i'm using a portable aircon in one of the rooms at the moment, the side the sun hits when it comes up... i've just got the exhaust ducting tied in after the carbon filter, and it puts cold air into the room the cube is in, then the cold air in the room gets sucked into the cube and goes from there...
its not an evaporative cooler, doesnt need water, it does drip into a tray that needs empying every 8-12 hours odd if its on maximum, but i'm going to setup an overflow for the little removable tray so it won't bother me again..
ive used it for some freakishly hot days, but generally i leave it on 19 degrees during lights off, ive found i've got noticeably denser & more crystal covered buds this way.. (although its not an issue in winter), its the peak of summer here at the moment though
hope this helps, regards