efficient low-lift cooling with radiant distribution, thermal storage and variable-speed chiller...
TRANSCRIPT
Efficient Low-Lift Cooling with Radiant Distribution, Thermal Storage and Variable-Speed Chiller Controls
Srinivas Katipamula, Ph.D.Peter Armstrong, Ph.D., Weimin Wang, Ph.D., Nick Fernandez, Heejin Cho, Ph.D.
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Clima 2010, May 10th, 2010, Antalya, Turkey
Outline of Presentation
Introduction to Low-Lift Cooling SystemEnergy Savings
Building prototypesClimate locationsSimulation Grid
U.S. National Technical Energy Savings PotentialEconomic Analysis – Simple Payback CalculationsConclusions and Future Work
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Introduction to Low-Lift Cooling System
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Low-Lift Cooling System
4
Peak-Shifting by Cooling at Night– Proven demand savings technology– Use building mass or thermal energy storage (TES)– Improves chiller load factor; milder condensing conditions (10-20oF)
Radiant Cooling Panels (RCP) and Dedicated Outside Air Supply (DOAS)– Emerging technology - Popular in Europe– 65°F panels or slabs provide “cooling” instead of 50°F air– DOAS with enthalpy recovery for fresh air – Eliminates wasteful reheat; reduces fan power (80%)
Low-Lift Vapor Compression Cooling Equipment– Combining low-lift chiller with RCP, TES and DOAS is a good match
for new buildings– Designed for efficient part-load and low-lift operation due to variable
speed compressors– Converts the favorable Exergy properties of DOAS/RCP and Peak-
Shifting/TES into energy savings
Add
Integrate
Sum of Energy Savings Greater than its Parts …Plus Comfort and Control Benefits
Start with
Energy Savings Estimation Methodology
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Energy Savings Estimation Methodology
EnergyPlus to generate thermal loads (coil loads)Matlab component models to estimate the energy consumption of low-lift chiller, DOAS, fan and pumpPer building energy savings were translated to national technical potential using new construction weights derived from McGraw Hill New Construction Database
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Building Prototypes and Climate Locations for Low-Lift Analysis
Building TypesOffice – small, medium and largeMercantile – Standalone retail and strip mallSchool – Primary and Secondary SchoolsFood Sales - supermarketHealth Care – outpatient and HospitalLodging – large hotelWarehouse – non-refrigerated warehouse
Climate LocationsMiami, FLHouston, TXPhoenix, AZAtlanta, GALos Angeles, CALas Vegas, NVSan Francisco, CABaltimore, MDAlbuquerque, NMSeattle, WAChicago, ILDenver, COMinneapolis, MNHelena, MTDuluth, MNFairbanks, AK
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Standard vs. High Performance Buildings
(a) Because the values vary by climate locations, the values are not listed in this table(b) Completely shade the solar direct beam(c) Load density during hours of the highest loads (d) Total HVAC fan power divided by total HVAC fan flow rate
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Component Performance Levels to be Analyzed
Component Baseline High Performance
Wall-Roof U-Factor 90.1-2004(a) 4/9th of 90.1-2004
Window U-Factor and SHGC 90.1-2004(a) 4/9th of 90.1-2004
Window-to-Wall-Ratio 40% 20%+Shading(b)
Lighting and Plug Load(c) Power Density (W/sf) 1.3+0.63 0.58+0.21
Fan Power (W/scfm)(d) 0.8 0.356
Analysis Grid for Low-Lift Analysis
12 Building Types16 Climate Locations2 Building Performance Levels and 3 System Combinations
ASHRAE Standard 90.1-2004 (referred to as Standard)High Performance (approximately 50% lower than Standard)With economizer, without economizer and energy recovery ventilation
