1. 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

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

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

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

5. 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

6. WACS Schemes
Centralised Piped Supply for Cooling Towers

7. WACS Schemes
District Cooling System
Chilled

8. WACS Schemes
Centralised Piped Supply for Condenser Cooling

9. 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.

10. 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.

11. Designated Areas

12. 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.

13. 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.

14. Examples of Completed Installations
A government building in Tsuen Wan

15. Examples of Completed Installations
A commercial building in Kowloon Tong

16. Examples of Completed Installations
A commercial building in Causeway Bay

17. Examples of Completed Installations
A commercial building in Mong Kok

18. 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).

19. 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.

20. 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.

21. 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

22. 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

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

24. 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.

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

26. 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.

27. CPSSCS at Central Reclamation III for Government Buildings

28. 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.

29. 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.

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

31. Pilot Scheme Areas and Potential/Planned DCS/CPSSCC Areas

32. 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.

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

34. Thank You