I don’t think you’re talking about geothermal in the same sense. You’re talking about a heat pump that takes advantage of the difference in temperature at different depths in the Earth. In that case, you are the one who supplies the water, and yes the water will remain good-to-use if kept in an enclosed system.
“I don’t think you’re talking about geothermal in the same sense. You’re talking about a heat pump that takes advantage of the difference in temperature at different depths in the Earth.”
Exactly right, the ground temp dictates what temp you can pull out of it. When you are situated over a thermal warm spot you are going to get a higher output. Like here, our soil at 6tf is 70 degrees. Our 499 ft well brings up 85 degree water. We are on a hot spot.
But you could do the same thing but on a personal basis. Drill a 500 ft hole and pull out 85 degree water, distribute it through your home, then dump it back in a shallow well hole.
With plastic pipe and clean outs to brush them out every ten years it would last hundreds of years as long as you can power the pump. As long as it was designed right, scale would not be a problem. Here is a thought, run your well water you already need from your existing well through your house before it goes to storage. Free heating and cooling on it’s way there...