8 Different Low-Lift HVAC Combinations1152 EnergyPlus Simulation9,216 Matlab Simulations
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Summary of Energy Savings
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Summary of Low-Lift Combinations
Case 0: Baseline – EnergyPlus Benchmark Case 1: 2-Speed Chiller, CAV/VAVCase 2: Variable-Speed Chiller, CAV/VAVCase 3: 2-Speed Chiller, CAV/VAV, TESCase 4: 2-Speed Chiller, CAV/VAV,TESCase 5: 2-Speed Chiller, RCP/DOASCase 6: Variable-Speed Chiller, RCP/DOASCase 7: 2-Speed Chiller, RCP/DOAS, TESCase 8: Variable-Speed Chiller, RCP/DOAS, TES
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National Technical Potential Savings
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Comparison of Annual Energy Consumption – Standard Performance Building
0
50,000
100,000
150,000
200,000
250,000Case 0: Baseline Case 1: 2-Speed Chiller, VAVCase 2: Var-Speed Chiller, VAV Case 3: 2-Speed Chiller, VAV, TESCase 4: Var-Speed Chiller, VAV, TES Case 5: 2-Speed Chiller, RCP/DOASCase 6: Var-Speed Chiller, RCP/DOAS Case 7: 2-Speed Chiller, RCP/DOAS, TESCase 8: Var-Speed Chiller, RCP/DOAS, TES
Medium Offi ce (STD)
Climate (Represented by City)
Chi
ller,
Pum
p, a
nd V
enti
lati
onIn
put
Ene
rgy
(kW
h/Y
ear)
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Range of Energy Reduction (Case 0 – Case 8)
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Building Type Minimum Maximum Average Minimum Maximum AverageOffice Small 68% 78% 76% -9% 56% 40%Office Medium 56% 67% 63% 43% 65% 57%Office Large 37% 62% 51% 30% 54% 44%Retail Standalone 67% 76% 72% 43% 67% 55%Retail Strip Mall 56% 70% 65% 7% 60% 37%Primary School 53% 69% 64% 35% 70% 56%Secondary School 53% 69% 60% 44% 66% 53%Hotel LargeSupermarket 64% 79% 72% 42% 66% 58%
Warehouse 53% 81% 73% -3% 69% 45%
Outpatient 78% 84% 81% 44% 68% 62%Hospital 60% 78% 72% 47% 68% 61%
Standard Building High Performance Building
Range of Energy Reduction (Case 1 – Case 8)
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Building Type Minimum Maximum Average Minimum Maximum AverageOffice Small 59% 77% 70% -19% 43% 25%Office Medium 13% 52% 37% 7% 50% 25%Office Large 21% 61% 40% -4% 36% 13%Retail Standalone 56% 73% 66% 31% 50% 41%Retail Strip Mall 45% 63% 56% -7% 41% 16%Primary School 46% 55% 51% 22% 46% 34%Secondary School 32% 49% 43% 10% 37% 26%Hotel Large 16% 57% 44% -11% 47% 29%Supermarket 59% 78% 68% 35% 63% 51%
Warehouse 50% 81% 69% -5% 69% 40%
Outpatient 65% 83% 78% 34% 67% 53%Hospital 48% 76% 64% 10% 49% 37%
Standard Building High Performance Building
National Technical Potential Estimation Methodology
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Per Building Energy Savings
Number of New Buildings Built
in a Year
By Climate Location
National Savings
Summary of Annual National Technical Site Electricity Savings Potential
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Low-Lift Cooling System – Case 8 (assuming 100% Penetration) in Comparison to Case 0
Low-Lift Cooling System – Case 8 (assuming 100% Penetration) in Comparison to Case 1
Quad PercentageStandard 0.005 56.7%High Performance 0.001 31.7%
National Cooling and Fan and Pump Electricity SavingsBuilding Performance Level
Quad PercentageStandard 0.011 72.1%High Performance 0.004 62.9%
Building Performance LevelNational Cooling and Fan and Pump Electricity Savings
Comparison of Annual National Technical Site Electricity Savings Potential
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For Various Low-Lift Cooling Design Option Set (assuming 100% Penetration) in Comparison to Case 0
0
0.002
0.004
0.006
0.008
0.01
0.012
2-Speed Chil ler, VAV
Var-Speed Chil ler, VAV
2-Speed Chil ler, VAV,
TES
Var-Speed Chil ler, VAV,
TES
