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GREEN SCHOOL ENERGY MODELLING &

CAPACITY BUILDING IN MONGOLIA

UNITED NATIONS ENVIRONMENTAL PROGRAMME

Green School Renewable Energy & Water Management Strategy Report

22 August 2016

ITP/UKP1224

Green school energy modelling &Capacity building in Mongolia Green School Renewable Energy & Water Management Strategy Report

ITP/1224 i 22 August 2016

United Nations Environmental Programme

IT Power reference: 1223

Green School Model Report

August 2016

IT Power St. Brandon’s House 29 Great George Street Bristol, BS1 5QT, UK Tel: +44 117 214 0510 Fax: +44 117 214 0511 E-mail: [email protected] www.itpower.co.uk

Document control

File path & name 0Projects\1224 Mongolia Green School TA\2 Work

Author – 11pt regular David Fernandez, Sushovit Adhikari

Project Manager David Fernandez

Approved

Date 22 August 2016

Distribution level Client Distribution

Template: ITP Report, Form 005 Issue 07;

mailto:[email protected]

http://www.itpower.co.uk/


ITP/1224 ii 22 August 2016

LIST OF FIGURES

Figure 1: School Space Heating & Hot Water Demand .................................................2

Figure 2: School Electrical Demands ......................................................................3

Figure 3: Vertical closed loop borehole systems ........................................................4

Figure 4: Horizontal loop heat pumps ....................................................................5

Figure 5: Solar PV Technology (Grid connected and offgrid systems) ...............................6

Figure 6: Sun Path for Ulaanbaatar ......................................................................7

Figure 7: Roof Plan and suitable locations for PV Panels ..............................................8

Figure 8: Solar Hot Water System with Gas Back Up ................................................. 10

Figure 9: Small Wind Turbine Components ............................................................ 12

Figure 10: Wind speed distribution for School Location in Ulaanbaatar ........................... 13

Figure 11: Wind Rose for School Location in Ulaanbaatar ........................................... 13

Figure 12: 150kW Inmecal Biomass Boiler ............................................................. 14

Figure 13: Dual flush toilets ............................................................................. 17

Figure 14: Aerated Taps .................................................................................. 18

Figure 15: Spray Taps ..................................................................................... 18

Figure 16: Percussion Taps ............................................................................... 19

Figure 17: Passive infrared Taps ........................................................................ 19

Figure 18: Water Efficient Showers ..................................................................... 20

Figure 19: Contribution to the total water savings from the 4 proposed measures ............. 23

Figure 20: Additional cost breakdown of the 4 proposed measures ................................ 24

Figure 21: Rainwater Harvesting System .............................................................. 25

Figure 22: Conceptual rainwater harvesting system ................................................. 26

Figure 23: School roof plan view ........................................................................ 26

Figure 24: Ulaanbaatar& Mongolia Average Monthly Rainfalls ...................................... 27

Figure 25: School monthly roof rain harvesting volume & water demands ....................... 28

Figure 26: Schematic of a greywater system .......................................................... 29

Figure 27: Greywater treatment and re-use systems ................................................ 30

Figure 28: Branched Drain System ...................................................................... 30

Figure 29: School water breakdown usage ............................................................. 31


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LIST OF TABLES

Table 1: Climatic Data for Ulaanbaatar ..................................................................8

Table 2: Financial assumptions 40kW PV Plant..........................................................9

Table 3: Number of toilets, showers, dishwashers and taps ........................................ 21

Table 4: Monthly school water consumption baseline ............................................... 21

Table 5: Monthly school water consumption after implementing water efficiency measures . 22

Table 6: Water Efficiency Measures Cost Benefit Analysis .......................................... 23

Table 7: Grey water reuse potential from basins and showers ..................................... 32


ITP/1224 iv 22 August 2016

TABLE OF CONTENTS

List of Figures ........................................................................................ ii

List of Tables ......................................................................................... iii

Table of contents .................................................................................... iv

Abbreviations and Acronym ........................................................................ v

Executive Summary ................................................................................. 1

