December 2004 Issue No.11

EMSD Heightens Green Efforts
of the Government Flying Service

For almost six years, EMSD's Airport Sector has been helping the Government Flying Service (GFS) in energy conservation.  The GFS has set a good example on how a relatively small government unit can make great strides in protecting the environment.

Since January 1999, the EMSD has been performing energy audits for the GFS, particularly at their headquarters at Chek Lap Kok. As a result of the improvement measures recommended and taken, the energy consumption of the GFS has been significantly reduced since then, as measured in terms of kilowatt-hours and costs. For instance, in 1999-2000, the GFS's energy consumption was 5.43 million kilowatt-hours and the energy bill amounted to $4.27 million. In 2003-04, the consumption was reduced by 21% to 4.28 million kilowatt-hours and the cost also dropped by 23% to $3.29 million as illustrated in Figure 1.

Although the GFS headquarters is a relatively new building which was commissioned in 1998, the EMSD was able to apply the latest technology and identify a number of energy management opportunities (EMOs) for further energy savings. EMOs are categorised into three levels, with Cat 1 needing only good housekeeping measures, Cat 2 requiring minor capital investments, and Cat 3 calling for relatively major capital investments.

The EMSD has helped the GFS to identify and implement a number of EMOs. The following are just a few examples:

(a) Adjusting and monitoring the setting of the air-conditioning system (Cat 1)
According to the actual requirements on temperature and relative humidity in the GFS offices and workshops, adjustments were made and a saving of 5% on the electricity bill (about $16,000 per month) was recorded in August 1999 after the adjustment.

(b) Resetting the programmable lighting control (Cat 1)
The on/off time of the lighting at the car park and corridors in the building was set according to the times of sunrise and sunset as advised by the Hong Kong Observatory. This has led to a saving of around $3,000 a month in energy cost.

(c) Maintaining chiller operation at optimum level  (Cat 1)
There are six chillers at the GFS headquarters. These chillers are divided into two groups supplying chilled water to different parts of the building under two control modes - day mode and night mode. Under the day mode, the two groups of chillers operate independently.  At night, when the heat load is much lower, the chiller operation will be switched to the night mode. The by-pass valve linking the two groups of chillers will be opened so that one group of chiller can provide sufficient chilled water and thus cool air for the whole building.  Because of the above reason and the reduction in demand for air-conditioning at night, only one chiller is required during night mode.

During winter, the chiller system will be operated in night mode round the clock. This has resulted in the reduction of monthly electricity cost of around $20,000 during the winter months.

(d) Replacement of electro-magnetic ballasts by electronic ballasts (Cat 2)
All electro-magnetic ballasts used for the fluorescent lamps at the GFS headquarters were replaced with electronic ballasts in 2001, resulting in a saving of $11,000 per month in electricity cost.

(e) Using CO detectors to control the fresh air units (Cat 3)
With the assistance of the EMSD, the GFS has installed a CO-based Demand Controlled Ventilation (DCV) System at their headquarters. This system modulates outside air ventilation based on real-time occupancy as detected by CO sensors installed inside the rooms.  As the fresh air intake is modulated, the heat gain is reduced. This reduces the loading of chiller and minimises the power consumption of fresh air intake fan.  It is estimated that the system can cut the electricity bill by $161,000 per year.

The EMSD has had a very fruitful experience in working with the GFS. The efforts made have contributed to significant cost savings and, directly and indirectly, to a greener environment.

The GFS is only one example of how EMSD's consultancy service can benefit other government departments and non-government clients. The EMSD is always ready to share its accumulated experience with other parties for the good of our Mother Earth.  If you are interested in how we can help save energy consumption in your organisation, please contact our Business Support Manager Mr. L S Lai at 2808 3804.