as they say "you are the man"!
To summarize, they were able to extract about half as much as an exposed collector. I don't believe it was an evacuated tube high efficiency system they were comparing to though.
This shop is in planning stages. It will not be heated to the extent our house is.
I am very familiar with ground loop systems.
This is my brother's system in Yakima. I did all the ground work there.
http://ecorenovator.org/forum/geothe...m-install.html
I am contemplating that as well. He jacks solar heat into his ground system too.
That 400 was for just the tubing and nothing more. Same for the insulation. I was talking about the bare bones that went under the metal.