1 Building Loads ............................................................................... 2

1.1 Heating Demand Profile ........................................................... 2

1.2 Electricity Demand Profile ........................................................ 3

2 Renewable Energy Strategy ............................................................... 4

2.1 Ground Source Heat Pumps ....................................................... 4

2.1.1 General description ....................................................... 4

2.1.2 Technology suitability& Building Integration .......................... 5

2.2 Solar Photovoltaics................................................................. 5


2.2.2 Solar Resource ............................................................. 6

2.2.3 Technology suitability & Building Integration ......................... 8

2.2.4 Cost Assessment ........................................................... 9

2.3 Solar Thermal ....................................................................... 10


2.3.2 Solar Resource ............................................................. 11


2.4 Wind Energy ......................................................................... 12


2.4.2 Wind Resource Assessment ............................................... 12


2.5 Biomass Energy ..................................................................... 14


2.5.2 Biomass Resource Assessment ........................................... 14


3 Renewable Energy – Conclussions & Recommendations ............................... 15

4 Water Management Technologies ........................................................ 16

4.1 Dual Flush toilets ................................................................... 17


4.2 Water and Shower Efficient Taps ................................................ 17


ITP/1224 v 22 August 2016


4.3 Water Efficient Showers .......................................................... 19

4.4 School Water Baseline Demand .................................................. 21

4.5 Water Saving Potential ............................................................ 21

4.6 Water Management – Conclusions & Recommendations ...................... 22

5 Rainwater Harvesting Systems ............................................................ 25

5.1 General description ................................................................ 25

5.2 Rainfall water levels Ulaanbaatar ............................................... 26

5.3 Rain Water Collection System– Conclusions & Recommendations........... 27

6 Greywater Systems ......................................................................... 29

6.1 General description ................................................................ 29

6.2 Greywater reuse potential – Recommendations & Conclusions.............. 31

7 Water Management – Conclussions & Recommendations .............................. 33


ITP/1224 v 22 August 2016

ABBREVIATIONS AND ACRONYM

agl - above ground level

DC- Direct Current

Defra - Department for Environment, Food & Rural Affairs

GDP- Green Development Policy

HVAC- Heating Ventilation and Air Conditioning

PAGE- The Partnership for Action on Green Economy

PV- Photovoltaic

0C-Degree Celsius

cm- centimetre

gpf- gallons per flush

kWh- Kilowatt Hours

m- Meter

m/s- meter per second

m2 – meter square

mph- miles per hour

rpm- revolutions per minute

s- Second

W- Watt


ITP/1224 1 22 August 2016

EXECUTIVE SUMMARY

The Government of Mongolia is committed in developing a green economy that will support creating new jobs in a new sector, reduce poverty levels, and reduce pollution levels and environmental impact. Mongolia has been the first country joining PAGE in 2013 and is leading the way in reframing its economic policies around sustainability.

In 2014, the Parliament of Mongolia approved the Green Development Policy (GDP). The objective of the GDP is the support of green development in Mongolia. The GDP has determined goals and objectives for green development up to 2030 and outlines actions to ensure these goals are achieved. The PAGE partnership in Mongolia has directly linked the development and implementation of the GDP, by providing technical support, fostering political commitment, and modelling economic, social and environmental implications of GDP targets. The partnership advances policy development and reform in specific sectors and thematic areas, such as green construction and sustainable public procurement.

The purpose involves the development of a Green School concept involving not only energy efficiency aspects, as well the implementation of feasible clean energy generation technologies. Therefore the project involves as well the assessment of building integrated renewable energy technologies such as solar photovoltaics, solar thermal, wind energy, etc. based on the site resources available, building features, consumption profiles, etc.

On the other hand the study will include a description and assessment of suitable water management measures to be implemented like dual flush toilets, water efficient showers and taps. Besides efficient usage recycling and reuse of water will also add to water efficiency strategies. Thus implementing rainwater collection strategies as well as water recycling technologies will help in reduce consumption of water from the main supply and thus reduce the school water demands.

It has to be noted that the Renewable Energy Strategy described in this report is crucial, however it is as important to implement the proposed energy efficiency measures in the “Energy Modelling and Energy Efficiency Report” in order to develop the green concept of the school. There is no point in fitting expensive renewable energy systems in a building that is wasteful of energy in other areas, a holistic approach is required. If the project is new build, all aspects of building energy use should be considered, including layout, insulation, heating system, lighting and window types, before considering the implementation of renewable energy technologies.


ITP/1224 2 22 August 2016

1 BUILDING LOADS

In the “Energy Modelling and Energy Efficiency Report” produced the school had been modelled using “DesignBuilder v4.6.0” software to estimate the building loads. The different areas, rooms, hot water consumptions etc. have been defined in the model: internal temperature requirements, occupancy profiles, type of heating systems etc. Once the model was completed a simulation was carried out. The energy profiles for the schools were obtained. The results and figures for the heating and electrical demands are shown below:

1.1 Heating Demand Profile

Based on NAP’s HVAC speciaist information, the heating system design based on following key aspects:

The coal space heating system operates between beginning of October and mid May.

The heating system would not provide space heating (except for minimum temperature maintenance needs to avoid condensation issues in the building) between mid December and Mid January.

The heating system operates from Monday to Saturday. However on Saturday most of the school will be empty except the Auditorium, Library and Gym that will be open. On Sunday the space heating does only operate if the building temperature drops below

12⁰C.

The space heating energy profile peaks in the winter months from 260 kWth until May where the system is switched off (Figure 1). The hot water profile stays constant over the year as it does not depend on the external temperatures.

Figure 1: School Space Heating & Hot Water Demand


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1.2 Electricity Demand Profile

The electricity profile will be constant over the year during occupied periods having an average electrical peak load of 53kWe (see Figure 2). As occurred for the heating profile in the summer months and Christmas periods the load is non existent as the building is not occupied.

Figure 2: School Electrical Demands

The school is an educational building, therefore in the summer months and Christmas festive periods the building will be empty hence as expected from the simulation no energy consumptions are observed (except the minimum space heating needs to keep temperatures

above 12⁰C). This aspect will be crucial when deciding regarding the suitability of specific renewable energy technologies integrated in the school and as well in terms of actual energy plant operational hours.


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2 RENEWABLE ENERGY STRATEGY

There are several renewable energy technologies that can be used in buildings, photovoltaics (PV), solar hot water, wind energy, biomass or ground source heat pumps.

2.1 Ground Source Heat Pumps

2.1.1 General description Ground source technologies involve the use of ground temperature or underground water sources (aquifers) which retain a near constant temperature all year round, hence in winter the underground temperature is warmer than the surface air temperatures, and in summer it is cooler. This temperature difference can be used to provide heating or cooling energy to buildings on the surface. Ground source heat pumps can be divided basically in 2 groups:

Vertical Closed Loop (U-Tube) Boreholes: Vertical closed loop ground coupling systems involve sinking vertical pipes containing water and refrigerants into the ground. The water pipework is a closed circuit, and heat is transferred to / from the pipes by conduction only. Loops can typically be up to 200m deep depending on ground conditions.

Figure 3: Vertical closed loop borehole systems1

Horizontal Loops: A horizontal loop field installation requires a great deal of land because a backhoe is used to dig up long trenches at low depth to lay the necessary amount of piping. In some cases horizontal loop fields can be less costly to install than vertical because there is no drilling requirement.

