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BenefitsBenefits ofof

Water-Cooled SystemsWater-Cooled Systemsvsvs

Air-Cooled SystemsAir-Cooled Systemsforfor

Air-Conditioning ApplicationsAir-Conditioning Applications

Written by: Michael D.Pugh


U.S. Government commitment toU.S. Government commitment toreduce greenhouse gas emissionsreduce greenhouse gas emissionscan have a significant impact oncan have a significant impact on

HVAC system considerationsHVAC system considerations


Kyoto Conference onKyoto Conference on Global Warming Global Warming

�� International effort to control greenhouseInternational effort to control greenhousegas emissionsgas emissions

�� Greenhouse gasses include:Greenhouse gasses include:——Carbon Dioxide (COCarbon Dioxide (CO22))

——Methane (CHMethane (CH44))

——Nitrous Acid (NNitrous Acid (N22O)O)

——Hydrofluorocarbons Hydrofluorocarbons ((HFC sHFC s))

——PerfluorocarbonsPerfluorocarbons ( (PFC sPFC s))

——Sulfur Sulfur Hexafluorides Hexafluorides (SF(SF44))


U.S. Commitment to KyotoU.S. Commitment to KyotoConferenceConference

�� Kyoto Protocol signed by ex-President BillKyoto Protocol signed by ex-President BillClinton in October, 1997Clinton in October, 1997

�� Commits U.S. to reduce greenhouse gasCommits U.S. to reduce greenhouse gasemissions to 7% below 1990 levels by 2012emissions to 7% below 1990 levels by 2012

�� Ratification by U.S. Senate pendingRatification by U.S. Senate pending


Total U.S. Greenhouse GasTotal U.S. Greenhouse GasEmissions by GasEmissions by Gas


U.S. Greenhouse Gas Emissions U.S. Greenhouse Gas Emissions

Carbon Dioxide (COCarbon Dioxide (CO22) emissions account for) emissions account for85% of U.S. greenhouse gas emissions85% of U.S. greenhouse gas emissions


Major COMajor CO22 Emission Sources Emission Sources

�� Transportation IndustryTransportation Industry

�� Heavy IndustryHeavy Industry

�� Utility IndustryUtility Industry


Major COMajor CO22 Emission Sources Emission Sources Utility Industry Utility Industry

�� Fossil Fuel Burning Power PlantsFossil Fuel Burning Power Plants——Produce 55% of U.S. electricityProduce 55% of U.S. electricity

——Accounts for 68% of the COAccounts for 68% of the CO22 emission emissionreductions required for Protocol compliancereductions required for Protocol compliance

——Addition of exhaust gas scrubbers notAddition of exhaust gas scrubbers noteconomically viable for most plantseconomically viable for most plants

——Only 16% (193 of 1,207) of Power Plants haveOnly 16% (193 of 1,207) of Power Plants haveexhaust gas scrubbersexhaust gas scrubbers


U.S. Government Plan to reduceU.S. Government Plan to reduceCOCO22 Emissions from Power Plants Emissions from Power Plants

�� Convert to less carbon intensive fuels orConvert to less carbon intensive fuels ornon-carbon fuelsnon-carbon fuels——Taxation of carbon fuelsTaxation of carbon fuels

——Regulation of emissions for new plantsRegulation of emissions for new plants

�� Reduce energy demandReduce energy demand——New energy-saving technologiesNew energy-saving technologies

�� Improve efficiency of equipment andImprove efficiency of equipment andsystemssystems


Fossil Fuel Burning Power PlantsFossil Fuel Burning Power Plants

�� Air-conditioning systems drive many powerAir-conditioning systems drive many powerplant peak loads and have been identified asplant peak loads and have been identified asenergy reduction opportunityenergy reduction opportunity


U.S. Actions Impacting HVACU.S. Actions Impacting HVAC Systems and Equipment Systems and Equipment

�� EPA ENERGY STAR ProgramEPA ENERGY STAR Program¨̈ Actively promotes participation in economicallyActively promotes participation in economically

justified energy saving projectsjustified energy saving projects

�� Energy Policy Act of 1992Energy Policy Act of 1992——ASHRAE Standard 90.1 as basis for energyASHRAE Standard 90.1 as basis for energy

efficiency for commercial buildings.efficiency for commercial buildings.——ASHRAE 90.1 revised in June,1999ASHRAE 90.1 revised in June,1999——submitted to D.O.E. for acceptancesubmitted to D.O.E. for acceptance——Recently adopted for ICC energy codeRecently adopted for ICC energy code

Energy Saving System Designs . . .Energy Saving System Designs . . .

. . .our . . .ourEnvironmental ResponsibilityEnvironmental Responsibility


Basic Air Conditioning SystemsBasic Air Conditioning Systems

�� Large Buildings ( >400 tons)Large Buildings ( >400 tons)——Water cooled systems provide clear-cutWater cooled systems provide clear-cut

economic and environmental justification.economic and environmental justification.

