tankerwater

Reduce the coal size (lower mesh size) to beused in boiler

Replace existing boiler system with a new FBCboiler of 32 kg/cm2 pressure coupled with backpressure turbine for cogeneration of 2 MWelectrical power

Insulate all 125 existing flanges

Install thermodynamic steam traps in the mainheader with a gap of 25 metres

Conduct regular air leak detection tests

Reduce the air pressure to optimum limit

Conduct load analysis on motors andreshuffle/replace optimum rating motors

Replace 40 W tube light fixtures with energy-efficient 30 W fixtures

Provision of skylight windows overhead toreduce lighting required during day time

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

Change in operating practicefor lighter fabric resulting inenergy savings

Obvious solution leading toenergy savings and betterquality of steam to besupplied at the user end

Obvious solution leading toenergy savings and betterquality of steam to besupplied at the user end

Good operation andmanagement practiceleading to energy savings

Change in operating practiceleading to energy savings

Obvious solution leading toelectrical energy savings

Obvious solution leading toelectrical energy savings


CP-EEoption no.


Remarks



Techno-economic and environmental analysis

Before implementing CP-EE options it is necessary to verify their techno-economic and

environmental feasibility. This provides a basis to prioritize implementation of the

options. The team identified 53 CP-EE options at LDPM. Of the 53 options, 8 (15%)

were rejected at the outset as they were evidently unfeasible. Sixteen options were

considered for direct implementation, as their financial and technical implications were

fairly minor and quite evident. The remaining 29 options were subjected to testing of

their technical feasibility and the viability of those found to be technically feasible was

then subjected to environmental and economic analysis. Table 1.8 summarizes the

results of the analyses.

CP-EE options Technical feasibility


Spaceavailability

Productionquality*(+/0/-)

2

3

4

6

7

9

Installation of large capacitydrum washer with indirectcooling mechanism for improvedproductivity and quality

Optimization of productionplanning for capacity utilizationof the existing drum washers

Installation of soft starter andvariable speed/frequency drivesin drum motors

Recovery of caustic by installingcaustic recovery system

Combining weight reduction,scouring and whiteningoperations into a single operation

Reduction in dye consumptionfrom 5.5% to 4.25% by changein process parameters (e.g.temperature from 130 ° to135 ° and retention time from30 minutes to 60 minutes)

Yes

Yes

Yes

Notavailable(reject)

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

+

+

+

+

+

+

Reducedwastewater volumeand pollution load

Reducedwastewater volumeand pollution load

Increase powerfactor and reducedGHG emission(accounted for inoption 42)

Reduced wastewater volume andpollution load

Reduction in dyeconsumption andpollution load

1 1361

NQ

909 permachine

NIL

NIL

NQ

NQ

682

NQ

NQ

NQ

NQ

18 months

Immediate

NQ

Table 1.8: Techno-economic and environmental feasibility of CP-EE options

CP-EEoption

no.

continued …

Environmentalbenefits

Investment(US$)

Annualsaving(US$)

Paybackperiod





Spaceavailability


10

11

12

13

14

16

17

18

19

20

21

Use of indirect steam to directsteam for heating and recoveryof condensate for reuse asboiler feed water

Optimizing capacity utilizationof jet dyeing machine byproduction planning andprocurement of new small jetdyeing machine

Replace acetic acid by tartaricacid

Eliminate usage of Citric W

Reduce usage of levellingagents by 10%

Replace the bottom basket injet dyeing machine by Teflonrods so as to increase the areaand enhance the capacity ofthe machine by 70 kg

Enhance capacity of the jetmachines by increasing theheight of the machine

Use of spent dye bath frompolyester dyeing by addingmake-up chemicals

Replacing ordinary water usedfor dyeing by RO/ DM waterfor high dye exhaustion rate

Install soft starters and variablespeed drives on jet machinemotors

Optimizing the washingoperations after dyeing

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

+

+

+

+

+

0

0

+

+

+

+

Reducedwastewater volume,and 230 t/yr GHG(by 150 t/yr coal)

Reducedreprocessing andreducedwastewater volumeand pollution load

Low pollution load

Reduced pollutionload


Increasedthroughput fromthe machine andreduced specificpollution load

Increasedthroughput fromthe machine andreduced specificpollution load


Reduced pollutionload (dyeexhaustionincreased by 8% intrials)

Reduced GHGemissions

Lower wastewaterand GHG emissions

795

13 633

Nil

Nil

Nil

23 permachine

909

2 272

909 per machine

NQ

5 453

NQ

NQ

NQ

NQ

NQ

NQ

1 818

568 per machine

NQ

15 months

NQ

NQ

Immediate

Immediate

Less than 3months

NQ

14 months

20 months

Immediate

Table 1.8: Techno-economic and environmental feasibility of CP-EE options (continued)

CP-EEoption

no.

continued …


Investment(US$)

Annualsaving(US$)

Paybackperiod





Spaceavailability


34

35

36

37

39

41

42

43

44

45

Operating the machine oncontinuous drive by installingauto cut off photovoltaic cell

Installing photovoltaic cut offswitch in padding mangle

Use of counter-current washingtechnique

Passing the cloth through rollersqueezes between each wash

REPLACEMENT OF EXISTINGLOOP AGER WITH DIRECT GASFIRED LOOP AGER SYSTEM(INNOVATIVE SYSTEMDEVELOPED AT THE PLANTAND NOW PATENTED)

Direct gas firing in sanforizingdrum by slit type of burner

Installation of damper andvariable speed drives for ID andFD fans

Preheat the feed water to boilerby exit flue gases

Use low TDS municipal water inplace of tanker water

Reduce the coal size (lowermesh size) to be used in boiler

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Space notavailable(reject)

Yes

Yes

Yes

Yes

Yes

Yes

Yes

0

0

0

Trial failed(reject)

+

+

0

0

0

0

Reduced GHGemission due tosavings of 6 300m3 gas/ year

Reduced GHGemission due tosavings of 6 000m3 gas/ year

Reduced GHG by2 300 t/yearthrough gassavings of 108 000m3/yr and coal1 270 t/yr

Reduced GHGemissions by fuelsavings of 7 tonslignite

Reduced GHGemission due toelectrical savings of75 000 kWh (allelectrical options)

Reduced GHGemissions due tolignite savings of784 t/yr

Reduced GHGemissions due tolignite savings of337 t/yr


227

227

45 445

1 136

7 953

2 272

NIL

1 432

1 363

73 598

3 749

6 817

28 403

12 270

6 months

6 months

7 months

3 months

10 months

2 months

Immediate


CP-EEoption

no.

continued …


Investment(US$)

Annualsaving(US$)

Paybackperiod

Combined with option 43





Spaceavailability


46

51

Replace existing boiler systemwith a new FBC boiler of32 kg/cm2 pressure coupledwith back pressure turbine forcogeneration of 2 MWelectrical power

Conduct load analysis onmotors and reshuffle/replaceoptimum rating motors

Yes

Yes

Yes

Yes

0

0

Reduced GHGemissions (about3 200 t/yr)


181 779

NQ

153 149

NQ NQ


CP-EEoption

no.


Investment(US$)

Annualsaving(US$)

Paybackperiod

* Production quality: 0 = no effect + = positive - = negative effect

Values marked ‘NQ’ cannot be quantified at present because data were missing; they would be quantified after implementation ofthe CP-EE solution.

Three CP-EE options were rejected on the basis of their technical feasibility analysis—one

because of non-availability of space in the company, another because trials were not

successful, and a third because of non-availability of proven technology at small scale.

The company has already implemented a number of low-cost options and has also

invested in at least one large, capital-intensive CP-EE option: conversion of the loop

ager system to combined direct gas firing and steam. Since implementation of this

system, the company has obtained a patent for it. Demonstration of the system at

LDPM's premises could persuade other companies to adopt this technology.

3.6 Benefits and achievementsThe LDPM unit has already implemented 27 CP-EE options fully and 12 more options

have either been partially implemented or are in the advanced stages of planning. No

consensus was arrived at for three options, which were left to be followed up later.

Since one of the objectives of the project is to reduce GHG emissions, special emphasis

was given to the GHG emission reduction potential of the CP-EE options. Table 1.9

indicates the GHG saving from various CP-EE options



CP-EE options Savings(coal/gas/electricity)

4

10

20

34

35

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

Installation of soft starter and variable speed/frequency drivesin drum motors

Use of indirect steam to direct steam for heating and recoveryof condensate for reuse as boiler feed water

Install soft starters and variable speed drives on jet machine motors

Operating the machine on continuous drive by installing autocut off photovoltaic cell

Installing photovoltaic cut off switch in padding mangle

Reuse the condensate (from cooking pan) to boiler

REPLACEMENT OF EXISTING LOOP AGER WITH DIRECT GASFIRED LOOP AGER (AN INNOVATIVE SYSTEM DEVELOPED ATTHE PLANT AND NOW PATENTED)

Two end overlapped feeding of cloth to the loop ager forlight weight fabric

Direct gas firing in sanforizing drum by slit type burner

Installation of damper and variable speed drives for ID and FD fans

Preheat the feed water to boiler by exit flue gases

Use low TDS municipal water in place of tanker water

Reduce the coal size (lower mesh size) to be used in boiler

Replace existing boiler system with a new FBC boiler of32 kg/cm2 pressure coupled with back pressure turbine forcogeneration of 2 MW electrical power

Insulate all 125 existing flanges

Install thermodynamic steam traps in the main header withgap of 25 metres

Conduct regular air leak detection tests

Reduce compressed air pressure to optimum limit

Reshuffle and replace optimum rating motors

Replace 40W tube light fixtures with energy efficient 30W fixtures

Provision of skylight windows overhead to reduce lightingrequired during day time

Increase power factor and reduced GHGemission (accounted for in option 42)

150 t/yr coal

Reduced GHG emissions

Reduced GHG emission due to savings of6 300 m3 gas/ year

Reduced GHG emission due to savings of6 000 m3 gas/ year


Reduced GHG by 2 206 t/year through gassavings of 108 000 m3/yr and coal 1 270 t/yr


Reduced GHG emissions by fuel savings of7 tons lignite

Reduced GHG emission due to electricalsavings of 75 000 kWh (all electrical options)

Reduced GHG emissions due to lignitesavings of 784 t/yr

Reduced GHG emissions due to lignitesavings of 337 t/yr


Reduced GHG emissions by about 3 200 t/yr

Reduced GHG emissions due to savings of30 t lignite/yr



Reduced GHG emissions due to savings of8 125 kWh/yr electrical power


Reduced GHG emissions by electrical powersavings of 70 664 kWh/year


TOTAL

-

230

NQ

15

15

NQ

2 206

NQ

10.7

67

1 200

516

NQ

3 200

46

NQ

NQ

7.2

NQ

63

NQ

7 756 t/yr

Table 1.9: GHG savings potential of CP-EE options

CP-EEoption no.

GHG reduction(tons/year)



The CP-EE team collected the data from the unit for the month of April 2003 and

compared this with the baseline data (i.e. before implementation of the CP-EE options).

Table 1.10 shows the comparison of various parameters before and after the

implementation of CP-EE options.

1 Original figures were given in Indian rupees, slight discrepancies between savings per unit price and total savings are due torounding after conversion to dollars. The figures indicate the magnitude of possible savings.

2 The reduction in dyes used cannot be attributed wholly to the improvement due to implementation of CP-EE solutions. Changesin market conditions, prevalent fashion requiring lighter shade, etc. would also result in reduction in dyes used.

Parameters Values before CP-EE

monthly average 2002

Value after CP-EE

implementation

monthly average 2002

1

2

3

4

5

6

Production

(tons of fabric)

Normalized

Water (m3/t fabric)

Purchased

Bore well

Recycled

Total

Electrical power

(kWh/t fabric)

Thermal

Lignite (t/t fabric)

Natural gas (m3/t fabric)

Chemicals

Dyes (kg/t fabric)

Gum (kg/t fabric)

Pollution load

COD (kg/t fabric)

GHG (t/t fabric)

Wastewater (m3/t fabric)

153.4

135

36

50

221

1 595

3.0

664

63.2

91

150

7.6

161

145

102

36

30

168

1 268

2.15

482

43

70

140

5.6

130

24.4

0

40

24

20.5

28.3

9.9

32.02

23.1

6.7

22.8

19.3

0.46/m3

0.017/m3

0.11/kWh

36/t

0.20/m3

9.18/kg

0.42/kg

364 240

85 595

73 552

31 879

21 232

NQ, reduced

O&M cost

of ETP

Table 1.10: LDPM before and after CP-EE

Section no.

averagechange

(%)

Remarks Average cost1

(US$)

Annual economicbenefit (basis =

2 400 tonsproduction/year)1

(US$)



3.7 CP-EE assessment barriersProject progress was hampered by barriers from the CP-EE assessment phase through

to the implementation phase. CP-EE implementation started very well but suffered

later, particularly because of market conditions and increasing competition.

Table 1.11 shows the major constraints encountered and indicates actions taken to

overcome them.

Barrier Consequences Actions undertaken to overcome barriers

a) Technical

b) Organizational

c) Financial

Inadequate in-house facility forlaboratory analysis

Lack of Instrumentation formeasurement of resources used in theprocess (e.g. steam and water)

Specifications of motors and pumpsnot available

Production is on ad hoc basis

Records for dye consumption indyeing and printing section notmaintained

Availability of cheap unskilled workersmaking automation less attractive

Some of the analyses, (such as dyeexhaustion) could not be carried outinitially and the results of trial werenot reflected immediately

Resources could not be quantifieddirectly and accurately

Motor load analysis for replacing/reshuffling motors of optimum ratingscould not be conducted in detail

Frequent changes in the productionpattern made monitoring difficult

Accurate analysis for dye usage andwaste in different sections notpossible

Payback period for the CP-EE optionsincreases

Initially samples were analysed by anexternal agency, later a smalllaboratory was set up in the plant itself

Estimated on the basis of indirectmeasurements

Technical specifications of similar typeand make of motors were collectedfrom manufacturer and the relevantparameters were compared.

Monitoring scheduled per batchesprocessed

Analysis done on the basis of therecords of 12 days (study period for1st phase)

–

Table 1.11: Major barriers to the CP-EE process

Category



3.8 ConclusionsThe CP-EE demonstration provided a number of valuable lessons, the most important

of which is that, when resources (e.g. groundwater) are low-priced, a CP solution alone

may not be attractive. However, when combined with EE benefits in terms of electricity

savings (e.g. per litre of water saved), a more attractive package can be proposed.

Energy audit studies were conducted in the past by external agencies which made

suggestions for improvements. However, subsequent change was neither continuous

nor regular. The CP-EE studies have enabled the management to build a system of energy

auditing and conservation into the day-to-day work pattern, thereby making the concept

sustainable. The case study reaffirms that appropriate monitoring is crucial in identifying,

assessing and driving CP-EE implementation. The results are summarized in Table 1.12.

Finally, due to an economic slowdown in the textile industry in India, the management

was restricted from implementing some feasible CP-EE measures. However, as the

CP-EE options adopted demonstrate, implementing CP-EE does not necessarily need

significant up-front investment. In fact, CP-EE can be an effective tool to sustain a unit

in tough economic conditions.

Item No. or value

1

2

3

4

5

6

7

8

9

10

Total no. of CP-EE options identified

Number of CP-EE solutions implemented so far

Number of CP-EE solutions under implementation

Total of options rejected, including for techno-economic feasibility

Savings in resource consumption/year

a) Water consumption (m3)

b) Natural gas (m3)

c) Electricity consumption (kWh)

d) Coal (lignite) (tons)

Reduction in pollution load/year

a) Wastewater volume (m3)

b) Water pollution load COD (tons)

c) Gaseous emissions (GHG) (tons)

Improved quality of the product

Total investment made

Direct savings

Payback period

53

27

12

11

127 200

158 400

784 800

2 040

78 000

24

4 152

Positive

US$73 393

US$227 490

4 months

Table 1.12: Results of the CP-EE studies at LDPM at a glance

Section no.


ENERGYEFFICIENCY


Contents listing




Module 1 provides background information on different

energy-using systems and information that will be helpful

in identifying areas of focus for CP-EE assessments. The

module covers:

• Thermal systems

• Electrical systems

Module 2 presents Energy Efficient Technologies.

Both modules include worksheets that can be used

during assesment.



Module 1:

Energy use in industrial production

spotlightCP-EE

At only 6 °C above therequired minimum

temperature, a lagged fueloil tank with a diameter of1.8 m and length of 4.6 m

would wasteapproximately 6 800 kg of

steam in a year.

spotlightCP-EE

Loss of even one drop of oil every second can

cost you more than4 000 litres a year.

Thermal systems

M1.1 Fuels—storage, preparation and handling

M1.1.1 Fuel oils

Fuel storage tanks are generally made from welded mild steel. Overhead tanks should

be mounted on concrete blocks and should be equipped with vent and drain pipes.

The drainpipe is used for periodic removal of accumulated water. Care should be taken

when oil is being decanted from tankers to storage tanks. All leaks from joints, flanges

and pipelines must be attended to as a matter of urgency.

Fuel oil should be free from contaminants such as dirt, sludge and water before it is fed

to the combustion system. A filtering system may be provided for optimum

combustion efficiency. It is desirable to preheat fuel oil to lower the viscosity

appreciably in order to light the burner.

Storage and pumping temperatureThe temperature at which oil can readily be pumped depends on the grade of oil.

Table M.1 can be used as a guide for the most common grades of fuel oil.

Pumping temperature (°C)

50

230

900

1 500

7

27

38

49

Table M.1: Viscosity vs. temperature

Viscosity (centistokes)

Oil should never be stored at a temperature above that necessary for pumping, as this

leads to higher energy consumption. The energy use snapshot (right) illustrates this.

Oil preheatingLine heaters are used to raise the oil from pumping temperature to burning

temperature. Table M.2 gives a rough guide to the heating required, but optimum

conditions can only be obtained by trial and error.


Part 2 Technical modules Module 1: Energy use in industrial production

Burning temperature (°C)

50

230

900

60

104

121

Table M.2: Preheating guide

Viscosity (centistokes)

It is advisable to use a positive displacement pump such as a gear pump to pump fuel

oil. Sometimes no oil is transferred through the pipes because of excessive pressure

drop and cavitation at the pump.

A centrifugal pump is not recommended because, as oil viscosity increases, the

efficiency of the pump drops sharply and the horsepower required increases.

M1.1.2 Coal

Uncertainty in the availability and transportation of fuel necessitates storage and

subsequent handling. Stocking of coal has disadvantages including build-up of

inventory, space constraints, deterioration in quality and potential fire hazards. Other

minor losses associated with the storage of coal include oxidation, wind and carpet loss

(formation of a soft ‘carpet’ of coal dust and soil). One per cent oxidation of coal is

equivalent to 1 per cent ash in coal and wind losses may account for 0.5–1.0 per cent

of total losses.

The main aim of good coal storage is to minimize carpet loss and losses due to

spontaneous combustion. Spontaneous combustion in coal heaps can be caused by

the gradual increase in temperature resulting from oxidation.

Measures that can help to reduce carpet losses are as follows:

• Preparing a hard ground for coal to be stacked.

• Preparing standard storage bays in concrete and brick.

In process industries, modes of coal handling range from manual to conveyor systems.

It is advisable to minimize the handling of coal to avoid further generation of fines and

segregation effects.

Preparation of coalPreparation of coal prior to feeding into the boiler is important for achieving good

combustion. Large and irregular lumps of coal may cause the following problems:

• Poor combustion and inadequate furnace temperature.

• Higher excess air resulting in higher stack loss.

• Increase of unburnts in the ash.

• Low thermal efficiency.

Sizing of coalProper coal sizing is one of the key measures in ensuring efficient combustion. Proper

coal sizing, specific to the type of firing system, helps towards even burning, reduced

ash losses, and better combustion efficiency.

Coal is reduced in size by crushing and pulverizing. Pre-crushed coal can be

economical for smaller units, especially those which are stoker fired. In a coal handling

system, crushing is limited to a maximum size of 6 or 4 mm. Table M.3 shows suitable

sizes of coal for different firing systems. The most commonly used devices for crushing

are the rotary breaker, the roll crusher and the hammer mill.



Type of firing system Size (mm)

1

2

3

4

Hand firing

a) Natural draught

b) Forced draught

Stoker firing

a) Chain grate

i. Natural draught

ii. Forced draught

b) Spreader stoker

Pulverized fuel fired

Fluidized bed boiler

25–75

25–40

25–40

15–25

15–25

75% below 75 micron1

< 10 mm

Table M.3: Sizes of coal for different types of firing systems

Section no.

1 micron = 1/1000 mm

Coal must be screened before crushing so that only oversized coal is fed to the crusher.

This helps to reduce power consumption in the crusher. Recommended practices in

coal crushing are:

• Incorporation of a screen to separate fines and small particles, to avoid extra fine

generation in crushing.

• Incorporation of a magnetic separator to separate iron pieces in coal, which may

damage the crusher.

Conditioning of coalThe fines in coal present problems in combustion, owing to segregation effects.

Segregation of fines from larger coal pieces can be greatly reduced by conditioning

coal with water. Water helps fine particles to stick to the bigger lumps (due to surface

tension of the moisture) and stops fines from falling through grate bars or being carried

away by the furnace draught. While tempering the coal, care should be taken to ensure

that moisture addition is uniform. It is preferable to do this in a moving or falling

stream of coal.

If the percentage of fines in the coal is very high, wetting of coal can decrease the

percentage of unburned carbon and the excess air level required for combustion.

Table M.4 shows the extent of wetting, depending on the percentage of fines in coal.



Surface moisture (%)

10–15

15–20

20–25

25–30

4–5

5–6

6–7

7–8

Table M.4: extent of wetting, fines vs surface moisture in coal

Fines (%)

Blending of coalWhen coal lots have excessive fines, it is advisable to blend predominantly lumped coal

with lots containing excessive fines. Blending coal in this way can help to limit the

extent of fines in coal being fired to no more than 25 per cent. Blending of different

qualities of coal may also help to provide uniform coal feed to the boiler.

M1.2 CombustionFossil fuels (coal, oil, gases) are combinations of carbon, hydrogen, undesired elements

(e.g. sulphur, oxygen, nitrogen etc.), and ash constituents. These elements are burned

in the presence of the oxygen in the combustion air. The efficiency of a boiler or

furnace depends on the efficiency of the combustion system. For example, combustion

of oil is effected by a burner which mixes fuel and air in the correct proportions for

complete combustion, with consequent release of heat.

Basic combustion reactions—ideal or stoichiometric combustionThe amount of air to be supplied for combustion of the fuel depends on the elemental

constitution of the fuel, i.e. the proportions of carbon, hydrogen, sulphur, etc. in the fuel.

Analyses of the compositions of some typical coals are shown in Tables M.5 and M.6. The

amount of air required, based on the chemical make-up of the fuel, is called the ideal or

stoichiometric amount. This is the minimum amount of air required if mixing of fuel and

air by the burner and combustion are to be perfect. For example, for ideal combustion

of 1 kg of a typical fuel oil containing 86 per cent carbon, 12 per cent hydrogen and 2

per cent sulphur, the theoretical minimum amount of air required is 14.1 kg.



1 dry basis

Lignite

Moisture (%)

Ash (%)

Volatile matter (%)

Fixed carbon (%)

50

10.411

47.761

41.831

5.98

38.65

20.70

34.69

4.39

47.86

17.97

29.78

9.43

13.99

29.79

46.79

Table M.5: Proximate analysis of typical coal

Bituminous coal(Sample 1)


Indonesian coal



Lignite

Moisture (%)

Mineral matter (%)

Carbon (%)

Hydrogen (%)

Nitrogen (%)

Sulphur (%)

Oxygen (%)

GCV (kcal/kg)

Dry basis

10.41

62.01

6.66

0.60

0.59

19.73

6 301

5.98

38.63

42.11

2.76

1.22

0.41

9.89

4 000

4.39

47.86

36.22

2.64

1.09

0.55

7.25

3 500

9.43

13.99

58.96

4.16

1.02

0.56

11.88

5 500

Table M.6: Ultimate analysis of typical coal



Indonesian coal

The main products of combustion are carbon dioxide (CO2), water vapour (H2O),

sulphur dioxide (SO2) and nitrogen oxides (NOx). Figure M.1 shows the different

constituents of flue gas after complete, i.e. stoichiometric, combustion.

AIR

COMBUSTION

CHAMBER

1 100–1 400 °C

21% oxygen (O2) by vol.

79% nitrogen (N2) by vol.

FUEL

86% carbon (C)

12% hydrogen (H2)

2% sulphur (S)

nitrogen oxides (NOx)

sulphur dioxide (SO2)

water vapour (H2O)

carbon dioxide (CO2)

Figure M.1 Combustion products

Table M.7 shows the heat of reaction from different constituents from fuel.



2C+O2 2CO + 2 430 kcal/kg of carbon

C + O2 CO2 + 8 084 kcal/kg of carbon

2H2 + O2 2H2O + 28 922 kcal/kg of hydrogen

S + O2 SO2 + 2 224 kcal/kg of sulphur

Table M.7: Heat from different fuel constituents

In normal operating conditions it is not possible to achieve complete combustion by

supplying just the theoretical amount of air required. A certain amount of excess air is

needed to achieve complete combustion and ensure release of all of the heat contained

in fuel. Too much excess air, however, leads to heat loss via the chimney; less air leads

to incomplete combustion and black smoke. Hence, there is an optimum level of

excess air that gives optimum combustion conditions—this varies from one fuel to

another. If excess air is used in combustion, sulphur trioxide (SO3) may also be formed.

When using liquid fuels (especially heavy fuel oil) there is a permanent danger that the

fuels will contain water. Water is put into the boiler (together with the useful fuel)

where the water is heated, evaporated and exhausted through the stack. Water cannot

be burned and is ballast, i.e. all of the heat used to heat and evaporate it is lost. When

using coal, part of the solid carbon put into the boiler leaves (without being burned)

directly in the ash.

The heat produced in a boiler by fuel combustion is used to heat water (fresh water or

preferably recovered condensate) to boiling point (which depends on the pressure of

the water); to evaporate the water (at constant temperature); and then, eventually, to

superheat the steam.

Air supply Since combustion is not instantaneous but takes place in stages, the fuel needs time to

burn in the hot furnace, with sufficient air to complete combustion. Air is therefore

admitted in two ways (i) as Primary Air entering the furnace with the fuel or, in the case

of solid fuel burning on a grate, through the fuel bed and (ii) as Secondary Air admitted

turbulently to complete combustion.

There are three usual mechanisms by which combustion air can be supplied, these are

listed below. Sometimes a combination of the three is employed.

i. Natural draught, created when the hot gases pass up the chimney, causing

suction in the furnace.

ii. Induced draught (ID), caused by a fan located at the boiler outlet sucking air

through the system and augmenting the suction of the chimney.

iii. Forced draught (FD), caused by a fan located before the furnace and blowing air

through.

A combination of induced draught and forced draught is known as balanced draught.

Control of air and analysis of flue gasFor optimum combustion, the real amount of combustion air must be greater than

that required theoretically. Part of the stack gas consists of pure air, i.e. air that is

simply heated to stack gas temperature and leaves the boiler through the stack.

Chemical analysis of the gases is an objective method that helps to achieve finer air

control. By measuring CO2 (see Figure M.2) or O2 (see Figure M.3) in flue gases (by

continuous recording instruments or Orsat apparatus or some cheaper portable

instruments) the excess air level and stack losses can be estimated (using graphs like

those shown in the figures). The excess air to be supplied depends on the type of fuel

and the firing system.



Figure M.2 Analysis of stack gases

exce

ss a

ir (

%)

carbon dioxide (%)

100

90

80

70

60

50

40

30

20

10

08.4 9 10 11 12 13 14

For optimum combustion of fuel oil the CO2 or O2 in flue gases should be maintained

as follows:

• CO2 = 14.5–15 %

• O2 = 2–3 %



Figure M.3 Relationship between residual oxygen and excess air

exce

ss a

ir (

%)

residual oxygen (%)

250

200

150

100

50

01 2 3 4 5 12 151413109876 11

Reasons for incomplete combustionCombustion should be complete within the furnace and this can only happen when

the ‘rule of the three Ts’ (i.e. TIME, TEMPERATURE, TURBULENCE) is strictly observed.

This means:

1. Allowing sufficient time for the fuel to burn in the hot furnace.

2. Having the fuel at a sufficiently high temperature to burn.

3. Mixing the fuel turbulently with sufficient air in the combustion chamber.

The following are a few possible reasons for incomplete combustion of fuel:

• Air pressure is not sufficient and air passes through the furnace without mixing

thoroughly with fuel.

• The fuel has not reached the ignition temperature to react with air.

• Fuel and air have not had time to react before the combustion products are cooled.

• Air ingress through peepholes, leakages at dampers and other places.

• Late combustion due to change in fuel properties, e.g. more moisture in fuel,

high ash content of coal.

M1.3 BoilersA boiler is a vessel that uses heat liberated by combustion of a fuel to produce hot water

or steam. Boilers are pressure vessels, designed to withstand the steam pressures needed

in processes. They can be very dangerous if not correctly operated and maintained. An

economizer, air heater, or super heater fitted to a boiler will enable most of the heat

liberated from the fuel to be used. Super heaters increase the temperature of steam and

are necessary to render the steam suitable for use in steam turbines or steam engines.

Types of boilersBoilers can be categorized broadly as follows:

• Water tube

• Smoke tube

• Fluidized bed boiler

Water tube boilerWater tube boilers are designed for higher pressures and steam generation rates, normally

above 4 tons per hour. They are generally characterized by the following features:

• Mechanical stokers giving better stoking efficiency for solid fuels.

• Forced, induced and balanced draught systems helping to improve combustion

efficiency.

• Lower tolerance for water quality making water treatment plant necessary.

• Higher thermal efficiency levels are possible than for Lancashire boilers.

A water tube boiler is shown in Figure M.4.



Smoke tube boilerTwo examples of smoke tube boilers are the package boiler and the Lancashire boiler:

Package boiler

Package boilers (see Figure M.5) are shell type boilers with smoke tube design. They

achieve high heat transfer rates by both radiation and convection. Package boilers are

characterized by the following features:

• Small combustion space and high heat release rate, resulting in faster

evaporation.

• Large number of small diameter tubes leading to good convective heat transfer.

• Forced or induced draught systems, resulting in good combustion efficiency.

• Several ‘passes’ resulting in better overall heat transfer.

• Higher thermal efficiency than other boilers.

Lancashire boiler

Lancashire boilers are characterized by the following features:

• Large thermal storage capacity permitting smooth handling of load fluctuations.

• Able to tolerate poor feed water quality.

• High thermal inertia (due to thermal storage) resulting in sluggish start up response.

• Poor convective heat transfer contributing to low thermal efficiency.



Figure M.4 Water tube boiler

Fluidized bed boilerDevelopments in combustion technology for solid fuels such as coal, rice husks, etc.

have heralded the introduction of fluidized bed combustion (FBC) boilers, which can

burn a wide variety of fuels including low-grade coals effectively. A typical FBC system

consists of a cylindrical vessel with air ducts connected to the bottom of the vessel. The

fire bed—consisting of sand particles, coal ash or alumina—rests on a distribution plate

near the bottom and is ‘fluidized’ by the passage of combustion air upwards through

it. A start-up system, using gas or oil burners, heats the bed to a temperature at which

coal can be burned. Coal is then fed (pneumatically) into the bed where it is distributed

and burns rapidly. The heat liberated by combustion is transferred to water tubes,

some of which may be immersed in the bed, to generate hot water or steam. Ash is

removed continuously to maintain a constant bed depth. Thermal efficiencies in excess

of 80 per cent can be expected of FBC boilers.

Types of FBC boilersFBC technology is, at present, divided into two distinct spheres:

• atmospheric FBC boilers; and

• pressurized FBC boilers.



Figure M.5 Package boiler

There are two types of atmospheric FBC boilers: bubbling fluidized bed (BFB) boilers

and circulating fluidized bed boilers.

Pressurized FBC boilers were mainly designed to operate gas turbines. Research work

into this technology is under way all over the world. In developing countries, BFB

technology has been developed and commercialized successfully, as it meets present

industrial requirements.

FBC technology and CPIt should be borne in mind that going in for these advanced technology boilers not

only means saving on operating costs, it also means helping to save the environment.

