Reply #7: A swamp cooler cools air by evaporation [View All]

A swamp cooler cools air by evaporation

http://www.wonderquest.com/swamp-coolers.htm

Q: What the heck is a swamp cooler and how does it work -Jack W., Washington D.C.

A: A swamp cooler (more formally called an evaporative cooler) is essentially a large box-like frame
containing a big fan and walled in by water-wetted pads, usually made of cedar shavings or cellulose.
The fan whooshes the hot outside air through the dripping pads (which are continually soaked by a
water pump), cooling the air by about 20 ºF as the air evaporates water molecules from the pads.
The fan then blows the water-cooled air through the house and out a deliberate vent.

Wet the back of your hand -- then blow on it. Your skin surface feels cooler.

That's evaporative cooling.

Folks differ on why it's called a swamp cooler. Some say because it makes the house feel
like a muggy swamp-but that's only when the late summer rains come and the cooler is less
efficient. On dry days-which is almost every day in a desert-a swamp cooler works fine.
In high humidity areas, like Washington D.C., they don't work at all because the water
does not evaporate appreciably and thus the air is not cooled.

Swamp coolers are popular in the southwest because they are relatively inexpensive, use a
quarter as much electricity as a refrigerated unit, are easy to maintain by the average
do-it-yourselfer, and add a comfortable level of humidity to the dry desert air.
The smell of fresh cedar pads on the first hot days of summer is delightful.



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A must have in the desert! They work great!