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Gadgets & Home Improvement

How do evaporative coolers work?

Evaporative coolers are particularly useful for outdoor areas, and dry places
CATS Classified In The Straits Times - March 14, 2011
By: Adele Ong
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How do evaporative coolers work?

Unlike fans, which only circulate the air in a room without lowering its temperature, evaporative coolers such as mist fans can lower the temperature of the space they operate in. They do this through the process of water evaporation.


These coolers fire out a very fine mist-spray into the air. The droplets of water in that spray are so tiny that they evaporate almost instantly. The process of evaporation itself can cool an area, because it uses up heat-energy to transform the water from a liquid state to a gaseous state, thus lowering air temperature. Evaporative coolers generally use less electricity and energy than air-conditioners do.


Many evaporative coolers are suitable for outdoor use. You may find them used at al fresco dining outlets, large outdoor events, and on patios. They are also useful in big semi-enclosed spaces like warehouses where people and machinery need to be kept cool, and where air-conditioning would either be ineffective, or effective only at very high cost.


Some mist fans are intended to be used indoors in homes and offices, and are billed as appliances that can be used anywhere you would use an air-conditioner. However, the evaporative process usually suits drier climates better than humid ones.


In Singapore, where the average humidity level is about 80 per cent, mist fans are mainly used in outdoor or semi-outdoor spaces. Despite the fact that the mist spray is extremely fine and evaporates instantly, it still contributes to the moisture in the air, and most home owners in non air-conditioned rooms usually find that the problems they face stem from too much humidity (eg musty odours, mould and fungal growths on fabrics and food), rather than too little (eg dry skin, throat discomfort, leather cracks).


However, if your home happens to have good ventilation but high temperatures, an indoor evaporative appliance may be more economical for you than an air-conditioner, and may perhaps be used in tandem with a convection fan and dehumidifiers to keep your place, and yourself, cool.


Air-conditioning sense and cents