Patent ID: 8033127

Claim:
A direct exchange geothermal heating/cooling system for use with a sub-terranean formation and having a system heating/cooling capacity rating, the system comprising: an interior heat exchanger; a vapor refrigerant line fluidly communicating with the interior heat exchanger, the vapor refrigerant line including an above-surface vapor line portion and a sub-terranean vapor line portion; a liquid refrigerant line fluidly communicating with the interior heat exchanger, the liquid refrigerant line including an above-surface liquid line portion and a sub-terranean liquid line portion; an exterior heat exchanger defined by the sub-terranean vapor line portion and the sub-terranean liquid line portion; a compressor disposed in the above-surface vapor line portion and configured to circulate a refrigerant through the interior heat exchanger, the vapor refrigerant line, and the liquid refrigerant line, the compressor having a compressor capacity rating in BTUs; a heating mode expansion device having a valve element disposed in the above-surface liquid line portion; a heating mode bypass disposed in the above-surface liquid line portion and configured to fluidly communicate around the valve element of the heating mode expansion device, the heating mode bypass having a flow restriction with a flow restriction diameter selected to be within 10% of a temperature adjusted flow restriction diameter based, at least in part, on the compressor capacity rating; and a temperature sensing bulb operatively coupled to the heating mode expansion device and thermally coupled to the vapor refrigerant line.