A central cooling system provides cooling for air-conditioning systems in common areas and/or a number of dwellings. A cooling tower is a device for lowering the temperature of water by evaporative cooling in which atmospheric air is in contact with falling water, thereby exchanging heat. Cooling towers consume water through evaporation, bleed, drift, splash and overflow.
There are a number of technical and design strategies that will reduce potable water consumption in cooling towers.
BASIX recognises the following measures:
- Private water metering
- Conductivity controllers
- Using alternative water sources for make-up water
Private water metering
By installing a water meter on the make up line and connecting this meter to a building management system, water loss in your cooling tower or evaporative cooling system using can be monitored and abnormalities in water consumption can easily be detected, minimising water loss through bleed, drift, splash and overflow.
A conductivity controller is used to manage the concentration of dissolved solids through the automatic control of water bleed to ensure minimum water loss and maximum water efficiency in a cooling tower or evaporative cooling system.
The make-up water may be supplied from alternative water sources such as rainwater, stormwater and suitably treated recycled water. Recycled water use in NSW is regulated by the NSW Department of Environment and Conservation and by NSW Health. You will need to obtain permission from NSW Health prior to use in cooling towers. The suitability of recycled water as condenser water make up will be dependant upon the recycled water quality.
More information on the water consumption of cooling towers is available in the Sydney Water publication "Water conservation: Best practice guidelines for cooling towers in commercial buildings".