�� Mid-size Buildings (200 - 400 tons)Mid-size Buildings (200 - 400 tons)——Air cooled systems may offer first costAir cooled systems may offer first cost

incentive to sacrifice energy efficiencies ofincentive to sacrifice energy efficiencies ofwater cooled systems.water cooled systems.


Theoretical Building Profile Theoretical Building Profile

�� Building loadBuilding load——400 tons400 tons

�� Building configurationBuilding configuration——square w/ five (5) floorssquare w/ five (5) floors

——one (1) air handling fan / floorone (1) air handling fan / floor

�� Air VolumeAir Volume——350 CFM/ton350 CFM/ton

——3-1/2 w.g. T.S.P.3-1/2 w.g. T.S.P.


400 Ton System Comparisons400 Ton System Comparisons

�� Chiller systems:Chiller systems:——Air-Cooled ChillerAir-Cooled Chiller

——Centrifugal ChillerCentrifugal Chiller

�� Packaged systems:Packaged systems:——Roof -Top UnitsRoof -Top Units

——Self-Contained UnitsSelf-Contained Units


System Energy Requirements System Energy Requirements�� 400 Ton Air-Cooled Chiller System400 Ton Air-Cooled Chiller System

KW /UnitKW /Unit Total KW Total KW

CompressorCompressor 406.00 406.00 406.00406.00

Condenser fans 62.50 Condenser fans 62.50 62.50 62.50

Air handling units 22.37Air handling units 22.37 111.85111.85

Chilled HChilled H220 pump 14.92 0 pump 14.92 14.9214.92

Total KWTotal KW 595.27595.27

�� KW/ton= 595.27/400 = KW/ton= 595.27/400 = 1.49KW/ton1.49KW/ton


System Energy Requirements System Energy Requirements�� 400 Ton Centrifugal Chiller System400 Ton Centrifugal Chiller System

KW /Unit KW /Unit Total KW Total KW

CompressorCompressor 220.0 220.00 220.0 220.00

Air handling unitsAir handling units 22.3722.37 111.85 111.85

Chilled HChilled H220 pump 14.920 pump 14.92 14.92 14.92

Condenser HCondenser H220 pump 11.19 11.190 pump 11.19 11.19

Cooling tower fan 18.65 Cooling tower fan 18.65 18.6518.65

Total KWTotal KW 376.61 376.61



Theoretical 400 Ton SystemTheoretical 400 Ton SystemComparisonsComparisons

�� Chiller systemsChiller systems——Air-cooled chiller system . . . . . . . Air-cooled chiller system . . . . . . . 1.49KW/ton1.49KW/ton

——Centrifugal chiller system . . . . . . . Centrifugal chiller system . . . . . . . 0.94KW/ton0.94KW/ton


System Energy Requirements System Energy Requirements

�� 400 Ton Roof-Top System: (5)80 Ton Units400 Ton Roof-Top System: (5)80 Ton Units KW /Unit KW /Unit Total KW Total KW

CompressorCompressor 74.65 74.65 373.25373.25

Air handling fan 29.84Air handling fan 29.84 149.20149.20

Condenser fanCondenser fan 8.60 8.60 43.0043.00

Total KW Total KW 565.45565.45



System Energy Requirements System Energy Requirements�� 400 Ton Self-Contained System: (5)80 Ton400 Ton Self-Contained System: (5)80 Ton

UnitsUnits KW /Unit KW /Unit Total KW Total KW

CompressorCompressor 63.12 63.12 315.60 315.60Air handling fan 22.37Air handling fan 22.37 111.85 111.85Condenser HCondenser H22O pump 11.19O pump 11.19 11.19 11.19Cooling tower fanCooling tower fan 18.75 18.75 18.7518.75Total KWTotal KW 457.39 457.39



System Energy Comparison System Energy Comparison

�� Chiller systemsChiller systems——Air-cooled chiller system . . . . . . . Air-cooled chiller system . . . . . . . 1.49KW/ton1.49KW/ton

——Centrifugal chiller system . . . . . . . Centrifugal chiller system . . . . . . . 0.94KW/ton0.94KW/ton

�� Packaged systemsPackaged systems——Roof-top units . . . . . . . . . . . . . . . Roof-top units . . . . . . . . . . . . . . . 1.42KW/ton1.42KW/ton

——Self-contained units . . . . . . . . . . . .Self-contained units . . . . . . . . . . . .1.14KW/ton1.14KW/ton


Basic HVAC System OptionsBasic HVAC System Options

�� Water-cooled systemsWater-cooled systems——More energy-efficient than air-cooled systemsMore energy-efficient than air-cooled systems

——Support environmental efforts to controlSupport environmental efforts to controlgreenhouse gas emissionsgreenhouse gas emissions


