A direct expansion geothermal heat exchange unit, which can be placed in sub-surface ground and/or water, consisting of at least one insulated refrigerant liquid/fluid line, with a liquid trap at the bottom of the liquid/fluid line, with at least one un-insulated refrigerant vapor/fluid line operatively connected to the insulated liquid/fluid line at a point above the liquid trap, where the un-insulated vapor/fluid line is in thermal contact with its adjacent sub-surface surrounding elements by means of a heat conductive fill material inserted as necessary to fill any void space, in any borehole or excavated area, between the vapor/fluid line and its respective adjacent sub-surface surroundings.