Evaporative Cooling - the old fashioned way to stay cool
You might not think that evaporative cooling is a personal technology, but that's how it originally was used. Imagine all those westerns you've seen with the cowboys in full length underwear, usually colored red. It was a way to stay warm, and it was a way to stay cool.
In the heat of the summer, it wasn't uncommon for folks to wear their red long johns to bed, but soak them in water just before retiring. Water evaporates at just about any temperature, and it requires energy for evaporation.
The energy required comes from your body, so while the long johns dried out, they were cooling you as well. That's evaporative cooling.
Try it yourself. Hose down some work pants on a hot summer day and see if they don't keep you plenty cool outside while you attend to tasks in the hot sun. It's even better if there is a breeze to go with it.
That's how your sweat keeps you cool. It evaporates in the air and removes heat from your body. If you don't sweat, you don't cool yourself, and that can kill you.
When "the Dude" overheats, I pop him in a warm shower for a minute or so and then let him air dry. It cools him down (without shocking him), and he stops panting like a maniac.
When I work on my drip irrigation system, I don't mind leaving the water on while I fix the damage caused by critters over the winter. Whether the water sprays on me or I simply kneel in a puddle, that moisture stays with me for hours and keeps me cool as I work.
If you want super evaporative cooling on a personal scale, get your long johns on, hop in the shower for a minute or so, then head off to bed. Place a fan so it circulates or blows air across the bed. You'll get down right chilled from that kind of activity.
I don't care how warm and uncomfortable you are, it you go to bed wet, you'll be cool in no time at all. I can't say this approach is the best for your bed or bedding, but it cures the heat in a hurry.
Done with Evaporative Cooling, back to Ways to Save Energy