The environmental aspects of production of steam and power are an inseparable part

of the energy scene and, today, production still relies predominantly on the burning of

fossil fuels. The penalty for this is to load the life-giving environment—our air, water

and soil—with pollutants such as dust particles, oxides of carbon, nitrogen and sulphur

and other substances which are dangerous to human beings.

FBC technology has been developed to cater for a variety of requirements all over the

world. In the United Kingdom it was developed for British coals with high sulphur

content. These could be burned successfully with low pollution when limestone was

added to the bed to absorb the sulphur during combustion. Adding the limestone

avoided the use of very extensive and costly filtering/washing system for the flue gases.

In India, FBC technology was developed to burn bituminous Indian coal with low

calorific value and high ash content but containing little or no sulphur. It was not

therefore necessary to add limestone.

Another important advantage of FBC systems is that low combustion temperatures—

in the region of 700–900 °C—lead to the formation of relatively little NOX. Nitrogen

oxides include dangerous gases that affect the human respiratory tract and form acids

when they mix with humidity in air.

Performance evaluation of boilersThe efficiency of a boiler depends on several aspects of construction, operation and

maintenance. The temperature of a boiler with optimum operation and maintenance

depends on its construction—above all on the number of passes (i.e. the number of

times the gas flows through the boiler, see Figure M.6).



fuel input

stac

k ga

s stoichiom.excess airunburnt

steam output

stac

kga

slo

sses

ash,

and

unb

urnt

part

s of

fuel

in a

sh

blow

dow

n

conv

ectio

n a

nd r

adia

tion

Heat balanceThe combustion process in a boiler can be described in the form of an energy flow

diagram (see Figure M.7). This shows graphically how the input energy from the fuel

is transformed into the various useful energy flows and into heat and energy loss flows.

The thickness of the arrows indicates the amount of energy contained in the respective

flows.



Figure M.6 Boiler design affects performance

Figure M.7 Boiler energy flow diagram

3 pass boiler 4 pass boiler

Essentially, a heat balance is an attempt to balance the total energy entering a boiler

against that leaving it in different forms. The following example (Figure M.8) illustrates

the different losses occurring when generating steam.



100% fuel BOILER

12.7% heat loss due to dry flue gas

8.1% heat loss due to steam in flue gas

1.7% heat loss due to moisture in fuel

0.3% heat loss due to moisture in air

2.4% heat loss due to unburnts in residue

1.0% heat loss due to radiation and other unnacounted loss

73.8% heat in steam

Figure M.8 Example of losses in steam generation

The energy losses can be divided into avoidable and unavoidable losses. The aim of CP

must be to reduce the avoidable losses, i.e. to improve energy efficiency. The following

losses can be avoided or reduced:

• Stack gas losses:

° Excess air

(reduce to the necessary minimum which depends on burner technology,

operation (i.e. control) and maintenance).

° Stack gas temperature

(reduce by optimizing maintenance (cleaning); load; better burner and boiler

technology).

• Losses as un-burned fuel in stack and ash

(optimize operation and maintenance; better burner technology).

• Blow down losses

(treat fresh water; recycle condensate).

• Losses with condensate

(recover the largest possible amount of condensate).

• Losses by convection and radiation

(better boiler insulation).

The methodology for assessment of boiler efficiency and losses is given below.

Evaporation ratioThe evaporation ratio is the quantity of steam generated per unit of fuel consumed (see

energy use snapshot, right).

Boiler efficiency Thermal efficiency of a boiler is defined as the percentage of (heat) energy input that

is effectively useful in the generated steam. As shown below, there are two ways of

calculating this.



spotlightCP-EE

Typical evaporationratio for:

(a) coal fired boilerproducing saturatedsteam at a pressure of10 bar, evaporation ratio = 6

(b) oil fired boilerproducing saturatedsteam at a pressure of10 bar, evaporationratio = 13

For (a):1 kg of coal can generate6 kg of steam

For (b):1 kg of oil can generate13 kg of steam

Boiler efficiency calculation

Direct method Indirect method

a. Direct methodParameters to be monitored for the calculation:

• Quantity of steam generated per hour (Q).

• Quantity of fuel used per hour (q).

• The working pressure and superheat temperature (if any).

• Temperature of feed water.

• Type of fuel and gross calorific value (GCV) of the fuel.

Boiler efficiency (η) =Q x (H – h)

q x GCV

(where H = Enthalpy of steam, h = Enthalpy of feed water)

(examples follow …)



• Type of boiler: Coal fired

• Quantity of steam generated: 8 TPH

• Steam pressure: 10 kg/cm2

• Steam temperature: 180 °C

• Quantity of coal consumed: 1.8 TPH

• Feed water temperature: 85 °C

• GCV of coal: 4 000 kcal/kg

• Enthalpy of steam at 10 kg/cm2 pressure: 665 kcal/kg

• Enthalpy of feed water: 85 kcal/kg

Example 1

• Type of boiler: Furnace, oil fired

• Quantity of steam generated: 35 TPH

• Steam pressure: 20 kg/cm2

• Steam temperature: 300 °C

• Quantity of F.O. consumed: 2.9 TPH

• Feed water temperature: 95 °C

• GCV of F.O.: 10 200 kcal/kg

• Enthalpy of steam at 20 kg/cm2 pressure and 300 °C: 723.5 kcal/kg

• Enthalpy of feed water: 95 kcal/kg

Example 2

Boiler efficiency (η) = = 74.4%35 x 1000 x (723.5 – 95) x 100

2.9 x 1000 x 10200

Boiler efficiency (η) = = 64.4%8 x 1000 x (665 – 85) x 100

1.8 x 1000 x 4 000

b. Indirect methodIn this method thermal efficiency is found by subtracting the percentages of all

the heat losses from 100. The following parameters have to be known for the

calculation:

• Ultimate analysis of fuel (H2, O2, S, C, moisture content, ash content).

• Percentage of oxygen or CO2 in the flue gas.

• Flue gas temperature, in °C (Tf).

• Ambient temperature, in °C (Ta), and humidity of air, in kg/kg of dry air.

• GCV of fuel, in kcal/kg.

• Percentage combustible in ash (in case of solid fuels).

• GCV of ash, in kcal/kg (in case of solid fuels).



Excess air supplied (EA) =O2 x 100

21 – O2

⇒ Theoretical Air Requirement (TAR)

⇒ Actual mass of air supplied/ kg of fuel (AAS)

i. Percentage heat loss due to dry flue gas:

Where k (Seigert const.) = 0.65 for coal

= 0.56 for oil

= 0.40 for NG

=(11 x C) + {34.5 x (H2 – (O2/8)) } + 4.32 x S)

100kg/kg fuel

=k x (Tf – Ta )

% CO2

= 1 + (EA/100) x Theoretical Air

ii. Percentage heat loss due to evaporation of water formed due to H2 in fuel:



=9 x H2 x {584 + 0.45(Tf – Ta ) }

GCV of fuel

=M {584 + 0.45(Tf – Ta ) }

GCV of fuel

=AAS x Humidity x 0.45 x (Tf – Ta ) x 100

GCV of fuel

=Ash x (100 – Comb. in Ash) x GCV of Ash x 100

GCV of fuel

Where H2 = the percentage of H2 in fuel

iii. Percentage heat loss due to evaporation of moisture present in fuel:

Where M = the percentage of moisture in fuel

iv. Percentage heat loss due to moisture present in air:

v. Percentage heat loss due to combustibles in ash:

vi. Percentage heat loss due to radiation and other unaccounted loss:

Actual radiation and convection losses are difficult to assess because of the

specific emissivity of various surfaces, their inclination and air flow pattern, etc.

Loss may be estimated appropriately depending on the surface condition.

Boiler efficiency (h) = 100 – (i + ii + iii + iv + v + vi )

Boiler feed water treatmentWater treatment and conditioning are important for boilers. Treating the water helps

to prevent formation of scale on heat transfer surfaces. Control of total dissolved solids

and alkalinity inhibits corrosion and deposits on superheater tubes, turbine blades, etc.



• Type of boiler: Oil fired

• Ultimate analysis of oil: C = 84%H2 = 12%S = 3%O2 = 1%

• GCV of oil: 10 200 kcal/kg

• Percentage of oxygen: 7%

• Percentage of CO2: 11%

• Flue gas temperature (Tf ): 220 °C

• Ambient temperature (Ta ): 27 °C

• Humidity of air: 0.018 kg/kg of d.a.

⇒ Excess air supplied (EA) = 50%

⇒ Theoretical air requirement (TAR) = 13.46 kg/kg of fuel

⇒ Actual mass of air supplied (AAS) = 20.19 kg/kg of fuel

i. Heat loss due to dry flue gas = 9.1%

ii. Heat loss due to evaporation of water formed due to H2 in fuel = 7.1%

iii. Heat loss due to moisture present in air = 0.30%

iv. Heat loss due to radiation and other unaccounted loss = 2.0%

Example 3

Boiler efficiency (η) = 81.5%

The water treatment processes are selected on the basis of the quality of available raw

water and boiler requirements. Boiler feed water treatment can be either internal or

external, or both. Internal treatment involves dosing of chemicals (sodium carbonate,

sodium phosphate, etc.) that help in the precipitation and coagulation of precipitated

scale-forming compounds (carbonate hardness) and help them settle in the boiler

drum. Hydrazine is also used internally to reduce dissolved oxygen in high pressure

boilers. External treatment may use a cold- or hot-lime process as pre-treatment,

followed by a base-exchange or demineralization process for further treatment.

At very low pressure, straight forward softening is still used. Sometimes a cation

exchanger, regenerated with sodium chloride, is also used. Demineralization is the only

process used for high pressures. At intermediate pressures, the removal of carbonates

(and if necessary of silica) is combined with softening by various methods. The main

processes used comprise:

• Cold lime process for removing carbonates, followed by softening.

• Hot lime and magnesia process for condensate removal, followed by softening.

• Removal of carbonates by carboxyl cation exchanger, followed by softening and

physical elimination of carbon dioxide.

All these processes must be followed by physical (deaeration) and/or chemical removal

of oxygen and conditioning treatment.

In most processes, steam condensate is collected from all indirect heating systems.

There is a danger of corrosion products (e.g. iron picked up from the equipment, steel

piping, copper oxides etc.); dissolved salts from condenser leaks; or accidental

pollution from black liquor heaters/evaporators; etc. becoming mixed with

condensate. Treatment of condensate, together with boiler water treatment, is

therefore important given the purity standards demanded for modern boilers.

Condensate treatment may consist of one or a combination of the following:

• Filtration through finely divided (fibrous or granular) materials such as cellulose

fibre filters, diatoms (which in addition to their filling properties have a specific

adsorbent effect for water only).

• De-ionization through cation/anion beds.

• Filtration through magnetic filters.



Tables M.8 and M.9 give the recommended feed water quality and boiler water limits

for low-, medium- and high-pressure boilers:



Total iron (max), ppm

Total copper (max), ppm

Total silica (max), ppm

Oxygen (max), ppm

Hydrazine residual, ppm

pH at 25 °C

Hardness

0.05

0.01

1.0

0.02

-

8.8–9.2

1.0

0.02

0.01

0.3

0.02

-

8.8–9.2

0.5

0.01

0.01

0.1

0.01

0.02–0.04

8.2–9.2

-

Factor Up to 20 ata 21–40 ata 41–60 ata

Table M.8: Recommended feed water limits

Total dissolved solids (TDS)

Total iron dissolved solids, ppm

Specific electrical conductivityat 25 °C (mho)

Phosphate residual, ppm

pH at 25 °C

Silica (max), ppm

3 000–3 500

500

1000

20–40

10–10.5

25

1 500–2 000

200

400

20–40

10–10.5

15

500–750

150

300

15–25

9.8–10.2

10

Factor Up to 20 ata 21–40 ata 41–60 ata

Table M.9: Recommended boiler water limits

Blow downThe water fed into the boiler contains dissolved materials and, as the water is

evaporated into steam, these are left to concentrate in the boiler in either a dissolved

or suspended state. Above a certain level of concentration, these solids encourage

foaming and cause carry over of water into the steam, leading to scale formation inside

the boiler. This can cause localized overheating which may result in tube failure, etc.

It is therefore necessary to control the level of concentration of solids. This is achieved

by the process of ‘blowing down’, where a certain volume of water is blown off and is

automatically replaced by feed water, thus maintaining the optimum level of total

dissolved solids (TDS) in the water. Blow down is necessary to protect the surfaces of

the heat exchanger in the boiler. It is important to recognize that blow down can, if

incorrectly carried out, be a significant source of heat loss.

This problem calls for careful monitoring and supervision of the water conditions in all

boilers, particularly modern, shell-type packaged units which are even more vulnerable

than earlier types because of their small water capacity and limited steam space in

relation to their output.

Table M.10 shows the maximum TDS concentration permissible in various types of

boilers.



1

2

3

4

Lancashire

Smoke and water tube boilers (12 kg/cm2 )

H.P. Water tube boiler with superheater, etc.

Package and economic boilers

10 000 ppm

5 000 ppm

3 000–3 500 ppm

3 000 ppm

Table M.10: Permissible TDS concentrations in boilers

Further to the above, manufacturers' guidelines must also be consulted. The following

formula gives the quantity of blow down required:

Blow down (%) =Feed water x % make up

(Permissible TDS in boiler – Feed water TDS)

= = 1.11%300 x 10

3 000 – 300

= = 33 kg/hr3 000 x 1.110

100

If the maximum permissible limit of TDS is 3 000 ppm (as in a package boiler),

percentage make up water is 10 per cent and TDS in feed water is 300 ppm, then the

percentage blow down is given as:

If the boiler evaporation rate is 3 000 kg/hr then required blow down rate is:

M1.4 Thermic fluid heaters

Like boilers, thermic fluid heaters (TFH) or fired heaters (FH) are units designed to

transfer heat from combustion to a 'working' or 'thermic' fluid. However, a TFH or FH

is not necessarily a pressure vessel and the working fluid—typically a petroleum-based

oil—does not change from its fluid state.

The units operate in a closed loop with the thermic fluid picking up heat energy at one

end of the loop and then transferring it to process equipment by indirect transfer via

heat exchangers.

TFHs and FHs are used for high-temperature heat transfer applications (270–300 °C).

They have advantages over boilers for applications requiring such temperatures: they

avoid the need for high-pressure steam and the related complexities such as water

treatment, pressure vessel regulations, etc.

Inputs to TFH and FH include:

• Heat from fuel

• Combustion air

• Motive power to auxiliaries (e.g. thermic fluid circulating pump, draught fans,

fuel-handling equipment, etc.)

The useful heat output is the heat transferred by the thermic fluid. Other outputs

include:

• Flue gases

• Solid waste from fuel combustion

• Unburned fuel in flue gases

In recent times, TFHs have found wide application in indirect process heating.

Employing petroleum-based fluids as the heat transfer medium, they provide

constantly maintainable temperatures for the user equipment. The combustion system

comprises a fixed grate with mechanical draught arrangements.

Modern oil fired TFHs are of double-oil, three-pass construction and are fitted with

modulated pressure jet systems. The heat carrying thermic fluid is heated (in the

heater), circulated through the user equipment where it transfers heat for the process



via a heat exchanger, and then returned to the heater. At the user end, the flow of

thermic fluid is controlled by a pneumatically operated valve, controlled by the

operating temperature. The heater operates on low or high fire, depending on the

temperature of the returning oil which varies with system load.

The advantages of these heaters are:

• Closed cycle operation with minimum losses compared to steam boilers.

• Non-pressurized system operation, even for temperatures of around 250 °C,

against 40 kg/cm2 of steam pressure required in similar steam systems.

• Automatic control settings, offering operational flexibility.

• Good thermal efficiency, as losses due to blow down, condensate drain and flash

steam do not exist in TFH systems.

The overall economics of a TFH depend on the specific application and reference basis.

Coal fired TFHs with a thermal efficiency range of 55–65 per cent compare favourably

with most boilers. Incorporation of heat recovery devices in the flue gas path further

enhances thermal efficiency levels.

TFH efficiencyThe efficiency of a heater is defined as the ratio of heat output to heat input.

Mathematically, this can be expressed as follows:



Heater efficiency =Heat output

Heat input

= x 100MTH x CTH x (TS – TR )

mf x GCV

Where:

MTH = mass flow rate of thermic fluid, kg/hr

CTH = specific heat of thermic fluid, kcal/kg °C

mf = quantity of fuel consumed, kg/hr

TS = forward temperature of thermic fluid, °C

TR = temperature of returning fluid, °C

GCV = gross calorific value of fuel, kcal/kg

M1.5 Steam distribution and utilization

M1.5.1 Steam traps

Steam generated by boilers is used in equipment and processes where it gives up its heat

and condenses back to water (condensate). Efficient removal of the condensate from

systems is one of the most important aspects of energy conservation. Removing

condensate efficiently helps to minimize energy consumption and maximize productivity.

Functions of steam trapsSteam traps have three important functions. They:

• discharge condensate as soon as it is formed;

• prevent steam from escaping; and

• discharge air and other non-condensable gases.

Types of steam trapsTable M.11 shows different types of steam traps and their principles of operation.



Mechanical trap

Thermodynamic trap

Thermostatic trap

Difference in density betweensteam and condensate

Difference in thermodynamicproperties of steam andcondensate

Difference in temperaturebetween steam andcondensate

Group Principle of operation Subgroup

Bucket type• open bucket• inverted bucket, with/without lever• float type• float with lever• free float

Disc typeOrifice type

Bimetallic typeMetal expansion type

Table M.11: Types of steam traps

Importance of steam trapping for energy efficiencyWith ever-increasing energy prices, improvement in steam trapping is a more

significant factor than ever in the field of steam applications. True energy efficiency can

only be achieved when: a) selection; b) installation; and c) maintenance of steam traps

are adequate for the purpose of the installation.

Factors affecting steam trap selectionGuidelines for steam trap selection are shown in Table M.12. Factors affecting their

selection are:

• Maximum and minimum working pressure

• Maximum and minimum pressure differentials

• Maximum working temperature

• Quantity of condensate to be discharged

• Size

• Connection type

• Type of steam trap

• Equipment to which trap is fitted



Steam mains

• Equipment• Reboiler• Heater• Dryer• Heat exchanger etc.

• Tracer line• Instrumentation

• Open to atmosphere, smallcapacity

• Frequent change in pressure• Low pressure–high pressure

• Large capacity• Variation in pressure and

temperature is undesirable• Efficiency of the equipment

is a problem

• Reliability with no over-heating

Application Feature Suitable trap

Thermodynamic type

Mechanical trap, bucket, inverted bucket, float

Thermodynamic andbimetallic

Table M.12: Guidelines for steam trap selection

Steam trap maintenanceThe purpose of steam trap maintenance is to maintain steam traps in optimum

condition to ensure efficient operation of the steam-using equipment in the plant. The

first step in troubleshooting is to observe the operation of the steam trap for symptoms

of failure. Steam trap failures can be classified into four groups as follows:

• Blockage

• Steam blowing

• Steam leakage

• Insufficient discharge

Steam loss through malfunctioning of steam trapIf a disc trap is blowing steam at a pressure of 5 kg/cm2, the annual steam loss is 168 tons.

Based on a unit price for steam of, say, US$20/ton, the annual monetary loss is around

US$3 360. A failed steam trap therefore causes great loss of steam and of distilled water,

wasting both money and resources. The following are therefore important:

• Periodic inspection of steam traps

• Replacement of failed steam traps with new ones



Worksheet: Technical specifications of steam traps

Seri

al n

o.

Trap

ref

. no.

Trap

typ

e

Trap

siz

e

Loca

tion

ref

. (p

lant

dep

t./

bloc

k)

Type

of

disc

harg

e (c

onti

nuou

s/se

mi-c

onti

nuou

s/in

term

itte

nt)

Trap

cap

acit

y (c

onde

nsat

e,kg

/hr)

OPEN FILE

Worksheet: Steam trap audit

Seri

al n

o.

Trap

ref

. no.

Trap

typ

e

Trap

siz

e

Trap

pre

ssur

e(k

g/cm

2 )

Trap

loca

tion

App

licat

ion

of t

rap

Func

tion

alst

atus

of

trap

Dia

gnos

is o

fsi

tuat

ion

Stat

us o

f tr

apfit

ting

s

Rem

arks

Trap type:Trip float trap; plan float trap;open top bucket trap; inverted bucket trap; balanced pressure thermostatictrap; liquid expansionthermostatic trap; bimetalthermostatic trap; impulsethermodynamic trap; pilotoperated thermodynamic trap;labyrinth thermodynamic trap;orifice plate thermodynamictrap; ogden pump.

Application:Steam mainlines; equipment;trace line; etc.

Functional status:Good; leaking; blowing steam;shutdown; blockage; bypassed.

Diagnosis:Replace with free float; replacewith disc type; dismantle andclean; incorrect trap selection.

Location:Plant ref.; block ref.;department ref.

Status of fittingsOK/not OK, for: sight glass;bypass valve; filter.

RemarksEstimate of steam loss,suggestions, etc.

OPEN FILE

M1.5.2 Steam leakage

Leakage from steam lines not only wastes heat, it also causes pressure drop in the lines.

The quantity of steam leaked depends on the size of the leak and on steam pressure.

If visibly evident steam leakage is observed, it must be stopped. Table M.13 gives an

indication of steam losses at different steam pressures and leak diameters.



1

2

3

4

1.5

3.0

4.5

6.0

29.0

116.0

232.0

465.0

667

2 668

5 336

10 695

47.0

193.0

433.0

767.0

1 081

4 439

9 959

17 641

Sectionno.

Diameterof leak(mm)

Annual steam loss

at 7 kg/cm2at 3.5 kg/cm2

tons US$ tons US$

Table M.13: Steam loss vs. leak diameter

M1.5.3 Removal of air from steam installations

Air and other non-condensable gases such as oxygen and carbon dioxide are a natural

hazard in any steam-using plant. They can slow down the rate of steam distribution,

create cold spots on the heating surface, cause distortion and stressing of the plant and

can be the root cause of corrosion related problems. However, it is perhaps their overall

effect on heat transfer that is most important from the production point of view.

Some practical examples:

• The presence of air in a jacketed boiling pan increased cooking time from 12.5

minutes to 20 minutes. Sixty per cent air in the steam going to a unit heater

reduced output by as much as 30 per cent.

• Dry saturated steam at 40 psi will have a temperature of 287 °C. If there is 90 per

cent steam and 10 per cent air, the temperature will be only 280 °C. With 25 per

cent air the temperature would drop to 270 °C. In all of these cases the pressure

gauge would remain at 40 psi.

In relative terms, the thermal conductivity of air is 0.2 compared to 5 for water,

340 for iron and 2 620 for copper. Which means that a film of air only one

1/1000 inch (0.025 mm) thick will offer the same resistance to heat flow as a wall

of copper 13 inches (32.5 cm) thick.

The removal of air is essential and can be carried out by either manual or

automatic venting. Manual air venting has the disadvantage of relying on the

human element (i.e. a staff member) knowing just when and how often the cock

should be opened. The best alternative is obviously an automatic air vent.

M1.5.4 Thermal insulation

The need for efficient thermal insulation has become more important as both

operating temperatures and energy costs have increased. The production, distribution

and use of steam require thermal insulation to ensure that process requirements are

satisfied. The first consideration is to ensure that steam generated at the boiler can be

delivered to the point of use at the correct temperature and pressure. To ensure that

energy loss remains within design tolerance it is essential to make the correct choice of

thermal insulation system.

Types and forms of insulation materialThermal insulation materials can be divided into four types: granular, fibrous, cellular

and reflective. Typical thermal insulation materials for use in the 50–1 000 °C

temperature range are given in Table M.14.



1

2

3

4

5

6

7

8

9

10

11

12

Cellular glass

Glass fibre

Rockwool andSlagwool

Calcium silicate

Magnesia

Diatomaceous

Silica

Alumino silicate

Alumino silicate

Aluminium

Stainless steel

Vermiculite

Cellular

Fibrous

Fibrous

Granular

Granular

Granular

Fibrous

Fibrous

Granular

Reflective

Reflective

Granular

a b

a b d e f

a b d e g

a b c

a b c

a b c j

d e f

d e f g

j

h

h

a b c d g j

150

10–150

20–250

200–260

200

250–500

50–150

50–250

500–800

10–30

300–600

50–500

450

550

850

850

300

1 000

1 000

1 200

1 200

500

800

1 100

Sectionno.

Insulation Type Approx. limitingtemperature (°C)

Availability* Density(kg/m3)

Table M.14: Typical insulation materials for the 50–1 000 °C temperature range

* Notes:

a = slabs

b = sections

c = plastics

d = loose-fill

e = mattress

f = textile

g = sprayable

h = reflective

j = insulating bricks

Economic thickness of insulation The effectiveness of insulation follows a law of diminishing returns. Hence, there is a

definite economic limit to the amount of insulation that is justified. Beyond a certain

level, increased thickness is not viable in terms of cost as this cannot be recovered

through small heat savings. This limiting value is termed the economic thickness of

insulation (ETI). Firms have different fuel costs and boiler efficiencies and these factors

can be brought together to calculate ETI. In other words, for a given set of

circumstances, a certain thickness results in the lowest overall cost of insulation and

heat loss over a given period of time. Figure M.9 illustrates the principle of ETI.



Figure M.9 Determining ETI

I + H

insulation thickness

I

H

M

cost

I = cost of insulation

H = cost of heat loss

I + H = total cost

M = economic thickness

Determining ETI requires attention to the following factors:

• Fuel cost

• Annual hours of operation

• Heat content of fuel

• Boiler efficiency

• Operating surface temperature

• Pipe diameter/thickness of surface

• Estimated cost of insulation

• Average exposure at ambient still air temperature

Heat savings and application criteriaA variety of charts, graphs and references are available for heat loss calculation. As this

manual is intended for CP practitioners, the more complex procedures for working out

heat losses are not considered. Surface heat loss can be calculated with the help of the

simple equation for energy loss shown below. This can be used for surface

temperatures up to 200 °C. Factors such as wind velocity or conductivity of insulating

material have not been considered.



S = 10 + (Ts – Ta) / 20 x (Ts – Ta)

Where:

S = Surface heat loss (kcal/hr/m2)

Ts = Hot surface temperature (°C)

Ta = Ambient temperature (°C)

Total heat loss/hr (Hs) = S x A

Where A is the surface area in m2.

Based on the cost of heat energy, the value of heat loss in US$ can be worked

out as follows:

Equivalent fuel loss (Hf)(kg/yr) =Hs x hours of operation per year

GCV x ηb

Annual heat loss in monetary terms ($) = Hf x Fuel cost (US$/kg)

Where:

GCV = Gross calorific value of fuel (kcal/kg)

ηb = Boiler efficiency (as %)

Example calculation follows …



Calculate the fuel savings when a steam pipe with a diameter of 100 mm, supplying steam at10 kg/cm2 to equipment, and un-insulated over 100 m of its length, is properly insulated with65 mm of insulating material.

Assumptions:

• Boiler efficiency: 80 %• Fuel oil cost: US$300/ton• Surface temperature without insulation: 170 °C• Surface temperature after insulation: 65 °C• Ambient temperature: 25 °C

Existing heat loss:

S = [10 + (Ts – Ta) / 20] x (Ts – Ta)Ts = 170 °CTa = 25 °CS = [10 + (170 – 25)/20] x (170 – 25)

= 2 500 kcal/hr m2

S1 = S = Existing heat loss (2 500 kcal/hr m2 )

Modified System:

After insulating with 65 mm of glass wool with aluminium cladding, the hot face temperature willbe 65 °C

Ts = 65 °CTa = 25 °C

Substituting these values:

S = [10 + (65 – 25) / 20] x (65 – 20)= 480 kcal/hr m2

S2 = S = Existing heat loss (480 kcal/hr m2)

Table M.15 illustrates this further.

Example 4



Pipe dimension

Surface area (existing) (A1)

Surface area after insulation (A2)

Total heat loss in existing system (S1 x A1)

Total heat loss in modified system (S2 x A2)

Reduction in heat loss

No. of hours operation in a year

Total heat loss (kcal/y)

Calorific value of fuel oil

Boiler efficiency

Price of fuel oil

Yearly fuel oil savings

Monetary savings

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

100 mm φand 100 m length

3.14 x 0.1 x 100

31.4 m2

3.14 x 0.23 x 100

72.2 m2

2 500 x 31.42

78 850 kcal/hr

480 x 72.2

34 656 kcal/hr

78 860 – 34 656

44 194 kcal/hr

8 400

44 194 x 8 400

371 229 600

10 300 kcal/kg

80 %

US$300/ton

371 229 600/10 300 x 0.8

45 052.136 kg/year

45.052 x 300

US$13 515.64

Table M.15: Calculating fuel savings

Table M.16 can be used as a guide for insulation schemes for steam and condensate

lines, and for hot surfaces.



Less than 100 °C

100–150 °C

150–200 °C

200–250 °C

250–300 °C

25 mm

25 mm

25 mm

25 mm

25 mm

25 mm

25 mm

40 mm

50 mm

50 mm

50 mm

50 mm

50 mm

50 mm

50 mm

50 mm

50 mm

65 mm

65 mm

75 mm

65 mm

65 mm

75 mm

75 mm

90 mm

50 mm

75 mm

90 mm

90 mm

100 mm

Temperature Flat surfaces

Pipe diameter

25 mm 50 mm 75 mm 100 mm 150 mm

Table M.16: Guide to insulation schemes

Worksheet: Insulation losses

Sect

ion

no.

Loca

tion

Equi

pmen

t re

fere

nce

Exis

ting

out

erdi

amet

er

Exis

ting

sur

face

tem

pera

ture

Exis

ting

insu

lati

onth

ickn

ess

(if

any)

Thermal insulation can be justified by balancing the cost of different heat losses or heat savingsagainst the cost of insulation.

OPEN FILE

M1.5.5 Condensate recovery

Steam is used very extensively as a heating medium in various types of plants—efficient

use of steam is therefore the key to energy conservation. The heat energy contained in

steam consists of sensible heat and latent heat, the latter only being used in most types

of steam-using equipment. When steam gives off its latent heat, it condenses back to

water at the saturation point. The sensible heat contained in the condensate amounts

to as much as 20–30 per cent of the total heat of the steam (see Figure M.10).



Figure M.10 Total enthalpy of saturated steam at 10 kg/cm2

Figure M.11 Benefits of condensate recovery

latent heat

sensible heat

481 kcal/kg

181 kcal/kg

Total heat = sensible + latent heat= 181 + 481= 662 kcal/kg

To maintain maximum efficiency of steam equipment, condensate forming in the

equipment should be discharged via steam traps as quickly as possible. In other words,

the higher the temperature of discharged condensate, the higher the efficiency of the

equipment, resulting in the most efficient use of steam.

In this case, the discharged condensate has the highest ‘quality’ of heat it can have, and

this heat can be used for other processes. In addition, the condensate itself can be used

as make-up water for the boiler. Figure M.11 shows the benefits of condensate recovery.

fuelinput steam

output

fresh water

totallosses

steamconsumer

dischargedcondensate

fuelinput steam

output

totallosses

steamconsumer

recovered condensate

Condensate recovery has numerous advantages, the most important of these are given

below:

A. Heat recovery• Boiler fuel is saved.

• Boiler efficiency is improved.

B. Water recovery• Water for industrial use is saved.

• Water treatment cost (and chemicals) are saved.

• Blow down is reduced.

C. Additional advantages• Air pollution is lessened by reduction in fuel consumption in boiler.

• No steam trap operating noise.

• No screening of moisture caused by flashing of condensate discharged

through steam traps.

Sizing the condensate return lineTable M.17 and Figure M.12 can be used to size the condensate return line, as

explained below.



EVERY 6 °C INCREASE IN BOILER FEED WATER TEMPERATURE

CAN SAVE 1 PER CENT BOILER FUEL

15

20

25

32

40

50

65

80

100

160

370

700

1 500

2 300

4 500

8 000

14 000

29 000

Pipe size (mm) Maximum capacity – starting load (kg/hr)

Table M.17: Sizing the condensate return line

From Table M.17, it is now possible to determine size, as indicated in Figure M.12,

below.



Figure M.12 Example of condensate return line sizing

R-450 kg

S-900 kg

R-250 kg

S-500 kg

R-110 kg

S-220 kg

R-400 kg

S-800 kg

900 kg/hr 1120 kg/hr 1620 kg/hr 2420 kg/hr

A B C D E

S = starting load/hr

R = running load/hr

Table M.17 can now be used to determine the sizes as follows:

• A to B carries 900 kg/hr—size required is therefore 32 mm.

