Benefits
of
Water-Cooled Systems
vs
Air-Cooled Systems
for
Air-Conditioning Applications
Written by: Michael D.Pugh
Cooling Technology Institute
www.cti.org
U.S. Government commitment to
reduce greenhouse gas emissions
can have a significant impact on
HVAC system considerations
Cooling Technology Institute
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Kyoto Conference on
Global Warming
I
International effort to control greenhouse
gas emissions
I Greenhouse gasses include:
—Carbon Dioxide (CO2)
—Methane (CH4)
—Nitrous Acid (N2O)
—Hydrofluorocarbons (HFC s )
—Perfluorocarbons (PFC s )
—Sulfur Hexafluorides (SF4)
Cooling Technology Institute
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U.S. Commitment to Kyoto
Conference
I
Kyoto Protocol signed by ex-President Bill
Clinton in October, 1997
I Commits U.S. to reduce greenhouse gas
emissions to 7% below 1990 levels by 2012
I Ratification by U.S. Senate pending
Cooling Technology Institute
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Total U.S. Greenhouse Gas
Emissions by Gas
Cooling Technology Institute
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U.S. Greenhouse Gas Emissions
Carbon Dioxide (CO2) emissions account for
85% of U.S. greenhouse gas emissions
Cooling Technology Institute
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Major CO2 Emission Sources
I
Transportation Industry
I Heavy Industry
I Utility Industry
Cooling Technology Institute
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Major CO2 Emission Sources
Utility Industry
I
Fossil Fuel Burning Power Plants
—Produce 55% of U.S. electricity
—Accounts for 68% of the CO2 emission
reductions required for Protocol compliance
—Addition of exhaust gas scrubbers not
economically viable for most plants
—Only 16% (193 of 1,207) of Power Plants have
exhaust gas scrubbers
Cooling Technology Institute
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U.S. Government Plan to reduce
CO2 Emissions from Power Plants
I
Convert to less carbon intensive fuels or
non-carbon fuels
—Taxation of carbon fuels
—Regulation of emissions for new plants
I
Reduce energy demand
—New energy-saving technologies
I
Improve efficiency of equipment and
systems
Cooling Technology Institute
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Fossil Fuel Burning Power Plants
I
Air-conditioning systems drive many power
plant peak loads and have been identified as
energy reduction opportunity
Cooling Technology Institute
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U.S. Actions Impacting HVAC
Systems and Equipment
I
EPA ENERGY STAR Program
¨ Actively promotes participation in economically
justified energy saving projects
I
Energy Policy Act of 1992
—ASHRAE Standard 90.1 as basis for energy
efficiency for commercial buildings.
—ASHRAE 90.1 revised in June,1999
—submitted to D.O.E. for acceptance
—Recently adopted for ICC energy code
Cooling Technology Institute
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Energy Saving System Designs . . .
. . .our
Environmental Responsibility
Basic Air Conditioning Systems
I
Large Buildings ( >400 tons)
—Water cooled systems provide clear-cut
economic and environmental justification.
I
Mid-size Buildings (200 - 400 tons)
—Air cooled systems may offer first cost
incentive to sacrifice energy efficiencies of
water cooled systems.
Cooling Technology Institute
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Theoretical Building Profile
I
Building load
—400 tons
I
Building configuration
—square w/ five (5) floors
—one (1) air handling fan / floor
I
Air Volume
—350 CFM/ton
—3-1/2 w.g. T.S.P.