1 Image source: www.rhienergiesltd.com


ITP/1224 5 22 August 2016

Figure 4: Horizontal loop heat pumps2

2.1.2 Technology suitability& Building Integration

Vertical ground source heat pumps

The feasibility of a ground source heat pump installation system is strongly dependant on the conductivity of the soil. A geological study would be necessary to size and obtain the optimum benefits of ground coupling system for any development. Assuming the conductivity of the ground is sufficient, the system should be sized to cover as much of the load as is affordable within the capital constraints of the project.

However this technology is suitable only if there is a balance demand between heating and cooling loads in the building. The extraction of heat from the ground strata during the colder months to heat the rooms needs to be rebalanced during the summer months with the heat extraction from the rooms to the ground. Otherwise a negative phenomenon’s such as “permafrost” and other negative effects on the plant performance would take place. As the School has no cooling loads and furthermore the building is empty in the summer months this technology is not suitable.

Horizontal ground source heat pumps

The horizontal heat pumps have the great advantage that they can be used for heating purposes only. Typically they are more suited for small heating demands, such as for homes or small residential areas because of the large space requirements demanding large extensions of space. This technology has already been proposed by NAP to satisfy the air treatment demands of the ventilation system.

2.2 Solar Photovoltaics

2.2.1 General description

Photovoltaic (PV) systems convert energy from the sun into electricity through semi conductor cells. PVs supply electricity to the building they are attached to, or to any other load connected to the electricity grid.

2Image source: www.hydro.mb.ca


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Electricity from PVs is usually supplied back to the national grid when the generated power exceeds the local need. PV systems can be off grid when the building demand during the weekends when most of the equipment is on stand-by is higher than the load generated from the PV systems. More electricity is produced with more sunlight, but energy can still be produced in overcast or cloudy conditions.

Figure 5: Solar PV Technology (Grid connected3 and offgrid4 systems)

Photovoltaic panels can be designed into new buildings typically roofs and facades or attached to individual items such as street lights or parking meters.

Ideally PVs in Ulaanbaatar should be facing pure South at an elevation of about 45-48⁰. Systems can also be fitted to shading elements providing both shade and electricity, or be façade integrated.

Incorporating photovoltaics into a development will enable the building to produce a percentage of its electricity from a renewable source.

Further benefits are as follows:

Normally those are fixed to the building and no moving parts are required and therefore little maintenance is necessary.

They are easy to install as modular and light.

Technically reliable – they are generally guaranteed to last between 10-25 years but are expected to last longer.

Architectural integration – PVs can be added to buildings, can be used as a design element or can lead the architectural concept of a building.

There are no emissions in use. Marketing impact showing a clear commitment about renewable energy.

Has a clear educational purpose especially in a school.

2.2.2 Solar Resource

The average annual solar resource in Ulaanbaatar is very good with an annual average of about 4.10 kWh/m2/day. The length of the day varies significantly over the course of the year. The shortest day is December 21 with 8:24 hours of daylight and the longest day is June 20 with16:02 hours of daylight. The longest day is nearly 8 hours longer than the shortest day. There is an

3Image Source: Skyway Electric and Solar (http://skyway-es.com/if-the-power-goes-out-what-happens-to-my-solar-system/)

4Image Source: Brightside solar ‘types of system’ (http://brightsidesolarinc.com/?page_id=129)

http://skyway-es.com/if-the-power-goes-out-what-happens-to-my-solar-system/

http://brightsidesolarinc.com/?page_id=129


ITP/1224 7 22 August 2016

average of 2600 hours of sunlight per year In Mongolia. The clearness index ranges from 47 %( cloudy) to 60% (mostly clear). The sky is cloudiest on July and clearest on March. The sun-path diagram for Ulaanbaatar is shown in Figure 6.

Figure 6: Sun Path for Ulaanbaatar 5

The different climatic parameters (Radiation, temperature, wind speed, clearness index (KT)) in Ulaanbaatar can be seen in Error! Reference source not found.:

Month

Global Horizontal Radiation (kWh/m2/day)

Diffused Radiation

(kWh/m2/day)

Clearness Index(KT)

Temperature

(0 C)

January 1.62 0.59 0.55 -24.4

February 2.66 0.74 0.59 -19.5

March 3.96 1.26 0.60 -7.5

April 4.88 2.15 0.54 2.7

May 5.48 2.22 0.51 10.4

June 5.79 2.68 0.50 17.6

July 5.18 2.72 0.46 20.1

August 4.49 2.15 0.46 17.3

September 3.77 1.77 0.50 10.1

5Image was extracted from Meteonorm 7.1


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October 2.94 1.05 0.56 -0.4

November 1.80 0.71 0.54 -13.1

December 1.32 0.48 0.53 -22.7

Average 3.66 1.55 0.52 -0.8

Table 1: Climatic Data for Ulaanbaatar6

2.2.3 Technology suitability & Building Integration

The most suitable application for photovoltaic cells at the school is to cover a proportion of the daily electrical loads of the development, for the following reasons:

Space is available for PV panels and plant rooms at roof level

End-users close to PV panels and plant (minimising distribution losses)

The plant roof area is 1750m2 from which the areas 1, 2, 3, 4 and 5 (Figure 7) cover an area of 932m2 and are potentially suitable for the allocation of PV panels.

Figure 7: Roof Plan and suitable locations for PV Panels

A preliminary calculation was carried out for a PV array design with a nominal power capacity of 40 kWp. The PV panels would be located in the areas where the shading impact is minimised

(Areas 1, 2, 3 and 4). It has to be noted the modules have a 45⁰deviation from South to South

East with a readjusted panel inclination of 42⁰. The panels would not be facing exactly South for aesthetic reasons, this obviously causes some additional losses against what would be the optimal orientation (losses estimated of 8.6%). However for integrative reasons the South-East orientation has been kept. The PV system would be installed on a mounted metal frame structure on the roof. Please note the space availability would allow having a larger plant up

6Source: Meteonorm


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to 80 kWp if most of the roof area would be covered, however a more modest system design has been selected to reduce the initial capital intensiveness.

