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 StorageMarket 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)

Mid-peak (US C/Kwh)

Off-peak (US C/Kwh)

Peak vs. Offpeak Rate Differential

Beijing 15.6

8.9 3.7 4.2 : 1

Shanghai 12.4 8.4 2.8 4.4 : 1

Hangzhou 15.8 11.2 6.7/4.6* 3.4 : 1

Guangzhou 12.4 7.8 3.9 3.2 : 1

Shenzhen 13.6 10.2 5.9/2.8* 4.8 : 1

Wuhan 13.4 7.8 4.0 3.4 :1

* Special Rate for TES

Take advantage of low temperature fluids andlarger temperature ranges

minimizing the size of the system components and energy consumption

Additional Benefits of Ice Thermal Storage Technology

Cold Air Distribution Design ReferenceElectric Power Research Institute HVAC&R Center

Benefits of Cold Air Distribution • Economics• Comfort & Indoor Air QualityDesign ConsiderationsFirst Cost and Operating Cost

ComparisonsCase Studies

Design Reference

Benefits of Cold Air Distribution

• Construction Benefits– Mechanical

mov

e 33

% le

ss a

ir

mov

e 50

% le

ss w

ater

13°C (55°F) Air System

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

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13°C (55°F) 13°C (55°F) 8°C (46°F) 5°C (40°F)

Supply Air Temperature

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tem

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gy S

avin

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$000

System Net Cost Annual Energy Savings

Source: Source: Fields, W.G. & D.E. Knebel, 1991, “Cost Effective Thermal Storage,” Heating/Piping/Air Conditioning Magazine, July, pp. 59-72.

State Power Management BuildingBeijing, 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, BeijingIce Thermal Storage Units

(8) 890 THIce Tanks

State Power Management BuildingIce Strategy

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500

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25000 2 4 6 8 10 12 14 16 18 20 22

Base Chiller Ice Build Glycol Chil ler Ice Discharge

USRT

CHILLER(3) 418 RT

ICE STORAGE TANK(8) 890 Ton-hours

Ice Melt Mode

V1 modulateV2 a-c

V1

V2

ab

c

a b

c

Heat Exchanger

Cooling Load

Base Chiller294 RT

20C

30C 120 C

TS-1

3300GPM

10.30C

State Power Management BuildingIce Storage System Diagram

First Cost Comparison

Non storage: 2400 RT, supply air temp = 12.8 CStorage: 1600 RT, 7120 TH ice storage, supply air temp = 7 C

Source: Hydin Engineering Technology Ltd.

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

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) 643,900 CFM• Super-cool Air (7 C) 431,600 CFM• Reduced Air 212,300 CFM• % Reduction of Supply Air 33%• Original Number of AHU 40• Revised Number of AHU 22

State Power Management Building First Cost Comparison

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ConventionalSystem

Ice Storage w/Conventional Air

Ice Storage w/Low Temp Air

Capital Cost ($mil)

State Power Management BuildingEnergy Cost Comparison

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100150200250300350400450

ConventionalSystem

Ice Storage w/Conventional Air

Ice Storage w/Low Temp Air

Energy Cost ($000)

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

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

Lowered building height1oC ice tank water temperature2oC chilled water temperature5.5oC cold air distribution

Taipei 101, TaiwanOne 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

7th & 8th floors37.8°F (3°C)

42nd floor39.2°F (4°C)

74th floor41.0°F (5°C)

Taipei 101Taiwan

Financial Center (1,100,000 Ft.2)

Zhongguangcun District Cooling, Beijing China28,560 TH Ice Storage

Supply/Return Water Temperature: 36oF/56oF (2oC/13oC)Leaving/Return Air Temperature: 45.6oF/78.8oF (7.5oC/26oC)

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, ChinaLargest Ice Storage Project in China

253,248 TH Ice Storage

Plant #4

Plant #3

Plant #2

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

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.

Questions ?