# Evaporative cooling in a tropical environment

I am an architect and am trying to understand the effects of evaporative cooling in a humid climate for buildings. I would like to use the example of a zeer pot for my question. I have read everywhere that evaporative cooling is not possible in a humid climate simply because humid ambient air is already approaching 100% saturation. Obviously when saturated air cannot take any more moisture - evaporation does not take place. I get that. However if humid air is heated then the saturation decreases quite a lot. For instance I remember looking at a chart that shows if air temperature is doubled then its ability to hold moisture increases about ten fold. In a tropical climate there is a lot of sun and heating air is easy. If air were heated to increase its moisture holding capacity and then passed over an extremely porous, moist surface will cooling take place or will the whole system gain heat? If a zeer pot for instance were placed inside a simple black metal chimney in the sun, open on the bottom and top, where humid air is heated and the heated air rises and passes over the pot will the pot cool or will it gain heat? Is there a formula (something I can understand) I can use to calculate heat gain and loss in this example? Roughly speaking is the concept of evaporative cooling possible in a humid climate if the humid air is heated?

• The effect of evaporative cooling in a humid environment is best summed up as "Not very #@~&#^"% much!". Lived with one of those things in New Mexico for a few years. It did a sweet and inexpensive job most of the time, but on the few even moderately humid days we did get It wasn't worth a thing. Commented Jul 13, 2014 at 21:28
• somewhat related physics.stackexchange.com/questions/114869/… Commented Jul 13, 2014 at 22:06