The PV system has been designed as grid connected, thus when the PV plant generates more electricity than what the school load demands the excess electricity would be directed onto the utility grid instead of storing it in batteries. The reason for not proposing batteries to store the excess electricity is because of the costs involved. Additionally the maintenance requirements of batteries and the degradation issues would mean that batteries would need to be replaced after periods between 4 to 10years depending on the use.

2.2.4 Cost Assessment

For a 40kWp PV plant a CAPEX estimate of USD104, 000 (plant cost assumption of $2.6/W7). The plant generates a net electricity output of 53,445 kWh/year. From all the electricity generated following assumptions have been made:

PV system electricity produced during school hours will involve an electricity cost saving. Thus at a daily electricity tariff of USD 0.0643/kWh (based on MEGDT information) the electricity saving can be estimated.

Electricity produced out of occupied hours would be feed into the distribution line. The potential capital gains from feeding the electricity to the grid would need to be understood. Currently the renewable energy feed in tariff scheme in Mongolia theoretically only applies for Utility scale projects. On the other hand no power purchase agreements (PPA) specifically for renewable energy have been found. Hence it has been assumed that the electricity feed to the grid is paid at the same rate as daily consumption rate. Thus applying a selling rate of USD 0.0643/kWh for the excess electricity.

Based on the previous assumptions a yearly cash inflow of USD3436 has been calculated. In order to estimate the financial viability of the project an electricity price growth of 3% has been assumed and yearly O&M costs at an inflation rate of 5.8%. Taking all this into consideration the payback would go above 25years hence not being financially attractive. However if the FiTs would be used the prospects would be much more promising as the established tariffs for PV utility scale projects range between USD0.15-0.18/kWh.

CAPEX

104,000 $

Yearly Electricity Savings 3,436 $

O&M 1,560 $

Life expectancy of installation 25 years

Inflation rate8 5.8 %

Electricity inflation rate 3 %

Payback 27 years

Table 2: Financial assumptions 40kW PV Plant

7Climate Investment Funds, 2015, SREP Investment Fund for Mongolia

8Image source: www.worldbank.org/en/country/mongolia


ITP/1224 10 22 August 2016

2.3 Solar Thermal

Solar thermal systems (STS) collect energy from the sun and transform it into heat used to raise the temperature of a heat transfer fluid. This fluid, which can be air, water or a specially designed fluid can be used directly for hot water or space heating/cooling needs. The heat generated can also be stored in a proper storage tank for use in the hours when the sun is not available. In all cases, thermal energy can be transferred by means of heat exchangers designed according to the application.

Solar thermal technologies are also used to provide hot water for commercial buildings and industrial processes. Solar thermal technologies can be applicable for a wide range of applications (e.g. water heating, space heating/ cooling and air conditioning for homes, businesses and industrial process heat). Whatever the application, some of the basic components, such as solar collectors and storage tank are same for most types of solar thermal applications. This technology brief focuses specifically on residential applications.


Solar thermal systems are a well established renewable energy source which can provide hot water heated by the sun for domestic and commercial use. Due to the presence most of the sun during summer months, when space heating is not required, solar thermal systems are normally used to provide a heating source for domestic hot water.

Solar thermal systems normally operate with a back-up source of heat. The solar system pre-heats the water up to the maximum hot water supply temperature. If there is not enough solar power available to fully heat the water it is “topped-up” to the desired temperature by the back-up heat source (Figure 8).

Figure 8: Solar Hot Water System with Gas Back Up9

A solar thermal system consists of one or more solar collectors to capture energy from the sun, a control system and some form of water storage, usually hot water cylinder(s). Heat is

9Image source: www.solarsunwerx.com.au


ITP/1224 11 22 August 2016

transferred from the solar collector to the water storage via pipes, typically in a closed loop system.

2.3.2 Solar Resource Please refer to section 2.2.2

2.3.3 Technology suitability & Building Integration Due to the varying nature of domestic hot water demand, throughout a typical day, if a solar collector system is sized to cater for the peak load it would produce an excess of heat that cannot be dissipated when hot water demand is low. Therefore a solar system should be sized so that it does not provide any more energy than is required in period of low demand.

In section 1 it can be observed from the heating profile that the building will be empty for almost 4 months between mid-April to October when the solar irradiation is at its highest hence there will not be any hot water demand. Furthermore during the weekends (Saturday & Sunday) the hot water demands are almost non existent.

Thus for long periods of times the system would not be operating and would need to be covered to avoid overheating issues. Otherwise stagnation would occur resulting in very high temperature and pressure conditions that could damage the system over time by subjecting it to extremes of expansion and contraction. In addition, when anti-freeze is superheated for a period of time, it tends to degrade and become acidic and hence becoming a corrosive substance that circulates through the system slowly damaging the components.

On the other hand if the solar installation is covered for approximately 4 months of the year that means that for more than 30% of the time the time the installation is not producing energy and in financial terms it is not paying back the initial investment. Therefore because of the building thermal demand profile solar thermal is not suitable for the school.


ITP/1224 12 22 August 2016

2.4 Wind Energy

2.4.1 General description A wind turbine is a machine for converting the kinetic energy in wind into mechanical energy.

When wind blows past a turbine, the blades capture the energy and rotate. This rotation allows

the internal shaft to spin connected to a gearbox increasing the speed of rotation, which is

connected to a generator that ultimately produces electricity. Most commonly, wind turbines

consist of a steel tubular tower, up to 100 metres, which supports both a hub and the nacelle

which houses the turbine's shaft, gearbox, generator and controls. The different components of

wind turbine can be seen in Figure 9.

Figure 9: Small Wind Turbine Components10

A wind turbine consists of three parts: the tower, the blades, and a box behind the blades,

called the nacelle. Inside the nacelle is where most of the action takes place, where motion is

turned into electricity. Small turbines have tail fans that orient the blades into the wind.

