GuitarPhotog wrote:If you have 120VAC to run a fan, you might as well run an air conditioner. At least they work in high humidity regions to.
1. Can work with a DC fan too
2. Fan uses on the order of 1/100th the power of an AC unit.
The idea of using ice blocks is not quite there when you are camping. You would need a lot of gallons of ice block to get you through a 100 degree night.
This is pretty close to a swamp cooler. Needs something to circulate water and media for surface area to evaporate for cooling.
In a simple one they use a bladed barrel with slow revolution in a pool of water with a fan blowing over. The barrel gets wet and provides surface area, the fan evaporates the water and blows cool air at you. That is considered a low density media and you can get a 10 to 15 deg. Temperature drop from about 100 down to 85 deg at best. With a standard commercially available high density media, you can get 20 to 25 deg. temp drop from 100 down to 75. All this assumes very low humidity in the 3-7% range found in the desert southwest. All those numbers go to crap in high humidity environments.
Keep in mind with swamp cooling your insulation doesn't do you much good because you need 100% makeup air from the outside. If you don't have makeup air the added humidity of recirculating kills the cooling potential pretty quick.
With all that said, I am in line for an AC unit and small propane powered generator.