Kyoto ConferenceKyoto Conference

If we do it right, protecting the climate willIf we do it right, protecting the climate willyield not costs, but profits; not burdens, butyield not costs, but profits; not burdens, butbenefits; not sacrifice, but a higherbenefits; not sacrifice, but a higherstandard of livingstandard of living

President Bill ClintonPresident Bill Clinton


Installed Cost Estimate SourcesInstalled Cost Estimate Sources

�� Air Cooled Chiller . . . . $350/Air Cooled Chiller . . . . $350/TrTr x 1.50 x 1.50

�� Centrifugal Chiller . . . . $250/Centrifugal Chiller . . . . $250/Tr Tr x 1.50x 1.50

�� Roof Top Units . . . . . . .$550/Roof Top Units . . . . . . .$550/TrTr x 1.25 x 1.25

�� Self Contained Units . . $400/Self Contained Units . . $400/Tr Tr x 1.50x 1.50

�� Air Handling Units . . . . $1.00/CFM x 1.25Air Handling Units . . . . $1.00/CFM x 1.25

�� Cooling Towers . . . . . . .$45/Cooling Towers . . . . . . .$45/TrTr x 1.50 x 1.50

�� Pump/Piping . . . . . . . . . Means Mech. Est.Pump/Piping . . . . . . . . . Means Mech. Est.


Installed Cost EstimateInstalled Cost Estimate Air Cooled Chiller System Air Cooled Chiller System

�� 400 ton air cooled chiller . . . . . . . $210,000400 ton air cooled chiller . . . . . . . $210,000

�� (5) 28,000 CFM air handlers . . . . $175,000(5) 28,000 CFM air handlers . . . . $175,000

�� 1,000 LF chilled water piping . . . $ 67,0001,000 LF chilled water piping . . . $ 67,000

�� Chilled water pump . . .. . . .. . . . .. $ 3,600Chilled water pump . . .. . . .. . . . .. $ 3,600

�� Total installed cost . . . . . . . . Total installed cost . . . . . . . . $455,600$455,600


Installed Cost EstimateInstalled Cost EstimateCentrifugal Chiller SystemCentrifugal Chiller System

——400 ton centrifugal chiller . . . . . . .$150,000400 ton centrifugal chiller . . . . . . .$150,000

——400 ton cooling tower . . . . .. . . . . $ 27,000400 ton cooling tower . . . . .. . . . . $ 27,000

——(5) 28,000 CFM air handlers . . . . $175,000(5) 28,000 CFM air handlers . . . . $175,000

——1,000 LF chilled water piping . . . $ 67,0001,000 LF chilled water piping . . . $ 67,000

——400 LF condenser water piping . . .$ 26,800400 LF condenser water piping . . .$ 26,800

——Chilled water pump . . .. . . .. . . . .. $ 3,600Chilled water pump . . .. . . .. . . . .. $ 3,600

——Condenser water pump . . . . . . . . . .$ 4,000Condenser water pump . . . . . . . . . .$ 4,000

——Mechanical equipment room . . . $ 45,000Mechanical equipment room . . . $ 45,000

——Total installed cost . . . . . . . . Total installed cost . . . . . . . . $498,400$498,400


Installed Cost EstimateInstalled Cost EstimateRoof-Top Unit SystemRoof-Top Unit System

�� (5) 80 ton roof top units . . . .(5) 80 ton roof top units . . . .

�� Installed cost . .. . . .. . . Installed cost . .. . . .. . . $275,000$275,000


Installed Cost EstimateInstalled Cost EstimateSelf-Contained Unit SystemSelf-Contained Unit System

�� (5) 80 ton self-contained units .. . . . . . . . $240,000(5) 80 ton self-contained units .. . . . . . . . $240,000

�� Closed circuit cooling tower . . . . . . . . . . $ 54,000Closed circuit cooling tower . . . . . . . . . . $ 54,000

�� Condenser water pump . . . . . . . . . . . . . . $ 4,000Condenser water pump . . . . . . . . . . . . . . $ 4,000

�� Condenser water piping . . . . . . . . . . . . . .Condenser water piping . . . . . . . . . . . . . . $ 26,800 $ 26,800

�� Installed cost . . . . . . . . . . . . . Installed cost . . . . . . . . . . . . . $324,800$324,800


Installed Cost Summary Installed Cost Summary

InstalledInstalled CostCost

Chiller systemsChiller systems Air-Cooled Chiller Air-Cooled Chiller $455,600$455,600 Centrifugal Chiller Centrifugal Chiller $498,400$498,400Packaged systemsPackaged systemsRoof-Top Roof-Top $275,000$275,000Self-ContainedSelf-Contained $324,800$324,800


System Energy Cost AssumptionsSystem Energy Cost Assumptions

�� 1800 Equivalent Full Load Hours per Year1800 Equivalent Full Load Hours per Year

