DIY Geothermal

I know that there have been a couple of geothermal threads on here but I'm asking about the possibility of a DIY type installation. I have lots of available land for a horizontal loop, access as well as expertise with a backhoe and experience with working on HVAC systems. Several companies sell kits that include the poly piping, heat exchanger, compressor and all the required fittings. It seems to me it's as simple as trenching for the 750' of pipe and adapting my existing ductwork to the new furnace/heat exchanger. Is there some sort of voodoo that I'm missing? The kits are coming in at 25% of the cost that local contractors are quoting me for the conversion.

You aren't counting labor.

Do you have to worry about getting below a frost line?

No voodoo that I've read about. You would be using a buried closed cooling loop that trades heat with the ground right? Have you compared the quotes to the kits to see where the price difference occurs?

There's quite a bit of engineering that goes into it. They probably use the engineering staff at the pipe manufacturer or have a consultant engineer design it.

You're in Ontario, right?

I wonder how deep the heat exchanger loop needs to be in order to be effective up there...

To get below the frost line here we have to go 4'. This is a rule of thumb since the frost rarely penetrates deeper than 2.5'. I buried the water lines to my paddocks at 6' since I knew that there would be motor traffic in some areas and that can drive the frost deeper. I'd do the same with the geothermal lines. As far as the engineering or sizing of the system I happen to work as a consulting engineer, albeit on the electrical rather than mechanical side of things. Luckily the firm I work for has mechanical and civil divisions that I interact with on a daily basis. The labour seems to be the largest cost here so if I can zero that then installing a geothermal system appears to be the way to go. Nothing will happen until spring now so I have a fair bit of time to plan things out.

no advise but very interested.

My uncle who lives in PEI talks about heat pumps (apparently they are very popular up there). They can heat your house using a temperature differential and can work down to -22 deg or something. Maybe you can have your geothermal lines heat the heat pump? or is that the idea and I'm slowly catching up?

It takes a lot to water to work, which simply means a very long lateral line. Can you use a (or several) water tanks to cut your work load? I don't know.

I only know that with a full, large pond as a heat sink it wouldn't work for me here in Texas.

When you get into it transferring the BTUs takes a very large surface are &/or a LOT of water.

This is a great site for diy stuff. Well I found it like 6 years ago. It was great then. No idea about now.

http://ecorenovator.org/forum/

Interested and watching