Cooling Technology Institute
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400 Ton System Comparisons
I
Chiller systems:
—Air-Cooled Chiller
—Centrifugal Chiller
I
Packaged systems:
—Roof -Top Units
—Self-Contained Units
Cooling Technology Institute
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System Energy Requirements
I
400 Ton Air-Cooled Chiller System
KW /Unit
Compressor
406.00
Condenser fans
62.50
Air handling units
22.37
Chilled H20 pump 14.92
Total KW
I
Total KW
406.00
62.50
111.85
14.92
595.27
KW/ton= 595.27/400 = 1.49KW/ton
Cooling Technology Institute
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System Energy Requirements
I
400 Ton Centrifugal Chiller System
KW /Unit
Compressor
220.0
Air handling units
22.37
14.92
Chilled H20 pump
Condenser H20 pump 11.19
Cooling tower fan
18.65
Total KW
I
Total KW
220.00
111.85
14.92
11.19
18.65
376.61
KW/ton= 376.61/400 = 0.94KW/ton
Cooling Technology Institute
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Theoretical 400 Ton System
Comparisons
I
Chiller systems
—Air-cooled chiller system . . . . . . . 1.49KW/ton
—Centrifugal chiller system . . . . . . . 0.94KW/ton
Cooling Technology Institute
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System Energy Requirements
I
I
400 Ton Roof-Top System: (5)80 Ton Units
KW /Unit
Total KW
Compressor
74.65
Air handling fan 29.84
Condenser fan
8.60
Total KW
373.25
149.20
43.00
565.45
KW/ton= 565.45/400 = 1.42KW/ton
Cooling Technology Institute
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System Energy Requirements
I
400 Ton Self-Contained System: (5)80 Ton
Units
Compressor
Air handling fan
Condenser H2O pump
Cooling tower fan
Total KW
I
KW /Unit
Total KW
63.12
22.37
11.19
18.75
315.60
111.85
11.19
18.75
457.39
KW/ton= 457.39/400 = 1.14KW/ton
Cooling Technology Institute
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System Energy Comparison
I
Chiller systems
—Air-cooled chiller system . . . . . . . 1.49KW/ton
—Centrifugal chiller system . . . . . . . 0.94KW/ton
I
Packaged systems
—Roof-top units . . . . . . . . . . . . . . . 1.42KW/ton
—Self-contained units . . . . . . . . . . . .1.14KW/ton
Cooling Technology Institute
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Basic HVAC System Options
I
Water-cooled systems
—More energy-efficient than air-cooled systems
—Support environmental efforts to control
greenhouse gas emissions
Cooling Technology Institute
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Kyoto Conference
If we do it right, protecting the climate will
yield not costs, but profits; not burdens, but
benefits; not sacrifice, but a higher
standard of living
President Bill Clinton
Cooling Technology Institute
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Installed Cost Estimate Sources
I
Air Cooled Chiller . . . . $350/Tr x 1.50
I Centrifugal Chiller . . . . $250/Tr x 1.50
I Roof Top Units . . . . . . .$550/ Tr x 1.25
I Self Contained Units . . $400/Tr x 1.50
I Air Handling Units . . . . $1.00/CFM x 1.25
I Cooling Towers . . . . . . .$45/ Tr x 1.50
I Pump/Piping . . . . . . . . . Means Mech. Est.
Cooling Technology Institute
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Installed Cost Estimate
Air Cooled Chiller System
I
I
400 ton air cooled chiller . . . . . . . $210,000
(5) 28,000 CFM air handlers . . . . $175,000
1,000 LF chilled water piping . . . $ 67,000
Chilled water pump . . .. . . .. . . . .. $ 3,600
I
Total installed cost . . . . . . . . $455,600
I
I
Cooling Technology Institute
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Installed Cost Estimate
Centrifugal Chiller System
—400 ton centrifugal chiller . . . . . . .$150,000
—400 ton cooling tower . . . . .. . . . . $ 27,000
—(5) 28,000 CFM air handlers . . . . $175,000
—1,000 LF chilled water piping . . . $ 67,000
—400 LF condenser water piping . . .$ 26,800
—Chilled water pump . . .. . . .. . . . .. $ 3,600
—Condenser water pump . . . . . . . . . .$ 4,000
—Mechanical equipment room . . . $ 45,000
—Total installed cost . . . . . . . . $498,400
Cooling Technology Institute
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Installed Cost Estimate
Roof-Top Unit System
I
(5) 80 ton roof top units . . . .
