District Cooling

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1. Overview 2.Benefits 3.Experience 4.Unparallel Project 5.Installation

District Cooling with ice thermal storage is the most cost-effective, reliable system approach to cooling offices, hospitals, universities, airports and other multi-building complexes.? These systems are environmentally friendly with lower energy consumption and reduced greenhouse gas emissions.

Baltimore Aircoil Company has extensive global experience in satisfying the cooling and heat rejection equipment need for district cooling systems.

Q：Why Ice Thermal Storage for District Cooling Projects?

A：Because only ice, on a simple and practical basis, can provide a constant 34°F (1°C) supply fluid temperature that yields:

1. Lowest first cost system that does not require utility incentives

2. Reduced energy costs by providing flexibility in when energy is used and reducing the total system kWh usage

3. Reduced maintenance by using smaller equipment with flexibility in service schedules

4. Improved system reliability ensuring constant cooling

5. Space savings with reduced equipment room and heat rejection requirements

6. Environmentally friendly systems with reduced energy consumption and global warming

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Lowest First Cost

An ice storage system that takes advantage of low temperature fluid is the lowest first cost design. Substantial savings in the chilled water distribution system are realized when the system design incorporates reduced flow rates that result from using a larger temperature range in the water loop. Use of a 20°F (11°C) temperature range instead of a conventional 10°F (5.6°C) to 14°F (7.8°C) temperature range results in a substantial reduction in pipe size. Smaller distribution piping can often be installed via trenching versures tunneling, allowing the piping to be installed with less time and expense.

The savings that result from the use of smaller distribution piping offset the cost of the thermal storage equipment. A 16,000 ton (5,632 Mw) district cooling plant designed with centrifugal chillers using 44°F (7°C) supply water and one with ice storage using 34°F (1°C) supply water were compared. The conventional plant required 30in (762 mm) diameter distribution piping ($7,680,000 installed) versus 18in (457 mm) for the ice storage system ($5,340,000 installed) that yielded savings of $2,340,000.

Cost	44°F (7°C) Supply Water System	34°F (1°C) Supply Water System
Chiller Equipment	2,960,000	2,865,000
Cooling Towers $ Evaporative Condensers	623,725	588,838
Pumping Equipment	551,905	402,106
Thermal Storage Equipment	N/A	2,957,920
Equipment Rigging	206,781	289,666
Mechanical Piping	2,560,000	2,711,200
Mechanical Insulation	844,800	894,696
Refrigerant	224,800	73,132
Refrigerant	224,800	73,132
Plant Ventilation	16,733	99,934
Automation System	993,218	1,805,987
Electrical Equipment	2,475,742	1,835,634
Building Cost	3,960,000	2,645,775
Sales Tax (Equipment & Material)	600,138	624,536
CONSTRUCTION COSTS	16,017,042	624,536
Project Management $ Engineering	1,927,113	2,053,249
Project Contingency	897,208	995,401
TOTAL PLANT COST	16,017,042	624,536
Street Distribution Piping Cost Estimate
6,000 Linear Feet: Trenching & Restoration	5,820,000	3,960,000
12,000 Linear Feet of Supply and Return Piping	1,860,000	1,380,000
TOTAL STREET PIPING COST	7,680,000	5,340,000
Total Building Connections Cost Estimate
Heat Exchangers	960,000	422,400
Stations	560,000	480,00
Piping, Erection & Insulation	2,960,000	1,977,600
TOTAL BUILDING CONNECTION COST	4,480,000	2,880,000
16,000 TON COOLING SYSTEM TOTAL	31,001,363	28,303,324

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Reduced Energy Cost

With smaller mechanical equipment, ice thermal storage can lower electrical demand charges up to 50%. In addition, total annual energy consumption is less because of the lower pumping horsepower (kW). As the electric industry continues to deregulate, and time-of-use rates, real time pricing schedules and negotiated power prices become standard, ice storage can provide even greater future savings in operating costs.

In a comparison of a 16,000 ton (5,632 MW) district cooling plant designed with centrifugal chillers using 44°F (6.7°C) supply water and one with ice storage using 34°F (1°C) supply water, the peak demand was 15,985 kW for the conventional plant and 10,135 kW for the ice plant, a 37% reduction in peak demand.

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Reduced Maintenance

The ice storage coils have no moving parts so very little maintenance is required. The only ice thermal storage maintenance required includes the air pump, system fluid and controls. Because the chillers, pumps and heat rejection equipment are smaller, the ice storage system will have less maintenance than a conventional system.

