Why not Contact Earth Sheltered Technology, and ask for Help?
Cobra51400,

Earth Sheltered Technology is now being run by Jeff Hickok, the son of its founder, Jerry Hickok. Jeff is new to the business, and is only now starting to learn the ins and outs of building underground homes. Jeff told me that he thought that the man who was having the house built, a Mr. Hinrichs, who had been a partner with his father in Earth Sheltered Technology, had been trying out idea of using underground tubes for heating and cooling, but had not found it to be successful and had abandoned the plan. I stress that this is only what Jeff had heard, and does not know for certain. Since the house was left unfinished, I have no way of knowing whether Mr. Hinrichs had in fact abandoned the idea or what he would have done if he had lived.

Earth Sheltered Technologies at the present time builds only the concrete shells for underground houses, although it once built them “turnkey.” I could try to contact some of the older employees, even Jeff’s father, to see if they have any further information, but I got the impression from Jeff that Mr. Hinrichs’ idea of using earth tubes was experimental even then, when Earth Sheltered Technology built houses to completion.