I Mechanism of action of cooling from fans with misters

[jsurow]

II'm trying to figure how adding misters to a fan, sprayed or nebulized water into the stream of air, yields increased cooling. Is it due to a non evaporative mechanism, perhaps better heat transport away from the person through humidified air versus dry air?
It seems to me that the minimal to know evaporation of the water at normal ambient temperatures would not be enough to cool the air directly. I'm also guessing that the amount of water deposited on the skin of a person in the mist is not enough

 

[hutchphd]

If the mist is injected perfectly one should be able to lower the temperature of the airstream to produce 100% rel humidity air at the dew point temperature. This is the principle of the "swamp cooler " In practice the comfort level thereby produced varies greatly I believe....I have never used one.

 

[russ_watters]

It seems to me that the minimal to know evaporation of the water at normal ambient temperatures would not be enough to cool the air directly.

Evaporation of water into the air does, in fact, cool the air directly.

I'm also guessing that the amount of water deposited on the skin of a person in the mist is not enough

Mist deposited on the skin will work exactly like sweat and cool the person as it evaporates.

If the mist is injected perfectly one should be able to lower the temperature of the airstream to produce 100% rel humidity air at the dew point temperature. This is the principle of the "swamp cooler " In practice the comfort level thereby produced varies greatly I believe....I have never used one.

General principle yes, but you wouldn't typically want to take it all the way to 100% RH. While cooling the air improves comfort increasing humidity reduces comfort. So it's best to use this type of cooling where you have dry air to begin with and don't end up with saturated air*. Or if you're outside and have no alternative.

[edit]
*Like the desert. They also make indirect evaporative coolers, which spray the water into an airstream that is separated from the room air by a heat exchanger, so the moisture doesn't come with it.