I was thinking of instead of using it like a well just put a sealed tank below the water line so it was always wet on the outside. It seems like it should be able to conduct enough heat through it to keep cool. I could be wrong though
The way the temperatures are here normally if I want to run a/c I normally turn it on at 12-1 and run it till about 5 or 6. There are enough trees around the house to keep it tolerable without a/c and just open windows with fans in them. I haven't turned on the a/c this year actually. Mainly because I haven't been in the house during the day so the fans keep it good enough. I figure 4 20" box fans are probably taking the same amount of power as one box fan and a small water pump but the house would be much cooler with the ground based setup.