Ice Thermal Storage Applications

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Ice Thermal Storage Applications in China

Baltimore Aircoil Company

Agenda
• Overview of Ice Thermal Storage Market in China • Ice TES Applications in China
– Low Temperature Air Distribution – Tall Building Application – District Cooling

Ice Thermal Storage Market in China
• Power shortages and rate differentials driving need for load shifting ⇒ growing demand for Ice Storage applications • Growing acceptance of TES system with low temp design • Growing interest in District Cooling

10 year presence in China 150 BAC ice thermal storage installations 1.2 million ton-hours of thermal storage capacity

Central China TV (CCTV) Beijing

Shanghai Science Museum

Thermal Storage Incentives in China
On peak (US C/Kwh) Beijing Shanghai Hangzhou Guangzhou Shenzhen Wuhan 15.6 12.4 15.8 12.4 13.6 13.4 Mid-peak Off-peak (US C/Kwh) (US C/Kwh) 8.9 8.4 11.2 7.8 10.2 7.8 3.7 2.8 6.7/4.6* 3.9 5.9/2.8* 4.0 Peak vs. Offpeak Rate Differential 4.2 : 1 4.4 : 1 3.4 : 1 3.2 : 1 4.8 : 1 3.4 :1

* Special Rate for TES

Additional Benefits of Ice Thermal Storage Technology

Take advantage of low temperature fluids and larger temperature ranges minimizing the size of the system components and energy consumption

Cold Air Distribution Design Reference
Electric Power Research Institute HVAC&R Center

Benefits of Cold Air Distribution • Economics • Comfort & Indoor Air Quality Design Considerations First Cost and Operating Cost Comparisons Case Studies

Design Reference

Benefits of Cold Air Distribution
13°C (55°F) Air System
– Mechanical
move 50% less water move 33% less air

• Construction Benefits

7°C (44°F) Air System
Source: Electric Power Research Institute (EPRI)

Benefits of Cold Air Distribution
• Construction Benefits
– Building cost savings
• Building height reduction
– Up to 30 cm/floor – One additional floor per 20 to 30 stories

• • • • • •

Building envelope (1 to 4%) Structural framework (minimum of 3%) Prefabricated walls (approximately 3%) Mechanical equipment rooms (reduced size) Elevators & stairs (shorter shaft height) Reduced electrical wiring (reduced wiring & transformers)
Source: Electric Power Research Institute (EPRI)

Designing Cold Air Systems
System Net Cost 1000 900 800 System Cost $000 700 600 500 400 300 200 100 0 13°C (55°F) 13°C (55°F) 8°C (46°F) 5°C (40°F) Supply Air Temperature
Source: Source: Fields, W.G. & D.E. Knebel, 1991, “Cost Effective Thermal Storage,” Heating/Piping/Air Conditioning Magazine, July, pp. 59-72.

Annual Energy Savings 50 45 40 35 30 25 20 15 10 5 0 Energy Saving per Year $000

State Power Management Building Beijing, China
70,000 square meters, Peak A.C. load: 2400 Tons Ice Storage equipment: 7120 ton-hours

Ice Thermal Storage Technology Provides the Building Owner and Occupants Significant Benefits Including

• • • •

Lower first cost Lower energy cost Better energy efficiency Better indoor air quality and comfort

State Power Building, Beijing Ice Thermal Storage Units

(8) 890 TH Ice Tanks

State Power Management Building Ice Strategy
USRT
2500 2000 1500 1000 500 10 12 14 16 18 20 22 0 2 4 6 8 0

Base Chiller

Ice Build

Glycol Chiller

Ice Discharge

State Power Management Building Ice Storage System Diagram
ICE STORAGE TANK (8) 890 Ton-hours
2C TS-1
0

b V1 a c a V2 b c

CHILLER (3) 418 RT
3300 GPM 10.30C

Ice Melt Mode V1 modulate V2 a-c
3C
0

Heat Exchanger

120 C

Base Chiller 294 RT Cooling Load

First Cost Comparison
Cost Item (USD) Chillers Cooling Towers Ice storage Glycol Pumps Piping&Insulation Heat Exchanger Air-handling Units Ductwork &Insulation VAV and Diffusers Controls Total Conventional Ice Storage System 1,069,778 827,160 133,333 101,235 620,988 61,728 123,457 149,383 891,358 854,333 95,062 1,456,461 780,247 2,127,089 1,665,432 982,475 824,309 1,392,593 928,395 8,176,543 6,908,272

Non storage: 2400 RT, supply air temp = 12.8 C Storage: 1600 RT, 7120 TH ice storage, supply air temp = 7 C Source: Hydin Engineering Technology Ltd.

