Evaporative Cooling - Comfort

The comfort of a person is mainly dependent upon the following factors:

An evaporative cooler decreases temperature and increases air flow but increases humidity. The effect of the temperature reduction far outweigh the increase in humidity. Any additional air flow further improves the comfort level.

It can be seen from the diagram below how the apparent conditions of the air changes by passing through an evaporative cooler.  If the air in a building is at 35°C and 35% relative humidity the conditions are quite extreme. However if we introduce evaporative cooling the air leaving the cooler would be 24 °C and 91% humidity. This means that the comfort level moves clearly into the more comfortable zone.

Category	Apparent Temperature	Dangers
Danger	40 - 54C	Heat exhaustion likely
Extreme caution	32 - 40C	Heat cramps, exhaustion possible
Caution	26 - 32 C	Exercise more fatiguing than usual
OK	< 26C

The evaporative cooler changes the hot conditions typically found in UK buildings and changes it from an ‘Extreme Caution’ level to a ‘OK’ situation.

The above is based on a study performed by J G Steadman