Ok, here's the deal. I work for an orchid grower in Georgia. Our biggest customer is Whole Foods Markets which is very big on green energy. For instance, last year I installed solar assisted radiant heating in one of the greenhouses and it's doing just great. Now it's time to think about cooling(the plants need cool nights to produce flowers) and the owner is ready to move. What we are using for cooling is evaporative coolers but the problem is the water reservoirs get hotter than we'd like and that reduces the effectiveness significantly since the outside humidity levels increase along with the Summer heat. Looking for a steady 20 degree drop in this 600 gallon in-ground tank. What I was thinking, as he's on city water, is a cold water circulation system using a heat exchanger such as this one. 30-plate Brazed Heat Exchanger (1" MNPT) There's approximately 1000 ft between the greenhouse's reservoir and the meter near the road. What I'm proposing is to tee off there or wherever makes the loop length short enough for the pump to handle. I'd have the option of a 2,000 foot loop that gets refreshed with city temp water every time the plants get watered or other major water uses in addition to the earth coupling without pulling any water through the meter. Has anyone done anything similar or have any thoughts regarding my current plan? Thanks in advance, it's much appreciated.