• Inverters have been fitted to the majority of Air Handling Units (AHU). The inverters reduce full power from 100% to 80% giving an immediate energy saving of 20%. They also reduce the electrical frequency, thereby halving the fan speed of the AHUs so they utilise less energy.

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Inverters fitted to Air Handling Units

• Swimming pool covers are now fitted every evening. This reduces heat loss from the pools and reduces the humidity within the pool area. Therefore the temperature of the pools can be lowered (slightly) and heating and extraction within the pool area can be reduced.
• A review of the Building Energy Management System (BEMS) was undertaken. The BEMS is a computer system that operates and controls the energy use time schedules for most of the areas within the leisure centre, ensuring the correct air temperatures and ventilation. This is an important area to review frequently, particularly if the use of the building or areas within it have changed. The review highlighted an area for major potential energy savings. Prior to the review, all of the air supplied to the leisure centre was fed in directly from outside and then had to be heated or cooled to the appropriate temperature as it supplied the rooms. The room extracts were then disposed of externally. The BEMS was reprogrammed to re-circulate useful air, thus preventing the loss of heated air.
• An after-hours survey was carried out in March 2006 to see what equipment was running and to experiment with different equipment and lighting options to identify what could be shut down.
• Lighting controls were fitted in areas where lights are constantly left on when there is limited occupancy, for example squash courts.
• The main hall lights are now switched off when not in use.
• Internal staff training was undertaken to ensure staff are aware of the issues surrounding the energy problem (costs and environmental).

_ Possible measures for the future

The Council is currently considering several further energy saving measures, particularly in terms of after-hours energy use. Some of these ideas were outcomes from a second after-hours survey conducted in September 2006.

_ The following ideas are currently under consideration :

• Further lighting controls including time controls, dimmers and daylight sensors ; replacement of some lights due to their age, cost of maintenance and energy consumption ; and removal of paint from roof lights to allow day lighting instead of 100% artificial lighting.
• Heat recovery within the swimming pool to conserve and re-use heated air. A partition may be erected between the concourse and the swimming pool. This would prevent heat loss from the pool air (which averages 31°C) to the concourse, which should have a lower air temperature (around 22°C).
• Programming of pool extraction fans so they are controlled via temperature and humidity, rather than running continuously.
• Using controls for air-conditioning and heat pumps.
• Using timers to turn off dispensing machines (e.g. drinks, sandwiches etc.) and electronic equipment (e.g. TVs, advertising boards) after hours.
• Managing and coordinating cleaning staff to reduce after-hours energy consumption. The September 2006 survey highlighted the fact that cleaning staff greatly affect after-hours energy consumption, particularly in the way they work and move from area to area. For example, currently all areas remain lit until they have been cleaned. Cleaning staff work alone ; this takes more time and means that more lights and equipment are in use at one time. Energy consumption could be reduced if staff work together to clean the main areas. Significant savings could also be made if cleaning staff start earlier and clean areas which are finished operating first, allowing these rooms to be closed and locked.
• Using renewable energy, such as solar thermal heating (for the pool), solar photovoltaic panels and CHP, to reduce carbon emissions.

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