The IIR has just published a new Informatory Note on Evaporative Cooling prepared by Renato Lazzarin, President of IIR Section E "Air conditioning, heat pumps and energy recovery".
The principle of evaporative cooling is based on the fact that the evaporation of a liquid absorbs significantly more heat than is required to raise its temperature by a few degrees.
Air that is unsaturated with moisture can absorb a certain additional amount of water vapour, in which case the heat contained in the air is absorbed by the vaporisation of the water. This liquid-to-vapour phase change causes the simultaneous cooling of the air and the water that remains in a liquid state.
The main evaporative cooling processes are: direct evaporative cooling, indirect evaporative cooling and a combination of both. The current note describes the applications and conditions under which these processes may offer a technical and economic advantage.
If climatic conditions allow, both indirect and direct evaporative cooling techniques can be used with significant energy savings.
On average, the energy consumption can be four times lower than that of a conventional device with the same cooling power, but it can be ten times lower in a hot and dry climate.
Evaporative cooling can find application not only for air conditioning in homes and workplaces, but also in rearing houses under hot and dry climates and for the short-term storage of products that can be subjected to relatively warm temperatures and would deteriorate rapidly in the event of more severe heat.
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