�� $0.06 per KW-Hour$0.06 per KW-Hour

�� $12 per KW Demand Charge for 6 Months$12 per KW Demand Charge for 6 Months


Annual Energy Cost Comparison Annual Energy Cost Comparison

Total Energy DemandTotal Energy Demand TotalTotal

KWKW CostCost CostCost CostCost

Chiller systemsChiller systems

Air-cooled chiller 595.27 $ 64,289 $42,860 Air-cooled chiller 595.27 $ 64,289 $42,860 $107,149$107,149

Centrifugal chiller 376.61 $ 40,674 $27,116 Centrifugal chiller 376.61 $ 40,674 $27,116 $ 67,790$ 67,790

Packaged systemsPackaged systems

Roof-top 565.45 $ 61,069 $40,712 Roof-top 565.45 $ 61,069 $40,712 $101,781$101,781

Self-contained 457.39 $ 49,398 $32,932 Self-contained 457.39 $ 49,398 $32,932 $ 82,330$ 82,330


System Cost Summary System Cost Summary

InstalledInstalled Energy Energy CostCost CostCost

Chiller systemsChiller systemsAir-cooled chiller $455,600Air-cooled chiller $455,600 $107,149$107,149Centrifugal chiller $498,400 Centrifugal chiller $498,400 $ 67,790$ 67,790Packaged systemsPackaged systemsRoof-top $275,000Roof-top $275,000 $101,781$101,781Self-containedSelf-contained $324,800 $324,800 $ 82,330$ 82,330


Water UsageWater Usage

�� Water cooled systems recycle 95% of theWater cooled systems recycle 95% of thetotal watertotal water

�� A small portion of the water is bled fromA small portion of the water is bled fromthe system to control the build-up ofthe system to control the build-up ofimpuritiesimpurities

Bleed Rate = Bleed Rate = Evaporation RateEvaporation Rate

Cycles of Concentration - 1 Cycles of Concentration - 1


Water Usage and CostWater Usage and Cost(400 ton sample system)(400 ton sample system)

Evaporation Rate = 3.0 GPM/100 tonsEvaporation Rate = 3.0 GPM/100 tons

= 12.0 GPM/400 ton system = 12.0 GPM/400 ton system





Bleed Rate = Bleed Rate = 12.0 GPM12.0 GPM

4 cycles -1 4 cycles -1

= 4.0 GPM = 4.0 GPM





Bleed Rate = Bleed Rate = 12.0 GPM12.0 GPM

4 cycles -1 4 cycles -1

= 4.0 GPM = 4.0 GPM

Consumption = Evaporation + BleedConsumption = Evaporation + Bleed

= 12.0 GPM + 4.0 GPM = 12.0 GPM + 4.0 GPM

= 16.0 GPM = 16.0 GPM



�� Annual Water ConsumptionAnnual Water Consumption——16.0 GPM X 60 Min/Hr x 1800 16.0 GPM X 60 Min/Hr x 1800 EqEq FLH FLH

——1,728,000 gallons/year1,728,000 gallons/year

�� Annual Water & Sewer CostAnnual Water & Sewer Cost——1,728,000 gal X $3.00/1000 gal1,728,000 gal X $3.00/1000 gal

——$5,184$5,184


Water Quality and Control CostWater Quality and Control CostConsiderationsConsiderations

�� Water-cooled systems require chemicalWater-cooled systems require chemicaltreatment to control scale/corrosion andtreatment to control scale/corrosion andbiological growthsbiological growths

�� These costs must be included in a costThese costs must be included in a costanalysis of water cooled and air cooledanalysis of water cooled and air cooledsystemssystems


Annual Water Treatment CostsAnnual Water Treatment Costs(400 ton sample system)(400 ton sample system)

�� Full Service Water TreatmentFull Service Water Treatment——Average annual program costs- $1.00/ton/monthAverage annual program costs- $1.00/ton/month

——400400 Tr Tr X $1.00/ X $1.00/TrTr//MnthMnth X 6 X 6 mnth mnth = $2,400/year = $2,400/year


Annual Water Cost EstimateAnnual Water Cost Estimate(400 ton sample system)(400 ton sample system)

Water Consumption - $5,184Water Consumption - $5,184

Water Treatment Water Treatment $2,400$2,400

Annual Water Cost Annual Water Cost $7,584$7,584



InstalledInstalled Energy Energy Water Water CostCost Cost Cost CostCost

Chiller systemsChiller systemsAir-Cooled chiller Air-Cooled chiller $455,600 $455,600 $107,149$107,149 N/A N/ACentrifugal chiller $498,400 $ 67,790Centrifugal chiller $498,400 $ 67,790 $7,584 $7,584Packaged systemPackaged systemRoof-Top Units $275,000Roof-Top Units $275,000 $101,781$101,781 N/AN/ASelf-ContainedSelf-Contained $324,800 $324,800 $ 82,330 $ 82,330 $7,584 $7,584



InstalledInstalled Energy Energy Water Water Payback Payback CostCost Cost Cost CostCost YrsYrs

