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Evaporative Air Coolers
By Vondex | 22/03/13 | Solar

How do they work? By the natural evaporation of water that is pumped onto an evaporation pad, normally made from treated paper or wood pulp, this cools the air and is then blown by a fan into the required space/area.  The process is the same as sweat evaporating from the skin which then cools the body, sweat evaporates easier in hot dry conditions than in humid conditions and is the same principal with these coolers.

Where can they be used? Most applications!! Whether inside or outside, doors and windows do not need to be closed as is necessary with air-conditioners.  All areas must be well ventilated to prevent excess humidity build-up, because of this, they are ideal for use in open rooms; tents & bush-camps; housing; offices; restaurants & kitchens; hospitals & clinics; hotels; schools; workshops & garages; agricultural greenhouses & enclosed livestock housing.

How Environmentally friendly are they? Extremely!!!  Because water is the natural coolant used, there is no need of refrigerants or chlorofluorocarbons (which deplete the ozone layer); they use very little electricity so save on fossil fuels and have a small carbon footprint.

Can they be used with Solar power? Yes, because of the very low power requirement they are ideal to operate from solar and especially in Zimbabwe where there is plenty of good quality sunshine.

How cost effective are they? Very, as they use about one eighth of the power of conventional air-conditioners; low capital cost; installation & maintenance costs are reduced as no refrigerants or re-gassing are needed; electricity costs are reduced; repairs are affordable because the fan motor & water pump are relatively inexpensive;

Are there any health benefits? Lots!!! Due to the constant and high volume of air flow the “age of air” in a building is greatly reduced and can be changed up-to 15 times per hour, this reduces “air-conditioner colds”.  The cooling pads of paper pulp and water are very effective filters to keep impurities and pollution out of a building, the increased humidity in hot dry conditions is good for general health and reduces problems of static electricity.

What are the other advantages? They are a viable and affordable alternative to air-conditioners for cooling any area; they are ideally suited to Zimbabwean conditions with high temperatures & relatively low humidity.      
The following table gives approximate cooling effects of evaporative air coolers.


Low Humidity 15% Outside Temp 320C Dew Point 20C Reduced Temp to +/- 160C
High Humidity 50% Outside Temp 320C Dew Point 200C Reduced Temp to +/- 240C


Herald 14th December 2012