I Installed cost . .. . . .. . . $275,000
Cooling Technology Institute
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Installed Cost Estimate
Self-Contained Unit System
I
I
I
I
(5) 80 ton self-contained units .. . . . . . . . $240,000
Closed circuit cooling tower . . . . . . . . . . $ 54,000
Condenser water pump . . . . . . . . . . . . . . $ 4,000
Condenser water piping . . . . . . . . . . . . . . $ 26,800
I Installed cost . . . . . . . . . . . . . $324,800
Cooling Technology Institute
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Installed Cost Summary
Installed
Cost
Chiller systems
Air-Cooled Chiller
Centrifugal Chiller
Packaged systems
Roof-Top
Self-Contained
$455,600
$498,400
$275,000
$324,800
Cooling Technology Institute
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System Energy Cost Assumptions
I
1800 Equivalent Full Load Hours per Year
I $0.06 per KW-Hour
I $12 per KW Demand Charge for 6 Months
Cooling Technology Institute
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Annual Energy Cost Comparison
Total
KW
Energy
Cost
Demand
Cost
Chiller systems
Air-cooled chiller 595.27 $ 64,289 $42,860
Centrifugal chiller 376.61 $ 40,674 $27,116
Packaged systems
Roof-top
565.45 $ 61,069 $40,712
Self-contained
457.39 $ 49,398 $32,932
Total
Cost
$107,149
$ 67,790
$101,781
$ 82,330
Cooling Technology Institute
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System Cost Summary
Chiller systems
Air-cooled chiller
Centrifugal chiller
Packaged systems
Roof-top
Self-contained
Installed
Cost
Energy
Cost
$455,600
$498,400
$107,149
$ 67,790
$275,000
$324,800
$101,781
$ 82,330
Cooling Technology Institute
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Water Usage
I
Water cooled systems recycle 95% of the
total water
I A small portion of the water is bled from
the system to control the build-up of
impurities
Bleed Rate =
Evaporation Rate
Cycles of Concentration - 1
Cooling Technology Institute
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Water Usage and Cost
(400 ton sample system)
Evaporation Rate = 3.0 GPM/100 tons
= 12.0 GPM/400 ton system
Cooling Technology Institute
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Water Usage and Cost
(400 ton sample system)
Evaporation Rate = 3.0 GPM/100 tons
= 12.0 GPM/400 ton system
Bleed Rate = 12.0 GPM
4 cycles -1
= 4.0 GPM
Cooling Technology Institute
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Water Usage and Cost
(400 ton sample system)
Evaporation Rate = 3.0 GPM/100 tons
= 12.0 GPM/400 ton system
Bleed Rate = 12.0 GPM
4 cycles -1
= 4.0 GPM
Consumption = Evaporation + Bleed
= 12.0 GPM + 4.0 GPM
Cooling Technology Institute
= 16.0 GPM
www.cti.org
Water Usage and Cost
(400 ton sample system)
I
Annual Water Consumption
—16.0 GPM X 60 Min/Hr x 1800 Eq FLH
—1,728,000 gallons/year
I
Annual Water & Sewer Cost
—1,728,000 gal X $3.00/1000 gal
—$5,184
Cooling Technology Institute
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Water Quality and Control Cost
Considerations
I
Water-cooled systems require chemical
treatment to control scale/corrosion and
biological growths
I These costs must be included in a cost
analysis of water cooled and air cooled
systems
Cooling Technology Institute
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Annual Water Treatment Costs
(400 ton sample system)
I
Full Service Water Treatment
—Average annual program costs- $1.00/ton/month
—400 Tr X $1.00/Tr/Mnth X 6 mnth = $2,400/year
Cooling Technology Institute
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Annual Water Cost Estimate
(400 ton sample system)
Water Consumption - $5,184
$2,400
Water Treatment
Annual Water Cost $7,584
Cooling Technology Institute
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System Cost Summary
Installed
Cost
Chiller systems
Air-Cooled chiller
Centrifugal chiller
Packaged system
Roof-Top Units
Self-Contained
Energy
Cost
Water
Cost
$455,600 $107,149 N/A
$498,400 $ 67,790 $7,584
$275,000 $101,781 N/A
$324,800 $ 82,330 $7,584
Cooling Technology Institute
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System Cost Summary
Installed
Cost
Chiller systems
Air-Cooled chiller
Centrifugal chiller
Packaged system
Roof-Top Units
Self-Contained
Energy
Cost
Water
Cost
Payback
Yrs
$455,600 $107,149 N/A
$498,400 $ 67,790 $7,584
Base
1.3
$275,000 $101,781 N/A
$324,800 $ 82,330 $7,584
Base
4.2
Cooling Technology Institute
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HVAC System Considerations
Cost analysis must consider the economic
impact that environmental and electric
power generation issues will have on
energy prices in the near future.