Chiller systemsChiller systemsAir-Cooled chiller Air-Cooled chiller $455,600 $455,600 $107,149$107,149 N/AN/A Base BaseCentrifugal chiller $498,400 $ 67,790Centrifugal chiller $498,400 $ 67,790 $7,584$7,584 1.3 1.3Packaged systemPackaged systemRoof-Top Units $275,000Roof-Top Units $275,000 $101,781$101,781 N/A N/A BaseBaseSelf-ContainedSelf-Contained $324,800 $324,800 $ 82,330 $ 82,330 $7,584$7,584 4.2 4.2


HVAC System Considerations HVAC System Considerations

Cost analysis must consider the economicCost analysis must consider the economicimpact that environmental and electricimpact that environmental and electricpower generation issues will have onpower generation issues will have onenergy prices in the near future.energy prices in the near future.


Kyoto Protocol Impacted EnergyKyoto Protocol Impacted EnergyPrices to Commercial Market*Prices to Commercial Market*

�� Projected Energy Price Increases (PProjected Energy Price Increases (PVV))——2005 Projected Increase. . . . . . . . 2005 Projected Increase. . . . . . . . + 17.3%+ 17.3%

——2010 Projected Increase . . . . . . . 2010 Projected Increase . . . . . . . + 65.3%+ 65.3%

�� * * per 1998 Energy Information Administration(EIA) report titledper 1998 Energy Information Administration(EIA) report titledImpacts of the Kyoto Protocol on U.S. Energy Markets an d EconomicImpacts of the Kyoto Protocol on U.S. Energy Markets an d EconomicActivityActivity


2010 Kyoto Impact on Simple 2010 Kyoto Impact on SimplePayback AnalysisPayback Analysis

Installed EnergyInstalled Energy Water Water CostCost Cost Cost CostCost

Chiller systemsChiller systemsAir-Cooled Chiller $455,600Air-Cooled Chiller $455,600 $177,153 $177,153 N/AN/ACentrifugal Chiller $498,400 Centrifugal Chiller $498,400 $112,079 $112,079 $7,584$7,584 Packaged systemPackaged systemRoof -Top units $275,000Roof -Top units $275,000 $168,278 $168,278 N/A N/ASelf-ContainedSelf-Contained $324,800 $324,800 $136,119 $136,119 $7,584$7,584


2010 Kyoto Impact on Simple 2010 Kyoto Impact on SimplePayback AnalysisPayback Analysis InstalledInstalled Energy Energy WaterWater Payback Payback CostCost Cost Cost CostCost YrsYrs

Chiller systemsChiller systemsAir-Cooled Chiller $455,600Air-Cooled Chiller $455,600 $177,153 $177,153 N/AN/A BaseBaseCentrifugal Chiller $498,400 Centrifugal Chiller $498,400 $112,079 $112,079 $7,584$7,584 0.750.75Packaged systemPackaged systemRoof -Top units $275,000Roof -Top units $275,000 $168,278 $168,278 N/A N/A BaseBaseSelf-ContainedSelf-Contained $324,800 $324,800 $136,119 $136,119 $7,584$7,584 2.0 2.0


Deregulation of Electric PowerDeregulation of Electric PowerGeneration IndustryGeneration Industry


Generation Transmission Distribution

Electric Power IndustryElectric Power Industry

Generation Transmission Distribution


Deregulation of Electric PowerDeregulation of Electric PowerGeneration IndustryGeneration Industry

�� Assuming no Kyoto ProtocolAssuming no Kyoto Protocol, 1998 U.S., 1998 U.S.Gov tGov t report projected reduction in average report projected reduction in averageretail electricity price from $0.067KWH toretail electricity price from $0.067KWH to$0.060/KWH by 2010 due to competitive$0.060/KWH by 2010 due to competitiveclimate established by deregulation.climate established by deregulation.

�� Agriculture Dept report(March, 1999)Agriculture Dept report(March, 1999)predicted 19 states expected higherpredicted 19 states expected higherelectricity prices as low cost producers sellelectricity prices as low cost producers sellinto higher price marketsinto higher price markets


DeregulationDeregulationExperienceExperience


Electric Power GenerationElectric Power Generation�� Industry standard - 15% more electricIndustry standard - 15% more electric

generating capacity than requiredgenerating capacity than required

�� Automatic brownout warnings occur whenAutomatic brownout warnings occur whenonly 10% more electric generating capacityonly 10% more electric generating capacityis availableis available


U.S. Electric Generating CapacityU.S. Electric Generating Capacity

�� 1980 1980 30% excess capacity30% excess capacity

�� 2000 2000 14% excess capacity14% excess capacity

�� 2005 < 10% excess capacity predicted2005 < 10% excess capacity predicted


Electric Generating CapacityElectric Generating Capacity�� Overall North American generatingOverall North American generating

capacity is marginalcapacity is marginal

�� Many areas with generating capacityMany areas with generating capacityshortfallsshortfalls——CaliforniaCalifornia

——New YorkNew York

——New EnglandNew England

——ArizonaArizona

——KansasKansas

——IndianaIndiana


TransmissionTransmission�� In 1995, there were only 25,000In 1995, there were only 25,000

transactions where electricity was sold fromtransactions where electricity was sold fromone region to anotherone region to another

�� In 1999, there were more than 2,000,000In 1999, there were more than 2,000,000transactions where electricity was sold fromtransactions where electricity was sold fromone region to anotherone region to another


Transmission GridlockTransmission Gridlock

�� There are sharp There are sharp locationallocational price differentials price differentialsdue to the inability to transmit enoughdue to the inability to transmit enoughpower from region to region.power from region to region.