2-Speed Chil ler,
RCP/DOAS
Var-Speed Chil ler,
RCP/DOAS
2-Speed Chil ler,
RCP/DOAS, TES
Var-Speed Chil ler,
RCP/DOAS, TES
Best Option
STD
HP
TOS
Ann
ual
Ene
rgy
Sav
ings
(Q
uads
/Yea
r)
Comparison of Annual National Technical Site Electricity Savings Potential
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For Various Low-Lift Cooling Design Option Set (assuming 100% Penetration) in Comparison to Case 1
0
0.001
0.002
0.003
0.004
0.005
0.006
Case 2: Var-Speed Chil ler,
VAV
Case 3: 2-Speed Chil ler,
VAV, TES
Case 4: Var-Speed Chil ler,
VAV, TES
Case 5: 2-Speed Chil ler,
RCP/DOAS
Case 6: Var-Speed Chil ler,
RCP/DOAS
Case 7: 2-Speed Chil ler,
RCP/DOAS, TES
Case 8: Var-Speed Chil ler,
RCP/DOAS, TES
Best Option
STD
HP
TOS
Ann
ual
Ene
rgy
Sav
ings
(Q
uads
/Yea
r)
Economic Analysis – Simple Payback
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Incremental Cost of Low-Lift System by Climate Location
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Houston 0.883Miami 0.903Phoenix 0.89Atlanta 0.902Los Angeles 1.022Las Vegas 1.057San Francisco 1.238Baltimore 0.931Albuquerque 0.898Seattle 1.039Chicago 1.149Denver 0.95Minneapolis 1.098Duluth 1.024Fairbanks 1.213
Medium Office Large Office Supermarket Secondary SchoolHouston $ - $ 321,000 $ 250,000 $ 550,000 Miami $ - $ 345,849 $ 249,228 $ 563,472 Phoenix $ - $ 340,870 $ 245,640 $ 555,360 Atlanta $ - $ 345,466 $ 248,952 $ 562,848 Los Angeles $ - $ 391,426 $ 282,072 $ 637,728 Las Vegas $ - $ 404,831 $ 291,732 $ 659,568 San Francisco $ - $ 474,154 $ 341,688 $ 772,512 Baltimore $ - $ 356,573 $ 256,956 $ 580,944 Albuquerque $ - $ 343,934 $ 247,848 $ 560,352 Seattle $ - $ 397,937 $ 286,764 $ 648,336 Chicago $ - $ 440,067 $ 317,124 $ 716,976 Denver $ - $ 363,850 $ 262,200 $ 592,800 Minneapolis $ - $ 420,534 $ 303,048 $ 685,152 Duluth $ - $ 392,192 $ 282,624 $ 638,976 Fairbanks $ - $ 464,579 $ 334,788 $ 756,912
Cost Index Cost
Energy Cost Savings by Building Type in each Climate Location
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Office Medium Office Large Supermarket Secondary SchoolHouston $ 12,102 $ 54,515 $ 20,385 $ 113,952 Miami $ 14,827 $ 68,925 $ 20,106 $ 140,302 Phoenix $ 11,249 $ 44,571 $ 14,995 $ 75,269 Atlanta $ 6,981 $ 35,237 $ 12,994 $ 62,120 Los Angeles $ 7,513 $ 51,594 $ 12,235 $ 66,231 Las Vegas $ 9,583 $ 51,822 $ 15,763 $ 72,036 San Francisco $ 4,867 $ 30,940 $ 12,198 $ 48,146 Baltimore $ 8,565 $ 40,335 $ 20,172 $ 82,866 Albuquerque $ 5,079 $ 71,515 $ 11,703 $ 41,735 Seattle $ 2,628 $ 19,976 $ 7,012 $ 21,373 Chicago $ 5,860 $ 30,612 $ 15,112 $ 53,048 Denver $ 3,954 $ 54,737 $ 13,895 $ 34,627 Minneapolis $ 4,286 $ 22,529 $ 14,111 $ 40,873 Duluth $ 3,023 $ 19,617 $ 14,910 $ 30,515 Fairbanks $ 3,370 $ 25,725 $ 26,780 $ 38,633
Simple Payback by Building Type for each Climate Location
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Office Medium Office Large Supermarket Secondary SchoolHouston - 5.9 12.3 4.8 Miami - 5.0 12.4 4.0 Phoenix - 7.6 16.4 7.4 Atlanta - 9.8 19.2 9.1 Los Angeles - 7.6 23.1 9.6 Las Vegas - 7.8 18.5 9.2 San Francisco - 15.3 28.0 16.0 Baltimore - 8.8 12.7 7.0 Albuquerque - 4.8 21.2 13.4 Seattle - 19.9 40.9 30.3 Chicago - 14.4 21.0 13.5 Denver - 6.6 18.9 17.1 Minneapolis - 18.7 21.5 16.8 Duluth - 20.0 19.0 20.9 Fairbanks - 18.1 12.5 19.6
Aggregate Payback - 9.3 17.3 8.8
Future Planned Activities
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Planned Activities
Identification and Evaluation of Potential Alternate Low-Lift OptionsDevelopment and Testing (simulated environment) of Predictive Control AlgorithmTesting of Predictive Control Algorithm in Real BuildingDevelop a Specification to Integrate the Predictive Controller into EnergyPlus
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