Cooling Technology Institute
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Kyoto Protocol Impacted Energy
Prices to Commercial Market*
I
Projected Energy Price Increases (P V)
—2005 Projected Increase. . . . . . . . + 17.3%
—2010 Projected Increase . . . . . . . + 65.3%
I
* per 1998 Energy Information Administration(EIA) report titled
Impacts of the Kyoto Protocol on U.S. Energy Markets an d Economic
Activity
Cooling Technology Institute
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2010 Kyoto Impact on Simple
Payback Analysis
Installed
Cost
Chiller systems
Air-Cooled Chiller
Centrifugal Chiller
Packaged system
Roof -Top units
Self-Contained
Energy
Cost
Water
Cost
$455,600 $177,153 N/A
$498,400 $112,079 $7,584
$275,000 $168,278
$324,800 $136,119
N/A
$7,584
Cooling Technology Institute
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2010 Kyoto Impact on Simple
Payback Analysis
Installed
Cost
Chiller systems
Air-Cooled Chiller
Centrifugal Chiller
Packaged system
Roof -Top units
Self-Contained
Energy
Cost
Water
Cost
Payback
Yrs
$455,600 $177,153 N/A
$498,400 $112,079 $7,584
Base
0.75
$275,000 $168,278
$324,800 $136,119
Base
2.0
N/A
$7,584
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Deregulation of Electric Power
Generation Industry
Cooling Technology Institute
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Electric Power Industry
Generation
Generation
Transmission
Transmission
Distribution
Distribution
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Deregulation of Electric Power
Generation Industry
I
Assuming no Kyoto Protocol, 1998 U.S.
Gov t report projected reduction in average
retail electricity price from $0.067KWH to
$0.060/KWH by 2010 due to competitive
climate established by deregulation.
I Agriculture Dept report(March, 1999)
predicted 19 states expected higher
electricity prices as low cost producers sell
Cooling Technology Institute
into higher price markets
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Deregulation
Experience
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Electric Power Generation
I
Industry standard - 15% more electric
generating capacity than required
I Automatic brownout warnings occur when
only 10% more electric generating capacity
is available
Cooling Technology Institute
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U.S. Electric Generating Capacity
I
1980
30% excess capacity
14% excess capacity
I 2000
I 2005 < 10% excess capacity predicted
Cooling Technology Institute
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Electric Generating Capacity
I
Overall North American generating
capacity is marginal
I Many areas with generating capacity
shortfalls
—California
—New York
—New England
—Arizona
—Kansas
—Indiana
Cooling Technology Institute
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Transmission
I
In 1995, there were only 25,000
transactions where electricity was sold from
one region to another
I In 1999, there were more than 2,000,000
transactions where electricity was sold from
one region to another
Cooling Technology Institute
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Transmission Gridlock
I
There are sharp locational price differentials
due to the inability to transmit enough
power from region to region.
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Transmission Gridlock
I
In many areas the transmission lines can t
carry any more power, and lines can t be
upgraded fast enough
I Some areas with transmission problems
—California
—Dallas/Ft. Worth
—Chicago
—NYC
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Distribution
I
Local distribution systems can t handle
increasing peak loads
I Cause of blackouts in NYC, Long Island,
Chicago and Detroit
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The power market is moving to
Real-Time Pricing
Cooling Technology Institute
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What does Real-Time pricing
mean?
High summer daytime rates
Examples
I San Diego $7.00/kWh
I Maine, Connecticut and NYC $6.00/kWh
I Texas $0.70/kWh
I Montana $0.13/kWh
What does Real-Time pricing
mean?
Low
summer night rates
Proposed Texas Utilities
Time-of-Day Rate Structure
$0.13
$ per KWH
0.15
0.10
0.05
$0.01
0.00
M
2
4
6
8
10
N
Hour
Source: Deregulation in Texas and the Impact on Rate Structures for
Thermal Storage Applications, J. Michael Sherburne - February 2000
2
4
6
8
10
M
Cooling Technology Institute
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University of North Carolina
Hourly Price - July 23, 1999
$0.23
0.25
$ per KWH
0.20
0.15
0.10
$0.02
0.05
0.00
8
9
10
11
N
1
2
Hour
Source: Real-time Electrical Rates and Thermal Utilities,
Engineered Systems - July 2000
3
4
5
6
7
Cooling Technology Institute
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What will be the result of
Real-Time pricing?
Highest electricity prices will
coincide with peak air-conditioning
loads
Cooling Technology Institute
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Energy Saving System Designs . . .
. . .our
Environmental Responsibility
Energy Saving System Designs . . .
. . .our
Fiscal Responsibility
EPA Climate Wise ProgramWise Rules to Energy Efficiency
—Process Cooling Wise Rule 1. Installing energy
efficient chillers and refrigeration systems can
save 1.2% of a facility s total energy use with
an average simple payback of 23 months.
—Process Cooling Wise Rule 2. Free cooling
with cooling tower water can reduce a facility s
total energy use by about 1% with an average
simple payback of 14 months
Cooling Technology Institute
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EPA Climate Wise ProgramWise Rules to Energy Efficiency
I
Process Cooling Wise Rule 3. Free
cooling can reduce cooling system energy
use by as much as 40% depending on
location and load profile.
