1 1 adoption of water-cooled air-conditioning systems for territory-wide energy improvement s k ho...
TRANSCRIPT
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Adoption ofWater-cooled Air-conditioning Systems
forTerritory-wide Energy Improvement
S K Ho
Chief Engineer
Energy Efficiency Office, EMSD
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Contents IntroductionWACS SchemesCentralised Piped Supply System for
Cooling TowersDistrict Cooling SystemCentralised Piped Supply System for
Condenser CoolingConclusion
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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
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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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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.
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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.
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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).
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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.
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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.
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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
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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.
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Centralised Piped Supply System for Condenser Cooling
Suitable for areas near to the sea and where there are constraints to the implementation of DCS.
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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
The total chiller plant capacity that could be served by this pumping station is about 20,000 TR.
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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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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.