Need suggestions on what is best in geo-thermal A/C - closed loop- - open loop - direct contact -??? In summer its 90 - 95* 80 to 90% humidity and A reguler A/C unit consumes power by the truck load. I have lots of 72* water, water sand starts at 5ft. down to 150ft. 20 to 30 GPM possible. I am thinking open loop heat exchanger unit, any comments would be appreciated.