Integrated demand water heating using a capacity modulated heat pump with desuperheater

A heat pump system for conditioning air for use in a space, comprising:

• a desuperheater heat exchanger having an active state and an inactive state and operable as a desuperheater or a condenser;
• a compressor configured to circulate a refrigerant, wherein the compressor is positioned immediately upstream of the desuperheater heat exchanger, wherein all of the refrigerant is conveyed through the desuperheater heat exchanger regardless of whether the desuperheater heat exchanger is in the active state or the inactive state;
• a refrigerant-to-liquid source heat exchanger operable as either a condenser or an evaporator to exchange heat between the refrigerant and a heat exchange liquid;
• a refrigerant-to-air load heat exchanger operable as either a condenser or an evaporator to exchange heat between the refrigerant and the air to condition the air for use in the space;
• a reversing valve including a first port connected to the desuperheater heat exchanger, a second port connected to the compressor, a third port connected to the refrigerant-to-air load heat exchanger, and a fourth port connected to the refrigerant-to-liquid source heat exchanger;
• a controller comprising a processor and memory and configured to control operation of the desuperheater heat exchanger, the refrigerant-to-liquid source heat exchanger, and the reversing valve;
• an expansion valve positioned between the refrigerant-to-liquid source heat exchanger and the refrigerant-to-air load heat exchanger;
• a first variable speed pump for circulating water through the desuperheater heat exchanger;
• and
• a second variable speed pump for circulating the heat exchange liquid through the refrigerant-to-liquid source heat exchanger;
• wherein in a space cooling mode to cool the air for use in the space, the controller is configured to:
• disable heat exchange in the desuperheater heat exchanger while the refrigerant is conveyed through the desuperheater heat exchanger;
• enable heat exchange in the refrigerant-to-liquid source heat exchanger;
• control the expansion valve and the reversing valve to convey the refrigerant from the first port to the fourth port and from the third port to the second port to cause the refrigerant to flow to the refrigerant-to-liquid source heat exchanger configured as a condenser, through the expansion valve, and then to the refrigerant-to-air load heat exchanger configured as an evaporator,
• wherein in a water heating mode, the controller is configured to control:
• the first variable speed pump to enable heat exchange in the desuperheater heat exchanger to heat domestic water pumped through the desuperheater heat exchanger;
• the second variable speed pump to enable heat exchange in the refrigerant-to-liquid source heat exchanger;
• the refrigerant-to-air load heat exchanger to be inactive;
• and
• the expansion valve and the reversing valve to convey the refrigerant from the first port to the third port and from the fourth port to the second port to cause the refrigerant to:
• flow from the desuperheater heat exchanger acting as a condenser to the refrigerant-to-air load heat exchanger;
• and
• return flow from the refrigerant-to-liquid source heat exchanger acting as an evaporator to the compressor.

A heat pump system for conditioning air for use in a space, comprising:

• a desuperheater heat exchanger having an active state and an inactive state and operable as a desuperheater or a condenser;
• a compressor configured to circulate a refrigerant, wherein the compressor is positioned immediately upstream of the desuperheater heat exchanger, wherein all of the refrigerant is conveyed through the desuperheater heat exchanger regardless of whether the desuperheater heat exchanger is in the active state or the inactive state;
• a refrigerant-to-liquid source heat exchanger operable as either a condenser or an evaporator to exchange heat between the refrigerant and a heat exchange liquid;
• a refrigerant-to-air load heat exchanger operable as either a condenser or an evaporator to exchange heat between the refrigerant and the air to condition the air for use in the space;
• a reversing valve including a first port connected to the desuperheater heat exchanger, a second port connected to the compressor, a third port connected to the refrigerant-to-air load heat exchanger, and a fourth port connected to the refrigerant-to-liquid source heat exchanger;
• a controller comprising a processor and memory and configured to control operation of the desuperheater heat exchanger, the refrigerant-to-liquid source heat exchanger, and the reversing valve;
• an expansion valve positioned between the refrigerant-to-liquid source heat exchanger and the refrigerant-to-air load heat exchanger;
• a first variable speed pump for circulating water through the desuperheater heat exchanger;
• and
• a second variable speed pump for circulating the heat exchange liquid through the refrigerant-to-liquid source heat exchanger,
• wherein in a space heating mode to heat the air for use in the space, the controller is configured to:
• disable heat exchange in the desuperheater heat exchanger while the refrigerant is conveyed through the desuperheater heat exchanger;
• enable heat exchange in the refrigerant-to-liquid source heat exchanger;
• control the expansion valve and the reversing valve to convey the refrigerant from the first port to the third port and from the fourth port to the second port to cause the refrigerant to flow to the refrigerant-to-air load heat exchanger configured as a condenser, through the expansion valve, and then to the refrigerant-to-liquid source heat exchanger configured as an evaporator,
• wherein in a water heating mode, the controller is configured to control:
• the first variable speed pump to enable heat exchange in the desuperheater heat exchanger to heat domestic water pumped through the desuperheater heat exchanger;
• the second variable speed pump to enable heat exchange in the refrigerant-to-liquid source heat exchanger;
• the refrigerant-to-air load heat exchanger to be inactive;
• and
• the expansion valve and the reversing valve to convey the refrigerant from the first port to the third port and from the fourth port to the second port to cause the refrigerant to:
• flow from the desuperheater heat exchanger acting as a condenser to the refrigerant-to-air load heat exchanger;
• and
• return flow from the refrigerant-to-liquid source heat exchanger acting as an evaporator to the compressor.