Author Topic: Cooling with ground water, sort of  (Read 1611 times)

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MountainMan

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Cooling with ground water, sort of
« on: December 16, 2005, 04:23:05 PM »
It never gets quite hot enough, long enough on my mountain in the summer for me to think seriously about putting in a central air system in my house when I build it.  I will be off the grid, so that would almost certainly require running a generator when it was used.  Once upon a time, I thought about using well-water as a source of "cold", and piping that through my "radiant heat" system.


Then I studied up on the type of deeeeeeeeep wells that are needed out here (about 800 feet), and realized that I could run a compressor cheaper than I could run a well pump to get water from that deep. (typically three to five horse power)


It just occurred to me this morning that perhaps when I have the guys out there drilling my well (into solid granite), I should also pay them to drill maybe a 75 or 100 foot hole that I can use for cooling.  Since the ground is solid rock, if I pour water in a 75 foot hole and pull water out of the hole at the same time, not much of it is going to disappear into the rocks.  Probably only loose a gallon or two a day.  A guess, obviously.


I don't think a closed system of pipes going down into the hole and back out would work.  Not enough heat transfer from the cold rocks to the "hot" pipe.  Would need the incoming water to run down the side of the hole and give up its heat to the rock as it made its way to the bottom, where it would get sucked up and sent back to the house again.


So I'm thinking maybe a two hundred watt pump to circulate 50 gallons of water in and out of my "short hole" should give me a low cost and low energy source of 50 degree water to pump through my floor system.  OK, probably would want to use a heat transfer tank (a couple of junked radiators in a small water tank) so that I don't run raw ground water through my floor system.


Other than the cost of the short well, what problems do  you guys foresee me running into with this scheme?


thanks,

jp

« Last Edit: December 16, 2005, 04:23:05 PM by (unknown) »