geothermal questions and possible DIY

[dodge man]

I get what you’re saying now. Mine is circulating water and bringing it in the house. I didn’t know they had a system that circulated Freon.

Freon is good for HVAC because at reasonable pressures, it goes through a phase change, liquid to a gas and back, which releases a lot of heat and cold.

 

[buckeyefarmer]

Very few done as DX. Most are water to Freon heat exchange, then Freon to air. I had a salesman for a company take me to see a DX install they were doing. It convinced me NOT to go that route. Too many concerns about copper direct in the ground.
I took IGSHPA installer course before doing mine, so it was done by a certified installer.

 

[kenmac]

I often wonder how my Ducted VRF unit compares in efficiency and cost to a GEO thermal system.
Just don't see geothermal systems here. I think I've seen a hand full in 30+ years

 

[LD1]

Very few done as DX. Most are water to Freon heat exchange, then Freon to air. I had a salesman for a company take me to see a DX install they were doing. It convinced me NOT to go that route. Too many concerns about copper direct in the ground.
I took IGSHPA installer course before doing mine, so it was done by a certified installer.

Same concerns here. But I also understand the direct benefit too. Direct heat exchange with the earth via a much more conductive material. And no need for the added expense and energy consumption of a water pumping setup.

In the end I also chose to burry loops. And since the digging is the expensive part, and I could get 800' continuous loops of poly....I upsized each loop from 600' of pipe to 800' of pipe per ton

 

[Popgadget]

I have seen and repaired many geothermal heat pumps, and I’ll confirm that the DX style can be a nightmare.

 

[LD1]

I often wonder how my Ducted VRF unit compares in efficiency and cost to a GEO thermal system.
Just don't see geothermal systems here. I think I've seen a hand full in 30+ years

The further south it seems geo isn't as common. I imagine in states like Kentucky, Tennessee, West VA etc how to get that many feet of loops in the ground become more expensive. And vertical wells for loops are also expensive.

We went on vacation last year around Gatlinburg Tennessee. Went to a cavern. Had a underground stream/river. They said water was 99.99% pure and constant temp. I thought how nice that would be to tap for geo....endless water and pretty darn pure. Tap into it and return just down stream.....but I suppose that wouldn't be much different than a deep water well open loop and returning down a separate well on the same aquifer

 

[LD1]

I have seen and repaired many geothermal heat pumps, and I’ll confirm that the DX style can be a nightmare.

What issues? Outdoor copper and corrosion?

Cause aside from that it's basically the same as any other heat pump type.

 

[kenmac]

The further south it seems geo isn't as common. I imagine in states like Kentucky, Tennessee, West VA etc how to get that many feet of loops in the ground become more expensive. And vertical wells for loops are also expensive.

We went on vacation last year around Gatlinburg Tennessee. Went to a cavern. Had a underground stream/river. They said water was 99.99% pure and constant temp. I thought how nice that would be to tap for geo....endless water and pretty darn pure. Tap into it and return just down stream.....but I suppose that wouldn't be much different than a deep water well open loop and returning down a separate well on the same aquifer

I know there's one in Tennessee Ruby falls . It is a deep cave with a constant river of water that flows

 

[Popgadget]

Primarily issues with shifting backfill damaging the heat exchangers. They need to be backfilled with soil for thermal transfer, you can’t use screenings or stone. One installation was close to basement wall and it froze the ground and broke the poured concrete wall. I suppose that you could blame the failures on installation errors, but the hundreds of open loop systems that I have seen had no installation issues, most of those used two wells. Most common failures in closed loop systems were circulating pumps, newer systems use a variable speed pump that is modulated to maintain a programmed delta T, those seem to be more reliable.

 

[japody]

We have a Bosch system. It is a closed loop with 5 runs of 600 foot loops, each buried 6 feet down. We 've had it 11 years. After the tax credit, the pay back period was 6 years. The thermostat stays on 73 year round. The backup strips have never been used, even in 0 degree weather. We are thoroughly pleased with the system.