Abstract: A geothermal direct expansion heat pump system wherein subterranean heat exchange tubes have an internal diameter to length ratio of between 1/4000 and 1/6000, with 5 tubes per ton of BTU capacity; where the interior air heat exchange tubes have 50% of the interior volume of the subterranean tubes; where the thermal expansion valve is sized to match the interior air handler capacity; where the receiver holds 75% to 95% of the total refrigerant volume; where a pump down sequence is employed on system shut down; where an oil trap is installed at the vapor line existing the subterranean heat exchange tubes; and where 4 refrigerant cut-off/isolation valves are installed for service convenience.
April 19, 1996
Date of Patent:
September 30, 1997
Geothermal Heat Pumps, Inc.
B. Ryland Wiggs, Jack L. Womack, William C. Bickford