Geothermal heat pump system

In a heating and cooling system having a subterranean heat exchanger in thermal communication with the earth, a dynamic load heat exchanger in thermal communication with a dynamic load, a conduit circuit for circulating a phase-change heat transfer fluid so as to convey thermal energy from one said heat exchanger to the other, a gas compressor in said conduit circuit for compressing said heat transfer fluid while in the gas phase, an expansion valve in a section of said conduit circuit that carries the heat transfer fluid from said dynamic load heat exchanger to said subterranean heat exchanger when the system is being operated in the heating mode, a trap vessel in said conduit circuit for trapping any liquid present in the heat transfer fluid that is about to be sucked into the compressor, and a receiver in said conduit circuit, the improvement wherein

• said receiver is a variable-capacity, dual direction receiver comprising:
• a vessel having a bottom, a side wall, and a top;
• a first tube having an end that extends through the top of said vessel to a position adjacent to the bottom of said vessel;
• a second tube having an end that extends through the top of said vessel to a position that may be selected to be a desired distance from the bottom of said vessel;
• and
• a third tube having an end that extends through the top of said vessel to a position intermediate the position of the end of the first tube and the position of the end of the second tube for carrying heat transfer fluid to the vessel during a cooling mode.

A subassembly for a heating and cooling system, said subassembly comprising:

• a receiver;
• a first heat transfer fluid conduit passing through said receiver;
• a flow-control valve located in said first heat transfer fluid conduit at a position external to said receiver;
• a bypass conduit comprising a second heat transfer fluid conduit having two ends, each end being connected to said first heat transfer fluid conduit at a different side of said flow-control valve, and a check valve located in said second heat transfer fluid conduit;
• and
• a third heat transfer fluid conduit having two ends, one end being connected to said first heat transfer fluid conduit at a connection point located at a side of said flow-control valve opposite said receiver, and the other end being located inside said receiver.