A simple styrofoam cooler, one or two dryer elbows. cut two holes left and right top of cooler for elbows. Get a small fan, cut a hole in top middle of cooler, place fan face down. Simply fill cooler with plastic bottles of frozen water, cover with the lid and turn on the fan. The fan air blows through the frozen bottles, cooling the air blowing out the dryer elbows. Rotate waves of frozen bottles, so when one thaws out, grab the next batch of bottles and so on. This DIY cooler, works remarkably well in a small to mid bedroom making sleeping at night much more tolerable. If you build one, let me know how it worked for you.