11

Adoption ofWater-cooled Air-conditioning Systems

forTerritory-wide Energy Improvement

S K Ho

Chief Engineer

Energy Efficiency Office, EMSD

22

Contents IntroductionWACS SchemesCentralised Piped Supply System for

Cooling TowersDistrict Cooling SystemCentralised Piped Supply System for

Condenser CoolingConclusion

33

Electricity End-uses in 2004 30% of total electricity consumption for air

conditioning.Electricity End-uses Year 2004

Spaceconditioning

30%

Lighting /Refrigeration

23%

Industrialprocess

/Equipment7%

Cooking3%

Hot water3%

Other34%

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Air Conditioning by Sectors 68% of which for air conditioning in non-

domestic buildings.Space conditioning by All Sectors 2004

Commercialsector68%

Industrial sector4%

Residentialsector28%

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Water-cooled AC Systems

EMSD had commissioned several consultancy studies on water-cooled air conditioning systems since 1999, such as Territory-wide Implementation Studies of

Water-cooled Air Conditioning Systems Implementation Study of District Cooling

System for South-East Kowloon Development

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WACS Schemes Centralised Piped Supply for Cooling Towers

City Main

Cooling Tower

Chiller

Building A

Cooling Tower

Building B

Chiller

77

WACS Schemes District Cooling System

Chilled

Chilled

88

WACS Schemes Centralised Piped Supply for Condenser

Cooling

Building B

Building A

Chiller Chille r Sea water Pump House

Seawater supply

Seawater discharge

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Centralised Piped Supply for Cooling TowersA pilot scheme for fresh water cooling

towers was implemented in June 2000.Non-domestic buildings (new or

existing) within designated areas were allowed to use fresh water cooling towers for heat rejection.

79 designated areas in the territory.

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Centralised Piped Supply for Cooling Towers

Covering 71% of total non-domestic floor area in the territory.

Most high cooling load density districts already under the designated areas of the scheme.

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Designated Areas

1212

Centralised Piped Supply for Cooling Towers

Already attracted over 270 applications to date.

Total cooling load of 1200 MW.Total non-domestic floor area of 8M m2.214 applications already obtained

support from EMSD.

1313

Centralised Piped Supply for Cooling Towers79 installations completed (520 MW of

cooling covering 3.5M m2 of area).Energy saving of completed installations

– 70M kWh per year, and a reduction of 49,000 tonnes of CO2.

Water consumption of completed installations – 2.4M m3 per year.

1414

Examples of Completed Installations

A government building in Tsuen Wan

1515

A commercial building in Kowloon Tong

Examples of Completed Installations

1616

A commercial building in Causeway Bay

Examples of Completed Installations

1717

A commercial building in Mong Kok

Examples of Completed Installations

1818

Centralised Piped Supply for Cooling TowersWhen the installations of all applications

are completed, energy saving could reach 185M kWh per year with a reduction of 129,000 tonnes of CO2, and water consumption could amount to 6.2M m3 per year (~0.6% of annual consumption).

1919

Centralised Piped Supply for Cooling Towers

If 50% of non-domestic floor area using fresh water cooling towers for their AC systems, energy saving could reach 1040M kWh per annum with a reduction of 730,000 tonnes of CO2.

2020

District Cooling Systems A central chiller plant provides chilled water to

buildings within its service area. For a building subscribing to district cooling

service, plant room area will be reduced and no need for condensers or cooling towers -> more flexible use of interior space and roof space of the building.

Building owner does not have to care about maintenance of the chiller plant, and no need to care about replacement of chiller plant upon the end of its service life.

2121

District Cooling Systems

For the whole service area, DCS can: reduce energy consumption reduce greenhouse gas emissions and

atmospheric pollutants from power plants create a more pleasant urban environment

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District Cooling Systems

Institutional type DCS DCS serves a group of buildings under same owner Example – university campus; holiday resort; large

commercial complex with office buildings, shopping centres and hotels

Utility type DCS DCS operator sells cooling energy to subscribers Two ways to implement utility type DCS (1) mandatory

subscription within service area (2) voluntary subscription

2323

Kai Tak Development

Outline Zoning Plan presented

in colors

2424

Centralised Piped Supply System for Condenser Cooling

A central seawater pump house located at the seafront supplies seawater to a number of buildings for condenser cooling purpose.

2525

Centralised Piped Supply System for Condenser Cooling

Suitable for areas near to the sea and where there are constraints to the implementation of DCS.

2626

Centralised Piped Supply System for Condenser Cooling

Advantage of central pump house over separate pump houses for individual developments: It is easier to allocate land to a

central seawater pump house than to several pump houses.

The central seawater pump house can be designed to be mostly underground and integrated with the surrounding environment, thus preserving valuable seashore space for public use.

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CPSSCS at Central Reclamation III for Government Buildings

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CPSSCS at Central Reclamation III for Government Buildings

The total chiller plant capacity that could be served by this pumping station is about 20,000 TR.

2929

CPSSCS by Private Developer

A proposal to build a seawater pump house with seven pumps to serve a group of buildings owned by a private developer -> approved by Town Planning Board in August 2006.

Planned total chiller capacity to be served by the pump house ultimately is 15,000 TR.

This seawater pump house will be a showcase of the use of CPSSCC in the private sector.

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Underground seawater pumphouse

Location of buildings to be served by the pumphouse

3131

Pilot Scheme Areas and Potential/Planned DCS/CPSSCC Areas

Pilot Scheme Areas DCSCPSSCC

3232

Energy Saving Potential

Central Piped Supply for Cooling Towers 1040 M kWh per annum, with reduction of 730,000

tonnes of CO2 Potential/Planned Central Piped Supply for C

ondenser Cooling Schemes 145 M kWh per annum, with reduction of 102,000 t

onnes of CO2 Equivalent to about 10% saving of the current

level of electricity consumption of all air-conditioning systems in Hong Kong.

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Conclusions

Success of WACS depends on a

multitude of factors.

Energy saving potential and

environmental benefits of WACS are

significant.

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Thank You