[VACList] Re: VACList Digest V3 #263 - Cooling from wind?

[waymark1@xxxxxxxx]

If a trailer (or any object) is sheltered from the sun, and the outside 
temperature is "103 degrees," the higher the wind speed, the faster the 
trailer will be heated to 103 degrees. If the trailer is out in the sun 
and it's heated thereby to higher than the 103 degrees, then the higher 
the wind speed is, the closer to 103 degrees the trailer will get, but 
it will go no lower than 103 degrees.
Wind chill to below the air temperature is effected by evaporation. Our 
skins exude moisture, which evaporates (except in Mississippi in the 
summer - 100+ relative humidity!) and provides a refrigerating effect. 
This is what ammonia, Freon, R134a and other refrigerants do inside a 
cooling unit in the evaporator. Total loss water evaporation coolers 
(desert coolers, swamp coolers) blow air through wetted screens, 
cooling the air and raising the humidity, which is desirable only in a 
very dry climate.
Since your trailer does not perspire, it cannot have the refrigerant 
effect that our skins have from perspiration. 
If you spray water on the trailer it will lower its temperature toward 
the temperature of the water, which here in Oregon is usually about 50 
degrees. If you kept the trailer skin wet enough, evaporation potentially 
could cool the trailer to below the water temperature, but as most of 
the water runs off rather than evaporates from the skin, this is not likely. 
The surface finish of the trailer skin would have to be such that would 
stay wet. A very coarse matte finish might stay wet.
Unfortunately cooling your trailer this way would take a LOT of water, 
which might not be welcomed if the RV park owner pays the water bill. 
Many parks don't even allow you to wash your rig, and charge $1 a day for 
each person over 2 (which keeps us out of many parks as there are 8 of us) 
due to additional water and electricity use.
Al Grayson