Last summer it was so hot and the power went out for a week. I had an idea and it kept me pretty cool until the power came back.

I took two 1 gallon zip top bags and filled them with water. When I got feeling hot I'd lay down with my shirt off and put one of the bags on my chest until the water in it drew enough heat from me to warm up. When that happened I switched bags. By the time the replacement heated up the first one was cool enough to use again.

Just thought I'd share for some reason.