A friend of my dad took one of those and replaced the side panel with some old car/truck radiators that he had laying around and then routed his irrigation water through the radiators on the way to the fields and my dad said that it kept his house as cold as a meat locker.

Here where I live we get the humid sea breeze from the gulf for 6 months out of the year so swamp coolers don't work very good - wish they did.