jmd445 said:
a swamp cooler adds moisture to the air to cool the space . . .
Actually, it's not "adding moisture" that cools the air, it's allowing the water to evaporate as the air passes through it that absorbs heat, just like perspiration evaporating on your skin. The reason high humidity feels hotter is that perspiration evaporation slows down as the air nears saturation, aka increasing in relative humidity.
Relative humidity is the percentage of water in the air compared to the amout that would be 100% at a given temperature. The same absolute humidity varies in relative humidity as the temperature varies. The dew point is the temperature at which a given absolute humidity would become 100% relative humidity.
Over 40 years ago, my dad owned a laundromat that had an evaporative cooling tower on the roof. It was a wood structure around 3' square and maybe 6' tall, with a solid roof and a downdraft fan, similar to a whole-house fan.
It had a water feed with a float ball and valve similar to a toilet inlet valve, a water pan around the bottom, and a small pump like a condensate lift pump. The four walls were louvered and stuffed with a straw-hay-like material.
The pump drew water from the pan and dripped it at the top of the hay, where it kept the straw damp as air passed through it, cooling the air quite effectively, and the float and valve kept the water level in the pan consistent.
He always had trouble with the valve, and when I went onto the roof with him to look at it, I suggested replacing the valve with a float switch and a solenoid valve. We went to Grainger's and bought the parts and put it together.
He never had a problem with it after that. I was maybe 13 or 14 at the time. He's called me his little genius ever since. :smile:
