Question

how does the desert cooler work??

please explain it breifly

Answer 1

Firstly, Heat transfer not only depends on temperature gradient but also on humidity content in the air. For example, in rainy season or in coastal areas though the temperature of the surrounding is less, but we still feel hot because humidity is more. Higher humidity at a given temperature leads to difficulty in heat transfer.

Secondly, for a water droplet to evaporate it absorbs energy that is Latent heat , the amount of heat that is needed to evaporate the liquid, is drawn from it's surroundings thus cooling the surroundings! A phenomenon that happens in porous earthern pots that leads to the water inside to be cooler!

Keeping the above in mind, desert coolers employ the processes of cooling+humidification( increase humidity) unlike coolers used in normal regions which apply cooling+dehumification(decrease humidity).

In deserts(dry climate), humidity is very less and temperature gradient more thus high rate of heat transfer, thus making us hot!! Apart from cooling surrounding air,water droplets are added to this air to reduce the rate of heat transfer,temperature gradient.

In normal regions, humidity is reduced in summers to aid heat transfer in the given temperature gradient, due to evaporation that is sweating in our case.

*Hope this helps

Answer 2

Explanation:

Desert coolers are based on the simple principle that when unsaturated air comes in contact with water, the water evaporates. In the process, the moisture content of air increases, while its temperature decreases. The resulting cold but moist air is used for providing cooling. Thus a desert cooler is a simple device, which consists of an arrangement for blowing dry and hot air over a wet surface and an arrangement for keeping the surface wet continuously. The cooler normally consists of a blower and a pump. Desert coolers are economical (both initial and running costs are low) and are effective in hot and dry areas. They are not effective in humid areas.