2.4.2 Wind Resource Assessment

The performance of wind turbines is highly sensitive to the location. Furthermore the resource varies continuously over time at any point in space thus the usual approach consists in estimating the numbers of hours during which ranges of wind speed occur typically known as “Weibull distribution”. The number of hours represented in Figure 10 amounts to one year, and to obtain a good view of average conditions, it is generally wise to measure wind speeds for at least this long and even for longer on at least an hourly basis.

MEGDT provided a yearly wind database for Ulaanbaatar (3hour measuring data @ agl 10m), a data analysis was undertaken and a Weibull distribution was developed (Figure 10) and as well a wind rose (Figure 11) to understand the main wind directions. It can be observed that there are prevailing winds from the North-West. Unfortunately the wind resource shows extremely

10Image Source: NREL


ITP/1224 13 22 August 2016

poor, especially the frequency of occurrence above 5m/s when the turbines start operating is below 5-7%.On the other hand the yearly mean wind speed is less than 2m/s (1.6 m/s), which shows extremely low. Normally a minimum of at least 6m/s average wind speeds are required to start assessing the viability of developing a wind project.

Figure 10: Wind speed distribution for School Location in Ulaanbaatar

Figure 11: Wind Rose for School Location in Ulaanbaatar


The poor wind resource disregards wind energy as a viable option for the school.

N

NNE

NE

ENE

E

ESE

SE

SSE

S

SSW

SW

WSW

W

WNW

NW

NNW

8-10

6-8

4-6

2-4

0-2


ITP/1224 14 22 August 2016

2.5 Biomass Energy


Biomass is the term used to describe a range of solid fuels from wood, straw and other waste materials. While carbon may be produced when biomass is burnt, it is considered to be almost carbon neutral as the carbon dioxide produced is offset by the carbon dioxide absorbed by the trees or crops when they were grown. Wood-fuelled boilers can run on logs, wood chip and pellets. Significant improvements in wood heating technology over the recent years have ensured that wood fuel (in chip and pellet form) may be harnessed as an extremely efficient and effective source of heating.

Figure 12: 150kW Inmecal Biomass Boiler11

2.5.2 Biomass Resource Assessment

Unfortunately in the area of Ulaanbaatar there are no biomass suppliers of wood logs, chips or pellets as the main fuel used is coal. On the other hand the actual type of landscape and biomass resources on the surroundings of the school is scarce. Thus biomass is a non-viable alternative.


The lack of biomass suppliers or resources in the area of Ulaanbaatar disregards biomass as a viable technology for the school (see section 2.5.2).

11Image source: www.inmecal.com/en/bind-plus


ITP/1224 15 22 August 2016

3 RENEWABLE ENERGY – CONCLUSSIONS & RECOMMENDATIONS

Upon reviewing all renewable energy options we would conclude:

Vertical Ground Source Heat Pumps are not a viable option because of unbalance

between the building loads (there are no cooling loads). However it has to be noted

that a Horizontal Ground Source Heat Pump has already been proposed in the

conceptual design from NAP.

Solar PV is a technically viable option, the school location has acceptable solar

resources and the building has roof space available. Furthermore the electricity would

be generated during daylight hours when the building is occupied and energy is

demanded. Hence the PV system will cover a percentage of the energy demands in the

building. Nevertheless it has to be mentioned that in financial terms a 27 years

payback has been estimated.

Solar thermal hot water is not viable because of the school heating demand profile as

the building will be empty for almost 4 months between mid April to October.

Wind energy is not a viable option as consequence of the very poor wind resources in

Ulaanbaatar.

Biomass energy is not a viable option as consequence of the lack of biomass suppliers

in the area of Ulaanbaatar.

Based on the above we would recommend the following:

The PV system would be proposed as the means of reducing on site the energy baseline

further in addition to the proposed energy efficiency measures in the “Energy

Modelling and Energy Efficiency Report”. However it has to be made clear that the in

financial terms the profitability is low.


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4 WATER MANAGEMENT TECHNOLOGIES

Mongolia faces strong water scarcity issues as an important part of the surface water resources are in the Northern areas of the country. Unfortunately, this water is inaccessible for most parts of the country. The problem relies in the fact that urban centers such as Ulaanbaatar are far from these major water sources. Thus Mongolia has a high dependence on groundwater resources. In 2010, groundwater accounted for 80 percent of all freshwater consumed.

Based on this issues water efficiency is crucial in the development of a green school. Effective water management is needed without sacrificing comfort or performance. Water efficiency planning involves the analysis and uses of water; specification of water-saving solutions; installation of water-saving measures; and verification of savings to maximize the cost-effective use of water resources. There are a number of strategies that can be employed to reduce the amount of water consumed at a facility. In general terms, these methods include:

System optimization (i.e., efficient water systems design, leak detection, and repair)

Water conservation measures; and

Water reuse/recycling systems.

More specifically, a wide range of technologies and measures can be employed within each of these strategies to save water and associated energy consumption. These includes:

Water-efficient plumbing fixtures (ultralow-flow toilets and urinals, waterless urinals, low-flow and sensored sinks, low-flow showerheads, and water-efficient dishwashers and washing machines)

Rainwater harvesting

Water recycling or reuse measures (Grey water and process recycling systems)


ITP/1224 17 22 August 2016

4.1 Dual Flush toilets


Dual-flush toilets provide two flushing options for solids and liquids. A schematic of the dual flush toilet type is shown in Figure 13.

Figure 13: Dual flush toilets12

The dual-flush toilet differs from conventional (siphon-flush) toilets as it uses gravity to remove waste from the toilet. Standard toilets use siphoning action, a method that employs a siphoning tube, to evacuate waste. A high volume of water enters the toilet bowl when the toilet’s flush is pulled and fills the siphon tube and pulls the waste and water down the drain. Dual flush toilets employ a larger trapway (the hole at the bottom of the bowl) and a wash-down flushing design that pushes waste down the drain. Because there's no siphoning action involved, the system needs less water per flush, and the larger diameter trapway makes it easy for waste to exit the bowl.

