Abstract: An improved heat transfer column for geothermal heating and cooling in which refrigerant lines are wound about a thin wall vertically oriented tube. The tube is surrounded by a flexible liner which is filled with water, the liner being positioned within a cavity in an earth mass. During operation, water within the tube rises by convection and transfers heat evenly to the water within the liner for subsequent transfer to the earth mass. This heat is subsequently extracted from the earth mass during a heating cycle, and means is provided for transfer of a portion of the heat in the water to the ambient atmosphere.

Abstract: A geothermal heating and/or cooling system includes one or more of a plurality of features that enhance the efficiency of the system. Preferably, the system includes a subterranean heat exchanger having tubes disposed against a conductive sheet. The system also preferably includes a reservoir vessel for holding a supply of heat transfer fluid in a liquid phase. Also, the system preferably includes heat exchange means for exchanging heat between the heat transfer fluid and the outdoor air. In addition, the system preferably has an automatically adjusting cooling expansion valve controlled by a sensor disposed to detect the pressure or temperature of heat transfer fluid exiting an indoor air handler in a cooling mode, the system also preferably has an automatically adjusting heating expansion valve controlled by a sensor that is preferably located so as to detect the temperature or pressure of heat transfer fluid flowing from the subterranean heat exchanger to a gas compressor.