Originally posted by Jersey:
Cecil,
You are correct, but lifting the well water uses a lot of energy ($$$). In my neck of the woods a well is 200-600 feet deep, so lifting 12gallons/min = 61,200 ft/lb/min = 1383 watts. Then you lose 30% efficiency in your pump motor, so it takes 1975 watts (about a 2HP pump) to lift the water, assuming a 600' well. A closed loop has no lifting load, only circulation, so we typically run a 1/15HP pump.
Also, how long can you pump 12g/min before your well gets low? Then what? Around here if you use a well for geothermal, you have to return the water into a seperate well.
I know a good bit about geothermal systems and how they work in warmer climates. Lakes around here will always be (relatively) cool on the bottom in summer and warm in winter. I suspect this is the same up north. If your pond is deep enough to not freeze solid.
Engineering would be fun if it weren't for all the technical stuff.
Good point. My situation is different. The well that supplies my geothermal and other household needs is only 70 feet deep and the static water level is only 16 feet. And I pump 41 gpms of well water 24/7 7 months of the year from the same aquifer different well for my trout pond with no problems. Supposidly in my area one can pump up to 2000 gpms with the right diameter well with no adverse effects to the aquifer. We are blessed with ground water here!