Transmission GridlockTransmission Gridlock

�� In many areas the transmission lines can tIn many areas the transmission lines can tcarry any more power, and lines can t becarry any more power, and lines can t beupgraded fast enoughupgraded fast enough

�� Some areas with transmission problemsSome areas with transmission problems——CaliforniaCalifornia

——Dallas/Ft. WorthDallas/Ft. Worth

——ChicagoChicago

——NYCNYC


DistributionDistribution

�� Local distribution systems can t handleLocal distribution systems can t handleincreasing peak loadsincreasing peak loads

�� Cause of blackouts in NYC, Long Island,Cause of blackouts in NYC, Long Island,Chicago and DetroitChicago and Detroit


The power market is moving toThe power market is moving to

Real-Time PricingReal-Time Pricing

What does Real-Time pricingWhat does Real-Time pricingmean?mean?

High summer daytime ratesHigh summer daytime ratesExamplesExamples

�� San Diego $7.00/kWhSan Diego $7.00/kWh

�� Maine, Connecticut and NYC $6.00/kWhMaine, Connecticut and NYC $6.00/kWh

�� Texas $0.70/kWhTexas $0.70/kWh

�� Montana $0.13/kWhMontana $0.13/kWh

What does Real-Time pricingWhat does Real-Time pricingmean?mean?

LowLow summer night rates summer night rates


Proposed Texas UtilitiesProposed Texas UtilitiesTime-of-Day Rate StructureTime-of-Day Rate Structure

0.00

0.05

0.10

0.15

M 2 4 6 8 10 N 2 4 6 8 10 M

Hour

$ p

er K

WH

Source: Deregulation in Texas and the Impact on Rate Structures for Thermal Storage Applications, J. Michael Sherburne - February 2000

$0.01

$0.13


University of North CarolinaUniversity of North CarolinaHourly Price - July 23, 1999Hourly Price - July 23, 1999

0.00

0.05

0.10

0.15

0.20

0.25

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

Hour

$ p

er K

WH

Source: Real-time Electrical Rates and Thermal Utilities, Engineered Systems - July 2000

$0.02

$0.23


What will be the result ofWhat will be the result ofReal-Time pricing?Real-Time pricing?

Highest electricity prices willHighest electricity prices willcoincide with peak air-conditioningcoincide with peak air-conditioning

loadsloads


. . .our . . .ourEnvironmental ResponsibilityEnvironmental Responsibility


. . .our . . .ourFiscal ResponsibilityFiscal Responsibility


EPA Climate Wise Program-EPA Climate Wise Program-Wise Rules to Energy EfficiencyWise Rules to Energy Efficiency

——Process Cooling Wise Rule 1.Process Cooling Wise Rule 1. Installing energy Installing energyefficient chillers and refrigeration systems canefficient chillers and refrigeration systems cansave 1.2% of a facility s total energy use withsave 1.2% of a facility s total energy use withan average simple payback of 23 months.an average simple payback of 23 months.

——Process Cooling Wise Rule 2.Process Cooling Wise Rule 2. Free cooling Free coolingwith cooling tower water can reduce a facility swith cooling tower water can reduce a facility stotal energy use by about 1% with an averagetotal energy use by about 1% with an averagesimple payback of 14 monthssimple payback of 14 months



�� Process Cooling Wise Rule 3.Process Cooling Wise Rule 3. Free Freecooling can reduce cooling system energycooling can reduce cooling system energyuse by as much as 40% depending onuse by as much as 40% depending onlocation and load profile.location and load profile.

�� Process Cooling Wise Rule 4.Process Cooling Wise Rule 4. Increasing Increasingchilled water temperature by 1chilled water temperature by 1 Deg Deg F Freduces chiller energy use by 0.6% to 2.5%reduces chiller energy use by 0.6% to 2.5%



——Process Cooling Wise Rule 5. Process Cooling Wise Rule 5. ReducingReducingcondenser pressure by 10 condenser pressure by 10 psipsi can decrease can decreaserefrigeration system energy use per ton ofrefrigeration system energy use per ton ofrefrigeration by about 6%.refrigeration by about 6%.

