chiller plant applications - airah · measure & verify optimize system automate system apply...

Chiller Plant Applications

Queensland 17 -11-2015

Johnson Controls - Proprietary

Many Considerations

Water

2

Criticality Redundancy

Energy NoiseIndoor space Outdoor space

ComfortAccessibility

Climate

Marketing Codes/Standards


Consumables + Water + Maintenance + ENERGY

Chiller Plant Operating Costs =

3

Holistic Chiller Plant Approach

Energy Cost of Plant =

Load Hours Efficiency RateStructureX X X


Measure & Verify

Optimize System

Automate System

Apply components effectively, optimally

Select components effectively, optimally

Design system infrastructure to max efficiency potential

Operating Decisions

Design Decisions

Maintain

Automation is a key component of the optimization processbut optimization is not just smart controls


Design Energy Vs. Annual Energy

Design Performance

Chiller58%

Tower5%

Fans24%

Pumps13%

Annual Energy Usage

Pumps22%

Tower2%

Chiller33%Fans

43%

Johnson Controls - Proprietary & Confidential

SustainabilitySustainability Life CycleLife Cycle

FlexibilityFlexibility

EfficiencyEfficiency

Air cooled vs Water cooledHeat rejection medium Air Water

Performance dry bulb based wet bulb based

Full Load Efficiency Lower Higher

Part load efficiency Lower# Higher

Chiller Size larger baseline

Water usage NO* YES

Location Outdoors Indoors (plant-room)

Installation Less complex More complex

Maintenance Less complex More complex

* Power generating stations use water to produce electricity# Plant efficiencies are dependent on climate, control, and other factors


4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

10 20 30 40 50 60 70 80 90 100

COP

% Capacity

YK CSD Constant CEFT YK CSD AHRI Relief YK VSD AHRI Relief YMC2 AHRI Relief

Chillers operate for 85% of the time within this capacity range

Constant Speed, Constant CEFT

Constant Speed, AHRI Relief

Variable Speed, AHRI Relief

Variable Speed, AHRI Relief + oil-free

VSD technology unlocks efficiency benefit of natural weather conditions

Note: Above is based on water cooled centrifugal compressor technology


The design process

•Minimize ‘transport’ energy

•Maximize the economics of high efficiency components

•Optimize ‘lift’


Metering device

1

6 condenser

pressure

Pressure‐ enthalpy diagram

2

35 4

compressor

enthalpy

evaporator


Pressure

Enthalpy

Lift or Differential Pressure

12.2° C6.7° C

29.4° C

Water cooled chillers Standard design lift condition

35° C


What is Heat Recovery?ASHRAE Handbook (2008):

“In many large buildings, internal heat gains require year-round chiller operation. The chiller condenser water heat is often wasted through a cooling tower”…“[Heat recovery] uses otherwise wasted heat to provide heat at the higher temperatures required for space heating, reheat, and domestic water heating”

11

Heat recovery creates and uses energy at higher chiller lift condition to improve overall building efficiency


Boiler

Condenser

Expansion Valve

Cooling Tower

Evaporator

What is Heat Recovery?

Heat Recovery

CompressorMotor

Building with Energy Recovery

(12.2ºC) (6.7ºC)

(35ºC)(40ºC)

12

Example – reheat cooled and de-humidified O/A to neutral condition for use with a passive chilled beam system with site recovered energy


Why use a heat recovery chiller?

Social / Environmental Advantages CO2 reductions Reduced water consumption

Economic Advantages Operational savings

13

Coincident heating and cooling

Cooling capacity 680 kWrHeat rejection 820 kWrPower input 140 kWe

Total COP = 1500 / 140 = 10.7


14

Lower tower water temps

Higher chilled water temps

What is lift relief ?

AND / OR

Less compressor work = lower input kWeJohnson Controls - Proprietary

Reduce liftCapitalizing on ‘off‐design’ conditions ‐most of the time

Evaporator

Compressor

Condenser

Pressure

EnthalpyReduces Energy Consumption

Lift

Lowering Condenser Water Temperature

Reduces Compressor Work

Lowers the Lift

Expansion


Reduce liftCapitalizing on ‘off‐design’ conditions ‐most of the time

Evaporator

Compressor

Condenser

Pressure

EnthalpyReduces Energy Consumption

Lift

Raising Chilled Water Temperature

Reduces Compressor Work

Lowers the LiftExpansion


50%

0%

ENER

GY

Evaporator Temp.

