Do a search for "RV evaporative cooler", TurboKool makes one that mounts in the std. 14"x14" vent opening, it is 750 cfm, 12VDC and costs between $500 and $600. There are probably some others as well. Also search for "portable", "personal" and "window" evaporative coolers. They will cost less and have cfm's in the range you want, but mounting them will be more difficult.
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