• B to C carries 1 120 kg/hr—size required is therefore 32 mm.

• C to D carries 1 620 kg/hr—size required is therefore 40 mm.

• D to E carries 2 420 kg/hr—size required is therefore 50 mm.

Lifting the condensateThe steam pressure at the steam trap does the lifting, but this may lead to back

pressure on the trap and, by doing so, reduce the pressure differential across the trap.

To avoid the problem of back pressure, there must always be sufficient steam pressure

at the trap to overcome the back pressure. Lifting condensate directly to the

condensate return line without considering the above facts has the followings

disadvantages.

• Back pressure in the equipment from which condensate is lifted.

• ‘Chattering’ in the equipment, resulting in leakages at joints.

• Reduced equipment output capacity, and hence an increase in energy

consumption.

• Effects on product quality, especially in paper/textile dryers, as condensate

accumulates.

It is advisable to avoid lifting condensate because, even under the most favourable

conditions, lifting can be a hindrance to start-up because it causes back pressure which

slows down clearance of condensate at precisely the time this is least desirable. All of

this can be avoided by draining the condensate to a receiver by natural fall, and then

sending it to the boiler house by an independent pump.



In a process house 3t/hr of steam at a pressure of 2.5 kg/cm2 are used indirectly in the equipment.There is no condensate recovery system. The boiler feed water temperature is 25 °C.

Example 5

Feed water temperature = 25 °C Feed water temperature = 65 °C

Before adjustment After adjustment

Condensatereturn = nil

Condensatereturn = 3 t/hr

Savings = US$37 830

The procedure for calculating the savings that can be achieved by condensate recovery

is illustrated in Figure M.13 on the following page.



Figure M.13 Fuel savings from condensate recovery

hourly condensate recovered:

x hours per year:

Coal

3 000

8 400

kg/hr

= annual condensate recovered: 25 200 000 kg/yr

x heat content increase,

feed water temperature = 40 °C(25 °C to 65 °C)

40 kcal/kg

= heat recovered: 1 008 x 106 kcal/yr

÷ boiler efficiency = 85%:




1.18

1.25

1.33

1.43

✓ ✓

= heat saved: 1 260 x 106 kcal/yr

Oil Gas

÷ calorific value of fuel

=

÷

= fuel saved

x

= annual savings

kcal/kg

kg/yr

kg/ton

tons/yr

price/ton

1 000

kcal/kg

kg/yr

kg/l

heavy

medium

light

litres/yr

price/kl

kcal/m3

m3/yr

m3/yr

price/m3

10 300

122 330

0.97

0.95

0.935

126 113

US$ 300

US$ 37 830

Factors to be considered in incorporating a condensate recovery system

• A high condensate temperature necessitates a review of the available net positive

suction head, to avoid vapour locking and cavitation problems of feed water

pumps. Table M.18 provides guidelines.



86

90

95

100

1.5

2.1

3.5

5.2

Feed water temperature (°C) Suction feed (m)

Table M.18: Feed water temperature vs. suction feed

• In cases where increased feed water temperature gives rise to steaming problems,

as in economizers, some of the return condensate can be diverted for process

applications.

• Overflowing of condensate in collection tanks is a common occurrence. This

should be avoided by use of a simple control system with float switch.

• Thermal insulation is often ignored for condensate recovery. It is worthwhile

insulating condensate lines to save heat.

M1.5.6 Flash steam recovery

Flash steam is produced when condensate at a high pressure is released at a lower

pressure. The recovery of flash steam from high pressure condensate constitutes an

important area of heat saving.

The graph in Figure M.14 illustrates the percentage of flash steam generated under

different operating conditions.



Figure M.14 Generation of flash steam

kg flash per kg condensate (%)

pres

sure

on

trap

s ga

uge

(kg/

cm2)

01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

2

4

6

8

10

12

16

14 0 kg/cm2 gauge

0.5 kg/cm2 gauge

1.0 kg/cm2 gauge

1.5 kg/cm2 gauge

2.0 kg/cm2 gauge

2.5 kg/cm2 gauge

Consider the case of a machine where 1 000 kg of condensate at 7 kg/cm2 is flashed toatmospheric pressure.

From Figure M.14, flash quantity (kg/kg) from condensate is 14.0 per cent.

The flash steam generated per hour per 1 000 kg is therefore 140 kg/hr.

With an evaporation ratio (see Section M1.3) of 13 (i.e. 1 kg of oil burned in the boiler canproduce 13 kg of steam), the equivalent fuel oil saving (kg) by flash heat recovery is 140 ÷ 13 = 10.76 kg of oil per hour.

The annual fuel oil saving for 6 000 working hours would be:= (10.76 x 6000) / 1000 = 64.6 t/year

Assuming a fuel oil price of US$300/ton, monetary savings would be:= 64.6t x US$300 = US$19 385 /year

Example 6

The following example may prove helpful:

Flash steam generated is recovered by incorporating a flash vessel. The guidelines in

Table M.19 illustrate some essentials of flash vessel design.



The flash vessel should be designed so that there is a considerabledrop in velocity. This allows condensate to fall to the bottom and bedrained out by the steam trap.

The height of the vessel should be such that as little water as possibleis entrained along with the flash steam. A minimum height of 1 metreand exit steam velocity of not more than 15 metres/second should beaimed for.

Table M.19: Guidelines for flash vessel design

In a flash steam recovery system—in the form of a small column—flashing vapours are

cooled by a spray. In this system, the vapours move up and lose their heat to the falling

water spray. Perforated baffles in the flow path help to provide intimate contact for

better heat transfer.

M1.6 FurnacesThe primary functions of an industrial furnace are to heat/melt/soak and generally treat

materials at given temperatures. Furnaces can be classified according to their method

of operation, their use and their method of utilizing fuel, as shown in Figure M.15.

M1.6.1 Types of furnace

Specific aspects of different types of furnaces are explained below and parameters of

various types are shown in Table M.20.

Forging furnaceForging furnaces are used to preheat billets and ingots to forge temperature. The furnace

temperature is maintained at around 1 200 to 1 250 °C (depending on the carbon

content of the steel). Normally, large pieces are soaked for 4 to 6 hours in the furnace to

attain a uniform temperature throughout the material. Actual soaking times vary with the

type and thickness of the material. Bigger pieces, weighing between 1 and 2 tons, may

be reheated several times. Charging and discharging of the material is done manually

and this results in significant heat loss during the forging operation. Forging furnaces use

an open fireplace system with most of the heat being transmitted by radiation.

Assessment of specific fuel consumption in this type of furnace is rather difficult

because it depends on the type of material and number of reheats required. On

average, the figure is between 0.65 to 0.85 tons of coal per ton of forging.

End fired (box type) furnaceThe ‘end fired’ box type furnace is used for batch type re-rolling mills. It is preferred to

the pusher type furnace (see below) when there is a wider variety of size and weight

of ‘material’ to be heated. End fired box type furnaces are used, usually, to heat scrap,

small ingots and billets weighing from 2 to 20 kg, for re-rolling. Charging and

discharging is manual, and the final product is in the form of rods, strips, etc.

Re-rolling (batch) furnaceRe-rolling (batch) furnaces operate 8 to 10 hours per day with an average output of

1 to 1.5 t/hr. The charge is loaded before firing, and nearly 1.5 hours of heat-up time

is required to attain a temperature of 1 200 °C. The total cycle time can be broken

down into heat-up time and re-rolling time. During heat-up time the material is heated

to the required temperature and is then removed manually for re-rolling. After



Figure M.15: Classification of furnaces

Furnaceclassification

According tomode of

heat transfer

According tomode ofcharging

Mode ofheat reovery

Open fireplace furnace

Heated through liquid

Periodical

Continuous

Forging

Recuperative

Regenerative

Re-rolling(batch/continuous pusher)

Pot

Glass tank melting(regenerative/recuperative

completing first re-rolling, which takes around 3.5 to 4 hours, the furnace is loaded

with fresh ‘material’, which takes only 30 minutes to heat-up for re-rolling.

Average output from these furnaces varies from 10 to 15 tons/day and the specific fuel

consumption varies from 180 to 280 kg of coal per ton of heated material. Specific coal

consumption varies with the weight of the material being heated for re-rolling and with

operating efficiency of the furnace.

Continuous pusher type furnaceContinuous pusher type furnaces have a distinct advantage over batch type furnaces.

Although the process flow diagram and operating cycles are the same as those of the

batch furnace, the cross-sectional area of the billet or ingot that can be fed into the

pusher furnace is 65 to 100 mm2 (45 to 90 kg weight/piece). These furnaces generally

operate 8 to 10 hours with an output of 20 to 25 tons per day; their normal rating is

around 4 to 6 tons/hour at peak load.

Since the length of a pusher furnace is generally between 13.7 and 15.25 metres, the

material itself can recover a part of the heat from flue gases as it moves down the

length of the furnace. Heat absorption by the material in the furnace is slow and steady

and uniform throughout the cross-section.

The material pushed into the furnace takes 2 to 2.5 hours to reach the soaking zone,

where the temperature is maintained at around 1 200 to 1 250 °C. After sufficient

soaking, which depends on cross-section, the material is removed manually for re-

rolling. Specific fuel consumption varies from 180 to 250 kg of coal per ton of heated

material. Inefficient furnace operation is one of the major reasons for wide variations in

specific fuel consumption.

Pot furnacesPot furnaces are usually used when the final product is small glassware, shells,

laboratory instruments, bangles, etc. or wherever a ‘batch’ is melted intermittently.

Coal is burned on a fixed grate with natural draught.

In pot furnaces the flue gas temperature just after the furnace is in the range of 1 200

to 1 250 °C. Specific fuel consumption is 1.2 to 1.5 tons of coal per ton of glass drawn.

This varies from unit to unit, depending on the type of product and coal quality.



Glass furnace: a typical glass furnace consists of 10 to 12 pots, each with a capacity of

200 kg of molten glass. The furnace temperature is maintained at around 1 350 to

1 400 °C. Around 14 to 18 hours are needed for complete melting and refining of a

batch of glass. Drawing of molten glass from the pots requires another 6 to 8 hours.

In the glass tank regenerative furnace, batch charging and glass drawing is continuous.

Normally, the quantity of glass drawn ranges from 10 to 20 tons per day in such

furnaces. A tank furnace consists of a bath, the bottom and sides of which are usually

made of refractory blocks. Ports are provided for mixing of fuel and air above the

melting level.

The coal is not burned directly in the glass tank furnace. Instead, it is used as a raw

material to first generate product gas which, in turn, is cross-flow-fired to heat the tank

across the width of the furnace.

The mixed batch, comprising sand, limestone, soda ash and cullet, is shovelled into the

furnace manually. Melting of the glass in tanks occurs in the following stages:



Design parameters

Length (mm)

Width (mm)

Height (mm)

Grate width (mm)

Grate length (mm)

Operating parameters

Furnace temperature (°C)

Flue gas temperature (°C)

CO2% in flue gas

Specific fuel consumption

Tons of coal/ton ofmaterial heated

3 000

1 850

900

900

1 850

1 200–1 250

1 100

3–10

0.6–0.8

6 000

2 000

1 100 (front end)

900 (rear end)

900

1 850

1 150–1 200

700–750

4–12

0.18–0.28

13 700/152 250

1 800

1 050 (front end)

400 (rear end)

900

1 850

1 200–1 250

550–600

4–12

0.18–0.25

Average weightof molten glass200 kg per pot

1 350–1 400

1 200–1 250

4–8(O2)

1.2–1.5

Depends on the capacity of the furnace

Static producer

1 400–1 450

200–350 (just after regeneration)

2–6 (O2)

0.55–1.0

Furnace Pot Glass tank melting (regenerative or

recuperative)

Forging(open

fireplace)

Re-rolling

Batch Continuous pusher

Table M.20: Furnace parameters

1. The batch is pushed into the furnace where it floats on the top of molten glass

and melts to a frothy state.

2. Temperature is held sufficiently high to remove gas bubbles and homogenize the

bath, refining the glass.

3. Glass then flows to the cooler working end for drawing at a carefully controlled

rate/temperature.

Molten glass is supplied from the working end to one or more operating units. The

forming of glassware may be carried out either by hand or by machine. The glassware

is then taken to an annealing furnace. Annealing avoids stresses being set up in the

glass by too rapid or uneven cooling, as this may increase its tendency to fracture.

Rejected articles, known as ‘cullet’, are recycled in the fresh batch.

M1.6.2 Fuel consumption and heat economy

For an industrial furnace, the term ‘efficiency’, when used in the true sense, refers to

the quantity of fuel expended to heat a unit weight of stock. While efficiency for boilers

ranges from 60 to 85 per cent, the efficiency of furnaces is sometimes as low as 5

per cent. One reason for the difference in efficiency between boilers and industrial

furnaces is in the final temperature of the material being heated. Gases can give up

heat to the charge only as long as they are hotter than the charge. Consequently, flue

gases leave industrial furnaces at a very high temperature. This factor is responsible for

low furnace efficiencies.

Examination of Figure M.16 will give a clear understanding of the distribution of heat

in a simple furnace.



Figure M.16 Flow of heat in a furnace

1

2

3

3

2

7

2

4

6

4

5

1

1 = stock

2 = ground and surroundings

5 = door

6 = protruding stock

3 = hearth

4 = cracks and openings

7 = stack

Heat flow in a furnaceIt is desirable for most of the heat liberated by the fuel to be imparted to the stock.

However, as shown in Figure M.16, some of the heat in a furnace passes into the

furnace walls and hearth, and some is lost to the surroundings by radiation and

convection from the outer surface of the walls or by conduction into the ground. Heat

is also radiated through cracks or other openings and furnace gases pass out around

the door, often burning in the open air and carrying off heat. Heat is also lost every

time the door is opened or can be dissipated if stock protrudes beyond the furnace

enclosure. Finally, most of the heat lost passes out along with the products of

combustion, either in the form of sensible heat or as incomplete combustion. Fuel

economy demands that the fraction of total heat that passes into the stock be as large

as possible and that all losses be minimized.

1.6.3 Factors affecting fuel economy

Complete combustion with minimum excess airTo achieve complete combustion of fuel with minimum excess air, a number of factors

(such as proper selection and maintenance of control, excess air monitoring, air

infiltration, pressure of combustion air) are to be considered. In addition to an

abnormal increase in stack losses, the ingress of too much excess air lowers flame

temperature, reducing furnace temperature and heating rate. If too little excess air is

used, combustion is incomplete and chimney gases will carry away unused fuel

potential in the form of unburned combustible gases such as carbon monoxide and

hydrogen, and unburned hydrocarbons which would otherwise have burned usefully

in the combustion chamber.

Proper heat distributionIdeally, a furnace should be designed so that, in a given time, as much material as

possible is heated to as uniform a temperature as possible, with the minimum fuel firing

rate. To achieve this, the following points should be considered.

i) The flame should not touch the stock and should propagate clear of any solid

object. Any obstruction whatsoever de-atomizes the fuel particles, affecting

combustion and creating black smoke. If the flame touches the stock, the scale of

losses is greatly increased.

ii) Refractories are leached if the flames touch any part of the furnace, as the

products of incomplete combustion can react with some of the refractory

constituents at high flame temperatures.



iii) The flames from burners in the combustion space should also remain clear of oneanother. If flames interact, inefficient combustion will occur. This can becontrolled by staggering the burners on opposite walls.

iv) The flame has a tendency to travel freely in the combustion space just above thematerial. In small reheating furnaces, the burner axis is never parallel to thehearth but always at an upward angle. Every precaution should be taken toensure that the flame never impinges on the roof.

v) A larger burner produces a long flame which may be difficult to contain within thefurnace walls. More burners of less capacity give better distribution of heat in thefurnace, and also reduce scale losses while increasing furnace life, as shown inFigure M.17.

vi) For uniform heating in smaller reheating furnaces it is advisable to maintain a longflame with a golden yellow colour when firing furnace oil. The flame should not beallowed to become so long that it enters the chimney and comes out at the top orthrough doors, as occurs when excessive oil is fired. This operational practice issometimes employed to increase production rate, in reality it helps only marginally.

vii) It is also desirable to provide a combustion volume that is adequate to the heatrelease rate.



stockflame stockflame

incorrect correct incorrect correct

flameflame

flame

Figure M.17 Heat distribution in furnaces

Operating at the desired temperatureThere is an optimum temperature for furnace operation for any given industrial heatingor melting operation. Table M.21 shows operating temperatures for different furnaces.

Operating at too high a temperature will not only mean unnecessary waste of fuel andheat, it will also cause overheating of the stock, its spoilage or excessive oxidation anddecarburization, as well as over-stressing of refractories. To avoid this, provision shouldbe made for temperature control instruments.

In the ‘off’ condition, only the atomizing air enters the furnace, bringing itstemperature down rapidly so that when the oil firing process recommences, the

amount of oil supplied to the furnace to raise the temperature is far greater than wouldbe necessary had the furnace been operated on ‘proportional control’.

Reducing heat losses from furnace openingsIn oil fired furnaces, substantial heat losses occur through furnace openings. For every

large opening, heat loss may be calculated by multiplying black body radiation at

furnace temperature by the emissivity (usually 0.8 for furnace brick work) and the factor

for radiation through openings. Black body radiation losses and radiation factors can be

obtained directly from curves and nomograms such as those shown in Figure M.18.



Figure M.18 Using black body radiation to calculate heat loss

Slab reheating furnaces

Rolling mill furnace

Bar furnace for sheet mill

Bogey type annealing furnace

Bogey type roll annealing furnace

Small forging furnace

Rotary iron melting furnace

Enamelling furnace

1 200 °C

1 180 °C

850 °C

659–750 °C

1 000 °C

1 150 °C

1 550 °C

820–860 °C

Table M.21: Furnace operating temperatures

0325

1 000blac

k bo

dy r

adia

tion

(kc

al/c

m2 /

hr)

temperature (°C)

2 000

3 000

4 000

5 000

6 000

500 750 1 000 1 250 1 500 1 650

tota

l rad

iati

on f

acto

r

0

1.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.2 0.4 0.6 0.8 1.0 2 3 4 5 60

a) Black body radiation b) Radiation through openings of various shapes

ratio =diameter or least width

thickness of wall=

Dx

x

Dvery long slot

2:1 rectangular opening

square opening

round (cylindrical) opening

Minimizing wall lossesIn intermittent or continuous furnaces, heat losses generally account for around 30–40

per cent of the fuel input to the furnace. The appropriate choice of refractory and

insulation materials goes a long way towards achieving fairly high fuel savings in

industrial furnaces.

In industrial furnaces, fuel consumption can be substantially reduced by judicious

application of external insulation. Several materials with different combinations of heat

insulation and thermal inertia should be considered to minimize heat losses through

furnace walls. For intermittent furnaces, the use of insulating refractories of appropriate

quality and thickness can cut down heat storage capacity of walls and the time

required to bring the furnace to operating temperature by as much as 60–70 per cent.

Control of furnace draughtIngress of uncontrolled free air must be prevented in any furnace. It is better to maintain

a slight excess pressure inside the furnace to avoid air infiltration. If negative pressures

exist in the furnace, air infiltration is liable to occur through the cracks and openings,

thereby affecting air/fuel ratio control. Neglecting furnace pressure could mean problems

of cold metal and non-uniform metal temperatures, which could affect subsequent

operations such as forging and rolling and could result in increased fuel consumption.

Furnace loadingOne of the most vital factors affecting efficiency is loading. There is a particular loading

at which the furnace will operate at maximum thermal efficiency. If the furnace is

under-loaded, a smaller fraction of the available heat in the working chamber will be

taken up by the load and the efficiency will accordingly be low. The best method of

loading is generally obtained by trial, noting the weight of material put in at each

charge, the time it takes to reach a given temperature and the amount of fuel used.

Care should be taken to load a furnace at the rate associated with optimum efficiency,

although it must be realized that limitations in achieving this are sometimes imposed

by availability of work or other factors beyond operational control.

Placing of stockThe load should be placed on the furnace hearth in such a way that:

• It receives maximum radiation from the hot surfaces of the heating chamber and

the flames.

• The hot gases circulate efficiently around the heat receiving surfaces.



• There is adequate spacing between the billets. Overlapping of materials results in

non-uniformity of temperature and should be avoided.

Stock should not be placed in the following positions:

• In the direct path of the burners or where the flame is likely to impinge.

• In an area which is likely to cause a blockage or restriction of the flue system of

the furnace.

• Close to any door or opening where cold spots are likely to develop.

Load residence timeIn the interest of fuel economy and work quality, the materials comprising the load

should remain in the furnace for the minimum stipulated time to obtain the required

physical and metallurgical requirements. When the materials attain these properties

they should be removed from the furnace to avoid damage and fuel wastage.

M1.7 Waste heat recovery

M1.7.1 What is waste heat?

Boilers, kilns, ovens and furnaces generate large quantities of hot flue gases. If some of

this waste heat can be recovered, a considerable amount of primary fuel can be saved.

Not all of the energy lost in waste gases can be recovered. However, much of the heat

can be recovered and losses can be minimized by adopting the measures described

below.

M1.7.2 Sources of waste heat

When considering the potential for heat recovery, it is useful to note all of the

possibilities, and to grade the waste heat in terms of potential value, as shown in

Table M.22.

M1.7.3 Waste heat recovery from flue gases

After identifying sources of waste heat and possible uses, the next step is to select

suitable heat recovery systems and equipment to recover and use the heat.

Considerable fuel savings can be made by preheating combustion air. The heat saving

devices used for this purpose are the recuperator and the regenerator.



RecuperatorIn a recuperator, heat exchange takes place between the flue gases and the air via

metallic or ceramic walls. Ducts or tubes carry the combustion air that is to be pre-

heated, the other side of the exchanger carries the waste heat stream.

Ceramic recuperators are bulky and offer considerable resistance to transfer of heat

because of low conductivity; they also have a greater tendency to leak. Metallic

recuperators are less prone to leaks and thermal expansion and can be controlled.

Metallic recuperators are easier to maintain and install and involve less initial cost. For

the reasons outlined above, ceramic recuperators are not widely used. Some of the

common flow arrangements used in recuperators are shown in Figures M.19–M.21.

Metallic recuperators can be of three basic types, depending on the method of heat

transfer: i.e. radiation, convection, or combined convection and radiation.

Ceramic recuperator

Ceramic tube recuperators have been developed to overcome the temperature limit of

metallic recuperators (around 1 000 °C on the gas side). The materials used for ceramic

recuperators allow gas side temperatures of up to 1 300 °C and temperatures up to

850 °C on the preheated air side.



1

2

3

4

5

6

7

Heat in flue gases

Heat in vapour streams

Convective and radiant heat lostfrom exterior of equipment

Heat losses in cooling water

Heat losses in providing chilledwater or in the disposal of chilledwater

Heat stored in products leaving theprocess

Heat in gaseous and liquid effluentsleaving process

The higher the temperature, the greaterthe potential value for heat recovery.

As above but when condensed, latentheat also recoverable.

Low grade—if collected may be used forspace heating or air preheats.

Low grade—useful gains if heat isexchanged with incoming fresh water.

a) High grade if it can be utilized toreduce demand for refrigeration.

b) Low grade if refrigeration unit used asa form of heat pump.

Quality depends on temperature.

Poor if heavily contaminated, thusrequiring alloy heat exchanger.

Section no. QualitySource

Table M.22: Sources of waste heat

The classification of recuperators based on their type of flow is given in Figure M.21.



Figure M.19 Recuperator Figure M.20 Metallic radiation recuperator

Figure M.21 Classification of recuperators

a) Parallel flow recuperator

Both gases flow in the same direction

c) Counter flow recuperator

Both gases flow in opposite direction

b) Cross flow recuperator

Gases flow at right angles to one another

Inlet air from atmosphere

Exhaust gas from process

Centre tube plate

Preheated air

Tube plate

Outside ducting

Coldinputfluid

Cold input fluid

Cold input fluidHot waste gas

Hot waste gas

Hot waste gas

Hot input fluid

Hot input fluid

Hot input fluid

Cooled waste gase

Cooled waste gase

Cooled waste gases

Flue gas

Cold airinlet

Hot air to process

Insulation andmetal covering

Waste gas

Radiation/convective hybrid recuperator

For maximum effectiveness of heat transfer, combinations of radiation and convective

designs are used, with the high-temperature radiation recuperator always first (see

Figure M.22). These are more expensive than simple metallic radiation recuperators,

but are less bulky.



Figure M.22 Radiation/convective hybrid recuperator

Table M.23 summarizes the applications and advantages of the different types of

recuperator.

Radiation type recuperators

(30% efficiency)

Convective recuperative system

(50–60% efficiency)

Advanced designs

(self-recuperative burners, up to

70% efficiency)

Steel industry (furnaces, soaking pots,

chimneys and flues)

Low temperature applications (food,

textiles, brewing, pulp and paper)

High temperature applications (flue

gases from kilns, metal processing

and glass melting furnaces, etc.)

Can handle very dirty,

abrasive dust-laden gases

Table M.23: Furnace operating temperatures

Energy performance Applications Advantages

Cooled waste gas

Hot air to process

Coldair

inletRadi

atio

n se

ctio

nC

onve

ctio

n se

ctio

n

Regenerator In a regenerator (see Figure M.23), the flue gases and the air to be heated are passed

alternately through a heat-storing medium, thereby resulting in transfer of heat. Long

periods of reversal result in lower average temperature of preheat and consequently

reduce fuel economy.



Figure M.23 Regenerator

Figure M.24 Economizer

EconomizerFor a boiler system, an economizer (see Figure M.24) can be provided utilizing the flue

gas heat to pre-heat the boiler feed water. In an air pre-heater, the waste heat is used

to heat combustion air. In both cases, there is a corresponding reduction in the fuel

requirements of the boiler.

Gas

Chimney

Air regeneratorGas regenerator

Flue gas outlet

Flue gas intlet

Water outlet

Water inlet

Economizer cells

Air

M1.7.4 Plate type heat exchangers

The cost of heat exchange surfaces is a major cost factor when temperature differences

are not large. One way of solving this problem is the plate type heat exchanger (see

Figure M.25), which consists of a series of separate parallel plates forming narrow flow

passages. Plates are separated by gaskets and the hot stream passes in parallel through

alternating plates while the counter-flow of liquid to be heated passes in parallel

between the hot plates. Plates are corrugated to improve heat transfer. Plate type

exchangers are summarized in Table M.24.



Figure M.25 Plate type heat exchanger

Plain form, cooling fluids flow

A series of separate,parallel plates formnarrow passages throughwhich the heating andcooling fluids flow

Temperature range 25–170 °C,(special design up to 200 °C). Easy toclean, replace parts and increasecapacity. Liquid-to-liquid systemsrecover up to 80–90% of availableheat. Widely used in brewing, dairyand chemical process industries; inregenerative recovery, and as acondenser for product heating.

Table M.24: Characteristics of plate heat exchangers

Type of plate heat exchanger Construction Comments

M1.7.5 Heat pipe

The heat pipe is a device that uses an evaporation-condensation cycle to transfer up to

100 times more thermal energy than copper, the best known conductor. It is a simple

device that absorbs and transfers thermal energy with no moving parts, and hence

minimum maintenance.

The heat pipe comprises three main elements: a sealed container; a working fluid; and

a capillary wick structure, (see Figure M.26).

The container encloses the working fluid which, because the container is sealed, is at

its own pressure equilibrium. Thermal energy applied to the outer surface of the heat

pipe causes the working fluid near the surface to evaporate instantaneously, picking up

the latent heat of evaporation. This region of the heat pipe is the ‘evaporator’. The

vapour, which now has a higher pressure, moves to the other, cooler, end of the pipe

where it condenses, giving up the latent heat of evaporation as it does so. This region

of the pipe forms the ‘condenser’. The capillary wick—fabricated as an integral part of

the inner surface of the evacuated container tube—provides a return path for the

working fluid, allowing the cycle to restart.

Performance and advantagesThe heat pipe heat exchanger (HPHE) is a lightweight compact heat recovery system.

It requires no input power for its operation and is free from cooling water and

lubrication systems. It also lowers fan horsepower requirement and increases overall

thermal efficiency of the system. HPHE recovery systems are capable of operating at

315 °C with 60–80 per cent heat recovery capability.

Typical applicationHeat pipes are used in following industrial applications:

a) Process to space heating: The HPHE transfers thermal energy from the process

exhaust for use in building heating. Preheated air can be blended if required. The

requirement for additional heating equipment to deliver heated make up air is

drastically reduced or eliminated.



Figure M.26 Heat pipe

Vapourized fluid condensesand gives up heat

Metal mesh wick actsas return path for

liquid working fluid

Heat evaporatesworking fluid

Heat in

Vapour

Liquid

Heat out

b) Process to process: Heat pipe heat exchangers recover waste thermal energy from

the process exhaust and transfer this energy to the incoming process air. The

warmed incoming air can be used for the same process or other processes, thus

reducing process energy consumption.

c) HVAC Applications:

Cooling: a HPHE can precool building make up air in summer, thus reducing the total

tons of refrigeration as well as providing savings in operation of the cooling system.

Heating: the process described above is reversed during winter to preheat the make

up air.

Other industrial applications are:

• Preheating of steam boiler combustion air.

• Recovery of waste heat from furnaces.

• Reheating of fresh air for hot air driers.

• Recovery of waste heat from catalytic deodorizing equipment.

• Recovery of furnace waste heat as heat source for other ovens.

• Pre cooling of cold air.

• Heat source for air conditioning.

• Cooling of closed rooms with outside air.

• Preheating of boiler feed water by waste heat recovery from flue gases in the heat

pipe economizers.

M1.7.6 Heat pumps

Heat pumps have the ability to upgrade heat from a source to a value more than twice

that of the energy required to operate the device. The potential for application of heat

pumps is growing and numerous industries have benefited by recovering low grade

waste heat, upgrading it and using it in main process streams.

Basically, a heat pump system comprises a compressor, condenser, expansion valve,

evaporator and a working fluid. It extracts heat from air, water or a process liquid

stream and supplies it, via an exchanger, at a higher temperature to a liquid or gas

stream. The heat pump employs the same basic principle as the common refrigerator,

and the cycle can also be used for cooling. The principle of operation is presented in

Figure M.27.



Heat pump applications (see Table M.25) are most promising when both the heating

and cooling capabilities can be used in combination. One example of this is a plastics

factory where chilled water from a heat is used to cool injection-moulding machines

whilst the heat output from the heat pump is used to provide factory or office heating.

Other examples of heat pump use include product drying, maintaining dry

atmosphere for storage and drying compressed air.



Figure M.27 Heat pump—operating principle

Heat drawn from warmexhaust can achieve COPs of 5 or 6

Maximum operatingtemperature can vary (40 °C,60 °C or 100 °C depending onchoice of working fluid)

Timber and woodproducts; ceramics andpottery; brickmanufacture and foodproducts

Reclaims heat at ambienttemperatures

Table M.25: Heat pump applications and advantages


Working fluid expansionvalve converts hot liquid to

low-pressure coldliquid/vapour mixture

Heat energy extracted from wasteair is absorbed by the working fluidin cooling coil

Heat absorbed by cold liquidconverts it to cold gas

Heat pump compresses cold gas tohigh pressure hot gas

Heating coil adding heat to supplyair from hot gas condensing to hotliquid under pressure

M1.7.7 Heat (thermal) wheels

A variation on the basic methods of heat transfer is the rotary regenerator which uses

a cylinder rotating through waste gas and air streams (see Figure M.28). The ‘heat’ or

‘energy recovery’ wheel is a rotary gas heat regenerator that transfers heat from an

exhaust stream to cooler incoming gases. Its main area of application is when there is

a requirement for heat exchange between large masses of air with small temperature

differences. Heating and ventilation systems and recovery of heat from dryer exhaust

air are typical applications.



Figure M.28 The heat wheel

The wheel rotor—which consists of sectors of either steel mesh or inorganic fibrous

materials with a hygroscopic coating of glass ceramic—offers a large surface area to the

air or gas flows. The wheel absorbs heat from the hot exhaust gases and, as the rotor

revolves, transfers heat to the cooler incoming stream. The speed of rotation of the

rotor is usually about 10–20 revolutions per minute. A purge bleed between the clean

and dirty gas streams is incorporated to avoid contamination between the two streams.