Condenser Temp.

Off-

Des

ign

Lift

Load

(weight of rock)

12.8°C ECWT

44°F (6.7°C) LCHWT

29.40 C ECWT

How does lower LIFT (compression ratio) impact efficiency ?

Variable Speed Chiller Energy Usage Analogy ‐


100%

Opportunities for Lower Lift

18

Lower Condenser Water Temperature

• Lower CW Design Temperatures• Oversize Towers

• Climate wet bulb relief• Control Strategy• Chiller / Tower optimization

• Series Counter‐flow

Higher Chilled Water Temperature

• Higher CHW Design temperatures• Climate wet bulb relief• Control strategy• chilled water reset

• Series & Series Counter‐flow• Multiple CHW loops• HT loop & LT loop


6 deg C 10 deg C 14 deg C

Series chillers

Lift is reduced 4 degrees C


Evaporator

Condenser

Evaporator

Condenser

ECWTLCWT

ECHWT LCHWT

Evaporator 1Compressor 1

Condenser 1

Pressure

Enthalpy

Lift 1Evaporator 2

Compressor 2

Condenser 2

Lift 2

Evaporator

Compressor

Condenser

Pressure

Enthalpy

Enhanced efficiency through series counter‐flow


160 C 110 C 60 C

290 C350 C 320 C

Today’s and tomorrow’s challenge

Additional component‐level efficiency gains will be insufficient. 1

"...we are reaching maximum technological limits at a component level and that in the future the industry will have to look at the full HVAC system for further improvements. AHRI is in the process of forming a new working group to address systems approaches for efficiency improvements and will work closely with Standard 90.1.”

- Dick Lord, co-writer of addendum ‘ch’ to ANSI/ASHRAE/IES Standard 90.1-2010, ASHRAE Press Release, December 12, 2012



The role of controls in the optimization processBest‐in‐class algorithms that take a holistic, system‐level approach

All variable speed plant

Most Energy Efficient Chiller Plant Design

JEM is identified as the “Greenest Building” in Singapore (2013)

+++=

6.7 Plant COP


System efficiency targets …

Singapore Green Mark v4 Platinum rating @ 0.55 kW/Ton = 6.4 plant COP

Low temp loop = 9/18 deg C with 2 x YORK YK series counter-flow CSD chiller pairs High temp loop = 15/20 deg C with 2 x YORK YK VSD chillers

Traditional chiller plant COP

JEM Project delivering 0.527 kW/TR system efficiency:


18 C

9 C 13.5 C

AHU(s)

LT CHW loop

VPF

DOAS

VPF 20 C

15 C

Efficient System Design Concepts applied to HVAC system …

HT CHW loop


Today’s variable speed chillers with optimized control strategies deliver outstanding real world plant-room efficiencies !


W.A>

BMS

Johnson Controls Metasys CPO

Internet Connection

Pump VSD’s

Fan VSD’s

Hardwired devices


Currently used HFC and Natural refrigerants

R134aR410a

R245fa R717

HydrocarbonJohnson Controls - Proprietary

30

Legislation has driven refrigerant direction. Investments are long‐term and require thoughtful insight to how the equipment will be used and operated throughout its lifetime.

2017200419871970’s1930’s1830’s

Address greenhouse gas emissions

Eliminate ozone depleting CFC’s & HCFC’sMake it safe & efficientMake it work

HFOs*

Lower GWP HFCs(i.e. R‐410A, R‐134a, R32)

HFCs(i.e. R‐410A, R‐134a, R‐404A, R‐507)

HCFCs(i.e. R‐22, R‐123)

CFCs(i.e. R‐11, R‐12)

Natural Refrigerants(i.e. CO2, ammonia, water, hydrocarbons)

Available Chemicals

(Ethers, Ammonia, Water, CO2, Methylene Chloride,

etc.)

Towards the end of this decade we will start to see the introduction of new low GWP refrigerants (HFO) . HFC’s with an acceptable GWP such as R134a will continue to be available


QUESTIONS ?

SUMMARYOptimization is a process.Innovative design is the foundation.

Chiller & Plant COP is improved when lift is reduced.

Where energy is recovered and used, Plant COP can be improved when lift is increased.

Further efficiency increases are currently being delivered at the system level.

JCI offers responsible refrigerant solutions for numerous applications.

R&D is progressing with next generation refrigerants.

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