I Process Cooling Wise Rule 4. Increasing
chilled water temperature by 1 Deg F
reduces chiller energy use by 0.6% to 2.5%
Cooling Technology Institute
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EPA Climate Wise ProgramWise Rules to Energy Efficiency
—Process Cooling Wise Rule 5. Reducing
condenser pressure by 10 psi can decrease
refrigeration system energy use per ton of
refrigeration by about 6%.
—Process Cooling Wise Rule 6. For each degree
decrease in condenser cooling water
temperature, until optimal water temperature is
reached, there is a decrease in chiller energy
use by up to 3.5%.
Cooling Technology Institute
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there s simply no
substitute for raw
(chiller)
efficiency
Equipment Cost Comparison*
Centrifugal Chiller
First Cost . . .
$250/ton
Means Mechanical Cost Data
Cooling Technology Institute
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Equipment Cost Comparison*
Centrifugal Chiller
First Cost . . .
$250/ton
Means Mechanical Cost Data
Cooling Tower
First Cost . . .
50/ton
Cooling Technology Institute
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Energy Saving Tip
Lower the design
condenser water
temperature.
Cooling Technology Institute
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ARI Nominal Condenser
Water Rating Condition
3 GPM / Ton
10 Deg F Temperature Rise
85 Deg F Condenser Water
Cooling towers can be
economically selected to
provide condenser water
temperatures within 4 Deg
F ( or less) of the
ambient wet bulb
temperature.
Effect of Condenser Water
Temperature on Chiller Energy
CW
Temp.
85 Deg F
83 Deg F
80 Deg F
75 Deg F
70 Deg F
Typ Chiller
Energy
Energy
Savings
0.570 kW/ton Base
0.542 kW/ton 5%
0.524 kW/ton 8%
0.484 kW/ton 15%
0.450 kW/ton 21%
Cooling Technology Institute
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Rule of Thumb for Saving
Chiller Energy
Chiller energy is reduced 2%
for every 1 Deg F of
reduced condenser water
temperature
Typical Office Building
500 Ton System
Operating Season
8 Months / Year
2,500 Equiv. Full Load Hours
$ 0.08/kWH Energy Rate
$ 10/kW Demand Charge
Cooling Technology Institute
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System Economics with Energy
Saving Cooling Tower
Nominal Cooling
Tower Selection . . .
1500 GPM 95/85/78
30 HP Fan Motor
Cooling Technology Institute
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System Economics with Energy
Saving Cooling Tower
Nominal Cooling
Tower Selection . . .
1500 GPM 95/85/78
30 HP Fan Motor
Energy Saving Cooling
Tower Selection . . .
1500 GPM 93/83/78
30 HP Fan Motor
Cooling Technology Institute
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System Economics with Energy
Saving Cooling Tower
Nominal Cooling
Tower Selection . . .
1500 GPM 95/85/78
30 HP Fan Motor
Energy Saving Cooling
Tower Selection . . .
1500 GPM 93/83/78
30 HP Fan Motor
First Cost Premium. . . . . . . . $7,800
Cooling Technology Institute
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Chiller Energy Savings with
2 Deg F Colder Condenser Water
Typical Chiller Energy
Based on 85 Deg F
Condenser Water:
0.570 kW/ton
Cooling Technology Institute
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Chiller Energy Savings with
2 Deg F Colder Condenser Water
Typical Chiller Energy
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
Cooling Technology Institute
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Chiller Energy Savings with
2 Deg F Colder Condenser Water
Typical Chiller Energy
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
Cooling Technology Institute
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Annual Energy Savings with
2 Deg F Colder Condenser Water
Chiller Peak Energy Reduction . . 0.028 kW/ton
500 Ton System . . . . . . . . . . . . . . . . . 500 Tons
Equivalent Full Load Hours / Year. . . 2,500 Hrs
Energy Cost . . . . . . . . . . . . . . . .X 0.08 $/kWH
Energy Savings . . . . . . . . . . . . . . . . . . . .$2,800
Demand Savings (0.028 kW/ton X
500 Tons X $10/ kW X 8 Months ). . .$1,120
Total Annual Energy Savings. . . $3,920
Cooling Technology Institute
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Payback Period for
2 Deg F Colder Condenser Water
Cooling Tower First
__Cost Premium
= $ 7,800
Annual Energy Cost
$ 3,920
Savings
= 2.0 Year
Payback
Cooling Technology Institute
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Total Energy Savings
20 Year System Life
700,000 kW-H Saved
$ 78,400 Saved
Cooling Technology Institute
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Energy Saving Tip
Evaluate the additional free
cooling hours with low
design water temperatures.
