Energy Efficiency Office, EMSD Adoption of Water-cooled Air-conditioning Systems for Territory-wide Energy Improvement S K Ho Chief Engineer Energy Efficiency Office, EMSD

Contents Introduction WACS Schemes Centralised Piped Supply System for Cooling Towers District Cooling System Centralised Piped Supply System for Condenser Cooling Conclusion

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

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

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

WACS Schemes Centralised Piped Supply for Cooling Towers

WACS Schemes District Cooling System Chilled

WACS Schemes Centralised Piped Supply for Condenser Cooling

Centralised Piped Supply for Cooling Towers A 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.

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.

Designated Areas

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.

Centralised Piped Supply for Cooling Towers 79 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.

Examples of Completed Installations A government building in Tsuen Wan

Examples of Completed Installations A commercial building in Kowloon Tong

Examples of Completed Installations A commercial building in Causeway Bay

Examples of Completed Installations A commercial building in Mong Kok

Centralised Piped Supply for Cooling Towers When 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).

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.

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.

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

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

Outline Zoning Plan presented in colors Kai Tak Development Outline Zoning Plan presented in colors

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.

Centralised Piped Supply System for Condenser Cooling Suitable for areas near to the sea and where there are constraints to the implementation of DCS.

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.

CPSSCS at Central Reclamation III for Government Buildings

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.

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.

Underground seawater pumphouse Location of buildings to be served by the pumphouse

Pilot Scheme Areas and Potential/Planned DCS/CPSSCC Areas

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 Condenser Cooling Schemes 145 M kWh per annum, with reduction of 102,000 tonnes of CO2 Equivalent to about 10% saving of the current level of electricity consumption of all air-conditioning systems in Hong Kong.

Conclusions Success of WACS depends on a multitude of factors. Energy saving potential and environmental benefits of WACS are significant.

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