Efficiencies of over 80 per cent are claimed for this device, but they vary depending on

the individual case (see Table M.26).

Supply air ducting Rotating regenerator

Warmed air to room

Warm room exhaust air

Exhaust air ductingDirection of rotation

Cooled exhaust air

Cold outside air

M1.7.8 Self recuperative burner

In self-recuperative burners (see Figure M.29), the recuperator is an integral part of the

burner, saving costs and making it easier to retrofit to existing furnaces. Recuperator

burners are operated in pairs. While one burner is used to burn the fuel, the other

burner uses a porous ceramic bed to store heat. After a short period (minutes), the

process is reversed and heat stored in the ceramic bed is used to preheat the

combustion air.



Waste heat recovery: 65% or more of available heatcan be recovered

Cost-effective infurnaces, ovens, printingmachinery, paper dryingand HVAC systems,metal melting furnaces

Reclaims heat at ambienttemperatures

More compact, lighter, and highertemperatures than comparablerecuperators

Lower gas exit temperatures aretherefore possible

Table M.26: The rotary wheel—applications and advantages


Figure M.29 Self-recuperative burner

Natural gas

Combustion airHot

combustionproducts

Combustion products

Hot combustionproducts

Waste gas outlet

M1.7.9 Waste heat recovery system for diesel generation sets

Exhaust gases from diesel generation (DG) sets are at high temperatures, ranging from

330 to 550 °C depending on the type or make of the engine and the fuel used. The

energy in the hot exhaust gases can be recovered usefully for steam, hot water, thermic

fluid heating and hot air generation (see Figure M.30).



Figure M.30: Hot water generation from DG exhaust

M1.7.10 Applicability of heat exchanger systems

Heat exchangers exist for nearly every possible combination of heat source and use.

Table M.27 indicates how common types are generally applied.

Thermic fluid pump

Thermic fluid in

350 °C

DG exhaust

To exhaust

Thermic fluid out

Typical processhot water bath



Radiation recuperator

Convective recuperator

Furnace regenerator

Metallic heat wheel

Ceramic heat wheel

Finned tube regenerator

Shell and tuberegenerator

Heat pipes

Waste heat boiler

High

Medium to high

High

Low tomedium

Medium to high

Low tomedium

Low

Low tomedium

Medium tohigh

Incinerator or boiler exhaust

Soaking or annealingovens, melting furnaces,afterburners, gasincinerators, radiant tubeburners, reheat furnaces

Glass and steel meltingfurnaces

Curing and drying ovens,boiler exhaust

Large boiler or Incineratorexhaust

Boiler exhaust

Refrigeration condensates,waste steam, distillationcondensates, coolants fromengines, air compressors,bearings and lubricants

Drying, curing and bakingovens, waste steam, airdryers, kilns andreverberatory furnaces

Exhaust from gas turbines,reciprocating engines,incinerators and furnaces

Combustion air preheat



Combustion air preheat,space preheat


Boiler make up water preheat

Liquid flows requiringheating

Combustion air preheat,boiler make up water preheat,steam generation, domestichot water, space heat

Hot water or steamgeneration

Table M.27: matrix of waste heat recovery devices and applications

Heat recoverydevice

Temperature range

Typical sources Typical uses

Electrical systems

M1.8 Electricity management systems

M1.8.1 Electricity cost

Electricity costs for an enterprise consist of the following:

• Energy costs in the true sense (i.e. the cost of the kWh consumed).

• Costs of power demand (i.e. the cost of the peak electrical power requirement).

Energy costs can be reduced primarily by reducing electricity consumption (i.e. by

increasing energy efficiency), while power demand costs can be reduced by other

means—by reducing peaks of power consumption. Reducing power peaks can lead to

reduced consumption of electrical energy, but this is not an inevitable consequence.

Both increasing energy efficiency and reducing maximum electrical load must be

preceded by analysis of the processes that consume electrical energy. Very precise

knowledge of the processes is necessary to define measures to increase energy

efficiency in an effective and economical way, and to be able cut off consumers during

(short) periods of time to reduce peak load.

M1.8.2 Electric load management and maximum demand control

IntroductionIf processes are not to be interrupted, electricity demand and supply must match

instantaneously. This requires reserve capacity to meet peak demands, and the costs of

meeting such demands—normally referred to as demand charges—are relatively high.

Managing electricity supply costs therefore requires integrated load management that

includes control of maximum demand and scheduling of its occurrence during peak/off-

peak periods. Figure M.31 gives an example of the load curve for an enterprise. How

such a curve can be plotted is explained in Example 7 (page 178).

Basically, there are two ways to reduce maximum load for an enterprise (see

Figure M.32):

a) cut off the peaks; or

b) reduce base load.





Figure M.31 A load curve

Figure M.32 Reducing the load

elec

tric

ity

use

(kW

)

time of day

120

90

80

70

60

50

40

30

20

10

000:00 02:00 04:00 06:00 08:00 12:00 22:0010:00 14:00 16:00 18:00 20:00

110

100

elec

tric

ity

use

(kW

)

time of day

120

90

80

70

60

50

40

30

20

10

000:00 02:00 04:00 06:00 08:00 12:00 22:0010:00 14:00 16:00 18:00 20:00

110

100 reduced peak by measures

peak load limitationby measure (control)

peak load limitationby reducing base load

Controlling peak load by load management

Load prediction

Before considering methods of load prediction, some terms used in connection with

power supply need to be defined.

• Connected load—the nameplate rating (in kW or kVA) of the apparatus installed

at a consumer’s premises.

• Maximum demand—the maximum load that a consumer uses at any time.

• Demand factor—the ratio of maximum demand to connected load.



A consumer has ten 40 kW electrical loads connected at a facility; the connected load is thus400 kW. However, the maximum number of loads actually used may be only nine—all ten maynever be used at once. Maximum demand is, therefore, 9 x 40 = 360 kW, and the demand factorof this load is 360/400 or 90 per cent. A consumer of electrical power will naturally use power asand when required and the load will therefore be constantly changing. As shown in Figure M.31,this can be represented by a graph known as a load curve that shows the consumer's loaddemand against time at different hours of the day.

When plotted for the 24 hours of a single day, the graph is known as a daily load curve. If it ispotted for a whole year, it is known as an annual load curve. This type of curve is useful inpredicting annual energy requirements, occurrence of loads at different hours and days in the year,and for power supply economics. As load is variable, it will only be at maximum for a certain timeand will be lower at other times. The average load during a 24 hour period, or other periodconsidered for the load curve, will be less than the maximum load. The ratio of average load tomaximum load is called the load factor.

The load factor can also be defined as the ratio of energy consumed during a given period to theenergy that would have been used if maximum demand had been maintained throughout thatperiod.

Example 7: Plotting a load curve

Load factor =Average load

Maximum load

Load factor =Energy consumed during 24 hours

Maximum recorded load x 24 hours



A residential consumer has ten 60 W lamps connected. Demand is as follows:

From 12 midnight to 5 a.m.: 60 WFrom 5 a.m. to 6 p.m.: NilFrom 6 p.m. to 7 p.m.: 480 WFrom 7 p.m. to 9 p.m.: 540 WFrom 9 p.m. to 12 midnight: 240 W

The average load, maximum load, load factor and electrical energy consumption during the daycan be calculated as follows:

i) Maximum load is 540 W for 2 hours of the day, from 7 p.m. to 9 p.m.

ii) Energy consumption during 24 hours of the day is:

(5 x 60) + (480 x 1) + (540 x 2) + (240 x 3) = 2 580 Wh

= 2.58 kWh/day

iii) % Load factor =

=

= 19.9%

iv) Average Load =

= 107.5 kW

Example 8: Calculating the average load

Energy consumed during 24 hours x 100%

540 W x 24 hours

2580 x 100%

540 W x 24 hours

2 580 kWh

24 hours

spotlightCP-EE

In a wire drawing unit,three items of preliminarywire drawing equipmentwith loads of 50 HP per

wire were usedsimultaneously during the

day shift. Thesimultaneous maximumdemand for the overall

plant was about 450 kVA.Operation of the threeitems of wire drawing

equipment wasrescheduled to the 3rdshift, when only a few

items of equipment wereoperating. With

rescheduling, maximumdemand was reduced by

150 kVA, resulting insavings of about

US$2 000 per year indemand charges, as well

as flattening the loadcurve considerably.

Rescheduling of loads

To minimize simultaneous maximum demands, running of units or carrying out of

operations that demand a lot of power can be rescheduled to different shifts. To do

this, it is advisable to prepare an operation flow chart and a process run chart.

Analysing these charts and adopting an integrated approach make it possible to

reschedule the operations and to run heavy equipment in such a way as to reduce

maximum demand and improve the load factor (see Figure M.33).



Figure M.33 Analysing peak load

elec

tric

ity

use

(kW

)

time of day

120

90

80

70

60

50

40

30

20

10

000:00 02:00 04:00 06:00 08:00 12:00 22:0010:00 14:00 16:00 18:00 20:00

110

100

What contributes to the peaks?Can the processes be shifted?

What happens here?Do machines etc. run unnecessarily?

spotlightCP-EE

In a pipe manufacturingplant, three automatic

moulds with motor loadsof 70 kW were operated

simultaneously. Theoperators were instructed

to incorporate a timedelay into the running of

these motors. Thisresulted in a reduction of

50 kVA in maximumdemand, and savings ofaround US$660 per year

in demand charges.

Staggering of motor loads

When running large capacity motors, staggering of running is advisable, with a suitable

time delay (as permitted by the process) to minimize simultaneous maximum demand

(depending on load conditions) from these motors.

Storage of products

It is possible to reduce maximum demand by using electricity during off-peak periods

to build up storage of products/materials or chilled/hot water. Additional machinery and

storage costs are often justified by reduction in demand charges—for example, storing

chilled water at night to provide day time air conditioning; adding raw material/clinker

grinding facilities in cement plants; storing chipped wood in paper plants; etc. Off-peak

operation can also help to save energy because of more favourable conditions—for

example, lower ambient temperatures can reduce needs for cooling, etc.

However, a cost-benefit analysis has to be made for solutions like those outlined above;

they will then be considered for implementation if economically viable.

Shedding of non-essential loads

When maximum demand tends towards a preset limit, it can be restricted by

temporary shedding of some non-essential loads. It is possible to install direct demand-

monitoring systems that switch off non-essential loads when a preset level of demand

is reached. Simpler systems give an alarm, and the loads are shed manually.

Sophisticated microprocessor controlled systems are available that provide a wide

variety of control options. These provide the following options:

• Accurate prediction of demand.

• Graphic display of present load, available load, demand limit.

• Visual and audible alarm.

• Automatic load shedding in a predetermined sequence.

• Automatic restoration of load.

• Recording and metering.

Simple load management systems with manual load shedding are employed in some

industries.

Operation of diesel generation sets

When diesel generation (DG) sets are used to supplement the power supplied by the

electricity utilities, it is advisable to connect the DG sets for the duration of peak

demand periods. This considerably reduces load demand on the utility supply, and

minimizes demand charges.

If the DG sets generate at the same voltage as the supply authority, it is advisable to

run the systems in parallel. This results in considerable reduction in maximum demand

if the diversity of loads in the plant is used to share the peak load on the system.

If the heat produced by the engine (cooling water, exhaust gases) can be used,

additional profit is gained. In this case, operation of the DG as a cogeneration plant

could be considered.



M1.8.3 Power factor improvement

Power factor basicsFor purely resistive electrical loads, voltage (V), current (I) and resistance (R) have a

simple linear relationship expressed by the equation:

V = I x R

and for power (kW):

kW = V x I

In practice, however, purely resistive loads are a rarity, and the alternating current

supplied by electricity utilities (usually at 50 or 60 Hz) is almost always applied to

inductive loads (e.g. motors, transformers, induction furnaces, etc.). Inductive loads

require an electromagnetic field to operate and they therefore draw additional

‘reactive’ power (kVAR) to provide for this magnetizing component. Figure M.34

illustrates this situation—KW, the active power (shaft power or true power required)

and the reactive power (kVAR) are 90° out of phase, with reactive power (kVAR) lagging

the active power (kW). (As will be seen below, the ‘lag’ has significance for power factor

correction). The vector sum of kW and kVAR, is the apparent power, termed kVA. It is

kVA that represents the actual electrical load on the distribution system.



Figure M.34

kW

kVAR

φ

kVA

From Figure M.34, it can be seen that if reactive power is zero (i.e. no inductive kVAR

needed) kVA and kW will be equal but if the inductive kVAR requirement increases, the

kVA required to provide the same active power (kW) also increases. In other words, the

ratio of kW to kVA varies with the reactive power drawn. This ratio is called the power

factor. It is always equal to or less than unity.

If all loads to which electricity utilities supply power had unity power factor, maximum

power would be transferred for the same distribution system capacity. In reality,

however, loads have power factors ranging from 0.2 to 0.9, and the lower power

factors place additional stress on the electrical distribution network. Low power factors

result largely from part load operation of motors and other equipment.

The effects of low power factors are:

• Maximum kVA demand for a given kW load increases.

• Line I2R losses increase considerably.

• On-line voltage drops are higher.

• Gross power consumption increases.

• Distribution system (transformers, cables) bear an increased load.



The table below shows the kVA requirements (demand) and current drawn at various power factorsby an industrial installation with a 150 kW load requirement.

Example 9: The effects of power factors

Notes:kW = kVA x P.F.Line current = kVA ÷ √3 x voltage in kilovolts

It can be seen that, for the same kilowatt load, line current varies with power factor from208.7 amps to as much as 347.8 amps, i.e. an increase of 66.7 per cent, with acorresponding increase in load on the distribution system, and increase in distribution lossesto 278 per cent.

kVA and current vs power factor (P.F.) for a 150 kW load

Load (kW) P.F. kVA drawn Line current at 415 volts

150

150

150

150

150

0.60

0.70

0.80

0.90

Unity

250

214.3

187.5

166.67

150

347.8

298.1

260.9

231.9

208.7

Electricity suppliers impose penalties on users with low power factors, as these place a

heavy burden on distribution system capacity. There is therefore good reason to

compensate for reactive power.

Compensating for reactive power A very effective and well-established method of improving power factor is to

incorporate capacitors. The capacitor is a device which stores energy in an electric field

and has the characteristic of drawing leading reactive power. In other words, current

in a capacitor leads voltage by 90° and the reactive kVAR is therefore in exact

opposition to inductive kVAR. It therefore tends to nullify the reactive power drawn, as

illustrated below in Figure M.35.

By connecting an appropriately sized capacitor across an inductive load, the effects of

a low power factor can be nullified.



kW

kVAR

without capacitor

kW

kVAR

with capacitor

kW = kVA

balancingcapacitivekVAR

The reactive power demand at plant level can be reduced to a considerable extent by

using capacitor banks. Maximum demand can also be reduced by maintaining

optimum power factor at the main incoming bus.

High-voltage capacitor banks (suitable for voltages of 11 kV and above) are available

with microprocessor-based control systems. These systems switch the capacitor banks

on and off in accordance with load power factors.

Figure M.35 Balancing inductive and capacitive kVAR

Selecting capacitorsThe figures given in Table M.28 are factors to be multiplied with the input power (kW)

to give the kVAR of capacitance required to change from one power factor to another.



• Type of industry: Food processing (pulverizing and grinding)• Total connected load: 247.5 HP• Maximum demand: 103 kVA• Instantaneous P.F.: 0.85• Existing capacitor banks: 4 x 20 kVAR

It was proposed to provide additional capacitors to improve the instantaneous power factor of highunit loads.

Additional requirement of capacitors to improve the instantaneous P.F. to 0.96 = 30 kVAR

Expected reduction in M.D. = 12 kVA

Savings in demand charges at US$3.0 per kVA M.D. = US$432

Estimated cost of installation = US$200

Simple payback period = Less than 0.5 years

Example 10: Using capacitor banks to reduce power demand

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.518

1.333

1.169

1.020

0.882

0.750

0.484

0.328

0.620

1.189

1.004

0.840

0.691

0.553

0.421

0.291

0.155

1.034

0.849

0.685

0.536

0.398

0.266

0.136

0.899

0.714

0.549

0.400

0.262

0.130

0.763

0.583

0.419

0.270

0.132

Table M.28: Factors for capacitive kVAR

Original P.F. Desired P.F.

1.0 0.95 0.90 0.85 0.80



The power factor for a 30 kW load is to be improved from 0.80 to 0.95. This is obtained as follows:

Size of the capacitor = kW x multiplication factor= 30 x 0.421= 12.63 (or) 13 kVAR

Example 11: Sizing the capacitor

Knowing the existing power factor, Table M.28 can be used to find the factor to raise

the power factor from its present value to a desired value.

For induction motors with different ratings and speeds, to improve power factor to

0.95 and above, the rating of the capacitor (in kVAR) for direct connection to induction

motor or a particular speed can be selected from Table M.29.

1.0

2.0

3.0

4.0

4.5

5.0

5.5

6.0

6.5

7.0

1.5

2.5

3.5

4.5

5.0

6.0

6.5

7.0

8.0

9.0

2.0

3.5

4.5

5.5

6.5

7.5

8.0

9.0

10.0

10.5

2.5

4.0

5.0

6.0

7.5

8.5

10.0

11.0

12.0

13.0

2.5

4.0

5.5

6.5

8.0

9.0

10.5

12.0

13.0

14.5

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

25.0

1.0

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Table M.29: Recommended capacitor rating for direct connection to inductionmotors (in kVAR) (to improve power factor to 0.95 or more)

Motor H.P. Motor speed (rpm)

3000 1500 1000 750 600 500

The rated voltage of the capacitor should be equal to the rated voltage of the system,

provided voltage variation is not more than 10 per cent. If the voltage variation is

more, say 15 percent, the capacitor rating must be higher, so that the maximum

permissible voltage of the capacitor bank is equal to or slightly higher than the

maximum system voltage. For such capacitors, the actual capacity at normal operating

conditions is given by:

Actual kVAR = Rated kVAR x

2Operating voltage

Rated voltage

Location of capacitorsLocation of capacitors is an important factor. For the benefit of electricity boards,connection of capacitors on the H.T. side is good enough. Although the cost of H.T.capacitor per kVAR is low, the cost of the associated switchgear is quite high. Apartfrom this, plant operations may be affected significantly from time to time because ofcapacitor problems. There is also a possibility that all of the reactive current will flowthrough the L.T. cable and transformers, leading to higher losses.

Alternatively, the capacitors can be connected on the L.T. side of the main substation,although this does not help in reducing distribution losses. The best solution forlocation of capacitors is to connect at load centres, e.g. connecting capacitors directlyto motors or group of motors at motor control centres. Operation of capacitorswithout load is not a significant problem as the plant will be operated under leadingP.F. and voltage may rise to a small extent. Automatic P.F. correction control is alsoavailable and is required only in special cases.

Correction of P.F. at motors has a number of advantages, since induction motors arethe main source of reactive currents in every industrial plant. Advantages include:absence of additional switchgear; no separate control of capacitor required forswitching on and off; reduced effect of motor inrush; etc.

On the other hand, there are common problems associated with direct connection:excess voltage due to self-excitation after switching off; and large transient torque afterfast reclosure. Generally, compensation at motor terminals is restricted to correctingthe no load current so that the P.F. at full load is corrected to 0.9–0.95 and, at partialload, the P.F. is near to unity. Table M.30 gives typical values of capacitors to beconnected directly with induction motors.

Other types of load requiring use of capacitors include induction furnaces, inductionheaters, arc welding transformers, etc. The capacitors are normally supplied withcontrol gear for use with induction furnaces and induction heating applications, asfrequency is often different and, essentially, load characteristics change during meltingor heating cycles. P.F.s for arc furnaces vary widely over the melting cycle, changingfrom 0.7 at the start to 0.9 at the end of the cycle.

Power factors for arc welders and resistance welders are corrected by connectingcapacitors across the primary winding of the transformers, without which their P.F.would be around 0.35. The recommended capacitor ratings for various sizes of weldingtransformers are given in Table M.31.





2

4

5

7

12.5

23

33

42

50

2.5

4.5

6

9

16

26

36

45

53

3.5

5.5

7.5

10.5

18

28

38

47

55

5

10

15

25

50

100

150

200

250

2

3

4

6

11

21

31

40

48

Table M.30: Capacitors for induction motors (kVAR)

Motor H.P. Motor speed (rpm)

3 000 1 500 1 000 750

9

12

18

24

30

4

6

8

12

18

Table M.31: Recommended capacitor ratings for welding transformers

Welding transformer rating (kVA)

Single-phase

57

95

128

160

16.5

30

45

60

Three-phase

Capacitor rating (kVAR)

M1.9 Electric drives and electrical end-use equipment

M1.9.1 Electric motors

More than 85 per cent of electricity consumed by industry passes through electric

motors. However, motors constitute only an interim stage in energy conversion, as the

motor shaft power is used to drive equipment of which the efficiency is also vital if

overall electricity consumption is to be optimized. The simple example in Figure M.36

illustrates the point.



Figure M.36 Comparison of efficiency effects

Input = 50 kW

Case 1: Existing

Case 2: Motor replaced for efficiency

Case 3: Pump replaced for efficiency

Input = 48.30 kW

Input = 37.95 kW

Motor

Efficiency = 85%

Motor

Efficiency = 88%

Motor

Efficiency = 88%

Output = 42.5 kW

Output = 42.5 kW

Output = 33.39 kW

Pump

Efficiency = 55%

Pump

Efficiency = 55%

Pump

Efficiency = 70%

Delivery = 23.375 kW



Electric motors are intrinsically highly efficient and the margins for savings from their

replacement or improvement are low in comparison to those for driven equipment,

where much higher savings can be obtained.

Squirrel cage induction motors, the mainstay in industry, have operational efficiency of

85–95 per cent, depending on the HP rating, rpm, age, and extent of loading.

Given the increasing costs of electricity, replacement of old and rewound motors by

energy-efficient ones can be advantageous, especially if the motors run for long hours.

The margin for kW savings is given by the following equation:



% kW savings =(New efficiency – Old efficiency) x 100

New efficiency

It should also to be appreciated that, at today’s electricity costs, the running cost of a

motor is 8 to 10 times its investment cost. It is therefore highly advisable to select

higher efficiency motors in the first place.

Recent technologies that improve motor operation and energy efficiency are:

• Electronic soft starters, to optimize inrush starting currents and increase life.

• Variable speed drives, to optimize energy needs in cases where capacity control is

needed.

Recommended good operational practices are:• Operating motor with correct, balanced voltage, giving 3–5 per cent savings and

longer life.

• Proper lubrication, to maintain efficiency and reduce failures.

• Proper ventilation and heat evacuation, to reduce failures and enhance life.

• Power factor correction at motor terminals is recommended, especially in cases

where H.P. ratings are over 50 and where running periods are long.

• Regular check on motor loading (amps) is recommended, to monitor variations.

• Alignment, bearings, cable terminations, lubrication and V-belt tension (in case of

belt drives) are points that warrant regular attention for safe/smooth operation.

Variable speed drivesBy design, common squirrel cage induction motors run at nearly constant speed.

Conversely, pumps, fans, compressors, conveyors, rolling mills, crushers, extruders and

many other motor applications are subject to load variation and require capacity

control. Some traditional forms of control, such as throttling, valves, damper

operations, bypass operations, have very poor energy efficiency.

A variety of variable speed drive alternatives are available to help improve energy

efficiency, offering a much more elegant method of speed and capacity control for

driven machines. Table M.32 presents a menu of advantages and disadvantages.



Variable pulley sheaves

Gears

Chains

Friction drives

Multi-speed motors

Eddy-current drives

Max. speed ratio 10:1

Fluid coupling drives

Max. speed ratio 5:1

Low cost

Low cost

Low cost

Low cost

Operation at 2 or 4 fixed speeds

Simple, relatively low cost,

stepless speed control

Simple, relatively low cost,

stepless speed control

Low efficiency

High maintenance costs

Low efficiency


Low efficiency


Low efficiency


Stepped speed control, lower

efficiency than single-speed motors

Low efficiency at less than 50%

rated speed

Low efficiency at less than 50%

rated speed

Voltage control

<25 kW, 20–100%

Voltage source inverter

(VSI) <750 kW, 100:1

Current source inverter

(CSI) <25 kW, 10–150%

Pulse width modulation

(PWM) < 750 kW, 100:1

Simple, low cost

Good efficiency, simple

circuit design

Regenerative braking, simple

circuit design

Good power factor,

low distortion

Harmonics, low torque, low efficiency,

limited speed range

No regenerative braking, problems at

low speed (< 10%)

Poor power factor, poor performance

at low speed

No regenerative braking, slightly less

efficient than VSI

Table M.32: Speed control alternatives for AC induction motors

VSD Type

Electro-mechanical control methods

Solid-state electronic control methods

Advantages Disadvantages

Example follows …

The table below shows measurements before and after installation of a PWM inverter variablespeed drive on a 45-kW, 4-pole blower fan motor in a yarn quenching application in a textile mill,indicating potential savings.

Example 12: Comparison before and after a variable speed drive installation



Note:Savings high at part loads, i.e. at low damper openings

Data before and after variable speed drive installation

Discharge pressure Damper opening (%)

With damper control

With speed control

Input power (kW)

3.6

4.8

5.4

6.8

3.0

3.4

4.8

5.6

6.8

30

40

60

70

100

100

100

100

100

34.83

37.71

38.33

42.52

15.40

17.44

21.71

26.32

32.25



Worksheet: Electric motor rated specifications

Seri

al n

o.

Mot

or d

rive

ref

.

Type

Pow

er in

put

(kW

)

Volt

age

(kV

)

Full

load

cur

rent

(Am

ps)

Pow

er f

acto

r(P

.F.)

Spee

d (r

pm)

Freq

uenc

y (H

z)

Effic

ienm

cy (

%)

Worksheet: Electric motor load survey

Seri

al n

o.

Mot

or d

rive

ref

.

Rate

d po

wer

(kW

)

Volt

age

(kV

)

Cur

rent

(Am

ps)

Pow

er f

acto

r(P

.F.)

Act

ual i

nput

pow

er (

kW)

Act

ual o

utpu

tpo

wer

(kW

)

% m

otor

lo

adin

g(w

.r.t.

rat

ed)

Actual measured electrical parameters

Note: ‘Type’ could include: induction motor, direct current (DC); synchronous motor

Notes:Actual output power = Actual measured motor input power x Rated motor efficiency factor

% motor loading = Actual measured output power

Rated motor power

OPEN FILE

OPEN FILE

M1.9.2 Transformers

A transformer is a device that transfers energy from one AC system to another.

Transformers receive energy at one voltage and deliver it at another. This allows

electrical energy to be generated at relatively low voltages; to be transmitted at high

voltages and low currents (reducing line losses); and to be used at safe voltages.

Transformers consist of two or more coils that are electrically insulated, but

magnetically linked. The primary coil is connected to the power source; the secondary

coil connects to the load. The turns ratio is the ratio of the number of turns in the

primary coil to the number of turns on the secondary. The secondary voltage is equal

to the primary voltage multiplied by the turns ratio. Ampere-turns are calculated by

multiplying the current in the coil by the number of turns. Primary ampere-turns are

equal to secondary ampere-turns. Voltage regulation of a transformer is the percentage

increase in voltage from full load to no load.

Losses and efficiency

• Transformers are inherently very efficient, by design.

• Efficiency varies from 96 per cent to 99 per cent.

However, transformer efficiency depends on load (% loading), making efficiency

dependent not only design but also on the effective operating load.

Transformer losses are of two types:

1. No-load loss, also referred to as ‘core loss’—the power consumed to sustain the

magnetic field in the transformer's core.

2. Load loss—associated with full-load current flow in the transformer windings and

due, primarily, to the resistance of the winding material. Because transformers

traditionally used copper windings, load loss is also referred to as ‘copper loss’.

From Ohm’s Law for power in a resistor (P=I2R), copper loss varies with the square

of the load current.

3. For a given transformer:

PTOTAL = PNO-LOAD + (% Load/100)2 x PLOAD

where % load = (actual load of transformer / rated power of transformer).



Reducing transformer losses

A. Proper transformer sizing

Greatly oversized transformers can contribute to inefficiency. When transformers are

matched to their loads, efficiency increases (see Table M.33).



100

125

160

200

250

315

400

500

630

800

1 000

500

570

670

800

950

1 150

1 380

1 660

1 980

2 400

2 800

2 000

2 350

2 840

3 400

4 000

4 770

5 700

6 920

8 260

9 980

11 880

97.5

97.66

97.81

97.90

98.02

98.15

98.23

98.28

98.37

98.45

98.54

kVA No-load loss (W) Full-load loss Efficiency

Table M.33: Losses in distribution transformers

100

160

200

250

315

500

630

750

1 000

60

90

110

160

180

240

300

360

430

1 635

2 000

3 000

3 280

4 000

5 600

6 300

7 200

9 000

Transformer kVA No-load loss (W) Full-load loss copper loss (W)

Table M.34: Amorphous core transformer losses

B. Energy efficient amorphous transformers

Amorphous iron is expensive but reduces core loss to less than 30 per cent of

conventional steel core losses. An alternative, less expensive core material is silicone

steel which has higher losses than amorphous iron but lower than standard carbon

steel (see Table M.34).



Worksheet: Transformer rated specifications

Sectionno.

Parameterreference

Units Transformer reference

1 2 3 4

1

2

3

4

5

6

7

8

9

10

Power rating

Primary voltage(high voltage)

Secondary voltage(low voltage)

Voltage ratio(HV/KV)

Primary current

Secondary current

Impedance

Power factor

No-load losses

Full-load losses

kVA

kV

kV

–

Amps

Amps

Ohms

–

kW

kW

Worksheet: Transformer operational parameters

Sectionno.

Parameterreference

Units Transformer reference

1 2 3 4

1

2

3

4

5

Power rating

Primary (average values)

a) Voltage

b) Current

c) Power Factor

d) Power Input

Secondary (average values)

a) Voltage

b) Current

c) Power Factor

d) Power Output

Efficiency

3d x 100

2d

% Loading

kVA

Volts

Amps

–

kVA kW

Volts

Amps

–

kVA kW

%

%

OPEN FILE

OPEN FILE



M1.9.3 Pump systems

Pumps are only one component of pumping systems which also include motors, drives,

piping and valves. Typically, much less than half the electricity input to a pumping

system is converted into useful movement of fluid. The rest is dissipated in the various

components that make up the system. Energy losses are even greater when the system

is not operating at its design point. There is, therefore, a considerable potential for

saving electricity, by both improving component efficiencies and through better

system design.

Centrifugal pumpsCentrifugal pumps are used for the vast majority of pump applications in industry.

Centrifugal pumps impart energy to the fluid by centrifugal action. They rely on the

flow of fluid to create a seal to prevent fluid flowing backward through the pump. The

volute type (see Figure M.37) is the most common centrifugal design. The impeller

vanes generally curve backwards, but radial and forward vanes are also used. The

velocity head of the fluid is converted into pressure head.

Figure M.37 Volute centrifugal pump casing design

Discharge

Impeller

Impeller vanes

Suction

Volute casing

Casing drain

Need for careful selection of pumpsThe characteristic curve of a centrifugal pump is shown in Figure M.38. Pumps have to

be selected so that they operate at their best efficiency point. Oversizing of flow during

initial selection can lead to shifting of the efficiency point, resulting in reduced

operational efficiency. An oversized pump also needs to be throttled for reduced flow

conditions.

The relationship between head, capacity and power is given by the following equation:



Figure M.38 Characteristic curve of a centrifugal pump

Head

capacity

300 gpm68 m3/h

250 ft.76 m

156 ft.47 m

A

B

C

D

E

55% 60%50%

Best efficiency point

Head (metres) x capacity (m3/h)

360= kW

The following example shows how the most appropriate size of pump can be selected

in practice.



A facility needed to pump 68 m3/hr to a 47 metre head with a pump that is 60 per cent efficientat that point.

Liquid power: 68 x 47 / 360 = 8.9 kW (Where ‘360’ is a constant)Shaft power: 8.9 / 0.60 = 14.8 kW (Where 0.6 is the efficiency at that point)Motor power: 14.8 / 0.9 = 16.4 kW (Where 0.9 is the motor efficiency)

As shown in Figure M.38, impeller ‘E’ is the one that should be used to do this, but the pump isoversized, so the larger impeller ‘A’ is used with the pump discharge valve throttled back to68 m3/hr, giving an actual head of 76 metres.

