A portable air conditioner made with 12 volt fans, a Styrofoam beer cooler, an air vent, and frozen beer, that will work on USB, AC adapter for an electrical outlet, or a 12V car lighter.
I made this portable air conditioner to use at a craft fair that I go to every Saturday to sell my art.
The only power available to me at the fair is either through my laptop, through rechargeable batteries, or through my cars 12 volt lighter and it is hot as Hades, so I hacked this together, since I always have the cooler full of beer with me anyway.
If you aren't a beer drinker, or find yourself in a situation where you can't freeze your beer, you can also use bagged ice.
You will need one Styrofoam beer cooler that you can get at the Dollar General Store for $2.50, an air vent that can be bought at a goodwill or thrift store for $1, three computer cooling fans that can run off USB or an AC adapter that can be bought at Wal*mart for $4 each, and a 12 pack of beer in aluminum cans.
Altogether, this project cost me about 30 bucks in start-up funds, including the beer, or about 35 bucks including beer and ice.
If you are using only ice, your cost will be about 20 bucks.