4.2 Water and Shower Efficient Taps


A large proportion of water consumption takes place in the bathrooms. A number of options are available to reduce water consumption from taps and showers, which help save money. Water efficient taps aim to provide high performance while at the same time reducing the amount of water required. The different types of water efficient taps are:

Aerated Taps

Tap aerators are devices that can be retrofitted to existing taps to mix air with the water, producing the same force of flow. Installing a tap aerator is a simple and inexpensive way to reduce water consumption at the tap outlet. Tap aerators are flow minimisers that limit the flow of water from tap without reducing the water pressure. It is an attachment that can be fitted to the water outlet part of the existing tap and it regulates the amount of water flow

12Image source: Plumbshop ‘Toilet types’ (http://www.plumbshop.ca/support/toilets/toilet-types/)

http://home.howstuffworks.com/toilet.htm


ITP/1224 18 22 August 2016

through the tap without any impact on the water pressure. A combination of air and water creates pressure giving the same feeling of higher water flow but in reality, the water used is much less than through a conventional tap.

Figure 14: Aerated Taps13

Spray Taps

Spray taps work by forcing water through small holes in the tap outlet, thus producing a mist or spray. Spray taps can reduce water use by between 60% and 70% compared with conventional taps. However, the spray head needs to be checked regularly for fouling from soap, grease and lime scale. When the flow rate is too low to produce an aerated or laminar stream, a spray device is used to produce a miniature flow pattern. Sprays are recommended for use in public lavatories.

Figure 15: Spray Taps14

Automatic shut-off taps

Automatic shut-off taps turn off the tap after a certain time. This makes them particularly useful in public areas. The main types of automatic shut-off taps are:

o Percussion or Push taps: are self-closing taps that close after they have been operating for a pre-set time, generally between 1 and 30 seconds, thus eliminating the possibility of water being left running. This type of taps can reduce water use by over 50%, compared with conventional taps. To be most efficient, push taps need to be well maintained to ensure correct operation. They can be supplied as kits, which simply fit onto existing standard tap bodies without the need to disrupt pipe work connections.

13Image Source: www.plumbingsupply.com

14Image Source: www.sensortaps.co.uk/water-saving-spout-aerators.html

http://www.sensortaps.co.uk/water-saving-spout-aerators.html


ITP/1224 19 22 August 2016

Figure 16: Percussion Taps15

o Passive infrared (PIR): These type of taps use of a PIR sensor that will automatically start and stop flow through a tap as it detects when the tap is used.

Figure 17: Passive infrared Taps16

4.3 Water Efficient Showers

Typically, a conventional shower uses 35 litres (for a 5-minute shower). Power showers use substantially more water (70 litres for a 5-minute shower). Water efficient showerheads (Figure 18) are available that can reduce the water consumption without diminishing the customer experience, provided the water pressure is adequate.

The amount of water used by a shower can be reduced by:

• Using a ‘water saver’ showerhead

• Installing a flow restrictor in the pipework upstream of the shower fitting or in the shower head

• Using a push button to control water use (applicable in public showers such as in changing rooms, leisure facilities, etc.).

15Image Source: www.heatandplumb.com

16Image Source: www.delabie.com/our-services/our-solutions/water-controls-for-hospitals


ITP/1224 20 22 August 2016

Figure 18: Water Efficient Showers17

17Image Source: www.oxygenics.com


ITP/1224 21 22 August 2016

4.4 School Water Baseline Demand

The estimation of the monthly water demand baseline in the school requires to undertake various assumptions regarding number of flushes of toilets, basin uses, kitchen water taps and dishwasher uses. This requires counting the number of total of components for each case, for the NAP’s plan floor drawings18 have been used.

Floor Toilet Basin Shower Dishwasher (Kitchen) Kitchen (water taps)

1 9 11 1 2 5

2 8 4

3 8 6

Total 25 21 1 2 5

Table 3: Number of toilets, showers, dishwashers and taps

Table 4 shows a detailed breakdown of the estimated water demands, please note the water volumes for the different uses was based on reference data obtained from Defra (Department for Environment, Food & Rural Affairs19) references. The monthly water demand has been estimated as 334m3.

Toilet Number of flushes

per toilet/day Water demand

per flush (l) Daily Water Demand (l)

Monthly Water Demand (l)

Monthly Water Demand (m3)

25 35 6 5,250 115,500 115.5

Basin Number of uses per basin/day

Water demand per use (l)

Daily Water Demand (l)



21 35 6 4,410 97,020 97.02

Dishwasher Number of uses per dishwasher/day





2 25 20 1,000 22,000 22

Kitchen water taps

Number of uses per basin/day





5 100 9 4,500 99,000 99

Total (m3)

334

Table 4: Monthly school water consumption baseline

4.5 Water Saving Potential

The identified water saving potentials are following:

For toilets instead of using conventional toilet with an average use of 6l per flush a dual flush toilet would be proposed with an average water volume use of 4l. Hence installation of 25 dual flush toilets.

For water basins instead of using traditional taps the employment of push taps that has the potential to reduce the water consumption by over 50% (see section 4.2). Hence installation of 21 push taps.

18NAP File: “GREEN SCHOOL ENG”

19 Defra, 2008, Waterwise washing machines and dishwashers


ITP/1224 22 22 August 2016

Employment of eco dish washer with consumption of 12l 20.Hence installation of 2 eco dish washers (energy rating A++).

Aerated taps assuming conservatively 50% water saving potential (see section 4.2). Hence installation of 5 aerated water taps.