The kilowatts now look like this: 68 x 76 / 360 = 14.3 kW being produced by the pump, and 14.3 / 0.50 = 28.6 kW required todo this. Subtracting the amount of kilowatts that should have been used gives: 28.6 – 14.8 = 13.8 extra kilowatts being used to pump against the throttled discharge valve.

Extra energy used = 8 760 hrs (i.e.1 yr) x 13.8 = 120 880 kW.

For the facility in question, that meant a saving of US$10 000/year.

In this example the extra cost of the electricity could almost equal the cost of purchasing two orthree pumps.

NOTE: Why the oversized pump?

• Safety margins were added to the original calculations.

• Several people were involved in the pump buying decision, and each of them was afraid ofrecommending a pump that would prove to be too small for the job.

• It was anticipated that a larger pump would be needed in the future, so it was purchased nowto save buying the larger one later on.

• It was the only pump the dealer had in stock and a pump was needed badly. The dealer mayhave proposed a ‘special deal’ on the larger size.

• The pump was taken out of the spare parts inventory. Capital equipment money is scarce so thelarger pump appeared to be the only choice.

Example 13: Pump selection

Affinity laws for pumpsThe basic laws governing a pump are:



Q1 / Q2 = N1 / N2,

e.g.: 100 / Q2 = 1750/3500,

Q2 = 200 GPM

H1/H2 = (N12) / (N22)

e.g.: 100 / H2 = 1750 2 / 3500 2

H2 = 400 Ft

P1 / P2 = (N13) / (N23)

e.g.: 5/P2 = 17503/ 35003

P2 = 40

Where: Q = discharge head

H = head

N = rpm

P = power

Flow control strategiesVarying flow requirements can be met by conventional and low cost options such as

by pass control or throttle control, but both of these methods are highly energy

inefficient. There are occasions when permanent change in the amount of fluid

pumped or a change in the discharge head of a centrifugal pump may be desirable.

This can be achieved economically by trimming the impeller or replacing it with a

reduced size impeller or, at the worst, replacing the pump itself.

The most efficient way to deal with varying flows is by means of a variable speed drive.

This ensures that the pump always operates at the best efficiency point and eliminates

the need for any throttling. The virtue of this method is that it reduces the energy input

to the system instead of dumping the excess. With decreasing costs in power

electronics, variable speed drives are becoming more popular today.

Variable flow requirements can also be met by multiple pump operation, with pumps

switching on and off as required.



Figure M.39: Rated pressure vs. rated flow

00

per

cent

rat

ed p

ress

ure

per cent rated flow

20

40

60

80

100

20 40 60 80 100 120

100%

80%

60%

40%

20%

Plm

Ppm

Worksheet: Pump rated specifications

Sectionno.

Parameter reference Units Pump reference

1 2 3 4

1

2

3

4

5

6

7

8

9

10

11

Make

Type (reciprocating/centrifugal)

Discharge capacity (flow)

Head developed

Density of fluid handled

Temperature of fluid handled

Pump input power

Pump speed

Pump efficiency

Specific power consumption

Pump motor:

Power

Full-load current

Voltage

Power factor

Speed

Frequency

Efficiency

m3/hr

mwc

kg/m3

°C

kW

rpm

%

kW/(m3/hr)

kW

Amps

Volts

PF

rpm

Hz

%

OPEN FILE



Worksheet: Pump performance evaluation

Sectionno.

Parameter reference Units Pump reference

1 2 3 4

1

2

3

4

5

6

7

8

9

10

11

12

13

Fluid flow measured or estimated (Q)

Suction pressure (include head correctiondue to pressure gauge location)

Discharge pressure (include headcorrection due to pressure gauge location)

Total dynamic head (3–2) (TDH)

Density of the fluid (γ)

Motor input power (P)

Frequency

Combined efficiency (pump + motor)(Q x γ ) x 9.81 x (TDH/γ) x 100

P

Pump efficiency =Combined efficiency x 100

motor efficiency


% Motor loadingw.r.t rated power

% Pump loadingw.r.t rated capacity

% Pump loadingw.r.t design TDH

m3/sec

mwc

mwc

mwc

kg/m3

kW

Hz

%

%

kW/(m3/hr)

%

%

%

OPEN FILE

M.1.9.4 Fan systems

IntroductionFans and blowers provide air for ventilation and industrial process requirements. They

are distinguished by the method used to move the air, and by the system pressure at

which they must operate. As a general rule, fans operate at pressures up to around 2 psi,

blowers at between 2 psi and 20 psi, although custom-designed fans and blowers may

operate well above these ranges. Air compressors are used for systems requiring more

than 20 psi. Figure M.40 shows the components of a centrifugal fan, one of the most

widely used air movers. The role of the components is explained below.



• Air inlet—air enters the turning impeller wheel.

• Impeller wheel—imparts energy to the air in the form of motion and pressure. As

the wheel turns, air between the blades is moved in the direction of the blade

and accelerated outward by centrifugal force.

• Shaft—turned by a motor coupled either directly to the shaft or via V-belts and

pulleys.

• Scroll housing—directs air from the impeller wheel to the fan outlet efficiently.

• Outlet—typically connected to a duct distributing the air to where it is needed.

Fans generate a pressure to move air (or other gases) against a resistance caused by

ducts, dampers, or other system components. The fan rotor receives energy from a

rotating shaft and transmits it to the air. The energy appears in the air, downstream of

the fan, partly as velocity pressure and partly as static pressure. The ratio of static to

velocity pressure varies for different fan designs. Fans are typically characterized by the

algebraic sum of the two pressures, known as total pressure. Parts of the fan other than

the rotor (such as the housing, straightening vanes, and diffusers) influence the ratio

of velocity and static pressure at the outlet, but do not add energy to the airflow.

Figure M.40 Fan system components

Air outlet Impeller wheel

Shaft

Air inlet

Scroll housing

Typical applications and efficienciesFan and blower selection depends on the volume flow rate, pressure, type of material

handled, space limitations, and efficiency. Fan efficiencies differ from design to design

and also between types. A range of fan efficiencies is shown in Table M.35. Table M.36

lists a few of the many applications and the type of equipment typically used.



Centrifugal fansAirfoil, backwardly curved/inclined

Modified radial

Radial

Pressure blower

Forwardly curved

Axial fan Van-axial

Tube-axial

Propeller

79–83

72–79

69–75

58–68

60–65

78–85

67–72

45–50

Table M.35: Typical efficiencies of various types of fans

Peak efficiency range Fan type

Material conveying system with high air/material ratioand fine, granular materials

Material conveying systems with low air/material ratioand materials prone to clogging distribution system

Supplying air for combustion

Boilers, forced draught

Boosting gas pressures

Boilers, induced draught

Kiln exhaust

Kiln supply

Process drying

Aeration and agitation systems

Plant ventilation and HVAC (clean air only)

Air knife blow off systems, clean-up air supply, vacuumcleaning systems

Radial, backward inclined fans Centrifugal blowers

Positive-displacement blowers

All fan types

Airfoil, backwards inclined, vane-axial fans

Centrifugal blowers

Forward curved, radial fans

Radial fans

Airfoil, backwards inclined, vane-axial fans

Airfoil, backwards inclined, radial, vane-axial, tube-axial fans. Centrifugal blowers

Centrifugal, positive-displacement blowers

Airfoil, backwards inclined, forward-curvedvane-axial, tube-axial, propeller fans

Centrifugal blowers

Table M.36: Applications of different types of fans and blowers

Application Type of fan or blower

Fan speed and gas flow rate A basic understanding of fan operating principles is necessary to evaluate the

performance of an industrial ventilation system. The fan speed, expressed as

revolutions per minute (rpm), is one of the most important operating variables. The

flow rate of the air moving through the fan depends on the fan wheel rotational speed.

As the speed increases, the airflow rate increases, as indicated by the sample data in

Table M.37.



800

900

1 000

1 100

1 200

16 000

18 000

20 000

22 000

24 000

Table M.37: Sample data—fan speed vs. airflow data

Air flow rate (actual cubic feet per minute — ACFM)

Fan wheel speed (rpm)

It is important to understand that a 10 per cent decrease in fan speed results in a

10 per cent decrease in the airflow rate through the ventilation system. This

relationship is expressed in the first fan law:

Note: The rate of airflow through a fan is always expressed in terms of actual cubic feet

per minute (ACFM).

Fan static pressure rise The air stream moving through the fan experiences a static pressure rise due to the

mechanical energy expended by the rotating fan wheel. As indicated in Figure M.41,

Where: Q1 = Baseline airflow rate, ACFM

Q2 = New airflow rate, ACFM

rpm1 = Baseline fan wheel rotational speed, revolutions per minute

rpm2 = New fan wheel rotational speed, revolutions per minute

Q2 = Q1

rpm2

rpm1

the static pressure at the outlet is always higher than the static pressure at the inlet.

The general equation for calculating the static pressure rise across a fan is:

Fan Sp∆ = SP(Fan outlet) – Sp Fan inlet) – VP(fan inlet)

Where: SP(Fan outlet) = Static pressure at fan outlet, in W.C.

SP(Fan inlet) = Static pressure at fan inlet, in W.C.

VP(Fan inlet) = Velocity pressure at fan inlet, in W.C.



The fan ∆SP (static pressure) is related to the square of the fan speed as indicated in

the second fan law shown below. The fan static pressure rise is usually expressed in

units of inches of water column.

Figure M.41 Static pressure rise (∆SP) across a fan

–10 in W.C

VP = 0.4 in. W.C.

Air in, ACFM

+0.05 in W.C

Air out, ACFM

Centrifugal fan

Fan ∆SP = [0.05 – (–10) – 0.4] in W.C. – 9.65 in W.C.

Where: Fan ∆Sp2 = Baseline fan static pressure rise, in W.C.

Fan ∆SP1 = New fan static pressure rise, in W.C.



Fan∆Sp2 = Fan∆SP1

rpm2

rpm1

2

The static pressure rise across the fan increases rapidly as fan speed increases. This is

illustrated in Table M.38, using sample data.

Speed vs. powerThe brake horsepower is related to the cube of the fan speed as indicated in the

third fan law, shown below:

Energy audit of a fanThe first step in the energy audit of a fan system is the collection of ducting details and

of fan characteristic curves. A typical curve is shown in Figure M.42.



Figure M.42 Fan characteristic curve

system

chara

cteris

tics

fan characteristics

efficiency

stat

ic p

ress

ure

acro

ss f

an (

kPa)

5.0

4.5

volume (m2/s)

00.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

10 20 30 40 50 60 70 80

fan

effic

ienc

y (%

)

100

90

0

10

20

30

40

50

60

70

80

Peak efficiency point A B Peak efficiency + 10%

3

800

900

1 000

1 100

1 200

5

5.6

6.3

6.9

7.5

Table M.38: Fan speed vs. fan static pressure rise

Fan ∆SP (in W.C.)Fan wheel speed (rpm)

Where: Q1 = Baseline brake horse power

Q2 = New brake horse power



BHP2 = BHP1

rpm2

rpm1

The fan and system operating efficiencies may then be determined from measurements

of the power input to the motor, the heads at various places in the system, and the

flow rate. The power input to the motor may be measured with a portable power

analyser. Heads may be measured by using a pitot tube and manometer. Along with

these measurements, the temperature of flow should also be measured (using a

thermometer or thermocouple) for calculation of flow density, using the known density

value at NTP (temperature 273 K and pressure 1 atm). The rpm of fan rotation may

also be measured using a tachometer.

Once the above measurements have been made, the fan and system efficiencies may

be calculated as follows:



Where: ρa = density of air at measured temp. (kg/m3)

ηm = efficiency of motor (0.85 for small kW motors, 0.9 for large kW motors

and 0.95 for HT motors)

Input kW = AC input power to motor terminals

Air kW =1000

Flow in TPH x1000

3600

Fan efficiency = x 100Air kW

ηm x input kW

( ) mmWC

1000( ) 100kg/m3

ρa( ) 9.81m/sec2( )kg

Secx mWC x x

CP-EE measures for fans and blowersImproving fan efficiency

When fan design efficiency is low, replacement by fans of a more efficient design may

be considered. Fan efficiency improvement may also be obtained when a fan impeller

design is changed from one of low intrinsic efficiency to one having higher intrinsic

efficiency, for example switching from radial bladed impeller to backward, straight

bladed impeller.

When fan-operating efficiency is low because of mismatch between fan and system

(resulting from over-design) the following may be considered:

• Reducing fan speed (by pulley change or variable speed drives).

• Replacement of impeller with a smaller one in the same series. Manufacturers

usually supply more than one impeller for the same casing, allowing a change in

head or flow. Depending on the specific job, this can allow either an increase or a

decrease in flow or head, typically 10–25 per cent.

• Reduction in impeller diameter, by cutting it.

Improving system efficiency

When system efficiency is to be improved, a detailed audit of the ducting may be done.

In addition to the losses from leaks/ingress there are often a number of flow losses that

can be reduced when the system is analysed to pinpoint specific areas where energy

savings can be made.

Even small leaks represent a constant parasitic loss of energy and of system efficiency.

All leaks in the ducting should be located and eliminated.

Examine the possibility of reducing pressure loss in bends, cross-sectional area changes

and stream splits and joints, through redesign.

Reducing damper losses

Throttle dampers are a very common means of controlling flow delivered by a fan.

They regulate the flow by offering mechanical resistance to it, thereby consuming a

large amount of energy in the form of head loss across the damper.

Where capacity regulation is desired it is, therefore, desirable to use one of the

following methods in preference to damper control:

• Inlet guide vanes.

• Variable speed fluid couplings or eddy current couplings.

• Liquid rotor resistance control.

• Variable speed AC/DC drives.

The variations in power consumption for different methods of capacity regulation are

shown in Figure M.43.





Worksheet: Rated fan specifications

Sectionno.

Parameter reference Units Fan reference

1 2 3 4

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

Make

Type (axial/centrifugal) (Backward curve/forward curve)

Discharge flow

Total head developed

Name of fluid medium handled

Temperature of fluid medium handled

Density of fluid handled

Dust concentration

Flow control type

Flow control range

Fan input power

Fan speed

Fan efficiency


Fan motor

Rated power

Full-load current

Voltage

Power factor

Speed

Frequency

Efficiency

–

–

m3/hr

mwc

–

°C

kg/Nm3

mg/Nm3

–

%

kW

rpm

%

kW/(m3/hr)

kW

Amps

Volts

PF

rpm

Hz

%

Energy savings from variable speed drives

From To % savings1. Constant volume Outlet dampers 112. Constant volume Inlet vanes 313. Constant volume VFDs 724. Outlet dampers Inlet Vanes 235. Outlet dampers VFDs 696. Inlet vanes VFDs 59

Figure M.43 variable speed drives for fans and pumps

OPEN FILE



Worksheet: Operating parameters and performance

Sectionno.

Parameter reference Units Fan reference

1 2 3 4

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Fluid (medium) flow (Q)(measured using pitot tube at fandischarge)

For suction pressure (measured at fan inlet using U-tubemanometer)

For discharge pressure (measured at fan discharge usingU-tube manometer)

Total head developed (TDH)[3–4/1000]

Temperature of fluid medium (measured at fan inlet using athermometer)

Density of fluid medium handled (r)(taken from standard data andcorrected to operatingtemperature/pressure conditions)

Motor input power (P) measured atmotor terminals or switchgear usingpanel or portable energymeter/power analyser

Frequency

Combined efficiency ( fan + motor)(Q x r) (9.81) (TDH/r) x 100

P x 1000

Fan efficiency =Combined efficiency x 100

Motor efficiency

% Motor loading w.r.t rated power

% Motor loading w.r.t rated capacity

% Motor loading w.r.t rated head


m3/sec

mmWC

mmWC

mWC

°C

kg/m3

kW

Hz

%

%

%

%

%

kW/(m3/h)

OPEN FILE

M1.9.4 Compressed air systems

Compressed air is used in almost all types of industries and accounts for a major share

of the electricity used in some plants. It is used for a variety of end-uses such as

pneumatic tools and equipment, instrumentation, conveying, etc. and is preferred in

industry because it is convenient clean, readily available and safe. Compressed air is

probably the most expensive form of energy available in a plant, yet it is still often

chosen for applications for which other energy sources would be more economical—

for example, pneumatic grinders are chosen rather than electric ones.

As a general rule, compressed air should only be used if safety improvement, significant

productivity gains, or labour reductions will result. Typical overall efficiency is around

10 per cent.

Depending on requirements, compressed air systems consist of a number of

components: compressors, receiver, filters, air dryers, inter-stage coolers, oil separators,

valves, nozzles and piping. Figure M.44 shows a system layout.

The compressor is the main system component—it must therefore be selected

carefully. The most commonly used compressors in industry are reciprocating and

screw types. Centrifugals are also used where very large volumes are required.



Figure M.44 Layout of a compressed air system

Reciprocating compressorsA reciprocating compressor (see Figure M.45) is a positive displacement machine that

uses a piston moving inside a cylinder to produce compression. The piston moves

through the cylinder, sucking in atmospheric air at one

end of its stroke and compressing it at the other.

Reciprocating compressors are available as ‘oil-free’ or ‘lubricated’ types. The reciprocating

compressor probably accounts for most of the compressors used worldwide.

Screw compressorsA screw compressor (see Figure M.46) is a positive displacement machine that uses a

pair of intermeshing rotors instead of a piston to produce compression. The rotors

comprise helical lobes fixed to a shaft.



Figure M.45 A reciprocating compressor

First stage

Second stage

Baseplate Crankcase (frame)Drive motor

Figure M.46 A screw compressor

One rotor, called the male rotor, will typically have four bulbous lobes. The other,female, rotor has valleys machined into it that match the curvature of the male lobes.Typically, female rotors have six valleys meaning that for one revolution of the malerotor, the female rotor only turns through 240°. For the female rotor to complete onecycle, the male rotor has to rotate 1.5 times. Screw compressors are available as oil-freemachines, oil-lubricated machines and, more recently, as water lubricated machines.

CP-EE options in compressed air systemsA comprehensive compressed air system audit should include an examination of both airsupply and usage and the interaction between supply and demand. An audit determinesthe output (flow) of a compressed air system, energy consumption in kilowatt-hours,annual cost of operating the system and total air losses due to leaks. All components of thecompressed air system are inspected individually and problem areas are identified. Lossesand poor performance due to system leaks, inappropriate use, demand events, poor systemdesign, system misuse, and total system dynamics are evaluated and CP-EE measures arederived. Important aspects of a basic compressed air system audit are discussed below.

Pressure dropA properly designed system should have a pressure loss of much less than 10 per centof the compressor's discharge pressure, measured between the receiver tank outputand the point of use. Excessive pressure drop will result in poor system performanceand excessive energy consumption.

LeaksAs illustrated by Figure M.47, leaks can be a significant source of wasted energy in anindustrial compressed air system, sometimes wasting 25–50 per cent of a compressor'soutput. Proactive leak detection and repair can reduce leaks to less than 10 per cent ofcompressor output.



Size Cost per year

1/16" US$523

1/8" US$2 095

1/4" US$8 382

Figure M.47 Leaks and losses

Cost calculated using electricity rate of US$0.05 per kWh,assuming constant operation and an efficient compressor.

In addition to being a source of wasted energy, leaks can also contribute to other

operating losses. Leaks cause a drop in system pressure, which can make air tools

function less efficiently, adversely affecting production. In addition, by forcing the

equipment to cycle more frequently, leaks shorten the life of almost all system

equipment (including the compressor package itself). Increased running time can also

lead to additional maintenance requirements and increased unscheduled downtime.

Finally, leaks can lead to addition of unnecessary compressor capacity.

Leakage can come from any part of the system, but the most common problem areas

are couplings, hoses, tubes, and fittings, pressure regulators, open condensate traps

and shut-off valves and pipe joints, disconnects, and thread sealants.

Estimating amount of leakage For compressors that use start/stop controls, there is an easy way to estimate the

amount of leakage in the system. This involves starting the compressor when there are

no demands on the system (i.e. when all the air-operated end-use equipment is turned

off). A number of measurements are taken to determine the average time it takes to

load and unload the compressor. The compressor will load and unload because the air

leaks will cause it to cycle on and off as the pressure drops from air escaping through

the leaks. Total leakage (percentage) can be calculated as follows:

where: T = on-load time (minutes)

t = off-load time (minutes)

Leakage will be expressed in terms of the percentage of compressor capacity lost. The

percentage lost to leakage should be less than 10 per cent in a well-maintained system.

Poorly maintained systems can have losses as high as 20–30 per cent of air capacity

and power. These tests should be carried out quarterly, as part of a regular leak

detection and repair programme.

Leak detection Since air leaks are almost impossible to see, other methods must be used to locate

them. The best way to detect leaks is to use an ultrasonic acoustic detector that

recognizes the high frequency hissing sounds associated with air leaks. These portable

units consist of directional microphones, amplifiers, and audio filters, and usually have



Leakage (%) = (T x 100)

(T + t)

either visual indicators or earphones to detect leaks. A simpler method is to apply

soapy water with a paintbrush to suspect areas. Although reliable, this method can be

time consuming.

How to fix leaks Leaks occur most often at joints and connections. Stopping leaks can be as simple as

tightening a connection or as complex as replacing faulty equipment such as

couplings, fittings, pipe sections, hoses, joints, drains, and traps. In many cases leaks

are caused by bad or improperly applied thread sealant. Select high quality fittings,

disconnects, hoses, tubing, and install them properly with appropriate thread sealant.

Non-operating equipment can be an additional source of leaks. Equipment no longer

in use should be isolated by a valve in the distribution system. Once leaks have been

repaired, the compressor control system should be re-evaluated to ascertain the total

savings potential

A leak prevention programmeA good leak prevention programme will include the following components: identification

(including tagging), tracking, repair, verification, and employee involvement. All facilities

with compressed air systems should establish an aggressive leak prevention programme.

A cross-cutting team involving decision-making representatives from production should be

formed. The leak prevention programme should be part of an overall programme aimed

at improving the performance of compressed air systems. Once leaks are found and

repaired, the system should be re-evaluated.

Rationalization of compressed air useThe need for compressed air should be questioned at every usage point. In some

instances, the volume of air may be more important than pressure. Under such

circumstances alternative options like centrifugal blowers or roots blowers can be

considered. Misuse of compressed air for cleaning should be avoided.

Using lower pressureCompressor discharge pressure should be closely matched with the requirement

(allowing for pressure drops in the distribution system). Higher than necessary

discharge pressure is detrimental to performance since it increases the compression

ratio and hence the power consumption.

Table M.39 illustrates the effect of increased discharge pressure on specific power

consumption of reciprocating compressors.



Heat recoveryAs much as 80–93 per cent of the electrical energy used by an industrial air compressor

is converted into heat. In many cases, a properly designed heat recovery unit can

recover anywhere from 50–90 per cent of this available thermal energy and put it to

use heating air or water.

Typical uses for recovered heat include additional space heating, industrial process

heating, water heating, make up air heating, and boiler make up water preheating.

Recoverable heat from a compressed air system is not, however, normally hot enough

to be used to produce steam directly.

Use of multiple compressorsWhen the demand on a compressed air system is variable in nature, and exhibits well

defined peak and slack demand periods, use of a single compressor designed to meet

peak demand would lead to under-loading of the compressor and increased duration

of the no-load cycle. Unloading power is 30 per cent of full load power. In this

situation, energy savings can be realized by using multiple compressors. The number

of compressors in operation is adjusted to the compressed air demand, thereby

avoiding under-loading of compressors.

Replacement/de-rating of oversized compressors In the case of oversized compressors, the power wastage during unloading can be

reduced by either replacing the compressor in the case of oversized machines, or by

de-rating. De-rating can be achieved by running the compressor at a lower speed.



1

2

3

4

7

8

10

15

Single

Single

Single

Single

Double

Double

Double

Double

21.1

20.3

19.3

18.0

19.0

18.9

19.5

19.2

2.22

3.40

4.60

5.14

6.47

6.76

7.67

9.25

Pressure (bar) No. of stages Volume flow(m3/min)

Specific power(kW/m3/min)

Table M.39: Effect of increased discharge pressure on specific power consumption



Empirical relationsSome useful empirical relationships for compressors are given below:

Leakage (Nm3/min) =

x (Compressor capacity Nm3/min)

Compressor Capacity (FAD) Nm3/hr =

Specific power consumption =

Load time

Unload time + Load time( )

Initial receive pressure kg/cm2.a – final receiver pressure kg/cm2.a

Atmosphere pressure kg/cm2.a( ) x

xVolume of receiver + volume of line between compressor and receiver in m3

Time taken to fill receiver from initial pressure to fonal pressure in minutes( )273

273 + reciever temperature °C( )

Actual motor power input

FAD (Nm3/m)( ) x 100



Worksheet: Compressor rated specification

Air compressor reference Units Compressor reference

1 2 3 4

Make

Type

No. of stages

Discharge capacity

Discharge pressure

Speed

Receiver capacity

Motor rating

Power

Full load current

Voltage

Power factor

Speed

Frequency


–

–

–

Nm3/min

kg/cm2.g

rpm

m3

kW

Amps

Volts

P.F.

rpm

Hz

kW/m3/min

OPEN FILE



Worksheet: Capacity testing

Air compressor reference Units Compressor reference

1 2 3 4

Receiver volume plus volumeof pipeline between receiverand the air compressor

Receiver temperature

Initial receiver pressure (P1)

Final receiver pressure (P2)

Time taken to fill receiverfrom P1 to P2 (t)

Atmospheric pressure (Po)

Air compressor capacity (free air delivery) Q

m3

°C

kg/cm2.a

kg/cm2.a

mins.

kg/cm2.a

Nm3/min

Note: Each compressor must have its own receiver.

Procedure:

1) The air compressor being tested for capacity is first isolated from the rest of thesystem, by operating the isolating non-return valve.

2) The compressor drive motor is shut-off.

3) The receiver connected to this air compressor is emptied.

4) The motor is re-started.

5) The pressure in the receiver begins to rise. Initial pressure, say 2 kg/cm2 , is noted. The stopwatch is started at this moment.

6) The stopwatch is stopped when receiver pressure has risen to, say, 9 kg/cm2.

7) Time elapsed is noted.

8) Compressor capacity is evaluated as:

(Nm3/min) = x xP2 – P1

P0 )( 273

273 + T)(Vr

t )(

OPEN FILE



Worksheet: Leakage testing

Compressor in operation Units Names of section of factory

Compressed air users

Load time (t1)

Unload time (t2)

Capacity of compressor

Leakage

Leakage cfm

x (Capacity of compressor)

--

Seconds

Seconds

Nm3/min

%

Two (assumed)

(Measured)

(Measured)

(Given)

(Evaluated)

(Evaluated)

Note:

1) Per cent or Nm3/min of compressed air leakage is evaluated, and the energy cost ofcompressed air is determined.

2) Plant survey is undertaken to physically identify obvious compressed air leakages. Noinstruments are really necessary. However, an ultra-sonic leak detector may be used,optionally.

3) Elimination of leakage sources leads to direct and immediate compressed air andelectricity cost savings.

Procedure:

1) Leakage test is conducted when entire plant is shut-down or when all compressed airusers are not working. It would be advantageous if separate sections could be isolatedfrom one another by isolating valves.

2) A dedicated compressor is switched on to fill the system network with compressed air.

3) Since there are no compressed air users, the air compressor will unload the momentthe system pressure reaches the set point (say, 8 kg/cm2.g).

4) If the system has no leaks, the air compressor will remain unloaded indefinitely.

5) However, since there are bound to be system leaks, the receiver pressure graduallybegins to drop, until the lower set point is reached, at which point the air compressoris loaded again and begins to generate compressed air.

6) Load and unload times are measured using a stopwatch over 5–6 cycles, and averageload and unload times are worked out.

7) Compressed air leakage (%) and quantity are then evaluated.

t1

t1 + t2x 100)(

Leakage %

100 )(

spotlightCP-EE

• Leakage will beexpressed in terms ofthe percentage ofcompressor capacity lost.

• The percentage lost toleakage should be lessthan 10 per cent in awell-maintained system.

• Poorly maintainedsystems can have lossesas high as 20–30 percent of air capacity.

OPEN FILE

M1.10 Cooling towers

M1.10.1 Basics of cooling towers

Heat removed from a process or building must be disposed of. In many cases, this heat

is transferred to water at a lower temperature via a heat exchanger. It is then

transferred to a heat sink.

Billions of gallons of water are used every day for air conditioning/refrigeration systems

and for industrial process cooling in, for example, paper mills, chemical plants, food

processing, etc. To reduce both water costs

and pressure on water supplies, much of

this cooling water is re-circulated. Final

exchange of heat from a building or

process to a heat sink is often by means of

a water-to-air heat exchanger, with the

atmosphere being the heat sink.

These water-to-air devices are called

cooling towers. They play a vital role in

water conservation, typically reducing

water consumption by 95 per cent or

more, depending on whether an

evaporative or dry tower is used.

From the thermodynamic point of view, there are three basic types of cooling tower.

Wet or evaporative towers are ones in which the water to be cooled comes in contact

with the outdoor air. Both latent and sensible cooling occurs. These towers have the

highest thermal efficiency. They also consume more water than the other two types

(see below), but a 95 per cent saving is still significant.

A dry tower is one in which the water to be cooled flows within an extended heat

transfer surface—a finned tube coil—over which atmospheric air is blown.

The third type of tower is the wet-dry type, which combines the functions of the two

previous types. Table M.40 includes some terminology to aid understanding. The

discussion thereafter focuses on wet towers.





Air flow

Approach

Capacity controldampers

Casing

Cavitation

Cold water basin

Composite

Concentrationratio

Conductivitymonitor

Cooling range

Cooling tower ton

Counter flow

Cross flow

Cycles ofconcentration

Discharge hood

Drift loss

Dry bulb

Total quantity of air including the associated water vapour flowing through thetower.

Difference between re-cooled water temperature and the inlet air wet bulbtemperature.

Airfoil blades placed at the discharge of a centrifugal fan that change positionso as to regulate airflow.

The part of a cooling tower enclosing the wet deck fill.

The phenomenon that occurs in a water pump when the pressure becomessufficiently low to allow vaporization of the fluid followed by a sudden collapseof the vapour ‘bubble’ as it passes to the high pressure area of the pump.

The collection point near the bottom of a cooling tower for the collection ofcooled water.

Construction material utilizing high strength glass materials held in place bycured epoxy resins in a precise order so as to maximize strength.

Ratio of the total mass of impurities in the circulating water to thecorresponding total mass in the make up water.

A device that measures the ease with which electricity passes through coolingsystem water. Conductivity is directly proportional to the amount of dissolvedsolids in the water and is used to initiate bleeding, feeding chemicals, etc.

Difference between the hot water temperature and the re-cooled watertemperature.

15 000 Btu/hr.

A cooling tower configuration where the air and water flow in oppositedirections.

A cooling tower configuration where the air and water flow at right angles toone another.

The number of times the solids content of water has been increased. Two fold = 2 cycles; three fold = 3 cycles, etc.

A discharge duct with sides that gently taper reducing the cross sectional areathereby accelerating the discharge air. Used to ‘blast’ discharge air from anenclosure to reduce recirculation potential. Note: suitable for centrifugal fantowers only.

Water loss caused by liquid drops carried away by the outlet air stream.

Temperature of air measured with a conventional thermometer with a dry bulb.

Table M.40: Table of cooling tower terminology

continued …



Eliminator

Equalizer line

Fan deck

Fill

Hot water basin

Latent heat

Louvers

Make up

Psychrometricchart

Purge

Range

Re-circulation

Sensible heat

Ton

Turn down

Velocity recoverystack

Wet bulb

A device placed in the discharge airstream of a cooling tower that attempts to‘eliminate’ entrained water droplets. It works by rapidly changing the directionof airflow causing the heavier water particles to collide with the eliminatorsurface and fall back inside the tower.

A pipe connected between the cold water basins of multiple cooling towers. Itspurpose is to force ‘equalization’ of water levels.

The upper horizontal surface surrounding the fan stacks of a draw-through,propeller fan cooling tower.

Material added to a cooling tower to enhance evaporation.

Water collection area at the top of a crossflow cooling tower the bottom ofwhich is perforated to distribute water over the wet deck fill.

Heat which changes the properties of a material without changing itstemperature.

