Never ever thought this discussion would end up on this forum.... Wow. I've tried this also, works great! Sort of..... I too had problems with humidity. Cooled well but still sticky. There are so many different factors to cooling its rediculous. I do my own manual j inspection every time we remodel another room (100+ year old farm house) and heating is easy, but cooling is far from. Btus, tons, latent and sensible heat, blah blah blah....
I did learn one useful piece of knowledge though, that every 1 ton of cooling requires a 600 foot slinky coil stretched out I. A trench about 60 feet long if you are going to have a continuously cooling water supply. Otherwise you heat the ground and it takes a long time for dirt to dissipate heat. If you really want to dive in to an amazingly rewarding project, Google "diy heat pump" I've torn into a few window AC units now and use r-290 (propane) as the refrigerant. It's user friendly, legal, and safe with common sense. The entropy cycle is very interesting to study for the technical minded or the extreme diy'er.
I might add, that in order to remove humid you need to be at a temperature lower than the dew point. And have a very efficient coil to cool large amounts of air very quickly, surface area is key. More fins the better. Don't forget you need to have somewhere for that moisture to drain to. A used A-frame coil from central cooling would be a good start.