> The systems I worked on were for cooling larger structures like commercial greenhouses, gov installations and mansions. 64° degree water would be pumped up from 400' down, run thru a series of chillers (for a/c) and then returned underground - about 20° or 25° warmer.

I read this several times in the context of _geothermal_ energy, and had no clue what you were talking about.

Then I realised, you must be an American and use 'freedom units', coupled with a misunderstanding of what geothermal means.