Horizontal blades placed at the air inlet of some cooling towers to preventwater from splashing out.

Water added to the circulating water system to replace leakage, evaporation,drift loss and purge.

A graphical representation of the physical characteristics of air.

Water deliberately discharged from the system in order to reduce theconcentration of salts and other impurities in the circulating water.

A cooling tower’s inlet water temperature minus its outlet water temperature.

The proportion of outlet air which re-enters the tower.

Heat that increases the temperature of a body to which it is added.

The rate of heat transfer represented by 2 000 tons of ice melting in a 24 hourperiod (12 000 Btu/hr).

The allowable percentage reduction of inlet water flow to a cooling tower.

A hyperbolic discharge plenum at the top of a draw-through, prop. fan coolingtower. The shape increases the efficiency of the fan by converting some of thevelocity pressure to static pressure for increased air flow.

The temperature read from the wet bulb of a thermometer placed in a movingair stream.

… Table M.40: Table of cooling tower terminology (continued)

spotlightCP-EE

Inefficient operation of atower with a cold water

temperature around1.5 °C higher than it

should be can increaseprocess plant energy

consumption by10 per cent or more.

M1.10.2 Energy audit of cooling towers

Cooling towers are energy audited to assess present levels of approach and range

against their design values; to identify areas of energy wastage; and to suggest

improvements. During an energy audit, parameters such as those listed below are

measured, using portable instruments:

• Wet bulb temperature of air

• Dry bulb temperature of air

• Cooling tower inlet water temperature

• Cooling tower outlet water temperature

• Exhaust air temperature

• Electrical readings of pump and fan motors

• Water flow rate

• Air flow rate

The instruments used and the corresponding parameters measured are listed in

Table M.41.



Various electrical parameters such as kW, kVA, P.F., voltage, current and frequency are

measured using the power analyser. Knowing the percentage loading and power factor

of a motor, it is possible to estimate its operating efficiency from motor characteristic

curves. If efficiency is low, the possibility of replacing it with a new motor may have to

be considered.

Sling hygrometer

Temperature indicator withthermocouple

Flow meter

Anemometer

Power analyser

Wet bulb and dry bulb air temperature

Water temperature

Water flow rate

Air flow rate

Pump and fan electrical parameters

Parameters measuredInstrument used

Table M.41: Instruments and the parameters measured



Worksheet: Cooling tower performance

Sectionno.

Parameter reference Units Cooling tower reference

1 2

1

2

3

4

5

6

7

8

9

10

11

12

Dry bulb temperature

Wet bulb temperature

CT inlet temperature

CT outlet temperature

Range

Approach

CT effectiveness

Average water flow

Average air quantity

Liquid gas (L/G) ratio

Evaporation loss

CT heat loading

°C

°C

°C

°C

°C

°C

%

kg/hr

kg/hr

kg water/kg air

m3/hr

kcal/hr

Basic equations used

a) CT Range (°C) = [CW inlet temp (°C) – CW outlet temp (°C)]

b) CT Approach (°C) = [CW outlet temp (°C) – Wet bulb temp (°C)]

c) CT Effectiveness (%) = 100 x (CW temp – CW out temp) / (CW in temp – WB temp)

d) L/G Ratio (kg/water/kg air) = Total CW water flow in CT (kg/hr) / Total air flow in CT (kg/hr)

e) CT heat loading (kcal/hr) = CW flow (m3/hr) x ∆T (°C) x density of water (kg/m3)

f) CT evaporation loss (CMH) = CW circulation (CMH) x CW Temp. difference across CT in °C rate / 675

g) % Evaporation loss in cooling tower = Evaporation loss in CMH x 100 / CW circulation rate CMH

OPEN FILE

M1.11 Refrigeration and air-conditioning

Refrigeration is the process of lowering the temperature of a substance below that of

its surroundings. Process industries are the major users of refrigeration facilities.

Refrigeration is used to remove the heat of chemical reactions; to liquefy gases; to

separate gases by evaporation and condensation; and to purify products by preferential

freeze-out of one component from a liquid mixture. It is also extensively used in air-

conditioning of plant areas for comfort, process and thermal environment uses, as well

as in hotels, hospitals and office buildings, etc.

M1.11.1 Unit of refrigeration

Refrigeration capacity is normally expressed in tons of refrigeration (TR).

One ton of refrigeration is the amount of heat extracted to produce one ton of ice at

0 °C from water at 0 °C in 24 hours:

1 TR = 210 kJ/min = 50 kcal/min

M1.11.2 Types of refrigeration

There are two popular types of refrigeration system used in industry: vapour

compression and vapour absorption.

Vapour compression refrigeration systemsFigure M.48 shows the vapour compression refrigeration cycle. The refrigerant enters

a compressor at low pressure and at a temperature a few degrees higher than its

boiling point at that pressure. In the compressor, both the temperature and the

pressure of the refrigerant gas rise. The types of compressors normally employed are:

reciprocating, rotary vane, twin screw, single screw, centrifugal, and scroll.

The hot gas from the compressor then goes into the condenser. The gas first cools

from the compressor discharge temperature to the condensing saturation temperature,

giving up its sensible heat. Most of the heat transfer in the condenser (latent heat)

occurs when the refrigerant changes from a gas to a liquid. The types of condensers

used are: water-cooled shell and tube, air-cooled, and evaporative.

The liquid refrigerant then passes to an expansion valve, where its pressure is reduced,

during which some of the liquid flashes off, forming a mixture of low temperature



liquid and low temperature vapour. Various types of valves are used: high-pressure float

valves, low-pressure float valves, and thermostatic expansion valves.

The liquid refrigerant passes to the evaporator where it is vaporized at constant

temperature. The refrigerant vapour is then returned to the compressor suction line

and the circuit is complete. Types of evaporators are: direct expansion, flooded shell

and tube, and re-circulation.

Vapour absorption refrigerationVapour absorption systems use a heat source instead of the compressor. This is an

economically attractive proposition where waste heat is available. The working

principle is described in Figure M.49 and important facts are listed below:

• The common commercial absorbent/ refrigerant pair is lithium bromide

(L-Br)/water.

• The refrigerant travels from the evaporator to the absorber as a vapour.

• The absorbent has a strong affinity for the refrigerant and absorbs it, creating a

vacuum (–0.2 psia in a L-Br system); the heat is removed by cooling water.

• The refrigerant–absorbent solution is then pumped towards the condenser,

passing through the generator.

• Heat applied to the generator causes the refrigerant to vaporize, leaving behind

the absorbent liquid.

• The refrigerant vapour, now separated from the liquid absorbent, travels to the

condenser.

• The liquid absorbent is re-circulated to the absorber through the regulating valve,

bringing it down to the evaporator pressure.



Figure M.48 The vapour compression cycle

high pressure liquid

low pressure liquidand flash gas

expansion valve

CONDENSER

EVAPORATOR

lowpressuregas

highpressuregas

suction

discharge

compressor

M1.11.3 Energy efficiency evaluation

Once a refrigeration system has been installed, its operating efficiency and overall

running costs will be largely determined by the effectiveness of day-to-day monitoring.

The commonly used figures for comparison of refrigeration systems are: the Coefficient

of Performance (COP), Energy Efficiency Ratio (EER), and Specific Power Consumption

(SPC).

If both the refrigeration effect (heat removed from evaporator) and the work done by

the compressor (or the input power) are in the same units (TR or kcal/hr or kW or

Btu/hr), the ratio is:

If the refrigeration effect is expressed in kcal/hr and the work done in watts, the ratio is:

The other commonly used and easily understood useful figure is Specific Power

Consumption (SPC):



Figure M.49 The vapour absorption cycle

COP = Refrigeration effect

Power supplied

EER = Refrigeration effect (Btu/hr)

Power supplied (Watts)

weaksolution

GENERATOR

ABSORBER

regulatingvalve

strongsolution

condenser

evaporator

throttlingvalve

cooling water

pump

waste heat/direct fired

SPC = Power consumption(kW)

Refrigeration effect (TR)

M1.11.4 Estimation of capacity of refrigeration system and

air-conditioning systems

The capacity of the liquid chilling system can be estimated if water/brine flows and

chiller inlet/outlet temperatures are known:

Where: Q = flow (m3/hr)

d = density (kg/m3)

s = specific heat (kcal/kg/°C)

Tin = temperature at inlet (°C)

Tout = temperature at outlet (°C)

Method of capacity estimation for systems having hot wells and cold wells tobalance primary and secondary refrigerantsFor this method of estimation of refrigeration capacity, the secondary pump (process

side) should be switched off for about 30 to 60 minutes. The compressor and primary

pumps should then be operated and the time to drop the temperature of the

secondary refrigerant in the hot and cold well by about 5 °C should be noted.

Where: V = volume of the secondary refrigerant in the hot and cold well (m3)

d = density of the secondary refrigerant (kg/m3)

∆T = drop in temperature (°C)

t = time taken (hours)

s = specific heat of the secondary refrigerant (kcal/kg/°C)



Heat load (TR) = Q x d x s x (Tin – Tout)

3023

Cooling capacity = +V x d x s x dT

(3023 x t)

Primary power pump (kWt)

3.51

M1.11.5 Heat load calculation for centralized air-conditioning systems

Where: Q = flow, m3/hr (can be measured with an anemometer)

D = density, kg/m3 (1.2 kg/m3 approx.)

hin = enthalpy at AHU inlet, kJ/kg

hout = enthalpy at AHU outlet, kJ/kg

(Dry bulb and wet bulb temperatures can be measured at the air-handling unit (AHU)

inlet and outlet; this data can be used with a psychrometric chart to determine the

enthalpy of air at the AHU inlet and outlet.)

The power consumption for these systems can be measured using a portable power

meter or an energy meter—specific power consumption can then be calculated.



Heat load (TR) = Q x d x (hin – hout)

4.18 x 3023



Worksheet: Refrigeration and AC system rated specifications

Sectionno.

Refrigeration compressor Units Machines reference

1 2 3 4

1

2

3

4

5

6

7

Make

Type

Capacity (of cooling)

Chiller:

a) No. of tubes

b) Diameter of tubes

c) Total heat transfer area

d) Chilled water flow

e) Chilled water temp. difference

Condenser:

a) No. of tubes

b) Diameter of tubes

c) Total heat transfer area

d) Condenser water flow

e) Condenser water temp. diff.

Chilled water pump:

a) Nos.

b) Capacity

c) Head developed

d) Rated power

e) Rated efficiency

Condenser water pump:

a) Nos.

b) Capacity

c) Head developed

d) Rated power

e) Rated efficiency

TR

–

m

m2

m3/hr

°C

m

m3/hr

°C

–

m3/hr

mWC

kW

%

–

m3/hr

mWC

kW

%

OPEN FILE



Worksheet: Operating parameters

Sectionno.

Parameter reference Units Refrigeration compressor reference

1 2 3 4

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

Chilled water flow (using a flow meter orassessed by level difference)

Chilled water pump motor input power

Chilled water pump suction pressure

Chilled water pump discharge pressure

Chiller water inlet temperature to chiller

Chiller water outlet temperature fromchiller

Condenser water inlet temperature

Condenser pump suction pressure

Condenser pump discharge pressure

Condenser water outlet temperature

Chiller (evaporator) outlet refrigeranttemperature

Refrigerant pressure

Condenser inlet refrigerant temperature

Refrigerant pressure

Actual cooling capacity [(1)*(6-5)/3024]

COP [11/(10-11)]

Compressor motor input power

Specific energy consumption

Input power to CT fan

Input power to chilled water pumps inoperation

Input power to condenser water pumpsin operation

Overall system specific powerconsumption [(2+17+19+20)/15]

m3/hr

kW

kg/cm2g

kg/cm2g

°C

°C

°C

kg/cm2

kg/cm2

°C

°C

kg/cm2 (or psig)

°C

kg/cm2 (or psig)

TR

–

kW

kW/TR

kW

kW

kW

kW/TR

OPEN FILE

M1.12 Lighting systems basicsA lighting system comprises all of the components necessary to deliver a desired level

of space illumination. It includes components such as switches to control power,

wiring, voltage stabilizers, lighting luminaires, fixtures, control gear, shade of walls,

shape of room, etc. A lighting system is shown in Figure M.50.



Periodic maintenance of the lighting system installed on the shop floor has a profound

impact on the energy consumed. In many industrial lighting systems, the fittings act

as dust traps. If they are not cleaned periodically, they will collect more dust resulting

in lower illumination.

Efficient lamps and luminaires can not only reduce maintenance costs, they can even

lower power consumption. For instance, use of twin-lamp fluorescent fittings with

polystyrene diffusers can provide the same degree of lighting with lower wattage

consumption. Similarly, high pressure sodium lamps provide energy savings of up to

80 per cent compared to high wattage tungsten filament lamps.

Figure M.50 A lighting system

ceiling

wiring

lightingcontrols

switch

electricity in

wall

floor

work surface

fixture

lens or diffuser

wall

desired area of illumination

In some systems, electronic control can provide energy conservation of around 25 per

cent at near unity power factor. Automatic switch off of lights can be provided when

they are not required. Solar or mechanical timer switches can be used to turn off

artificial lighting as soon as the optimum light level is reached.

M1.12.1 Choice of lighting

The following guidelines will help in choosing lighting:

Choose the right light

which is positioned where it is needed

used only when it is needed

for as long as it is need

and at the illumination level needed.

Search for savingsWith so many different types of lighting on the market, levels of efficiency and

performance must be known if the best choice is to be made. Table M.42 gives the

luminous efficiency of various lamp sources.



1

2

3

4

5

6

7

8

Incandescent lamps

Cool daylight fluorescent tubes

White fluorescent tubes

High pressure mercury vapour lamps

80 W

125 W

400 W

High pressure sodium lamps

70 W

250 W

400 W

Low pressure sodium lamps

10 W

18 W

Tungsten halogen

Metal halide

15

50–60

60–85

36

41

52

82

100

117

100

175

25

60–85

1 000

5 000

5 000

5 000

5 000

5 000

10 000

10 000

10 000

10 000

10 000

5 000

5 000

Section no. Efficiency (lumens/watt)

Average workinglife (hours)

Light sources

Table M.42: Luminous efficiencies

The table shows ranges of efficiency and lamp-life. As can be seen, the lighting

efficiency (lumens per watt) of a low-pressure sodium lamp is many times

(10–17 times) greater than that of an incandescent (tungsten-filament) lamp. It should

also be noted that, in general, the efficiency of a specific lamp type is higher for higher

power lamps.

Fittings should always be suitable for the maximum wattage of lamp with which they

are used. Higher wattage of lamps will produce more heat and could damage the

fittings or shade and may even cause a fire.

Fluorescent tube lights are preferred to general lighting service (GLS) lamps because,

for the same amount of electricity consumption, they produce four times the amount

of light obtainable from GLS lamps. The tubes last much longer, as they have a life

of 6 000 to 7 000 hours, although frequent switching on and off shortens this

substantially.

Today, so-called ‘electricity saving’ bulbs can be used as a substitute for tungsten

filament bulbs. These are compact fluorescent tubes which can be screwed into the

existing conventional bulb socket. These compact fluorescent bulbs consume about 80

per cent less electricity than a conventional bulb while producing the same amount of

light. They also have a life about 6 to 8 times longer.

Table M.43 shows norms of illuminance required for various work stations.

M1.12.2 Control of lighting

Even with efficient lamps and luminaires, energy used for lighting can be wasted in

several ways. In general, people usually turn lighting on only when they need it, but

cannot be relied upon to turn it off when daylight would provide adequate light, or

when rooms are unoccupied. The ideal solution would be to provide a manual switch

and some form of control for switching off.

A further source of unnecessary use results from the common practice of controlling

large areas of lighting with small numbers of switches, or by having confusing

switch layouts so that individual requirements can only be met by turning on many

luminaires. Controls are a very effective way of reducing lighting costs, but before

incurring significant capital costs, it is suggested that occupancy patterns and

behaviour be studied.





General lightingfor rooms andareas usedinfrequentlyand/or casuallyor for simplevisual tasks.

General lightingfor Interiors

20

30

50

75

100

150

200

300

500

750

1 000

1 500

2 000

Minimum service illuminance in exterior circulation areas

Outdoor stores and stockyards

Exterior walkways and platforms, indoor tasks, car parks

Docks and quays

Theatres and concert halls, hotel bedrooms, bathroomsand corridors

Circulation areas in industry, stores and stock rooms

Minimum service illuminance for a task (visual tasks notrequiring any perception of detail)

Rough bench and machine, motor vehicle assembly, printingmachine rooms, general offices, shops and stores, retail salesareas

Medium bench and machine, motor vehicle assembly,printing machine rooms, general offices, shops and stores,retail sales areas

Proofreading, general drawing office, offices with businessmachines

Fine bench and machine work, office machine assembly,colour work and critical drawing tasks

Very fine bench and machine work, instrument and smallprecision mechanism assembly, electronic componentsgauging and inspection of small intricate parts; may bepartly provided by local lighting

Minutely detailed and precise work, e.g. very small parts ofinstruments, watch making and engraving, operating areain operating theatres—2 000 lux minimum

Lighting systems Illuminance (lux)

Table M.43: Luminous efficiencies

Manual controlsSwitch arrangements should at least permit individual rows of luminaires parallel and

nearest to window walls to be controlled separately.

Switches should be as near as possible to the luminaires which they control. One simple

method which has been used effectively is the pull-cord operating ceiling switches

adjacent to each luminaire, or pull-chord switches with timer controls so that the lamp

automatically switches off after a pre-set period.

Automatic controlsa) Photo-electric controls

Photo-electric control of lighting can ensure that lighting is turned off when

daylight alone provides the required illuminance. For example, a photo-electric

sensor could respond to the exterior illuminance at the work place.

b) Time controls

If the occupation of a building effectively ceases at a fixed hour every working

day, it may be worth installing a time switch so that most of the lighting is

switched off at that time.

c) Mixed control systems

Switch control can give considerable energy savings. For instance, a time control

system can switch off all selected lights for fixed period in the day, but personal,

local override (switch on) controls can be provided.

This general principle is well suited to multi-occupant spaces such as group offices.

An idea of wastage of electrical energy due to unnecessary lighting can be obtained

from Table M.44.





40 W Tube light

60 W Ceiling fan

100 W Bulb

250 W Air cooler

450 W HPMV lamp

500 W Incandescent lamp

1 HP Electric motor

1 ton Window A.C.

1.5 ton Window A.C.

1 ton Water cooler

15

22

37

91

146

183

137

445

602

308

0.88

1.26

2.14

5.30

8.51

10.03

7.95

25.86

35.03

17.91

Item Consumption (in kWh) Value* (US$)

Table M.44: Loss in electrical energy as a result of misuse or wastage and its value per year

* Cost of electricity is considered as US$0.055 per kWh

Efficient use of energy is an on-going process. Research and development (R&D)

around the world is constantly leading to development of new processes and devices.

The basic objective of major R&D efforts on energy systems is to cut down on waste,

whether in the form of flue gases; heat lost through conduction, convection or

radiation; or to improve efficient use of electrical energy. This chapter presents some

generic examples—most of them well proven—to increase readers’ awareness of

energy systems already available or likely to be so in the future.

M2.1 New electrical technologies

● HVDC transmission system

Reduces distribution losses from 18–22 per cent to 8–10 per cent. Relevant to

utility companies, thermal power stations, etc.

● Steam-based cogeneration plant (back pressure/topping/

extraction turbine)

The primary fuel requirement to meet heat and power demand is substantially

reduced. Relevant to large process industries such as sugar, pulp and paper,

chemical and petrochemicals, etc.

● Combined cycle based cogeneration plants for industries

Higher system efficiency: 70–80 per cent in the cogeneration mode, compared to

25–36 per cent for conventional thermal stations. Obtained by integration of

thermal and electrical energy from the same source. Relevant to natural gas

consuming process industries with steam demand above 10 TPH.

● Energy efficient DG sets

Lower rpm and higher efficiency than conventional DG sets.

● High efficiency fans and pumps

High efficiency centrifugal pumps and fans are now available from most leading

pump and fan manufacturers. Efficiency range: 75–83 per cent. Relevant to

almost all industrial units.



Module 2:

Energy efficient technologies

● Maximum demand controllers

Load factor improvement and peak demand reduction. Relevant to

industrial/commercial establishments/utilities.

● Automatic power factor controllers

Power factor improvement. Relevant to all industries.

● High efficiency motors

Motors with efficiencies of 92–96 per cent, often with a 10 year performance

guarantee, are available on the market from all leading motor manufacturers.

They are capable of working at temperatures as high as 80–100 °C.

● Static variable speed drives, frequency drives, inverters

Thyristor control systems where speed is controlled by varying the voltage and

frequency. Higher efficiency at partial loads. Relevant to medium and large

industries and power plants.

● Energy efficient fluorescent lighting system (fluorescent lamps, sodium

vapour lamps, compact fluorescent lamps)

Higher lumens per watt. Relevant to shop floor working bays, buildings, street

lights and yard lighting.

● Electronic regulators for fans

Reduction in energy loss during part load operation. Relevant to industrial offices,

technical buildings, domestic applications.

● Solid-state soft starters

Solid-state thyristor control systems. Applied voltage is varied with load on motor.

Higher efficiency at part loads. Relevant to conveyor belts, inching loads and

equipment operating frequently with part loads in medium and large industries.


Part 2 Technical modules Module 2: Energy efficient technologies

M2.2 Boiler and furnace technologies

● Air preheater

Improvement in thermal efficiency by preheating the combustion air with waste

heat available in flue gases.

i) Metallic recuperator/regeneratorPreheat to 350 °C. Relevant to large boilers, small furnaces.

ii) Metallic recuperator (special steels)Preheat to 700 °C. Relevant to furnaces, rolling and soak pits, glass furnaces,

ceramic kilns.

iii) Ceramic recuperator/regeneratorPreheat to 1 000 °C. Relevant to integrated steel plants, glass tank furnaces.

● Film burners

Higher turn down to 7:1, reduced excess air level. Relevant to industrial boilers

and furnaces, reheating furnaces heat treatment furnaces, etc.

● Low excess air burners (0–5% x suction air)

Improvement in system efficiency. Relevant to industrial boilers, furnaces, kilns.

● Regenerative burners

Higher flame temperature and improved heat transfer. Relevant to industrial

furnaces and kilns.

● Fluidized bed boilers

Efficient combustion of inferior, high-ash-content coals and washery rejects.

● Waste heat boilers

Steam generation with waste heat available in flue. Relevant to sulphuric acid,

chemical, petrochemical, fertilizer and steel plants.

● Closed condensate recovery system

Efficient condensate recovery system. Relevant to all process and chemical

industries where indirect steam is used.



● High efficiency steam turbines

High efficiency impulse steam turbines of 5 MW and less have been developed

with efficiencies as high as 70 per cent. The back pressure class of turbines can be

used in designing cogeneration systems for industries. This would not only help in

reducing purchased energy but also in providing valuable power in cases of grid

power shortage.

● Innovation in cogeneration system

The steam based cogeneration system (bottoming cycle) may be suitable where

steam to power ratio is high. If steam to power ratio is low, gas turbine based

cogeneration systems (topping cycle or combined cycle) are more appropriate. The

latter system can absorb steam fluctuations to a certain level without sacrificing

overall system efficiency. A recent development is based on the ‘Cheng’ cycle where

any excess steam is superheated and injected back into the gas combustor. This

system allows maximum electric power generation with no or less process steam or

maximum power, as well as process steam generation simultaneously.

● On-line plugging of leaks

Leak prevention in steam and compressed air systems. Relevant to continuous

industries, power stations.

● Ceramic fibre

Reduction in heat storage and radiation losses, due to low thermal mass. Relevant

to furnaces, kilns, fired heaters, heaters, ovens, heat treatment furnaces, etc.

● Luminous wall furnace

High emissivity refractory coatings—a development of the US Space Programme—

prevent high temperature of refractory linings of furnaces. The results are 10–15 per

cent fuel savings; increased furnace structure radiation; improved temperature

uniformity; and increased working life of refractory and metallic components.

● Dynamic insulation

Air or other fluid is forced through the insulating material to oppose (contraflux)

or enhance (proflux) the transmission of heat, as required. It has additional

benefits, e.g. building insulation, pre-heated supply of filtered fresh air is readily

available. Can be used for boiler and furnace as pre-heated combustion air.



M2.3 Heat upgrading systems

● Organic rankine cycle

Utilizing low grade waste heat for generation of power in a turbine cycle

operating with organic liquids. Relevant to cement industry, large chemical and

petrochemical plants and refineries.

● Thermo compressor

Enables utilization of low grade energy by using thermal energy in higher

pressure steam in conjunction with vapours. Relevant to process industries such as

sugar, food processing, dairy, chemicals and petrochemicals.

● Vapour absorption refrigeration system

Steam powered or by tapping low grade waste streams (150–250 °C) provides

absorption cycle refrigeration using lithium bromide or ammonia. Relevant to

process and engineering industry.

● Mechanical vapour recompression system

The low grade steam from evaporators, driers, distillation columns is upgraded.

Relevant to food processing, chemical and petro-chemicals industries.

● Heat pipes

Waste heat recovery from process streams at lower and medium temperature

levels. Faster heat transfer rate, compact design. Relevant to process chemical

industries. The heat pipe acts like a super-heat-conductor: 1 000 times more

effective than a solid copper bar of the same size.

● Thermal energy wheels

Energy wheels are compact and are available not only for recovering heat from

centrally heated and cooled buildings but also for recovering heat from boiler and

furnaces at high temperature. With the use of glass ceramic materials, they can

now withstand temperatures as high as 1 250 °C.

● Heat pumps

Heat pumps enable heat to be upgraded and transferred to a point of use. They

cut down energy consumption and are a viable alternative to electrical resistance

heating, as their coefficient of performance is in the 3–5 range. Heat pumps also



utilize low temperature waste heat sources and upgrade them to temperature

levels at which they become useful.

● Condensing heat exchanger

Extracts not only sensible but also latent heat of water vapour in flue gases of

boilers and furnaces. Condensing heat exchangers comprise Teflon coated

heat exchanger surfaces resistant to acidic corrosion, thereby allowing the flue

gases to be cooled to very near ambient temperature, thus increasing the

efficiency of boilers substantially—to over 92 per cent in the case of oil and

gas firing systems.

● Special design heat exchanger

Heat transfer rate can be dramatically increased at sonic velocity. Based on this

principle, a special design of heat exchanger with much higher overall heat

transfer coefficients than those attainable in shell and tube type heat exchangers

has been developed. These devices are relatively maintenance free. Heat

exchangers with spherical matrices and helical inserts in the tubes have been

developed, reducing heat exchanger surfaces by 25–30 per cent.

● Microprocessor based system

More precise control of critical parameters. Relevant to boilers, furnaces, utilities,

distillation columns, process plants, power plants.

M2.4 Other utilities

● Air curtains

Reduction in air infiltration in air conditioning or space heating systems. Relevant

to textile and man-made fibres, cold storage plants, air conditioned buildings, etc.

● Flat belt

Modern flat belts have transmission efficiency of the order of 95–98 per cent as

compared to V-belt transmission efficiency of 80–85 per cent. Improved efficiency

is due to less friction losses between belt and pulley as well as absence of

wedging. Relevant to pulley driven drives.



● Industrial drying by electromagnetic radiation

Infrared, microwave, radio frequency and ultraviolet radiation are now being used

for drying purposes. Drying efficiencies increase by as much as 50–70 per cent.

All these techniques, are useful for particular types of product drying, e.g.

microwave for food processing; radio frequency for drying of paper, yarn

packages, etc.; infrared for curing of adhesives; ultraviolet for paint curing.




Contents listing




Part 3 provides the following tools and resources:

• Checklists of procedures that improve energy

efficiency and safety in energy-using equipment.

• Thumb Rules, for rapid assessment of the efficiency

of major energy systems.

• A list of Measuring Instruments that can be used

to quantify and monitor energy flows.

• Greenhouse Gas Emissions Indicator: a spreadsheet-

based calculator designed to help governments and

industry estimate greenhouse gas emissions.

• Information Resources to help in further

development of CP-EE and other energy-related

initiatives.

• Conversion Tables to provide a standardized

approach to energy measurements and calculations.

• A list of Acronyms and Abbreviations used.

A.1 Fuel oil checklists

● Daily checks

i. Oil temperature at the burner

ii. Oil/steam leakages

● Weekly tasks

i. Cleaning of all filters

ii. Draining of water from all tanks

● Yearly jobs

i. Cleaning of all tanks

● Troubleshooting hints

Oil not pumpable• Viscosity too high

• Blocked lines and filters

• Sludge in oil

• Leak in oil suction

• Vent pipe choked

Blocking of strainers• Sludge or wax in oil

• Heavy precipitated compounds in oil

• Rust or scale in tank

• Carbonization of oil due to excessive heating

Excess water in oil• Water delivered along with oil

• Leaking manhole

• Seepage from underground tank

• Ingress of moisture from vent pipe

• Leaking heater steam coils



A: Checklists for enhancing efficiency

and safety of energy equipment

Remember!

Spilled oil is irretrievable.

Plug all leaks.

Impurities in furnace oil

affect combustion.

Filter oil in stages.

Oil has to be preheated

to obtain the right

viscosity for supply to

the burner. It is essential

to provide adequate

preheater capacity.

Pipeline plugged• Sludge in oil

• High viscosity oil

• Foreign materials such as rags, scale and wood splinters in line

• Carbonization of oil

A.2 Combustion checklists and troubleshooting

Step by step procedure for efficient operation of burners

● Start up

• Check for correct sized burner/nozzle.

• Establish air supply first (start blower). Ensure no vapour/gases are present

before light up.

• Ensure a flame from a torch or other source is placed in front of the nozzle.

• Turn ON the (preheated) oil supply (before start-up, drain off cold oil).

● Operations

• Check for correct temperature of oil at the burner tip (consult viscosity vs.

temperature chart).

• Check air pressure for LAP burners (63.5 cm to 76.2 cm w.c. air pressure is

commonly adopted).

• Check for oil drips near burner.

• Check for flame fading/flame pulsation.

• Check positioning of burner (ensure no flame impingement on refractory walls

or charge).

• Adjust flame length to suit the conditions (ensure flame does not extend

beyond the furnace).

● Load changes

• Operate both air and oil valves simultaneously (For self-proportioned burner,

operate the self-proportioning lever. Do not adjust valve only in oil line).

• Adjust burners and damper for a light brown (hazy) smoke from chimney and

at least 12 per cent CO2.


Part 3 Tools and resources A: Checklists for enhancing efficiency and safety



Causes and remedies

1. Starting difficult

2. Flame goes out or splutters

3. Flame flashesback

4 Smoke and soot

5. Clinker onrefractory

6. Cooking of fuelin burner

7. Excessive fueloil consumption

i. No oil in the tank.ii. Excess sludge and water in storage tanks.iii. Oil not flowing due to high viscosity/low temperature.iv. Choked burner tip.v. No air.vi. Strainers choked.

i. Sludge or water in oil.ii. Unsteady oil and air pressures.iii. Too high a pressure for atomizing medium which tends to blow out flame.iv. Presence of air in oil line. Look for leakages in suction line of pump.v. Broken burner block, or burner without block.

i. Oil supply left in ‘ON’ position after air supply cut off during earliershut off.

ii. Too high a positive pressure in combustion chamber.iii. Furnace too cold during starting to complete combustion (when

temperature rises, unburned oil particles burn).iv. Oil pressure too low.

i. Insufficient draft or blower of inadequate capacity.ii. Oil flow excessive.iii. Oil too heavy and not preheated to the required level.iv. Suction air holes in blower plugged.v. Chimney clogged with soot/damper closed.vi. Blower operating speed too low.

i. Flame hits refractory because combustion chamber is too small or burneris not correctly aligned.

ii. Oil dripping from nozzle.iii. Oil supply not ’cut off’ before the air supply during shut-offs.

i. Nozzle exposed to furnace radiation after shut-off.ii. Burner fed with atomizing air over 300 °C.iii. Burner block too short or too wide.iv. Oil not drained from nozzle after shut off.

i. Improper ratio of oil and air.ii. Burner nozzle oversized.iii. Excessive draft.iv. Improper oil/air mixing by burner.v. Air and oil pressure not correctvi. Oil not preheated properly.vii. Oil viscosity too low for the type of burner used.viii. Oil leaks in oil pipelines/preheater.ix Bad maintenance (too high or rising stack gas temperature).