——Process Cooling Wise Rule 6. Process Cooling Wise Rule 6. For each degreeFor each degreedecrease in condenser cooling waterdecrease in condenser cooling watertemperature, until optimal water temperature istemperature, until optimal water temperature isreached, there is a decrease in chiller energyreached, there is a decrease in chiller energyuse by up to 3.5%.use by up to 3.5%.

there s simply nothere s simply nosubstitute for rawsubstitute for raw(chiller)(chiller)efficiencyefficiency


Equipment Cost Comparison*

Centrifugal ChillerFirst Cost . . .

$250/ton

Means Mechanical Cost Data


Equipment Cost Comparison*Equipment Cost Comparison*

Centrifugal ChillerFirst Cost . . .

$250/ton

Means Mechanical Cost Data

Cooling Tower

First Cost . . .

50/ton


Lower the designLower the design

condenser watercondenser watertemperature.temperature.

Energy Saving Tip

ARI Nominal CondenserARI Nominal CondenserWater Rating ConditionWater Rating Condition

3 GPM / Ton3 GPM / Ton10 Deg F Temperature Rise10 Deg F Temperature Rise85 Deg F Condenser Water85 Deg F Condenser Water

Cooling towers can beCooling towers can beeconomically selected toeconomically selected toprovide condenser waterprovide condenser watertemperatures within 4 Degtemperatures within 4 Deg

F ( or less) of theF ( or less) of theambient wet bulbambient wet bulb

temperature.temperature.


Effect of Condenser WaterEffect of Condenser WaterTemperature on Chiller EnergyTemperature on Chiller Energy CWCW Typ Typ Chiller Chiller EnergyEnergy

Temp.Temp. Energy Energy SavingsSavings

85 Deg F85 Deg F 0.570 kW/ton0.570 kW/ton Base Base

83 Deg F83 Deg F 0.542 kW/ton0.542 kW/ton 5% 5%




Rule of Thumb for SavingRule of Thumb for SavingChiller EnergyChiller Energy

Chiller energy is reduced 2%Chiller energy is reduced 2%for every 1 Deg F offor every 1 Deg F of

reduced condenser waterreduced condenser watertemperaturetemperature


Typical Office BuildingTypical Office Building500 Ton System500 Ton System

Operating SeasonOperating Season8 Months / Year8 Months / Year2,500 Equiv. Full Load Hours2,500 Equiv. Full Load Hours

$ 0.08/$ 0.08/kWHkWH Energy Rate Energy Rate

$ 10/kW Demand Charge$ 10/kW Demand Charge


System Economics with EnergySaving Cooling Tower

Nominal Cooling

Tower Selection . . .

1500 GPM 95/85/78

30 HP Fan Motor



Nominal Cooling


1500 GPM 95/85/78

30 HP Fan Motor

Energy Saving Cooling


1500 GPM 93/83/78

30 HP Fan Motor



Nominal Cooling


1500 GPM 95/85/78

30 HP Fan Motor



1500 GPM 93/83/78

30 HP Fan Motor

First Cost Premium. . . . . . . . $7,800


Chiller Energy Savings with 2 Deg F Colder Condenser WaterTypical Chiller Energy

Based on 85 Deg F

Condenser Water:

0.570 kW/ton



Based on 85 Deg F

Condenser Water:

0.570 kW/ton

Typical Chiller Energy

Based on 83 Deg F

Condenser Water:

0.542 kW/ton



Based on 85 Deg F

Condenser Water:

0.570 kW/ton

Typical Chiller Energy

Based on 83 Deg F

Condenser Water:

0.542 kW/ton

Saves 0.028 kW/ton


Annual Energy Savings withAnnual Energy Savings with2 Deg F Colder Condenser Water2 Deg F Colder Condenser Water

Chiller Peak Energy Reduction . . 0.028 kW/tonChiller Peak Energy Reduction . . 0.028 kW/ton

500 Ton System . . . . . . . . . . . . . . . . . 500 Tons500 Ton System . . . . . . . . . . . . . . . . . 500 Tons

Equivalent Full Load Hours / Year. . . 2,500 HrsEquivalent Full Load Hours / Year. . . 2,500 Hrs

Energy Cost . . . . . . . . . . . . . . . .Energy Cost . . . . . . . . . . . . . . . .X 0.08 $/X 0.08 $/kWHkWH

Energy Savings . . . . . . . . . . . . . . . . . . . .$2,800Energy Savings . . . . . . . . . . . . . . . . . . . .$2,800

Demand Savings (0.028 kW/ton XDemand Savings (0.028 kW/ton X

500 Tons X $10/ kW X 8 Months ). . 500 Tons X $10/ kW X 8 Months ). . .$1,120.$1,120

Total Annual Energy Savings. . . Total Annual Energy Savings. . . $3,920$3,920


Payback Period forPayback Period for2 Deg F Colder Condenser Water2 Deg F Colder Condenser Water

Cooling Tower FirstCooling Tower First

__ __Cost Premium Cost Premium = = $ 7,800 $ 7,800 = = 2.0 Year2.0 Year

Annual Energy Cost $ 3,920 PaybackAnnual Energy Cost $ 3,920 Payback

Savings Savings


Total Energy SavingsTotal Energy Savings

20 Year System Life20 Year System Life

700,000 kW-H Saved700,000 kW-H Saved

$ 78,400 Saved$ 78,400 Saved


Energy Saving Tip

Evaluate the additional free

cooling hours with low

design water temperatures.

