High efficiency heat pump system

A high efficiency gas fired heat pump system comprising:

• a power circuit including
• a gas fired heater heating and vaporizing a first working fluid;
• a power unit having a first chamber, said first chamber having a driving piston movably mounted therein;
• a valve for selectively delivering and exhausting first working fluid from the first chamber of the power unit wherein said driving piston undergoes movement responsive to said delivery and exhaust of first working fluid;
• a first condenser in connection with said valve for receiving first working fluid exhausted from the first chamber, the first condenser in fluid communication with the gas fired heater wherein condensed first working fluid is returned thereto;
• a heat pump circuit including:
• a second chamber in the power unit;
• the second chamber having a second piston therein in driven operative connection with the first piston wherein a second working fluid is compressed in the second chamber;
• an exterior coil having a first expansion device in connection therewith;
• an interior coil having a second expansion device in connection therewith;
• and
• a control valve for selectively directing the compressed second working fluid from the power unit to one of either the interior or exterior coil for condensation therein and directing said condensed second working fluid to said other of said coils through the expansion device in connection therewith, wherein said other coil returns vaporized second working fluid to the second chamber of the power unit.