Checklist 1: Troubleshooting chart for combustion

Complaint

● Shut down

• Close oil line first.

• Shut the blower after a few seconds (ensure gases are purged from

combustion chamber).

• Do not expose the burner nozzle to the radiant heat of the furnace. (When oil

is shut off, remove burner/nozzle or interpose a thin refractory between nozzle

and furnace).

A.3 Boilers

● Periodic tasks and checks outside of the boiler

• All access doors and platework should be maintained air tight with effective

gaskets.

• Flue systems should have all joints sealed effectively and be insulated where

appropriate.

• Boiler shells and sections should be effectively insulated. Is existing insulation

adequate? If insulation was applied to boilers, pipes and hot water cylinders

several years ago, it is almost certainly too thin even if it appears in good

condition. Remember, it was installed when fuel costs were much lower.

Increased thickness may well be justified.

• At the end of the heating season, boilers should be sealed thoroughly, internal

surfaces either ventilated naturally during the summer or very thoroughly

sealed with tray of desiccant inserted. (Only applicable to boilers that will

stand idle between heating seasons).

● Safety and monitoring

• Explosion relief doors should be located and/or guarded to prevent injury to

personnel.

• Safety valves should have self-draining discharge pipes terminating in a safe

location that can be easily observed.

• Installed instruments should be maintained in working order and positioned

where they can be seen easily.

• Provide test points with removable seal plugs in the flue from the boiler, to

enable flue gas combustion tests to be carried out.

• Do you check boiler combustion conditions periodically? CO2 or O2 readings

and exit temperatures can be obtained using relatively inexpensive portable



Important!

Burners should be

dismantled and cleaned

periodically, preferably

once per shift

(always keep spare

burners ready).

equipment. Adjusting combustion by optimizing the fuel/air ratio costs

nothing and can make substantial savings.

• Do you monitor exit temperatures? There should be a steady rise between boiler

flue-duct cleaning intervals and this should not be allowed to exceed, say, 40 °C.

Try to clean based on temperature indications, rather than on the calendar.

• Some older sectional boilers and certain smoke tube type shell boilers can be

fitted with baffles or ‘retarders’ to improve heat transfer and therefore

efficiency. Have you checked whether this is possible on your boilers?

• Is there adequate ventilation to give sufficient combustion air for the boilers?

Insufficient ventilation can, at the least, lead to poor combustion and at worst

could enable dangerous gases to accumulate in the boiler house.

• Check the water side of the boiler periodically for corrosion or scale formation.

• Do you know the actual load on the boiler? A rough guide can be obtained from

oil or gas burners by timing the on/off periods, or the time on full flame for fully

modulating burners. With underfeed coal stokers, see what is the lowest speed

that will cope with demand, or put on full speed and time the on/off periods.

• If the boiler is oversized, either permanently or during part of the year, consider

whether it can be de-rated during those periods by adjusting burners or stokers

to operate only up to a top limit that is lower than full maximum output. Try to

keep the boiler operating for the highest possible percentage of time.

• Is there adequate boiler/burner control to match the load and prevent

excessive and unnecessary cycling?

• If you have more than one boiler, do you isolate boilers which are in excess of

load requirements? Automatic flue isolation should be used, if possible, to

prevent excessive purging by chimney draught during idle periods.

• In multi-boiler hot water installations, are the boilers hydraulically balanced to

ensure proper sharing of the load?

• Consider fitting heat exchangers/recuperators to flues; these can recover

5–7 per cent of energy available.

● Boilers: extra items for steam-raising and hot-water boilers

• Check regularly for build-up of scale or sludge in the boiler vessel or check

TDS of boiler water each shift, but not less than once per day. Impurities in

boiler water are concentrated in the boiler and the concentration has limits

that depend on type of boiler and load. Boiler blow down should be

minimized, but consistent with maintaining correct water density. Recover

heat from blow down water.



• With steam boilers, is water treatment adequate to prevent foaming or priming

and consequent excessive carry over of water and chemicals into the steam

system?

• For steam boilers: are automatic water level controllers operational? The

presence of inter-connecting pipes can be extremely dangerous.

• Have checks been made regularly on air leakages round boiler inspection doors,

or between boiler and chimney? The former can reduce efficiency; the latter can

reduce draught availability and may encourage condensation, corrosion and

smutting.

• Combustion conditions should be checked using flue gas analysers at least

twice per season and the fuel/air ratio should be adjusted if required.

• Both detection and actual controls should be labelled effectively and checked

regularly.

• Safety lock-out features should have manual re-set and alarm features.

• Test points should be available, or permanent indicators should be fitted to oil

burners to give operating pressure/temperature conditions.

• With oil-fired or gas-fired boilers, if cables of fusible link systems for shutdown

due to fire or overheating run across any passageway accessible to personnel,

they should be fitted above head level.

• The emergency shut down facility is to be situated at exit door of the boiler

house.

• In order to reduce corrosion, steps should be taken to minimize the periods

when water return temperatures fall below dew point, particularly on oil and

coal fired boilers.

• Very large fuel users may have their own weighbridge and so can operate a

direct check on deliveries. If no weighbridge exists, do you occasionally ask

your supplier to run via a public weighbridge (or a friendly neighbour with a

weighbridge) just as a check? With liquid fuel deliveries do you check with the

vehicle’s dipsticks?

• With boiler plant, ensure that the fuel used is correct for the job. With solid

fuel, correct grading or size is important, and ash and moisture content should

be as the plant designer originally intended. With oil fuel, ensure that viscosity

is correct at the burner, and check fuel oil temperature.

• The monitoring of fuel usage should be as accurate as possible. Fuel stock

measurements must be realistic.

• With oil burners, examine parts and repairs. Burner nozzles should be changed

regularly and cleaned carefully to prevent damage to burner tip.



• Maintenance and repair procedures should be reviewed especially for burner

equipment, controls and monitoring equipment.

• Regular cleaning of heat transfer surfaces maintains efficiency at the highest

possible level.

• Ensure that the boiler operators are conversant with the operational

procedures, especially any new control equipment.

• Have you investigated the possibility of heat recovery from boiler exit gases?

Modern heat exchangers/recuperators are available for most types and sizes of

boiler.

• Do you check feed and header tanks for leaking make up valves, correct

insulation or loss of water to drain?

• The boiler plant may have originally been provided with insulation by the

manufacturer. Is this still adequate with today’s fuel costs? Check on optimum

thickness.

• If the amount of steam produced is quite large, invest in a steam meter.

• Measure the output of steam and input of fuel. The ratio of steam to fuel is

the main measure of efficiency at the boiler.

• Use the monitoring system provided: this will expose any signs of

deterioration.

• Feed water should be checked regularly for both quantity and purity.

• Steam meters should be checked occasionally as they deteriorate with time

due to erosion of the metering orifice or pilot head. It should be noted that

steam meters only give correct readings at the calibrated steam pressure.

Recalibration may be required.

• Check all pipe work, connectors and steam traps for leaks, even in inaccessible

spaces.

• Pipes not in use should be isolated and redundant pipes disconnected.

• Is someone designated to operate and generally look after the installation?

This work should be included in their job specification.

• Are basic records available to that person in the form of drawings, operational

instructions and maintenance details?

• Is a log book kept to record details of maintenance carried out, actual

combustion flue gas readings taken, fuel consumption at weekly or monthly

intervals, and complaints made?

• Ensure that steam pressure is no higher than need be for the job. When night

load is materially less than day load, consider a pressure switch to allow

pressure to vary over a much wider band during night to reduce frequency of

burner cut-out, or limit the maximum firing rate of the burner.



• Examine the need for maintaining boilers in standby conditions—this is

often an unjustified loss of heat. Standing boilers should be isolated on the

fluid and gas sides.

• Keep a proper log of boiler house activity so that performance can be

measured against targets. When checking combustion, etc. with portable

instruments, ensure that this is done regularly and that load conditions are

reported in the log: percentage of CO2 at full flame/half load, etc.

• Have the plant checked to ensure that severe load fluctuations are not caused

by incorrect operation of auxiliaries in the boiler house, for example, ON/OFF

feed control, defective modulating feed systems or incorrect header design.

• Have hot water heating systems been dosed with an anti-corrosion additive

and is this checked annually to see that concentration is still adequate? Make

sure that this additive is NOT put into the domestic hot water heater tank, it

will contaminate water going to taps at sinks and basins.

• Recover all condensate where practical and substantial savings are possible.

● Boiler rooms and plant rooms

• Ventilation openings should be kept free and clear at all times and the

opening area should be checked to ensure this is adequate.

• Plant rooms should not be used for storage, airing or drying purposes.

• Is maintenance of pumps and automatic valves in accordance with the

manufacturers’ instructions?

• Are run and standby pump units changed over approximately once per month?

• Are pump isolating valves provided?

• Are pressure/heat test points and/or indicators provided each side of the

pump?

• Are pump casings provided with air release facilities?

• Are moving parts (e.g. couplings) guarded?

• Ensure that accuracy of the instruments is checked regularly.

• Visually inspect all pipe work and valves for any leaks.

• Check that all safety devices operate efficiently.

• Check all electrical contacts to see that they are clean and secure.

• Ensure that all instrument covers and safety shields are in place.

• Inspect all sensors, make sure they are clean, unobstructed and not exposed to

unrepresentative conditions, for example temperature sensors must not be

exposed to direct sunlight nor be placed near to hot pipes or process plant.

• Ensure that only authorized personnel have access to control equipment.



• Each section of the plant should operate when essential, and should preferably

be controlled automatically.

• Time controls should be incorporated and operation of the whole plant

should, preferably, be automatic.

• In multiple boiler installations, boilers not required to be available should be

isolated on the water side and—if safe and possible—on the gas side too.

Make sure boilers cannot be fired.

• Isolation of flue system (with protection) also reduces heat losses.

• In multiple boiler installations the lead/lag control should have a change round

facility.

• Where possible, any reduction in the system operating temperature should be

made by devices external to the boiler, the boiler plant operating in a normal

constant temperature range.

● Water and steam

• Water fed into the boilers must meet the specifications given by the

manufacturers. The water must be clear, colourless and free from suspended

impurities.

• Hardness nil. Max. 0.25 ppm CaCO3.

• pH of 8 to 10 retard forward action or corrosion. pH less than 7 speeds up

corrosion due to acidic action.

• Dissolved O2 less than 0.02 mg/l. Its presence with SO2 causes corrosion problems.

• CO2 level should be kept very low. Its presence with O2 causes corrosion,

especially in copper and copper bearing alloys.

• Water must be free from oil—it causes priming.

● Boiler water

• Water must be alkaline—within 150 ppm of CaCO3 and above 50 ppm of

CaCO3 at pH 8.3.

• Alkalinity number should be less than 120.

• Total solids should be maintained below the value at which contamination of

steam becomes excessive, in order to avoid cooling over and accompanying

danger of deposition on super heater, steam mains and prime movers.

• Phosphate should be no more than 25 ppm P2 O5.

• Make up feed water should not contain more than traces of silica. There must

be less than 40 ppm in boiler water and 0.02 ppm in steam, as SiO2. Greater

amounts may be carried to turbine blades.



• Water treatment plants suitable for the application must be installed to ensure

water purity, and chemical dosing arrangement must be provided to further

control boiler water quality. Blow downs should be resorted to when

concentration increases beyond the permissible limits stipulated by the

manufacturers.

• Alkalinity not to exceed 20 per cent of total concentration. Boiler water level should

be correctly maintained. Normally, 2 gauge glasses are provided to ensure this.

• Operators should blow these down regularly in every shift, or at least once per

day where boilers are steamed less than 24 hours a day.

● Blow down (BD) procedure

A conventional and accepted procedure for blowing down gauge is as follows:

1. Close water lock

2. Open drain cock (note that steam escapes freely)

3. Close drain cock

4. Close steam cock

5. Open water cock

6. Open drain cock (note that water escapes freely)

7. Close drain cock

8. Open steam cock

9. Open and then close drain cock for final blow through.

The water that first appears is generally representative of the boiler water. If it is

discoloured, the reason should be ascertained.



Maximum boiler water concentration (ppm)

0–20

20–30

30–40

40–50

50–60

60–70

70–100

3 500

3 000

2 500

2 000

1 500

1 250

1 000

Table A.1: Maximum boiler water concentrations recommendedby American Boiler Manufacturers Association

Boiler steam pressure (ata)



Daily Weekly Monthly Annual

BD and watertreatment

Feed water system

Flue gases

Combustion airsupply

Burners

Boiler operatingcharacteristics

Relief valve

Steam pressure

Fuel system

Belts for glandpacking

Air leaks in waterside and fire sidesurfaces

Air leaks

Refractories onfuel side

Elec. system

Hydraulic andpneumatic valves

Check BD valves do notleak. BD is not excessive.

Check and correctunsteady water level.Ascertain cause of unsteadywater level, contaminantsover load, malfunction etc.

Check temp. at twodifferent points.

Check controls areoperating properly. Mayneed cleaning several timesa day.

Check for excess loadswhich will cause excessivevariation in pressure.

–

Condensate receiver,deaerator system pumps.

Same as weekly. Record references.

Same as weekly, clean andrecondition.

Remove and recondition.

Clean and reconditionsystem.

Clean surface as permanufacturer’srecommendation annually.

Check for leaks aroundaccess openings and flame.

Repair.

Clean, repair terminals andcontacts etc.

Repair all defects andcheck for proper operation.

Make sure solids do notbuild up.

Nil

Same as weekly. Comparewith previous readings.

Check adequate openingsexist in air inlet. Cleanpassages.

Same as weekly.

Check pumps, pressuregauges, transfer lines.Clean them.

Check for damages. Checkgland packing for leakagesand proper compression.

Inspect panels inside.

Clean equipment, oilspillages to be arrested andair leaks to be avoided.

–

Check controls by stoppingthe feed water pump andallow control to stop fuel.

Measure temp. andcompare composition atselected firings and adjustrecommended valves.

Clean burners, pilotassemblies, check conditionof spark gap of electrodeburners.

Observe flame failure andcharacteristics of the flame.

Check for leakages.

Clean panels outside.

Checklist 2: Boiler periodic checklist

System



Don‘ts

1. Soot blowing regularly

2. Clean blow down gauge glass once a shift

3. Check safety valves once a week

4. Blow down in each shift, to requirement

5. Keep all furnace doors closed

6. Control furnace draughts

7. Clear, discharge ash hoppers every shift

8. Watch chimney smoke and control fires

9. Check auto controls on fuel by stoppingfeed water for short periods occasionally

10. Attend to leakages periodically

11. Check all valves, dampers etc. for correctoperation once a week

12. Lubricate all mechanisms for smoothworking

13. Keep switchboards neat and clean andindication systems in working order

14. Keep area clean, dust free

15. Keep fire fighting arrangements inreadiness always. Rehearsals to be carriedout once a month.

16. All log sheets must be truly filled

17. Trip FD fan if ID fan trips

18. CO2 or O2 recorder must be checked/calibrated once in three months

19. Traps should be checked and attended toperiodically

20. Quality of steam, water, should be checkedonce a day, or once a shift as applicable

21. Quality of fuel should be checked once aweek

22. Keep sub heater drain open during start up

23. Keep air cocks open during start and close

1. Don’t light up torches immediately after afireout (purge)

2. Don’t blow down unnecessarily

3. Don’t keep furnace doors openunnecessarily

4. Don’t blow safety valves frequently (controloperation)

5. Don’t over flow ash hoppers

6. Don’t increase firing rate beyond thatpermitted

7. Don’t feed raw water

8. Don’t operate boiler blind fold

9. Don’t overload boiler as a practice

10. Don’t keep water level too high or too low

11. Don’t operate soot blowers at high loads

12. Don’t trip the ID fan while in operation

13. Don’t look at fire in furnace directly, usetinted glasses

14. Avoid thick fuel bed

15. Don’t leave boiler to untrained operators/technicians

16. Don’t overlook unusual observation (soundchange, change in performance, controldifficulties), investigate

17. Don’t skip annual maintenance

18. Don’t prime boilers

19. Don’t allow steam formation in economizer(watch temps.)

20. Don’t expose grate (spread evenly)

21. Don’t operate boiler with water tubeleaking

Checklist 3: Boiler dos and don’ts

Dos

B.1 Thermal energy

● Boilers

• 5 per cent reduction in excess air increases boiler efficiency by 1 per cent (or1 per cent reduction of residual oxygen in stack gas increases boiler efficiencyby 1 per cent).

• 22 °C reduction in flue gas temperature increases boiler efficiency by 1 per cent.• 6 °C rise in feed water temperature brought about by economizer/condensate

recovery corresponds to a 1 per cent saving in boiler fuel consumption. • 20 °C increase in combustion air temperature, pre-heated by waste heat

recovery, results in a 1 per cent fuel saving.• A 3 mm diameter hole in a pipe carrying 7 kg/cm2 steam would waste

32 650 litres of fuel oil per year.• 100 m of bare steam pipe with a diameter of 150 mm carrying saturated

steam at 8 kg/cm2 would waste 25 000 litres furnace oil in a year.• 70 per cent of heat losses can be reduced by floating a layer of 45 mm

diameter polypropylene (plastic) balls on the surface of a 90 °C hotliquid/condensate.

• A 0.25 mm thick air film offers the same resistance to heat transfer as a 330mm thick copper wall.

• A 3 mm thick soot deposit on a heat transfer surface can cause a 2.5 per centincrease in fuel consumption.

• A 1 mm thick scale deposit on the water side could increase fuel consumptionby 5 to 8 per cent.

B.2 Electrical energy

● Compressed air

• Every 5 °C reduction in intake air temperature would result in a 1 per centreduction in compressor power consumption.

• Compressed air leaking from a 1 mm hole at a pressure of 7 kg/cm2 meanspower loss equivalent to 0.5 kW.

• A reduction of 1 kg/cm2 in air pressure (8 kg/cm2 to 7 kg/cm2) would result ina 9 per cent saving in input power.

• A reduction of 1 kg/cm2 in line pressure (7 kg/cm2 to 6 kg/cm2) can reduce

the quantity leaking from a 1 mm hole by 10 per cent.



B: Thumb rules for quick efficiency

assessment in major energy systems

● Refrigeration

• Refrigeration capacity reduces by 6 per cent for every 3.5 °C increase in

condensing temperature.

• Reducing condensing temperature by 5.5 °C results in a 20–25 per cent decrease

in compressor power consumption.

• A reduction of 0.55 °C in cooling water temperature at condenser inlet reduces

compressor power consumption by 3 per cent.

• 1 mm scale build-up on condenser tubes can increase energy consumption by

40 per cent.

• 5.5 °C increase in evaporator temperature reduces compressor power

consumption by 20–25 per cent.

● Electric motors

• High efficiency motors are 4–5 per cent more efficient than standard motors.

• Every 10 °C increase in motor operating temperature beyond the recommended

peak is estimated to halve the motor‘s life.

• If rewinding is not done properly, efficiency can be reduced by 5–8 per cent.

• Balanced voltage can reduce motor input power by 3–5 per cent.

• Variable speed drives can reduce input energy consumption by 5–15 per cent. As

much as 35 per cent of energy can be saved for some pump/fan applications.

• Soft starters/energy savers help to reduce power consumption by 3–7 per cent of

operating kW.

● Lighting

• Replacement of incandescent bulbs by CFL’s offer 75–80 per cent energy savings.

• Replacement of conventional tube lights by new energy-efficient tube light with

electronic ballast helps reduce power consumption by 40–50 per cent.

• 10 per cent increase in supply voltage will reduce bulb life by one-third.

• 10 per cent increase in supply voltage will increase lighting power consumption

by an equivalent 10 per cent.

● Buildings

• An increase in room temperature of 10 °C can increase the heating fuel

consumption by 6–10 per cent.

• Installing automatic lighting controls (timers, daylight or occupancy sensors) saves

10–25 per cent of energy.

• Switching off 1 ton window A/C for 1 hour daily during lunch hour avoids

consumption of 445 kWh.


Part 3 Tools and resources B: Thumb rules for quick efficiency assessment

C.1 Measuring instruments in practiceAn energy audit to identify and quantify energy necessitates measurements, and

measurements require the use of instruments. These must be portable, durable, easy

to operate and relatively inexpensive. The parameters usually monitored for an energy

audit include the following:

Basic Electrical Parameters in AC and DC systems: voltage (V), current (I), power

factor (PF), active power (kW), apparent power (demand) (kVA), reactive power (kVAr),

energy consumption (kWh), frequency (Hz), harmonics, etc.

Important non-electrical parameters: such as temperature and heat flow,

radiation, air and gas flow, liquid flow, revolutions per minute, air velocity, noise and

vibration, dust concentration, total dissolved solids, pH, moisture content, relative

humidity, flue gas analysis (CO2, O2, CO, SOx, NOx), combustion efficiency, etc.

C.2 Key instruments for energy auditsExamples of key measuring instruments are provided below. In all cases the operating

instructions must be understood and staff should familiarize themselves with the

instruments and their operation prior to actual use in an audit.



C: List of energy measuring

instruments

● Electrical measuring instruments

Electrical measuring instruments

measure major electrical parameters

such as kVA, kW, PF, Hertz, kVAr, current

and voltage. Some instruments also

measure harmonics. The instruments are

used ‘on-line’, i.e. on running motors

without the need to stop the motor.

● Hand-held instruments


Part 3 Tools and resources C: List of energy measuring instruments

● Combustion analyser

● Fuel efficiency monitor

Instantaneous measurements can be made

with hand-held meters. More advanced

meters provide cumulative readings with

print-outs at specified intervals.

Combustion analysers have in-built chemical

cells that measure gases such as O2, CO, NOX

and SOX.

Fuel efficiency monitors measure oxygen

levels and flue gas temperatures. Calorific

values of common fuels are fed into the

microprocessor which calculates the

combustion efficiency.

● Infrared thermometer



● Fyrite®

● Contact thermometer

A hand-operated bellow-pump draws a flue gas sample

into the solution inside the Fyrite. A chemical reaction

changes the liquid volume giving an indication of the

amount of gas. Separate Fyrites can be used for O2 and

CO2 measurements.

Contact thermometers are thermocouples that

measure, for example, the temperatures of flue gases,

hot air or hot water by insertion of a probe into the

stream. A leaf type probe is used with the same

instrument to measure surface temperature.

Infrared thermometers are non-contact type

instruments giving a temperature read out when

pointed directly at a heat source. They are useful for

measuring hot spots in furnaces, surface temperatures,

etc.



● Pitot tube and manometer

● Water flow meter

Air velocity in ducts can be measured using a pitot tube

and manometer. Useful for further flow calculations.

This non-contact flow measuring device uses the

Doppler effect or ultrasound. A transmitter and receiver

are positioned on opposite sides of the pipe and the

meter indicates the flow directly. Water and other fluid

flows can be measured easily with this meter.

● Speed measurements

Speed measurements are critical in any audit

exercise, as they may change with frequency, belt

slip or loading. A simple tachometer is a contact

type instrument used where direct access is

possible. More sophisticated and safer instruments,

such as stroboscopes, are of the non contact type.



● Leak detectors

● Lux meters

Ultrasonic leak detectors are available to detect leaks of

compressed air and other gases which cannot normally

be detected by the human senses.

Illumination levels are measured with a lux meter. The

instrument comprises a photo cell which senses the

light output and converts this to electrical pulses used

to produce a read out in lux.

D.1 What is the Greenhouse Gas Emissions Indicator?UNEP has developed the Greenhouse Gas (GHG) Emissions Indicator (UNEP Guidelines for

Calculating Greenhouse Gas Emissions for Businesses and Non-Commercial Organizations) to

provide a methodology for estimating GHG emissions that is adaptable to all

organizations, varieties of fuel mix and other related factors. The purpose of the Indicator

is to establish a common, worldwide method of reporting on GHG emissions. It will also

provide baseline information that will help in assessing progress towards targets such as

those set by international agreements like the Kyoto Protocol, or in designing Clean

Development Mechanism and emissions trading schemes. The Indicator contains tools

(Worksheets) that can be used to calculate GHG emissions directly. Originally developed

in document form, these are now available in spreadsheet format:

a) on this CD-ROM (see box on right); and

b) on the UNEP DTIE website: http://www.uneptie.org/energy/tools/ghgin/index.htm


Part 3 tools and resources

D: Greenhouse Gas Emissions Indicator

Figure D.1 GHG calculator

FUEL and ENERGY

DATA

CONVERSION

DATAAGGREGATION NORMALIZATION

FUEL CONSUMPTION

ELECTRICITY USE

TRANSPORT FIGURES

PROCESS RELATEDEMISSIONS

GHG EMISSIONFACTOR

TOTAL GHG NORMALIZEDGHG

Using the Indicator allows a company (or other organization) to analyse its major GHG

emission sources (e.g. direct fuel consumption, electricity use, transport for personnel and

freight, and production process). Then, using conversion data provided and the calculator

tools, GHG emission factors can be applied to calculate the company’s or organization’s

emissions. Finally, normalizing factors such as turnover, production, added value and

numbers of employees are applied to normalize total emissions. Details of the GHG

Indicator are explained below in a question and answer format.

The GHG Indicator

is included on the

CP-EE CD-ROM together

with this Manual.

Click here to access the

files on the CD-ROM

http://www.uneptie.org/energy/tools/ghgin/index.htm

D.2 The GHG Indicator in detail

● Who can use the GHG Indicator?

Governments can use the Indicator to estimate national GHG emissions. Companies or

other organizations can use the Indicator to convert their fuel and electricity use into

GHG emissions.

● Frequently asked questions about the GHG Indicator

“I am from a company in Thailand that uses coal. How can I convert our coal consumption(1 000 ton/year) to GHG emissions using the GHG Indicator?”

• First, use Table D.1 to find the emission factor (EF) for coal in Thailand (1.85 tons

of CO2/ton of coal used).

• Multiply your company’s coal consumption by the EF.

• Your company‘s CO2 emissions amount to 1.85 x 1 000 = 1 850 tons.


Part 3 Tools and resources D: Greenhouse Gas Emissions Indicator

NCV (TJ/ton) CO2 EF (tons CO2/ton of coal used)

AustraliaBangladeshChinaEgyptIndiaIranIraqIsraelJapanKazakhstanKuwaitKyrgyzstanMalaysiaNepalNew ZealandPakistanSingaporeSouth KoreaSri LankaSyriaThailandUnited ArabUzbekistanDefault

21.22716.329

16.3717.71016.45417.71017.71017.25027.75818.67317.71018.67319.40717.54323.78115.70113.10519.17617.71017.71019.88717.71018.67319.841

1.971.521.521.651.531.651.651.602.581.731.651.731.801.632.211.461.221.781.651.651.851.601.731.84

Table D.1: Emissions from fuel use—country-specific net calorific values (NCV) forcoal and CO2 emissions

Country

“What if my country is not listed in Table D.1 and I want to calculate GHG emissions?”

• If your country is not listed, you can use the default value (1.84 tons of CO2/ton

of coal) at the end of Table D.1.

“What if I use more than one fuel?”

• Refer to Worksheet D.1 which gives EF values for CO2 emissions from different

types of fuels. Multiply the respective EFs for the relevant fuels by the amounts

of those fuels your company uses to obtain the CO2 emissions.

• You can also total the respective CO2 emissions and divide by the total weight

of fuel to get an overall EF for your company.



Worksheet D.1: CO2 emissions from fuel use

Fuel types Basic Unit Emission Amount ofCO2 (t)

Coal

Petrol

Natural Gas

Gas/Diesel Oil

Residual Fuel Oil

LPG

Jet Kerosene

Shale Oil

Ethane

Naphtha

Bitumen

Lubricants

Petroleum Coke

Refinery Feedstock

Refinery Gas

Other Oil Products

Total

0.0059

0.0067

0.007

0.00222

0.00268

0.00300

0.00165

0.00258

0.00224

0.00263

0.00254

0.0003413

0.0002496

0.0002020

0.0002667

0.0002786

0.0002271

0.0002575

0.0002218

0.0002641

0.0002905

0.0002641

0.0003631

0.0002641

0.0002641

0.0002403

0.0002641

1.84

3.07

2.93

3.19

3.08

2.95

3.17

2.61

2.90

3.27

3.21

2.92

3.09

3.25

2.92

2.92

Therms Litres KWh Tons X tCO2 tCO2 tCO2 tCO2 =

“How do I calculate GHG emissions for the utility generated electricity consumed by mycompany? (My company consumes 100 000 kWh per year.)”

• A complete list of emission factors for electricity usage by country (using IEA

data) is given in Table D.2. First, find your country and determine its EF (e.g. for

Thailand, the emission factor is 0.000618). Multiply the EF by consumption (in

this example this gives: 100 000 x 0.000618 = 6.18 tons of CO2).

“My company exports power and steam for economic as well as social reasons. How do Icalculate in this case?”

• Your company should not be accountable for the associated emissions. Such

emissions should be accounted for by the user of the electricity or heat. The

emissions corresponding to the amount or heat exported should be calculated

and should then be deducted from your company’s emission total.

“My company imports electricity or heat generated by public CHP. How do I calculate?”

• If you import electricity from a public CHP plant, use the electricity factors given

in Table D.2 and then use Worksheet D.1 to calculate the CO2 emissions. The

electricity emission factors in Table D.2 incorporate public CHP schemes in the

energy mix.



A refinery consumes coal, refinery feedstock and petroleum coke. Its total CO2 emissions (in tons)and emission factor are calculated as shown below.

Fuel Annual fuel consumption (tons) EF tCO2

Coal 500 x 1.85 = 925

Refinery feedstock 3 502 x 3.25 = 11 382

Petroleum coke 45 x 3.09 = 139

Totals 4 047 12 446

Total fuel consumption = 4 047 tonsTotal CO2 emissions released = 12 446 tCO2CO2 Emission Factor for the refinery = Total CO2/total fuel input

= 12 446/4 047= 3.075 t CO2 per ton of fuel

Example: Calculating CO2 emissions for several fuels



1990 emission factor 1996 emission factor

Africa

Asia (excl. China)

Australia

Bangladesh

China

Egypt

Emirates

Europe

India

Iran

Iraq

Israel

Japan

Kazakhstan

Korea

Kuwait

Malaysia

Middle East

Nepal

New Zealand

Non-OECD:

Pakistan

Singapore

South Africa

Sri Lanka

Syria

Tajikistan

Thailand

Turkey

Turkmenistan

United Arab

Venezuela

0.00066

0.000658

0.000777

0.000604

0.00071

0.000546

0.000616

0.000496

0.000761

0.000541

0.000549

0.000814

0.000346

0.000000

0.000317

0.000591

0.000664

0.000632

0.000674

0.000103

0.00041

0.00089

0.000796

0.000003

0.000546

0.000000

0.000619

0.000492

0.000000

0.000237

0.000663

0.000724

0.000791

0.00054

0.000772

0.000561

0.000783

0.00042

0.00089

0.000534

0.000554

0.000801

0.000321

0.001312

0.000297

0.000512

0.000594

0.00065

0.000632

0.000099

0.000438

0.000622

0.00077

0.000205

0.00065

0.000068

0.000618

0.000461

0.000731

0.000176

Table D.2: Electricity emission factors for different countries (tCO2/kWh) for 1990 and 1996

Country

Sour

ce IE

A.

.

Worksheet D.2: Process-related greenhouse gas emissions

Trace Gas Basic Unit X Conversion values = CO2(GWP,100) equivalent

Carbon dioxide

CC1 4

CFC-11

CFC113

CFC 116

CFC12

CFC114

CFC115

Chloroform

HCFC 123

HCFC 124

HCFC 22

HFC 125

HFC 32

HFC

Methane

Methylene chloride

1

1300

3400

4500

6200

7100

7000

7000

4

90

430

1600

2800

650

150

21

9

“My company generates GHGs other than CO2 from its process. How do I account forGHG emissions?”

• Production of process-related GHGs is estimated (in tons) and converted to CO2

equivalents using the global warming potential (GWP) for a 100 year-time horizon

as a conversion factor. Worksheet D.2 can be used for process-related emissions.





“How do I account for my transport related emissions?”

• Emissions from transport are broken down by transport mode. The guidelines in

the GHG Indicator cover:

i) road vehicle transport;

ii) non-road transport.

• For road vehicle transport, first calculate the total fuel consumption for three

major transport fuels, and use Worksheet D.3 to calculate the CO2 emissions.