Table 5 shows that implementing the described water efficiency measures would reduce the monthly water consumption from 334m3 to 189m3. This represents a 43% saving which totalling a yearly saving of 1015m3, that translates into a cost saving of USD535 (based on the water tariff information provided by MEGDT).

Toilet Number of flushes

per toilet/day Water demand

per flush (l) Daily Water Demand (l)



25 35 4 3,500 77,000 77

Basin Number of uses per basin/day





21 35 3 2,205 48,510 48.51

Dishwasher Number of uses per dishwasher/day





2 25 12 600 13,200 13.2

Kitchen water taps

Number of uses per basin/day





5 100 4.5 2,250 49,500 49.5

Total (m3)

189

Table 5: Monthly school water consumption after implementing water efficiency measures

4.6 Water Management – Conclusions & Recommendations

Table 6 breaks down the water efficiency savings against baseline. The column of additional costs of implementing the different technologies represents the increased cost against installing traditional systems. It can be concluded that:

The push tap and aerated tap have immediate paybacks and are highly recommended. Furthermore these 2 measures represent 52% of the total water savings achieved from the proposed management measures (see Figure 19). Furthermore the additional costs are almost neglectable compared to the remaining efficiency measures (see Figure 20).

The dual flush toilets achieve water savings of 33% compared to typical standard toilets. However in terms of profitability the payback is of 18 years.

The installation of the eco dish washer is more capital intensive compared to the previous measures and has a payback of 22 years, thus not profitable. Nevertheless it has to be noted that the dish washer savings have been assessed in terms of water savings but the lower energy consumptions of the more efficient dishwasher have not been assessed.

20 Defra, 2008, Waterwise washing machines and dishwashers


ITP/1224 23 22 August 2016

Dual Flush Toilet

Estimated Additional Unit Cost

($)

Water Saving Potential (m3/month)

Water Saving Potential (m3/year)

Cost Saving Potential

(USD/year)

Simple Payback (years)

25 2500 38.5 269.5 141.5 17.7

Push Tap


($)*




(USD/year)


21 0 48.5 339.5 178.2 Inmediate

Eco Dishwa

sher


($)




(USD/year)


2 720 8.8 61.6 32.3 22.3

Aerated Taps


($)




(USD/year)


5 32.5 49.5 346.5 181.9 0.2

Table 6: Water Efficiency Measures Cost Benefit Analysis

*Note: The cost of a push tap against a traditional has been assumed the same, hence no additional cost assumed.

Figure 19: Contribution to the total water savings from the 4 proposed measures

20.4%

25.7%

4.7%

26.2%

Dual Flush Toilet Push Tap Eco Dishwasher Aerated Taps


ITP/1224 24 22 August 2016

Figure 20: Additional cost breakdown of the 4 proposed measures

76.9%

0.0%

22.1%

1.0%

Dual Flush Toilet Push Tap Eco Dishwasher Aerated Taps


ITP/1224 25 22 August 2016

5 RAINWATER HARVESTING SYSTEMS

5.1 General description

Rainwater harvesting is the collection of rainwater running off from surfaces upon which it has fallen. Rainwater harvesting system collects rainwater from where it falls rather than allowing it to drain away. It includes water that is collected within the boundaries of a property, from roofs and surrounding surfaces. The various ways of harvesting water are:

Capturing run-off from rooftops

Capturing run-off from local catchments

Rainwater is collected from roof buildings and then stored inside of a special tank. Rainwater harvesting systems are designed after assessing site conditions for rainfall pattern, incident rainfall, subsurface strata and their storage characteristics.

Figure 21: Rainwater Harvesting System 21

The collected rainwater can be used for many different purposes around the home including laundry, washing dishes and more.

The rainwater system has following components:

Collection pipework

Collection Tank

Treatment

Pump

Distribution pipework

Controls

21Image Source: www.whatgreenhome.com


ITP/1224 26 22 August 2016

Figure 22: Conceptual rainwater harvesting system

5.2 Rainfall water levels Ulaanbaatar

The understanding of the size of the catchment area or roof for the school (see Figure 23) will determine how much rainwater can be harvested. The area is based on the “footprint” of the roof, which can be calculated by finding the area from the building roof plan. The net roof catchment area has been estimated as 1642m2.

Figure 23: School roof plan view

In order to estimate the water collection potential the rainfall levels for Ulaanbaatar are needed. Figure 24 shows the monthly rainfall levels, as can be observed the capital receives its greatest average monthly precipitation in June and August.

Rainwater TreatmentCollection

Tank

PumpWater uses:

• WC flushing

• Garden irrigation

• Other uses


ITP/1224 27 22 August 2016

Figure 24: Ulaanbaatar& Mongolia Average Monthly Rainfalls22

5.3 Rain Water Collection System– Conclusions & Recommendations

It has to be clarified that not all the rainfall that falls on the collection area will be caught. There are different types of losses such as:

Overflow losses from the gutters when heavy rains take place (unlikely in Ulaanbaatar)

Evaporation losses with light rainfall levels

Filter losses the efficiency of the filter also affects the amount of water that can be captured.

Thus for a rainwater system in the school run off and filter efficiencies need to be considered. Conservatively filter efficiencies of 90% and run off efficiencies of 40% (concrete roof block material assumed23) have been assumed. Taking into consideration and comparing the monthly rainfall water collection potential and actual school water demands (see Figure 25) it is clear that:

The greatest rainfall water collection takes place between June and August. These months represent more than 65% of the total water rainfall volumes over the year. Unfortunately on that period the school empty thus not taking advantage of the higher rainfall.

The lower rainfall levels during the winter months and the system efficiencies make the system harvesting potential minimal. From Figure 25 it can be concluded that there is a small benefit from collecting water in the months of September and May but meaningless for the remaining months (January - April and October – December).

