If air conditioner efficiency improves when it rains outside, why don't all air conditioners include water sprayers to help cool them?

submitted by magnora7 from (self.science)

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[–]magnora7[S] 1 insightful - 1 fun1 insightful - 0 fun2 insightful - 1 fun -  (1 child)

So I looked it up, it takes 2.45 Wh to raise the temperature of one gallon by one degree F. So if the water goes from 80F to 120F, that's 98 Wh. That's remarkably close to the 100 Wh break-even.

So if you had access to cheap water, or had expensive electricity, this might actually save money and use less energy overall. Or if the water delta is more than 40 degrees, that'd made it cost effective too.

[–]Tom_Bombadil 2 insightful - 1 fun2 insightful - 0 fun3 insightful - 1 fun -  (0 children)

It's way better than that.

That method is for heating water. Evaporation draws many times more heat energy away. Many.

The transition from liquid to gas is 540x the energy to raise the same mass 1 deg C.

You get the best results from evaporation. Your body cools when sweat evaporates. If it doesn't evaporate then you're hot and miserable.

Fans don't cool, but increase the rate of thermal transfer (increased air mass in physical contact per unit time), which also increases the evaporation rate. Moving air can also hold more moisture (from memory, needs verification).