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Improved System Reliability

	Ice Storage systems provide the reliability necessary to ensure air-conditioning is available. With conventional systems, installing multiple chillers provides redundancy. In the event of a mechanical failure of one chiller, the second chiller provides limited cooling capacity. The maximum available cooling for the conventional system would only be 50% on a design day.

Most ice storage systems utilize two chillers in addition to the ice storage equipment. Two chillers are designed to provide approximately 60% of the required cooling on a design day while the ice storage provides the remaining 40% of the cooling capacity. In the event only one chiller is available to provide cooling during the day, up to 70% of the cooling capacity is available. The one operable chiller provides 30% of the cooling requirement while the ice provides up to 40%. Base on typical HVAC load profiles and ASHRAE weather data, 70% of the cooling capacity would meet the total daily cooling requirements 85% of the time.

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Space Savings

Ice Thermal Storage saves equipment room and heat rejection space since smaller chillers, pumps and heat rejection equipment is required. A district cooling plant with ice thermal storage requires two-thirds of the chiller and heat rejection capacity of a conventional system. The chilled water pumps will be half the size of a typical 10°F (5.6°C) temperature differential system, and the condenser water pumps will be two-thirds the size of a conventional system. The plan area required for the equipment room and heat rejection equipment can be cut by one-third. The thermal storage can be located outdoors, in a sub-basement or under a parking lot, it does not have to be part of the equipment room. Chilled water storage requires 4 to 10 times the space of ice thermal storage. The use of sensible cooling combined with storage inefficiencies make chilled water storage tanks larger.

傳統系統的設備室

Environmentally Friendly

Reducing energy consumption and using electricity at night will reduce global warming. District cooling, using new energy efficient water-cooled chillers and ice storage, will significantly reduce energy consumption. Electricity generated at night generally has a lower heat rate (lower fuel use per power output), and therefore, lower carbon dioxide and greenhouse gas emissions resulting in less global warming.The California Energy Commission concluded that the use of electricity at night created a 31% reduction in air emissions over the use of electricity during the day. The use of an environmentally friendly and energy efficiency ammonia refrigerant, can be considered for may district cooling systems.

Q：Why Ice Thermal Storage for Air Conditioning Projects??

A：BAC provides Proven Technology, as a result of :

BAC has been involved in the design and manufacture of ice thermal storage for over 25 years.

Over 3000 ice thermal storage installations worldwide, with more than one million ton-hours (3,530 MWh) dedicated for district cooling.

Dedication to research and development in BAC’s 25,000 square foot (2,323 square meter) test facility, designed and built exclusively for the testing and development of heat transfer and thermal storage equipment.

Twelve patents on ice thermal storage products.?The BAC product offering provides system flexibility.

- Above Grade Concrete Tanks

- Above Grade Cylindrical Steel Tanks

- Below Grade Concrete Tanks

Proven Technology

BAC has successfully applied ice thermal storage technology to more than 2,600 installations worldwide. These include more than one million ton-hours (3,530 MWh) of district cooling capacity. BAC has the application and system experience to assist you in the design, installation and operation of your ice storage system.
The BAC product offering provides system design flexibility. Ice can be built using various refrigerants or glycols on steel coils and is used to provide either chilled water or glycol to the cooling system. This flexibility, combined with a broad range of application experiences, allows BAC to provide a cost-effective product to meet your specific requirements.

1. Exelon Thermal Technologies Plants
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Multiple integrated facilities provide a combined total of 314,400 ton-hours (1,110 MWh) of ice storage used to serve the offices and hotels of downtown Chicago. The ice is used to provide 34°F (1°C) water to the district cooling loop and to allow the chillers to be shut off when power is scarce in Chicago.

2. Baltimore Convention center

A total of 89,655 ton-hours (317 MWh) installed in multiple separate tanks provides cooling for Baltimore’s downtown offices, sports stadiums and tourist attractions.

3. Cosmo Square

A highly efficient district cooling plant that provides cooling to several buildings including the World Trade Center and Asia Trade Center in Osaka, Japan. A total of 29,300 ton-hours (103 MWh) is installed in the underground mechanical room.

4. Software Park

The ice thermal storage equipment provides 22782RTH for Taiwan Taibei company.

5. Public Service of Colorado

The ice thermal storage equipment provides 75000RTH for Denver center office building.

6. Stanford University

An existing chilled water storage tank was retrofitted with 93,200 ton-hours (329 MWh) of ice thermal storage. System storage capacity was increased and chilled water supply temperature lowered to increase plant output.

