Originally Posted by hotdog
If you are camping in an arid climate, a swamp cooler (evaporation cooler) works pretty good. It does not cool as well as AC but it can drop the temperature 10-20 degrees. The beauty of a swamp cooler is it only needs a fan and a little water so it is a low power drain.
I grew up in Southern AZ and we had a Swamp-Box on the house and Dad had a 56 Oldsmobile that he had installed a removable swamp-box. He would set it in front of the front seat, where it's legs straddled the floor hump. It plugged into the cig-lighter outlet and we would add a little water once in a while. It was no AC, but it did provide some cooler air
If a person could find one of these old/small units, it might help cool a small trailer, but I wouldn't run out and buy a sweater yet... The humidity has to be very low for these things to do too much... Good idea to investigate though and good luck with it...