Heat pump with supplemental heat source

A heat pump comprising:

• a compressor having a compressor inlet and a compressor outlet;
• an indoor heat exchanger and an outdoor heat exchanger;
• an outdoor thermal expansion valve;
• an auxiliary heat exchanger;
• an auxiliary fluid line;
• an auxiliary fluid pump;
• and
• wherein;
• the compressor outlet, the indoor heat exchanger, the outdoor thermal expansion valve, the auxiliary heat exchanger, the outdoor heat exchanger, and the compressor inlet can be placed in respective serial fluid communication with one another to thereby circulate a refrigerant fluid;
• the auxiliary fluid pump is configured to circulate an auxiliary heat transfer fluid through the auxiliary fluid line;
• the auxiliary heat exchanger is configured to exchange heat between the refrigerant fluid and the auxiliary heat transfer fluid;
• the auxiliary fluid line is in thermal energy communication with a primary source of auxiliary heat;
• a septic tank, and wherein the septic tank is configured to contain a fluid which provides the primary source of auxiliary heat;
• a fan configured to force atmospheric air past the outdoor heat exchanger to thereby facilitate heat transfer to the atmospheric air from the refrigerant passing through the outdoor heat exchanger;
• a motor for driving the fan;
• a refrigerant thermal sensor configured to detect a temperature of the refrigerant passing from the auxiliary heat exchanger to the outdoor heat exchanger and to generate a temperature signal in response thereto;
• and
• a fan motor thermal switch to receive the temperature signal and to stop the motor when the signal indicates that the temperature of the refrigerant passing from the auxiliary heat exchanger to the outdoor heat exchanger is above a predetermined level.