Lower First Cost
• By utilizing ice thermal storage technology, significant cost savings can be achieved through reduced pumping, piping, and air distribution system

Lower Airside Equipment Cost
• % Air Volume = Delta T Air Conventional/Delta T Cold Air = (25oC-13oC)/(25oC-7oC)=12/18=0.67 • • • • • • Original Supply Air (13 C) Super-cool Air (7 C) Reduced Air % Reduction of Supply Air Original Number of AHU Revised Number of AHU 643,900 CFM 431,600 CFM 212,300 CFM 33% 40 22

State Power Management Building First Cost Comparison
Capital Cost ($mil) 10 8 6 4 2 0 Conventional System Ice Storage w/ Conventional Air Ice Storage w/ Low Temp Air

State Power Management Building Energy Cost Comparison
Energy Cost ($000) 450 400 350 300 250 200 150 100 50 0 Conventional System Ice Storage w/ Conventional Air Ice Storage w/ Low Temp Air

Lower Energy Costs
• Electric Rate Differential
– Peak to off-peak rate differential: 3.5 to 1

• Lower Pumping Energy
– Larger fluid temperature range equates to a 45% reduction in flow rate or 45% reduction in pump energy consumption

• Lower Fan Power Consumption
– Colder supply air equates to a 33% reduction in air volume. Since the relationship of air volume to fan power is the power of 3, fan energy consumption can be reduced by as much as 70%

Improved Occupant Comfort
• In a cold air system with 7°C supply air, the space relative humidity will be approximately 10% lower than in a similar 13°C system resulting in improved occupant comfort As condensation on air handling unit coil fins is much greater than standard conditions, more impurities in the air such as dust or dirt are removed providing superior indoor air quality Better air quality and a more comfortable working environment can also mean increased employee productivity





China National Petroleum Corp. (CNPC) Plaza, Beijing 中石油大厦
Lowered building height 1oC ice tank water temperature 2oC chilled water temperature 5.5oC cold air distribution

(24) TSC-678AS, 16272RTH. BAC 3412A, (4)31056A CTI Certified Cooling Towers

Taipei 101, Taiwan One of the World’s Tallest Buildings

(51) Ice Thermal Storage Tanks (30) TSU 17,760 TH Podium Portion (21) TSU 18,690 TH Tower Portion (12) VT1-1335 (7) 15201 Cooling Towers

Taipei 101 Taiwan
74th floor 41.0°F (5°C)

42nd floor 39.2°F (4°C)

7th & 8th floors 37.8°F (3°C)

Zhongguangcun District Cooling, Beijing China 28,560 TH Ice Storage

Supply/Return Water Temperature: 36oF/56oF (2oC/13oC) Leaving/Return Air Temperature: 45.6oF/78.8oF (7.5oC/26oC)
Financial Center (1,100,000 Ft.2) Underground Commercial Space (1,500,000 Ft.2)

Zhongguangcun District Cooling Plant, Beijing China

Chiller Plant

Ice Thermal Storage Tank

Zhongguangcun District Cooling, Beijing China

Ice Tank

Guangzhou University District Cooling Project, China Largest Ice Storage Project in China

253,248 TH Ice Storage

Three District Cooling Plants Serving - 10 University Campuses - 250,000 Students

Plant #2 Plant #3

Plant #4

Lower Pumping and Piping Costs
• % Flow Rate = Delta T Conventional/Delta T Ice Storage = (12°C-7°C)/(12°C-3°C) = 5/9 = 0.55 • The flow rate of the ice storage system is 55% that of the flow rate of the conventional system representing significantly reduced pump and piping costs

Coils Outside Plant #3

Conclusion
• Ice thermal storage is being widely used in China to shift electric demand from peak to off-peak periods. • In addition, ice thermal storage inherently produces very cold chilled water that can be beneficially used to reduce initial system cost, energy cost, and improve energy efficiency.

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