Hong Kong property company takes long-term approach to reducing energy consumption

CIBSE Awards
A continuous programme of improvements for over 10 years has reduced the energy consumption of Festival Walk in Hong Kong by 30%.

Swire Properties Management (SPL) is no newcomer to working towards reducing energy use and carbon impact. Virtually ever since Festival Walk in Hong Kong was built in 1998, the company has been working on improving its energy performance. A reduction of 4115 MWh in 2008/9 alone followed 10 years of consistent and steady improvement, winning the award for client of the year — low-carbon operation.

When it was opened in November 1998, Festival Walk was the biggest shopping mall in Hong Kong, with 200 shops, 27 restaurants, an 11-screen cinema, 20 000 m2 of office space and an indoor skating rink. Since 2000, annual energy consumption has been reduced from 41 to 29 GWh, or almost 30%.

One of the early improvements was to replace the air-cooled condensers of the 22 MW-cooling chiller plant with cooling towers when the government started to permit the use of potable water for heat rejection. That conversion was completed in 2003 and achieved a reduction of 4.8 GWh a year.

That initiative was followed by the development of a control logic to solve the common problem of the mismatch between cooling demand and chilled-water flow. The new control logic enables the chiller to run at a higher average part load, with much less mixing of return and supply water. This small investment reduced annual energy consumption by 400 MWh a year.

Since April 2008, SPL has worked with Tsinghua University to analyse operating data from the BMS and actual site measurements to identify faults and opportunities for improvement.

During the first year, the cooling load of equipment was redistributed, cooling valves were recommissioned, operating parameters such as pressure, temperature and control logics were reset, redundant equipment was switched off, and faults identified were diagnosed and rectified. The outcome was a saving of 2 GWh a year.

The subsequent replacement of four of the six chillers in June 2009 with more efficient units is saving 3.8 GWh a year.

Recent work with tenants to encourage them to help save energy could have considerable relevance to the UK CRC Energy Efficiency Scheme. The electricity consumption of tenants accounts for about 40% of consumption, and also affects the energy use of chillers. Since 2008, SPL has carried out free energy audits for tenants. By September 2009, 149 MWh of potential savings had been identified, of which 134 MWh has been achieved by tenants adopting recommendations.

SPL is also supplying tenants, at its own cost, new T5 lighting fitting to replace existing T8 lamps. By September 2009, about 2800 fittings had been replaced, reducing tenants’ electricity consumption by 250 MWh a year.

The work continues, and SPL plans to complete energy audits for office tenants within three years from 2010. Energy advice is also to be given to new tenants as they move in.

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