Additional Free CoolingAdditional Free CoolingEnergy SavingsEnergy Savings

250 Ton Winter Load250 Ton Winter Load

55 Deg F Building Loop Water55 Deg F Building Loop Water

52 Deg F Condenser Water52 Deg F Condenser Water



Nominal Cooling


1500 GPM 95/85/78

Model 33520

30 HP Fan Motor

Winter WB - 42 Deg F

4007 Hours



Nominal Cooling


1500 GPM 95/85/78

30 HP Fan Motor


4007 Hour



1500 GPM 93/83/78

30 HP Fan Motor


4438 Hours



Nominal Cooling


1500 GPM 95/85/78

30 HP Fan Motor


4007 Hour



1500 GPM 93/83/78

30 HP Fan Motor


4438 Hours

Additional Energy Savings . . . . . . . . . .$4,265


Cooling Tower Payback with Free Cooling

Cooling Tower First

Cost Premium = $ 7,800 < 1.0 Year

Annual Energy $3,920 + $4,265 Payback

Cost Savings


Total Energy Savings

20 Year System Life

1,766,700 kW-H Saved

$ 163,700 Saved


Energy Saving Tip # 3

Take advantage of low

ambient wet bulb

temperatures.


ASHRAE 0.4% Wet BulbASHRAE 0.4% Wet BulbTemperaturesTemperatures

LocationLocation Wet Bulb Wet BulbBaltimore, MD Baltimore, MD 78 Deg F78 Deg FNew York, NYNew York, NY 76 Deg F 76 Deg FBoston, MABoston, MA 75 Deg F75 Deg FLos Angeles, CALos Angeles, CA 72 Deg F72 Deg FSeattle, WASeattle, WA 66 Deg F66 Deg FDenver, CODenver, CO 65 Deg F65 Deg F


Chiller Energy Savings with NominalSystem in Various Locations

Location WB CWT

Baltimore 78 Deg F 85.0 Deg F

New York 76 Deg F 83.5 Deg F

Boston 75 Deg F 82.7 Deg F

Los Angeles 72 Deg F 80.5 Deg F

Seattle 66 Deg F 76.0 Deg F

Denver 65 Deg F 75.0 Deg F



Location WB CWT Energy

Baltimore 78 Deg F 85.0 Deg F 0.57 kW/T

New York 76 Deg F 83.5 Deg F 0.55 kW/T

Boston 75 Deg F 82.7 Deg F 0.54 kW/T

Los Angeles 72 Deg F 80.5 Deg F 0.53 kW/T

Seattle 66 Deg F 76.0 Deg F 0.49 kW/T

Denver 65 Deg F 75.0 Deg F 0.48 kW/T



Location WB CWT Energy SaveBaltimore 78 Deg F 85.0 Deg F 0.57 kW/T Base

New York 76 Deg F 83.5 Deg F 0.55 kW/T $2 K

Boston 75 Deg F 82.7 Deg F 0.54 kW/T $3 K

Los Angeles 72 Deg F 80.5 Deg F 0.53 kW/T $4 K

Seattle 66 Deg F 76.0 Deg F 0.49 kW/T $6 K

Denver 65 Deg F 75.0 Deg F 0.48 kW/T $9 K


Energy Saving TipsEnergy Saving Tips

Tip #1Tip #1 - - Lower the DesignLower the DesignCondenser Water TemperatureCondenser Water Temperature..

Tip #2Tip #2 -- Evaluate Additional Free Evaluate Additional FreeCooling Hours.Cooling Hours.

Tip #3Tip #3 - Take Advantage of Low- Take Advantage of LowAmbient Wet Bulb Temperatures.Ambient Wet Bulb Temperatures.


ConclusionConclusion�� Air-conditioning system evaluations shouldAir-conditioning system evaluations should

take the pending impact of environmentaltake the pending impact of environmentalissues into considerationissues into consideration

�� Water cooled systems provide the mostWater cooled systems provide the mostenergy efficient systems and can helpenergy efficient systems and can helpprotect building owners and operators fromprotect building owners and operators fromuncertainties in electricity pricing.uncertainties in electricity pricing.


BenefitsBenefits ofof

Water-Cooled SystemsWater-Cooled Systemsvsvs

Air-Cooled SystemsAir-Cooled Systemsforfor

Air-Conditioning ApplicationsAir-Conditioning Applications

Written by: Michael D.Pugh

for air-conditioning applicationscooling technology institute benefits of water-cooled systems vs...

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