Integrated heating system using a Stirling heat pump

An air handler unit, the air handler unit including:

• a housing;
• a primary indoor coil in the housing, the primary indoor coil configured to exchange thermal energy between a refrigerant fluid and a conditioned air;
• a secondary air conditioning heating coil in the housing, the secondary air conditioning heating coil configured to exchange thermal energy between a heating fluid and the conditioned air, wherein the heating fluid is routed through a heating fluid circuit that includes a control valve,
• wherein the heating fluid circuit is thermally coupled to a hot side chamber of a Stirling heat pump, the Stirling heat pump including the hot side chamber, a cold side chamber, and a working fluid fluidly connected between the hot side chamber and the cold side chamber;
• a fan configured to circulate the conditioned air over the primary indoor coil and the secondary air conditioning heating coil to condition the conditioned air;
• and
• control circuitry communicatively coupled to the control valve and configured to:
• direct the heating fluid through the secondary air conditioning heating coil in response to a request for heating.

A method of heating both conditioned air and water using a heating fluid, the method including:

• circulating the heating fluid through a heating fluid circuit with a circulation pump;
• heating the heating fluid;
• routing the heating fluid to an air conditioning heating coil in the housing of an air handling unit holding an indoor heat exchanger configured to simultaneously exchange thermal energy between a refrigerant fluid and the conditioned air, the air conditioning heating coil configured to heat the conditioned air circulated through the air handling unit;
• routing the heating fluid to a hot water heating coil, the hot water heating coil configured to heat the water within a hot water heater;
• and
• at least one of adjusting a flow of the heating fluid from the circulation pump to the air conditioning heating coil or adjusting a flow of the heating fluid from the circulation pump to the hot water heating coil.