Shameless plug-the DH works here PT. But it's an excellent product for those who need evaporative cooling and are off-grid 8-):
http://www.nvo.com/southwestsolar/door/
Small 3-4 person business but they ship to arid regions world-wide. They even sent one to Puerto Rico last week, seems a little humid for evap. but, I've never been there.
Judy
Thanks for the link, Judy. I have a customer doing full solar who may have an interest in this.
We were off-grid for a long time and had one. It worked beautifully as long as the humidity was low, which is the nature of evap cooling. The DH started working there after we found the company in our search for a way to cool our total solar house.
Judy
Leeward sides of the mountains may be very arid indeed--e.g., just inland from Makaha on the North Shore on Oahu, and presumably PR as well.
Even Waikiki may only have 12 or so inches of rain a year.