Evaporative coolers are very effective in the right situation. BUT, be aware they are also a breeding ground for mold can cause respiratory issues if not cleaned and disinfected on a regular basis.

I once installed one in in a greenhouse that was 4 feet tall and 120 feet long. Water was circulated to the pads with a 2hp electric pump drawing water from a 300 gallon stock tank. The pads were in the windward wall of the greenhouse, air was drawn out via 6 large ventilation fans on the opposite end of the structure.