Thus the investment cost of rainfall system can hardly be justified if 65% of the water collection potential takes place when the building is empty in the summer months. Therefore as

22Word Bank Data, 2012, Mongolia Rainfall Levels

23CIBSE KS1, 2005, Reclaimed water

0

10

20

30

40

50

60

70

80R

ain

fall (

mm

)

Month

Mongolia Average MonthlyRainfalls (1990 -2012)(mm)

Monthly rainfall averageUlaanbaatar (mm)


ITP/1224 28 22 August 2016

consequence of the school water consumption profile the rainwater harvesting system does not look suitable.

Figure 25: School monthly roof rain harvesting volume & water demands

0

50

100

150

200

250

300

350

400

Wat

er

Vo

lum

e (

m3 /

mo

nth

)

Month

Roof Rainwater Collection (m3) Monthly Water Demand (m3)


ITP/1224 29 22 August 2016

6 GREYWATER SYSTEMS

6.1 General description

Greywater can be defined as any domestic wastewater produced, excluding sewage. Grey Water is the water from showers, bathtubs, laundry and bathroom sinks. Properly treated this water can be recycled and reused typically for flushing toilets and landscape irrigation. A schematic showing a greywater system can be seen in Figure 26.

Figure 26: Schematic of a greywater system24

The main types of greywater treating systems are:

Treatment and Re-Use System

Treated greywater can be used indoors for laundry and toilet. Toilets and washing machines are two of the biggest water consumers, so using greywater in these appliances can save considerable water volumes. A high level filtration system and secondary treatment with disinfection is required for greywater when used indoors. These systems treat water to a standard fit for domestic use. This water can be used for toilet flushing, washing clothes and above-ground irrigation. This high water recycling system is connected to the bathtub, shower, washing machine and sewage. It captures the relatively clean grey water and filters it before storing it inside the storage/separation tank. Here flotation and settling takes place to further separate the impurities. In this system first, the grey water is filtered then put inside a settling tank for further purification. After treatment it is pumped out to be used for toilet flushing and laundry washing (Figure 27).

24 Image source: www.towergreenliving.com


ITP/1224 30 22 August 2016

Figure 27: Greywater treatment and re-use systems25

Branch Drain System

In branched drain greywater system the greywater from the building drains through a series of branching pipes and is dispersed into the landscape into basin outlets. Typically branched drain systems are installed on showers, and a laundry to landscape system is installed on the washing machine. Drains from greywater fixtures are combined into a single pipe, which is diverted away from the sewer and outside the building. An example schematic diagram showing the system is shown in Figure 28.

Figure 28: Branched Drain System26

25Image Source: smart-systems-for-reusing-grey-water.pdf

26Image source : Judy's Cottage Garden (http://judyscottagegarden.blogspot.in/2014_03_01_archive.html)

http://judyscottagegarden.blogspot.in/2014_03_01_archive.html


ITP/1224 31 22 August 2016

6.2 Greywater reuse potential – Recommendations & Conclusions

A breakdown of the water use in the school is shown in Figure 29. From the water used in the school a subdivision in 2 types has been made:

Water from basins and shower. This greywater if appropriately treated can be reused indoors for toilet flushing or irrigation.

Water from toilets, kitchen water taps and dishwasher have high levels of grease, bacteria and chemicals. Because of the potential for contamination by pathogens and grease, water from kitchens and dishwashers should be excluded from greywater and considered as blackwater.

The basin water represents 29% of the total water used in the school (please refer to section 4.4 for further details). This greywater if treated could be reused for the flushing of toilets that represents almost 35% of the total water consumption in the school. The reuse of the greywater from basins and showers could achieve a yearly water saving of 310m3 potentially achieving a 13% water saving (see Table 7).

Figure 29: School water breakdown usage

Month Total Water Demand

(m3/month) Toilet Water Demand

(m3/month) Grey water reuse from basins

& showers (m3/month)

January 167.0 57.8 38.8

February 334.0 115.5 38.8

March 334.0 115.5 38.8

April 334.0 115.5 38.8

May 167.0 57.8 19.4

June 0.0 0.0 0.0

34.6%

29.0%

6.6%

29.6%

Toilet Basin Dishwasher Kitchen water taps


ITP/1224 32 22 August 2016

July 0.0 0.0 0.0

August 0.0 0.0 0.0

September 167.0 57.8 19.4

October 334.0 115.5 38.8

November 334.0 115.5 38.8

December 167.0 57.8 38.8

Annual 2,338.0 808.5 310.5

Table 7: Grey water reuse potential from basins and showers

The greywater system will need a tank capacity for 2days storage with an estimated volume of 2.5m3 (including the treatment equipment). The cost of such a system strongly depends on the technology, in any case an indicative average cost estimation of USD10,17027 was made.

For a yearly water saving of 310.5m3 at a water tariff USD0.525/m3 (based on the water tariff information provided by MEGDT) that equals to USD163 water cost reduction per year. Even if the yearly maintenance costs are not included the simple payback of such an investment is above 60years. Thus from the water saving point of view greywater harvesting is positive nevertheless the cost benefit analysis does not show it as an attractive investment.

27EU, 2013, Greywater treatment and flow rate regulation as a job generator, water, energy and CO2 saver


ITP/1224 33 22 August 2016

7 WATER MANAGEMENT – CONCLUSSIONS & RECOMMENDATIONS

Upon reviewing all water management options we would conclude:

The push taps and aerated taps are highly recommendable. A small additional cost involved and an almost immediate paybacks are achieved.

The dual flush toilets achieve considerable water savings of 35% compared to standard toilets. However in terms of profitability the payback is very long (18 years).

The eco dish washers achieve important savings however the capital intensiveness compared of the investment translates into payback of 22 years, thus not profitable.

The rainwater system is not feasible as the most important rainfall levels take place

during the summer months when the school is empty.

They greywater systems do achieve considerable water saving unfortunately the

system is not attractive in terms of cost effectiveness.

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