“My company rents transport for employees. How do I calculate GHG emissions in this case?”

• The nature of rented transport makes it difficult to calculate the consumption of

specific fuel types. Vehicle-kilometre calculations are used in this instance.

• Worksheet D.3 can be used to calculate CO2 emissions for rented transport and

non-road transport.

Worksheet D.3: Fuel emissions from transport

Transport Basic unit No. of CO2 E.F. CO2 E.F. CO2 emissions mode basic units X (tCO2/km) (tCO2/mile) = (tonnes)

Average petrol car

Average diesel car

HGV

Passenger air (short haul)

Passenger air (long haul)

Passenger train

Air freight (short haul)

Air freight (long haul)

Freight train

Inland shipping(freight)

Marine shipping(freight)

kilometre or mile

kilometre or mile

kilometre or mile

person.kilometre orperson.mile



tonne.kilometre ortonne.mile





0.000185

0.000156

0.000782

0.00018

0.00011

0.000034

0.000158

0.00057

0.000047

0.00003

0.000010

0.000299

0.000251

0.00126

0.00029

0.00018

0.000054

0.00025

0.00091

0.000075

0.000056

0.000016

“I have finally managed to calculate all energy and process emissions from my company.What do I do next?”

• Aggregate all the emissions and then normalize the data.

“What is aggregation?”

• Aggregation means summing of energy and transport related CO2 and process-

related emissions. See Table D.3 and the accompanying note.

“What is normalization?”

• Normalization is the process of dividing total CO2 emissions by turnover,

employees, added value and unit production. Table D.4 gives an example of

normalizing for a cement plant emitting 1 500 000 tCO2/year.

GHG source Tons of CO2 equivalent

1

2

3

4

5

6

Fuel; combustion

Electricity

CHP

Road transport

Unit. kilometre transport

Process-related GHG emissions

TOTAL CO2

Table D.3: Total global warming impact as CO2 equivalent aggregation Step 1Insert the relevant totals of CO2from the previous worksheetsfor each category.

Step 2Add the column and insert thetotal in box at the bottom.





Group consolidated figures(Column 1)

Normalized CO2 equivalents (tonnes per normalizing factor)

(Column 2)

Turnover

Added value

Employees

Unit production

$ 20 000 000

$ 500 000

500

1 350 000 tons

0.075

3

3 000

1.11

Table D.4: Normalizing CO2 potentialStep 1From your group/companyaccounts, insert the relevantfigures in column 1.

Step 2Divide the total CO2 by column1 and insert the answer incolumn 2.

Step 3Use the answers in column 2 asthe ratio for amount of CO2produced for each of thenormalizing factors, e.g. 1.11 t.CO2 for every ton of cementproduced.



E: Information resources

D I S C L A I M E R

UNEP DTIE has no control over any of the Internet resources listed in this

Manual and therefore cannot guarantee that the information held therein will

always be accurate and complete.

Although UNEP DTIE endeavours to provide links to websites which contain

accurate information, we are unable to guarantee that these pages will not

contain errors, or incomplete or out-of-date information.

Therefore, neither UNEP DTIE nor any of its contributors can be held responsible

for any loss, damage or expense that might be caused by any action, or lack of

action, that a user of this service might take as a result of reading material on a

site found using the links provided. Responsibility for such actions, or lack of

actions, remains with the reader.

This section provides links to Cleaner Production and Energy Efficiency resources on the

Internet. Resources are grouped together under various headings for ease of

navigation. Clicking on the blue hyperlinks in the text will launch your web browser

and link you directly to the appropriate resource.

Please read the Disclaimer (below) before consulting any of the Internet resources listed

in this Manual.

E.1 Energy systems

• Compressed air

An overview of Best Practices for compressed air system resources to help

industrial end users achieve efficiency improvements and related cost savings.

(Resources include compressed air tip sheets; technical publications.)

http://www.oit.doe.gov/bestpractices/compressed_air/

• Motor systems

Best Practice resources specific to motor systems. Includes publications, software

tools and training information. Most can be downloaded from this site.

http://www.oit.doe.gov/bestpractices/motors/

• Process heating

Information on process heating that can help companies realize significant savings

through system improvements and technology implementation. (Resources

include process heating ‘Tip Sheets’; technical publications.)

http://www.oit.doe.gov/bestpractices/process_heat/

• Steam system efficiency

Information on steam generation, steam distribution, steam use and steam

recovery that should be considered for improvements to help reduce

operating costs.

http://www.oit.doe.gov/bestpractices/steam/efficiency.shtml

• Motor solutions on-line

Comprehensive information and guidance, as well as practical information and

tools, to help make the right choices about electric motors.

http://www.greenhouse.gov.au/motors/

• Energy conservation in motors

Includes: terms related to motors; standard designs of motors; types of motors; motor

losses; why motors fail; equipment to read motor parameters; features of energy

efficient motors; energy conservation in motors; and energy conservation analysis.

http://www.letsconserve.org/terms_related_to_motors1.php


Part 3 Tools and resources E: Information resources

http://www.oit.doe.gov/bestpractices/compressed_air/

http://www.oit.doe.gov/bestpractices/motors/

http://www.oit.doe.gov/bestpractices/process_heat/

http://www.oit.doe.gov/bestpractices/steam/efficiency.shtml

http://www.letsconserve.org/terms_related_to_motors1.php

http://www.greenhouse.gov.au/motors/

• Motors and drives

Covers all aspects of motors, from an explanation of how they work, to the

advantages/disadvantages of adjustable speed drives. Also included are special

pages on motor maintenance and troubleshooting, and economic implications of

replacing existing motors with different types of motors. The information on this

site is especially valuable for commercial and industrial consumers.

http://cipco.apogee.net/mnd

• Commercial energy systems

Covers the following areas in energy systems for commercial buildings (from fast

food to retail stores, to commercial operations of all descriptions): lighting; power

quality; commercial cooking; HVAC design; HVAC systems; CES design; building

design process; commissioning.

http://cipco.apogee.net/ces

• Various energy systems

How facilities can save thousands on fan, pump and compressor, blower, motor

and AC unit costs. The site includes typical problems, opportunities, a system cost

calculator and an optimization checklist for the benefits of optimizing the

system(s) in a facility.

http://www.productiveenergy.com/home/index.asp



http://cipco.apogee.net/mnd

http://cipco.apogee.net/ces

http://www.productiveenergy.com/home/index.asp

E.2 Financing CP & EE projects

• Financing sustainable energy directory (on-line database)

An on-line database inventory of lenders and investors that provide finance to the

renewable energy and energy efficiency sectors. It is intended for project

developers and entrepreneurs seeking capital as well as for investors looking for

financing vehicles.

http://www.fse-directory.net

• International Finance Cooperation (IFC)

In recent years, the IFC has been actively seeking to finance a greater number of

energy efficiency (EE) projects and to develop special initiatives to accelerate the

market penetration of these technologies. The IFC’s efforts in this area are driven

by the significant benefits that EE projects offer from a sustainable development

standpoint, including cost savings and the realization of local and global

environmental benefits.

http://www.ifc.org/enviro/EFG/EEfficiency/eefficiency.htm

• Promotion of energy efficiency in industry and financing of related

public and private investments

This publication is divided into five parts: Part 1 presents an introductory overview

of policy issues. Part 2 gives an overview of financing options for investors. Part 3

describes policies and experiences of three selected industrialized and newly

industrializing countries that have emphasized active energy efficiency investment

to counter the growing energy import dependencies of their respective

economies. Part 4 discusses the particular difficulties faced by countries with

economies in transition in the promotion of investments for energy efficiency.

Part 5 presents an outlook on international cooperation in financing energy

efficiency investments.

http://www.unescap.org/publications/detail.asp?id=757

• Profiting from Cleaner Production

UNEP has developed and presented a series of awareness raising and training

courses on cleaner production financing. The resource kit is meant for the

industrial, financial and public sectors. It has been published on a CD-ROM and is

now available on-line, free of charge to registered users.

http://www.financingcp.org/training/training.html



http://www.fse-directory.net

http://www.ifc.org/enviro/EFG/EEfficiency/eefficiency.htm

http://www.unescap.org/publications/detail.asp?id=757

http://www.financingcp.org/training/training.html

• UNEP Sustainable Energy Finance Initiative

The Sustainable Energy Initiative is a joint effort of UNEP and its collaborating

centre the Basel Agency for Sustainable Energy (BASE) aimed at fostering the

sustainable energy community, growing its common knowledge set and building

alliances and partnerships that, together, positively influence the flow of capital

into the sustainable energy sector.

http://sefi.unep.org

E.3 CP-EE technology providers

• The Energy Efficiency Best Practice Programme

The Energy Efficiency Best Practice Programme (EEBPP) is a UK Government

programme providing free information to organizations to help them cut their

energy bills by offering detailed technical advice on a wide range of energy

efficiency measures.

http://www.energy-efficiency.gov.uk/

• Persistent organic pollutants (POPs)—database of alternatives

Information on POPs alternatives and approaches to replace and/or reduce the

releases of POPs chemicals.

http://www.chem.unep.ch/pops/newlayout/infaltapp.htm

• GREENTIE

Using the search facility on this site, browse the full international directory of

suppliers whose technologies help to reduce GHG emissions.

http://www.greentie.org/directory/index.php

• Advanced test and measurement devices

A leading company in the development and manufacture of advanced test and

measurement technologies for use both in the field and leading edge facilities

around the world.

http://www.hioki.co.jp/eng/product/



http://sefi.unep.org

http://www.energy-efficiency.gov.uk/

http://www.chem.unep.ch/pops/newlayout/infaltapp.htm

http://www.greentie.org/directory/index.php

http://www.hioki.co.jp/eng/product

• Product and supplier finder

More than 11 000 on-line catalogues covering: sensors, transducers and

detectors; manufacturing and process equipment (e.g. heating and cooling

equipment, industrial heaters, industrial machine safeguarding, inspection tools

and instruments, materials processing equipment); material handling; data

acquisition and signal conditioning; mechanical components; industrial

computing; motion and controls; flow transfer and control; and test and

measurement equipment.

http://www.globalspec.com/ProductFinder/

• Association of Energy Services Professionals

The Association of Energy Services Professionals is dedicated to advancing the

professional interests of individuals working to provide value through energy

services and energy efficiency by sharing ideas, information and experience.

http://www.aesp.org/

• SEE-Tech Solutions Pvt. Ltd.

A company specializing in consulting, training and performance auditing in the

areas of energy conservation, energy efficiency improvement and industrial safety.

The company also provides software solutions for energy auditing.

http://www.letsconserve.org/seemain.php

• Trade portal for Indian products

On-line marketplace for industrial process equipment and accessories, and many

other Indian products.

http://www.easy2source.com/

• CADDET Energy Efficiency

A collection of studies (analysis reports) made by experts from CADDET Energy

Efficiency members and other IEA agreements, providing detailed reviews across a

wide range of topical energy efficiency subjects. They can be obtained from

CADDET Energy Efficiency National Teams (a summary can be provided, for a fee).

http://www.caddet-ee.org/reports/index.php



http://www.globalspec.com/ProductFinder

http://www.aesp.org

http://www.letsconserve.org/seemain.php

http://www.easy2source.com

http://www.caddet-ee.org/reports/index.php

• National Inventory of Manufacturing Assistance Programs (NIMAP)

The NIMAP inventory is linking sources with consumers of technical information

and services. Simple lack of awareness on the part of eligible recipients is a major

barrier to achieving energy policy goals.

http://www.oit.doe.gov/bestpractices/nimap/

• Database for Energy Efficient Resources (DEER)

Database for Energy Efficient Resources (DEER) contains extensive information on

selected energy-efficient technologies and measures. The DEER provides estimates

of the average cost, market saturation, and energy-savings potential for these

technologies in residential and non-residential applications.

http://www.energy.ca.gov/deer

• Thai-Danish cooperation on sustainable energy

The Sustainable Energy Database provides an overview of activities and players in

the field of sustainable energy in Thailand, and in the Isaan region in particular.

http://www.ata.or.th/indexeng.html

• Tata Energy Research Institute (TERI)

TEDDY Online (TERI Energy Data, Directory and Yearbook) provides ready-to-use

information on different segments (energy and environment) of the Indian

economy and some aspects of international economy.

http://www.eldis.org/static/DOC4556.htm

• IEA Clean Coal Centre

The world’s foremost provider of information on efficient coal supply and use, IEA

Coal Research—The Clean Coal Centre enhances innovation and continued

development of coal as a clean source of energy.

http://www.iea-coal.org.uk/

• Energy Technology Systems Analysis Programme

The Energy Technology Systems Analysis Programme (ETSAP) of the International

Energy Agency (IEA) is a research partnership dedicated to enabling its partners

and their clients to develop sound integrated energy and environmental policy.

http://www.etsap.org/index.htm



http://www.oit.doe.gov/bestpractices/nimap

http://www.energy.ca.gov/deer

http://www.ata.or.th/indexeng.html

http://www.eldis.org/static/DOC4556.htm

http://www.iea-coal.org.uk

http://www.etsap.org/index.htm

• ETDE’s Energy Database

ETDE’s Energy Database contains a large collection of energy literature, with more

than 3.8 million abstracted and indexed records. Updated twice monthly, the

database contains bibliographic references to, and abstracts from, journal articles,

reports, conference papers, books and other documents. The database covers a

variety of subjects including environmental aspects of energy production and use,

and energy policy and planning, as well as the basic science that supports energy

research and development.

http://www.etde.org/edb/energy.html

• The Bureau of Energy Efficiency (BEE)

The BEE website, is a comprehensive source of information on energy

conservation- (EC) related developments and issues. It provides an update on the

related policy framework especially in the context of the EC Act 2001 as well as

topical write-ups, news and highlights on developments in India. The site also

features activities taken up by the BEE with stakeholders, co-opting expertise from

bilateral/multilateral agencies.

http://www.bee-india.com/

• National Lighting Product Information Programme

NLPIP, helps lighting professionals, contractors, designers, building managers,

homeowners and other consumers find and use efficient, quality products that

meet their lighting needs. With the support of government agencies, public benefit

organizations and electrical utilities, NLPIP disseminates objective, accurate, timely,

manufacturer-specific information about energy-efficient lighting products.

http://www.lrc.rpi.edu/programs/NLPIP/index.asp

E.4 CP-EE sector-specific resources

• Energy efficiency technologies

This link provides information on R&D projects in energy saving technologies for

a number of vital industries including: mining; metal casting; aluminium;

chemicals; forest products; glass; metal casting; mining; petroleum; steel; and

supporting industries).

http://www.eere.energy.gov/industry/



http://www.etde.org/edb/energy.html

http://www.bee-india.com

http://www.lrc.rpi.edu/programs/NLPIP/index.asp

http://www.eere.energy.gov/industry

• Textile: smart guide

A useful guide including a summary of business cases in textile manufacturing in

different countries.

http://www.emcentre.com/unepweb/tec_case/textile_17/house/casename.shtml

• US EPA Sector Notebooks

The US EPA Sector Notebooks are comprehensive overviews of environmental

issues in about 30 major industries. Each includes descriptions of the industry,

including operations, pollutants and regulations, pollution prevention methods,

and related resources. Highly recommended.

http://www.epa.gov/compliance/resources/publications/assistance/sectors/notebooks/

• European Integrated Pollution Prevention and Control Bureau

The European Integrated Pollution Prevention and Control Bureau produces

comprehensive guides to industry sector environmental management. About 15

guides have been completed; many others are being developed.

http://www.jrc.es/pub/english.cgi/0/733169

• Australian National Pollutant Inventory Industry Handbooks

The Australian National Pollutant Inventory Industry Handbooks are manuals for

estimating emissions from about 50 types of industries. Each Handbook has

detailed process descriptions, information about emission sources, and

benchmarks and formulas for estimating emissions. Highly valuable to engineers.

http://www.npi.gov.au/handbooks/approved_handbooks/index.html

• On-line collection of pollution prevention references

This on-line collection of pollution prevention core references includes technical

references, fact sheets and case studies on pollution prevention for 30 selected

industry sectors.

http://wrrc.p2pays.org/industry/indsector.htm

• Energy Data and Analysis database (Asia Pacific )

The Expert Group on Energy Data and Analysis (EGEDA) is responsible for

providing policy relevant energy information to APEC bodies and the wider

community, through collecting energy data of the APEC region, managing the

operation of the APEC Energy database through the coordinating agency.

http://www.ieej.or.jp/egeda/database/database-top.html



http://www.emcentre.com/unepweb/tec_case/textile_17/house/casename.shtml

http://www.epa.gov/compliance/resources/publications/assistance/sectors/notebooks

http://www.jrc.es/pub/english.cgi/0/733169

http://www.npi.gov.au/handbooks/approved_handbooks/index.html

http://wrrc.p2pays.org/industry/indsector.htm

http://www.ieej.or.jp/egeda/database/database-top.html

E.5 Software and tools

• Electrical engineering calculators

Basic formulas, plus calculators for: conductors, resistors, capacitors and PCB’s;

semiconductors and integrated chips; and power supplies.

http://www.ifigure.com/engineer/electric/electric.htm

• Engineering calculators

Free on-line calculators for: steam approximations; power cycle analysis (carnot,

cycle, brayton, otto, and diesel cycles); power cycle components/processes;

compressible flow; unit conversion; engineering equations; and miscellaneous

engineering tools.

http://members.aol.com/engware/calcs.htm

• Mechanical engineering calculators

Engineering conversion factors; hydraulics tools (fluid flow calculator, water pump

calculator, and pump tables and charts); and heating and air conditioning tools

(psychometric calculator, saturated steam tables and air duct calculator).

http://www.ifigure.com/engineer/mechanic/mechanic.htm

• On-line calculators and formulas for power system analysis

The formulas on this web page can be used in designing power factor correction

systems and harmonic filter banks.

http://www.nepsi.com/formulas.htm

• FireCAD

User-friendly FireCAD design software products are available, developed using the

latest boiler and software technologies, for fire tube boiler, water tube package

boiler, economizer, air heater and superheater. Trial versions of these software

packages can be downloaded.

http://www.firecad.net/

• Material safety data sheets (database)

A card and the information that it contains relate to a specific chemical substance

and are concerned with the intrinsic hazards posed by that chemical. Also, a basic

tool to supply information on the properties of chemicals used. (Available in 14

languages).

http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/index.htm



http://www.ifigure.com/engineer/electric/electric.htm

http://members.aol.com/engware/calcs.htm

http://www.ifigure.com/engineer/mechanic/mechanic.htm

http://www.nepsi.com/formulas.htm

http://www.firecad.net

http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/index.htm

• Motor solutions online self assessment tool

This self-assessment tool is designed to assist organizations in rating motor and

equipment management skills, from initial selection to eventual replacement. Not a

test, rather a tool to help identify and prioritize change within an organization—

change that can reduce life-cycle cost of equipment ownership and increase profits.

http://www.peak.co.nz/ausat/

E.6 Energy legislation

• European energy legislation (by country)

Details of both European and national laws, policies, directives, regulations,

standards, etc. Data can be searched by country.

http://www.managenergy.net/submenu/Sleg.htm

• Asia energy conservation legislation

Compendium on energy conservation legislation in countries of the Asia and

Pacific region.

http://www.unescap.org/esd/energy/publications/compend/cec.htm

• Energy Charter Treaty (Europe/Asia)

The fundamental aim of the Energy Charter Treaty is to strengthen the Rule of

Law on energy issues by creating a level playing field of rules to be observed by

all participating governments, thus minimizing the risks associated with energy

related investments and trade.

http://www.encharter.org/index.jsp



http://www.peak.co.nz/ausat

http://www.managenergy.net/submenu/Sleg.htm

http://www.unescap.org/esd/energy/publications/compend/cec.htm

http://www.encharter.org/index.jsp



Système International (SI) and metric units have been adopted internationally for

energy calculations. For instance, the joule, the SI unit of energy, is commonly used in

conjunction with other SI units such as the metre, the kilogram and the kelvin (for

temperature).

The conversion tables presented below show how some units commonly used in

engineering and other professions equate to SI and metric units.

F: Conversion tables

T = tera = One million million = 1 000 000 000 000 = 1012

G = giga = One thousand million (Also one billion) = 1 000 000 000 = 109

M = mega = One million = 1 000 000 = 106

k = kilo = One thousand = 1 000 = 103

d = deci = One tenth = 0.1 = 10-1

c = centi = One hundredth = 0.01 = 10-2

m = milli = One thousandth = 0.001 = 10-3

m = micro = One millionth = 0.000001 = 10-6

n = nano = One billionth = 0.000000001 = 10-9

p = pico = One millionth of a millionth = 0.000000000001 = 10-12

Table F.1: Abbreviations for quantities


Part 3 Tools and resources F: Conversion tables

Btu

Btu/lb °F andkJ/kg °C

Btu in/ft 2handW/m2 °C

bar

bbl

cal and(kcal)

grain

ha

HP

imp

J and (kJ)

kWh

l (also ltr)

psiandkPa

therm

tonne

W (kW)

The British thermal unit, a measure of heat energy.

Units for the specific heat capacity of a substance—a measure of the quantity of(heat) energy required to raise the temperature of a given quantity of the substancethrough one degree.

In the imperial system, it is the number of British thermal units required to raise onepound weight of the substance by one degree on the Fahrenheit scale.

In SI units it is the (kilo) joules of heat energy required to raise one kilogram of thesubstance by one degree on the Celsius (or Centigrade) scale.

Thermal conductance—a measure of the rate at which heat energy passes through agiven thickness of material per unit of area, with a one degree temperaturedifference between the two sides.

In imperial units it is the number of British thermal units that will pass through onesquare foot of material of one inch thickness in one hour with a temperaturedifference of one degree Fahrenheit between the warmer and cooler surfaces.

Using SI units, it is watts of heat power that will pass through one square metre ofmaterial with one degree Celsius (Centigrade) difference.

An alternative unit of pressure equal to 105 pascals. Its value is slightly higher thannormal atmospheric pressure. The bar is often divided into millibars, (abbreviationmbar) equal to one thousandth of a bar.

U.S. Barrel, used in the oil industry as a standard unit of oil production (equivalent to42 US gallons or 35 imperial gallons).

The calorie, a metric system unit of energy now superseded by the SI unit, the joule.(1 kcal = 1 000 calories).

An older imperial unit of weight still used occasionally for very small amounts ofmaterial (7 000 grains = 1 pound).

Hectare, metric unit of ground area (equivalent to 2.47 acres), equal to 10 000 m2.

Horsepower, the rate of mechanical work.

Abbreviation for ‘imperial’. When used alongside a unit it indicates that the unitbelongs to the imperial system (e.g. 1 gal (imp) is 1 imperial gallon).

The joule, the SI unit of energy (1 kJ = 1 000 joules).

A measure of energy equivalent to consumption of 1 kW of power for one hour. ThekWh is the traditional ‘unit’ of electricity in industry. It is the unit usually used oninvoices to show the amount of electrical energy used by the consumer.

The litre, a metric unit of volume.

Units of pressure.

In imperial units (pounds per square inch, psi), pounds force applied to one squareinch of surface.

In SI units, (kilo pascals, kPa), a force of 1000 pascals applied over one square metreof surface. (The pascal is a pressure of one newton applied to one square metre).

A unit of heat used traditionally by the gas industry.

The metric tonne, slightly smaller than the imperial ton (around 1.6 per cent less).

The watt, a unit of power (1 kW = 1 000 watts).

Table F.2: Commonly used units and what they mean



Metric to British British to metric unit

Volume

1 cm3 = 0.061 cu.in. 1 cu.in = 16.387 cm3

1 m3 = 35.32 ft3 1 ft3 = 0.0283 m3

1 m3 = 1.308 cu.yd 1 cu.yd = 0.7646 m3

Specific volume and weights

1 m3/kg = 16.02 ft.3 /lb 1 ft.3/lb = 0.0624 m3/kg

1 kg/m3 = 0.0624 lb/ft3 1 lb/ft3 = 16.01 kg/m3

Pressure

1 kg/cm2 = 14.223 lb/sq.in.(psi) 1 lb/sq.in = 0.0703 kg/cm3

1 mm WC = 0.002937 in. of Hg 1 in. of Hg = 340.39 mm WC

1 ounce/sq.in = 43.9 mm WC

Velocity

1 m/sec = 196.9 ft/min. 100 ft/min = 0.508 m.sec

1 m/sec = 3.28 ft/sec 100 ft/sec = 30.4 m/sec

Flow

1 m3/hr = 0.589 CFM (cu.ft /min) 1 CFM = 1.7 m3/hr

Table F.3: Conversion of measurements



1 Btu

1 Btu

1 Btu/sec

1 Btu/lb.

1 Btu/cu.ft

1 Btu/sq.ft.h

1 Btu/sq.ft.h °F

1 Btu/ft.h °F

1 Btu/lb °F

1 Btu/cu.ft °F

1 kcal

1 kW

1 kcal

1 kWh

1 kJ

1 kW

1 kJ/kg

1 W/m °C

1 W/m2 °C

1 kJ/kg °C

1 kJ/m3 °C

1 kcal/kg

1 kcal/m3

1 kcal/m3 h

1 kcal/m3 h °C

1 kcal/mh °C

1 kcal/mh °C m3

1 kcal/kg °C

1 kcal/m3 °C

860 kcal

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

0.252 kcal

1.055 kJ

1.055 kW

0.556 kcal/kg (2.3244 kJ/kg)

8 900 kcal/m3 (37.26 kJ/m3)

2.71 kcal/m3 h (3.155 kW/m2)

4.886 kcal/m2 h °C (5.678 kW/m2 °C)

1.49 kcal/mh °C (17.296 kW/m °C)

1.001 kcal/kg °C (4.187 kJ/kg °C)

16.2 kcal/m3 °C (67070 kJ/m3 °C)

3.968 Btu

0.948 Btu/sec

0.239 kJ

860 kcal

0.948 Btu

3412 Btu/h

0.4302 Btu/lb

0.578 Btu/h ft °F

0.1761 Btu/h ft2 °F

0.239 Btu/lb °F

0.0149 Btu/ft3 °F

1.80 Btu/lb

0.112 Btu/cu.ft.

0.369 Btu/sq.ft.h

0.205 Btu/sq.ft.h °F

0.67 Btu/ft.h °F

8.07 Btu in/sq.ft. °F

0.999 Btu/lb °F

0.0624 Btu/cu.ft. °F

1 kWh

Table F.4: Conversion of common units of heat (thermal power and energy)



PSI

PSI

kg/cm2

Atmosphere

Bar

1

14 223

14.69

14.5

0.07031

1

1.033

1.019

0.06804

0.9678

1

0.986

0.069

0.981

1.0133

1

Table F.5: Conversion of pressure units

kg/cm2 Atmosphere Bar

kcal/sec

kcal/sec

kW (kilo watt)

HP

Ch

1

0.239

0.178

0.176

4.188

1

0.746

0.736

5 616

1.341

1

0.987

5.67

1.359

1.014

1

Table F.7: Conversion of power units

kW (kilo watt) HP Ch

kcal

kcal

kJ (kilo-joule)

kWh

HPh

1

0. 239

860

642.5

4 187

1

3 600 x 103

22 685 500

0.001161

27.77 x 10-5

1

0.74565

0.001556

37.23 x 10-5

1.3411

1

Table F.6: Conversion of energy units

kJ (kilo-joule) kWh HPh



F.O.

Density (approx. kg/m3 at 15 °C)

Flash point (°C)

Pour point (°C)

GCV (kcal/kg)

Sediment (max. % weight)

Sulphur total (max. % weight)

Water content (max. % volume)

0.89–0.95

66

20

10 200

0.25

4.0

1.0

0.88–0.98

93

72

9 500

0.25

1.0

1.0

0.85–0.98

93

72

9 500

0.25

1.0

1.0

0.85–0.87

66

12 (winter)18 (summer)

10 700

0.1

1.8

0.25

Table F.8: Characteristics of fuel oils

PropertiesLS.H.S H.P.S. L.D.O.

Fuel oils

GeneralCDM Clean Development Mechanism

CP Cleaner Production

CP-EE Integrated Cleaner Production and Energy Efficiency

EE Energy Efficiency

EMS Environmental management system

JI Joint Implementation

LDPM Luthra Dyeing and Printing Mills (facility assessed for Case Study in Chapter 3)

MoU Memorandum of understanding

NCPC National Cleaner Production Centre

NGO Nongovernmental organization

POPs Persistent Organic Pollutants

UNEP DTIE UNEP’s Division of Technology, Industry and Economics

UNEP United Nations Environment Programme

Scientific and technical°C Degree Celsius (or centigrade)

A/C Air conditioning

ACFM Actual cubic feet per minute

AHU Air handling unit

ata Atmosphere (as a unit of pressure)

BD Blow down

BFB Bubbling fluidized bed

BFW Boiler feed water (pumps)

BOD Biochemical oxygen demand (water)

BW Boiler water

CES Commercial Energy System

CFL Compact fluorescent light (lamp)

CFM Cubic feet per minute

CHP Combined heat and power

CMH Cubic metres per hour

CO Carbon monoxide

CO2 Carbon dioxide

COD Chemical oxygen demand (water)

COP Coefficient of performance



G: Acronyms and abbreviations

CSI Current source inverter

CT Cooling tower

CW Cooling water

DG Diesel generator

DM Demineralized (water)

DP Pressure drop

EER Energy efficiency ratio

ETI Economic thickness of insulation

ETP Effluent treatment plant

F.O. Fuel oil

FAD Free air delivery

FBC Fluidized bed combustion

FD Forced draught (fans)

FH Fired heater

FIFO First in, first out

GCV Gross calorific value

GHG Greenhouse gas

GLS General lighting service

GPM Gallons per minute

H.P. Horsepower

H.T. High tension (voltage)

H2 Hydrogen (molecular)

H2O Water

Hg Mercury (also used in pressure units, i.e. mercury column)

HVAC Heating, ventilation and air conditioning

HVDC High voltage direct current

I Electrical current

ID Induced draught (fans)

IRR Internal rate of return

LAP Low air pressure (burners)

L.T. Low tension (voltage)

M&E Material and energy (balance)

M.D. Maximum demand

N Speed of rotation (machinery, etc.)

N2 Nitrogen (molecular)

NCV Net calorific value

NG Natural gas

NOx Nitrogen oxides


Part 3 Tools and resources G: Acronyms and abbreviations

NPV Net present value

NTP Normal temperature and pressure (273 K, 1 atm)

O&M Operating and maintenance (costs)

O2 Oxygen (molecular)

P Pressure

PCB Printed circuit board

P.F. (PF) Power factor

PFD Process flow diagram

PI Profitability index

PPM Parts per million

PWM Pulse width modulation

R Refrigeration

R&D Research and development

RFT Right first time

RO Reverse osmosis (water treatment)

RPM Revolutions per minute

S Sulphur

SO2 Sulphur dioxide

SO3 Sulphur trioxide

SOx Sulphur oxides

SOP Standard operating practice

SPC Specific power consumption

TD Thermodynamic

TDH Total dynamic head

TDS Total dissolved solids (water)

TFH Thermic fluid heater

TR Ton of refrigeration (also refrigeration ton)

TS Total solids (water)

VSD Variable speed drive

VSI Voltage source inverter

WB Wet bulb

W.C. (WC) Water column

W.R.T. With respect to

WHR Waste heat recovery

Commonly used and standard abbreviations for units are not included here. The

Conversion Tables (pages 287–292) give explanations of units used in the Manual which

may not be familiar to all readers, in addition to their equivalents in SI or metric units.


Part 3 Tools and resources G: Acronyms and abbreviations

For more information:

UNEP

Division of Technology, Industry and Economics

Tour Mirabeau

39–43 quai André Citroën

75739 Paris Cedex 15

France

Tel: +33 1 44 37 14 50

Fax: +33 1 44 37 14 74

E-mail: [email protected]

Website: www.uneptie.org

WWW.unep.orgUnited Nations Environment Programme

P.O. Box 30552 Nairobi, KenyaTel: (254 2) 621234Fax: (254 2) 623927

E-mail: [email protected]: www.unep.org

mailto:[email protected]

http://www.unep.org

mailto:[email protected]

http://www.uneptie.org

cleaner production & energy efficiency manual

Documents

heart of cleaner production

energy programmes

unepcleaner production

draft manual

cpee methodologypart

energy management principles

cpee manualpart

manualthis electronic