Cooling Technology Institute
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Additional Free Cooling
Energy Savings
250 Ton Winter Load
55 Deg F Building Loop Water
52 Deg F Condenser Water
System Economics with Energy
Saving Cooling Tower
Nominal Cooling
Tower Selection . . .
1500 GPM 95/85/78
Model 33520
30 HP Fan Motor
Winter WB - 42 Deg F
4007 Hours
Cooling Technology Institute
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System Economics with Energy
Saving Cooling Tower
Energy Saving Cooling
Nominal Cooling
Tower Selection . . .
Tower Selection . . .
1500 GPM 95/85/78
1500 GPM 93/83/78
30 HP Fan Motor
30 HP Fan Motor
Winter WB - 42 Deg F Winter WB - 45 Deg F
4007 Hour
4438 Hours
Cooling Technology Institute
www.cti.org
System Economics with Energy
Saving Cooling Tower
Energy Saving Cooling
Nominal Cooling
Tower Selection . . .
Tower Selection . . .
1500 GPM 95/85/78
1500 GPM 93/83/78
30 HP Fan Motor
30 HP Fan Motor
Winter WB - 42 Deg F Winter WB - 45 Deg F
4007 Hour
4438 Hours
Additional Energy Savings . . . . . . . . . .$4,265
Cooling Technology Institute
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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
Cooling Technology Institute
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Total Energy Savings
20 Year System Life
1,766,700 kW-H Saved
$ 163,700 Saved
Cooling Technology Institute
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Energy Saving Tip # 3
Take advantage of low
ambient wet bulb
temperatures.
Cooling Technology Institute
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ASHRAE 0.4% Wet Bulb
Temperatures
Location
Baltimore, MD
New York, NY
Boston, MA
Los Angeles, CA
Seattle, WA
Denver, CO
Wet Bulb
78 Deg F
76 Deg F
75 Deg F
72 Deg F
66 Deg F
65 Deg F
Cooling Technology Institute
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Chiller Energy Savings with Nominal
System in Various Locations
Location
WB
Baltimore 78 Deg F
New York 76 Deg F
Boston
75 Deg F
Los Angeles 72 Deg F
Seattle
66 Deg F
Denver
65 Deg F
CWT
85.0 Deg F
83.5 Deg F
82.7 Deg F
80.5 Deg F
76.0 Deg F
75.0 Deg F
Cooling Technology Institute
www.cti.org
Chiller Energy Savings with Nominal
System in Various Locations
Location
WB
Baltimore 78 Deg F
New York 76 Deg F
Boston
75 Deg F
Los Angeles 72 Deg F
Seattle
66 Deg F
Denver
65 Deg F
CWT
Energy
85.0 Deg F 0.57 kW/T
83.5 Deg F 0.55 kW/T
82.7 Deg F 0.54 kW/T
80.5 Deg F 0.53 kW/T
76.0 Deg F 0.49 kW/T
75.0 Deg F 0.48 kW/T
Cooling Technology Institute
www.cti.org
Chiller Energy Savings with Nominal
System in Various Locations
Location
WB
Baltimore 78 Deg F
New York 76 Deg F
Boston
75 Deg F
Los Angeles 72 Deg F
Seattle
66 Deg F
Denver
CWT
Energy
85.0 Deg F
83.5 Deg F
82.7 Deg F
80.5 Deg F
76.0 Deg F
0.57 kW/T
0.55 kW/T
0.54 kW/T
0.53 kW/T
0.49 kW/T
Save
Base
$2 K
$3 K
$4 K
$6 K
65 Deg F 75.0 Deg F 0.48 kW/T $9 K
Cooling Technology Institute
www.cti.org
Energy Saving Tips
Tip #1 - Lower the Design
Condenser Water Temperature.
Tip #2 - Evaluate Additional Free
Cooling Hours.
Tip #3 - Take Advantage of Low
Ambient Wet Bulb Temperatures.
Cooling Technology Institute
www.cti.org
Conclusion
I
Air-conditioning system evaluations should
take the pending impact of environmental
issues into consideration
I Water cooled systems provide the most
energy efficient systems and can help
protect building owners and operators from
uncertainties in electricity pricing.
Cooling Technology Institute
www.cti.org
Benefits
of
Water-Cooled Systems
vs
Air-Cooled Systems
for
Air-Conditioning Applications
Written by: Michael D.Pugh
Cooling Technology Institute
www.cti.org