Adoption of
Water-cooled Air-conditioning Systems
for
Territory-wide Energy Improvement
S K Ho
Chief Engineer
Energy Efficiency Office, EMSD
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Contents
 Introduction
 WACS
Schemes
 Centralised Piped Supply System for
Cooling Towers
 District Cooling System
 Centralised Piped Supply System for
Condenser Cooling
 Conclusion
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Electricity End-uses in 2004

30% of total electricity consumption for air
conditioning.
Electricity End-uses Year 2004
Space
conditioning
30%
Other
34%
Hot water
3%
Cooking
3%
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Industrial
process
/Equipment
7%
Lighting /
Refrigeration
23%
Air Conditioning by Sectors

68% of which for air conditioning in nondomestic buildings.
Space conditioning by All Sectors 2004
Industrial sector
4%
Residential
sector
28%
Commercial
sector
68%
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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

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Centralised Piped Supply for Cooling Towers
WACS Schemes

District Cooling System
Chilled
Chilled
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WACS Schemes

Centralised Piped Supply for Condenser
Cooling
Building
A
Sea water
Pump House
Chiller
Building
B
Chiller
Seawater supply
Seawater discharge
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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.
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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
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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 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.
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Examples of Completed Installations

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A government building in Tsuen Wan
Examples of Completed Installations

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A commercial building in Kowloon Tong
Examples of Completed Installations

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A commercial building in Causeway Bay
Examples of Completed Installations

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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).
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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



Utility type DCS


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DCS serves a group of buildings under same owner
Example – university campus; holiday resort; large
commercial complex with office buildings, shopping
centres and hotels
DCS operator sells cooling energy to subscribers
Two ways to implement utility type DCS (1) mandatory
subscription within service area (2) voluntary
subscription
Kai Tak Development
Outline Zoning
Plan presented
in colors
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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:


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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
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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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Underground
seawater
pumphouse
Location of
buildings to be
served by the
pumphouse
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Pilot Scheme Areas and
Potential/Planned DCS/CPSSCC Areas
Pilot Scheme Areas
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CPSSCC
DCS
Energy Saving Potential

Central Piped Supply for Cooling Towers


Potential/Planned Central Piped Supply for
Condenser Cooling Schemes


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1040 M kWh per annum, with reduction of 730,000
tonnes of CO2
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 airconditioning 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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Thank You
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