7. Johns Hopkins University

The central plant has 22,400 ton-hours (79 MWh) of ice thermal storage to cool the main campus. Ice thermal storage was added in two phases to increase the capacity of the existing chilled water plant. The addition of new campus buildings and the increased cooling requirements of the existing buildings made the expansion necessary.

8. Shanghai Caohejing District Cooling

The ice thermal storage equipment provides 16590RTH, The total area of about 230000 square meters, total construction scale of about 800000 square meters, including underground building about 200000 square meters, construction area of about 600000 square meters on the ground. Planning has a five-star hotels, large comprehensive shopping malls, corporate headquarters office, and other functions.

9. Beijing Zhongguancun District Cooling

The ice thermal storage equipment provides28560RTH, a total construction area is 600000 square meters. To provide chilled water for nearby mansions, users do not need to set up separate refrigeration station, saving a large amount of architectural space, is the world's most advanced one of the ice storage system.

10. Shanghai Huawei

The ice thermal storage equipment provides19200RTH, the project construction area is about 310000 square meters, 30m tall buildings, three floors underground and five up. It consists with office, data center, research and development laboratory, restaurant.

11. Guangzhou University District Cooling

The ice thermal storage equipment provides 253248RTH, Guangzhou university city construction area of 7.24 million square meters, is Chinese largest ice storage cold district cooling system. According to the measure, through the ice storage cold district cooling, it can save 130 million yuan, and save room for land area of 55000 square meters, reduce the installed load is 52000 kw, reduce transmission facilities investment about 170 million yuan; Every year to reduce air-conditioning maintenance costs 20 million yuan of above; System operating costs than the monomer building central air conditioning by 28%.

12. Guangzhou Zhujiang New Town

The ice thermal storage equipment provides 80000RTH, Is located in west China, Guangzhou Tianhe. East from rapid trunk line, west to Guangzhou avenue, the pearl river in the south, and Huangpu road in the north. It covers an area of 6.44 million square meters, which runs through Guangzhou new urban central axis. Existing opera house, sea heart sand, red post landmark tower, library, etc.

Above Grade Concrete Tanks
The following section shows the flexibility in locating the thermal storage equipment. Examples include above grade concrete storage tanks at the Tampa Electric Company (TECO) Miami Plant, below grade tanks at Baltimore Comfort Link? Camden Yards District Cooling Plant and above grade round steel tanks at the Baltimore Comfort Link? District Plant II. Ice thermal storage equipment can be located below parking facilities, gardens, and driveways, in basements, on grade near the chiller plant or in the chiller plant.

1. Empty concrete tank with liner

2. Rigging first ice coil
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3. Placement of the first two-coil module

4. Final placement of the first pair of two-coil modules
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5. All coils in place in the tank. The coils are arranged four-coils high by two-coil modules wide by four-coils long.

6. Tank with glycol supply and return piping above coils

7.?Outdoor tank complete with concrete covers.Typical arrangement of glycol chillers in plant adjacent to the tank.

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Above Grade Cylindrical Steel Tanks

Above grade round steel tanks at the Baltimore Comfort Link? District Plant II
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Aerial view of Baltimore’s Comfort Link? District Cooling Plant II. The concrete building with cooling towers on the roof, houses the chiller plant. Behind the chiller plant are two round steel ice thermal storage tanks.

Steel tanks located behind the cooling towers out of sight
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Welded steel tank ready for ice thermal storage coils. No liner was required.

Final thermal storage coil being rigged into place

Ice coil pattern inside steel tank

Competed ice tanks


Below Grade Concrete Tanks

Overview of Baltimore’s Comfort Link? Camden Yard’s below grade concrete tank. The chiller plant and an additional ice thermal storage tank (located in the basement) is in the Convention Center across the street. Today a parking lot is located above the tank.

Excavation of the tank

Pouring concrete slabs

Glycol supply and return piping to chiller plant in the Convention Center across the street. The piping is located under a busy downtown street.

Field erected chillers in the Comfort Link? Chiller Plant located in the Convention Center
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Ice Thermal Storage Tank roof poured in place

The roof of the tank is insulated

Access opening for rigging the coils in place

View from inside the tank

Installation of coils into tank through the access opening

Installation of coils into tank through the access opening

Ice Thermal Storage Coils in their final location in the tank

Completed ice tank with parking lot above. Below the dark paving on the street is the piping to and from the Convention Center chiller plant. The tank is accessible through bulkhead door (circled in photo) located adjacent to parking lot.