Heat pump and water heater

Abstract

An embodiment of the instant disclosure comprises a reversible heat pump and water heating system for conditioning a space and heating water. The system comprises a refrigerant circuit that includes a compressor, a source heat exchanger, a space heat exchanger, and an expansion device. A 4-way reversing valve alternates between heating and cooling modes of operation. The system includes a heat exchanger for heating water in the water heating loop, and a 3-way valve that either actuates the refrigerant flow through the water heater heat exchanger or bypasses at least a portion of the refrigerant flow around the water heater heat exchanger. The heat pump system is operable in at least five modes—space heating only, space cooling only, water heating only, and either space heating or space cooling combined with water heating. Use of a modulating 3-way valve allows the amount of the refrigerant flow through the water heating heat exchanger to be adjusted to precisely match space conditioning and water heating demands and stable operation of the heat pump system. Either of the space and source heat exchangers may be bypassed and deactivated to reduce the heat pump system power consumption.

What is claimed is: 
     
         1 . A heat pump system, comprising:
 a compressor configured to circulate a refrigerant through a refrigerant circuit, the compressor having a discharge outlet port and an inlet suction port;   a source heat exchanger configured to exchange heat between the refrigerant and a source heat exchange medium;   a space heat exchanger configured to exchange heat between the refrigerant and a space heat exchange medium;   a bi-directional expansion valve disposed on the refrigerant circuit and positioned between the source heat exchanger and the space heat exchanger;   a liquid heat exchanger configured to exchange heat between the refrigerant and a liquid to heat the liquid;   a 3-way valve disposed along the refrigerant circuit between the compressor, the liquid heat exchanger, and a liquid heat exchanger bypass circuit, wherein the 3-way valve is configured to selectively direct the refrigerant from the compressor to either the liquid heat exchanger or to the liquid heat exchanger bypass circuit;   a reversing valve disposed along the refrigerant circuit, the reversing valve including a first port configured to receive the refrigerant from the liquid heat exchanger bypass circuit and/or from the liquid heat exchanger, a second port connected to the inlet suction port of the compressor, a third port connected to the space heat exchanger, and a fourth port connected to the source heat exchanger,   wherein in a first operating mode the reversing valve is configured to convey the refrigerant from the first port to the fourth port and from the third port to the second port to direct the refrigerant to the source heat exchanger configured to operate as a condenser, through the bi-directional expansion valve, and to the space heat exchanger configured to operate as an evaporator, and   wherein in a second operating mode the reversing valve is configured to convey the refrigerant from the first port to the third port and from the fourth port to the second port to direct the refrigerant to the space heat exchanger configured to operate as a condenser, through the bi-directional expansion valve, and to the source heat exchanger configured to operate as an evaporator.   
     
     
         2 . The heat pump system of  claim 1 , including a space heat exchanger bypass circuit and a source heat exchanger bypass circuit connected to the refrigerant circuit, wherein the space heat exchanger bypass circuit is configured to convey the refrigerant away from the space heat exchanger to deactivate the space heat exchanger, and wherein the source heat exchanger bypass circuit is configured to convey the refrigerant away from the source heat exchanger to deactivate the source heat exchanger. 
     
     
         3 . The heat pump system of  claim 1 , wherein the bi-directional expansion valve is a fixed orifice valve, a mechanical valve, or an electronic valve. 
     
     
         4 . The heat pump system of  claim 1 , wherein the liquid heat exchanger is a refrigerant-to-liquid heat exchanger configured to exchange heat between the refrigerant in the refrigerant circuit and the liquid in a liquid storage loop. 
     
     
         5 . The heat pump system of  claim 4 , including a pump for circulating the heated liquid in the liquid storage loop and through the liquid heat exchanger. 
     
     
         6 . The heat pump system of  claim 5 , wherein the pump is driven by a variable speed motor. 
     
     
         7 . The heat pump system of  claim 1 , including a controller configured to control operation of the compressor, the reversing valve, the 3-way valve, the bi-directional expansion valve, and a pump for circulating the liquid through the liquid heat exchanger. 
     
     
         8 . The heat pump system of  claim 1 , wherein the reversing valve and the 3-way valve are configured to alter a flow of the refrigerant to change a mode of operation between the first operating mode defining a space cooling mode, a space cooling and liquid heating mode, the second operating mode defining a space heating mode, a space heating and liquid heating mode, and a primary liquid heating mode. 
     
     
         9 . The heat pump system of  claim 8 , including a second 3-way valve connected to a source heat exchanger bypass circuit to permit the refrigerant to bypass the source heat exchanger in the space cooling and liquid heating mode. 
     
     
         10 . The heat pump system of  claim 9 , including a third 3-way valve connected to a space heat exchanger bypass circuit to permit the refrigerant to bypass the space heat exchanger in the space heating and liquid heating mode and in the liquid heating mode. 
     
     
         11 . The heat pump system of  claim 8 , wherein to operate in the space cooling mode,
 the 3-way valve is configured to direct the refrigerant from the compressor to the reversing valve via the liquid heat exchanger bypass circuit;   the reversing valve is configured to direct the refrigerant, via the first port and the fourth port, to the source heat exchanger that is configured to operate as a condenser,   the bi-directional expansion valve is configured to receive the refrigerant from the source heat exchanger,   the space heat exchanger is configured as an evaporator and receives the refrigerant from the bi-directional expansion valve, and   the reversing valve is configured to receive, via the third port, the refrigerant from the space heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         12 . The heat pump system of  claim 8 , wherein to operate in the space cooling and liquid heating mode,
 the 3-way valve is configured to direct the refrigerant from the compressor to the liquid heat exchanger,   the reversing valve is configured to receive, via the first port, the refrigerant from the liquid heat exchanger and direct, via the fourth port, the refrigerant to the source heat exchanger that is configured to operate as a condenser,   the bi-directional expansion valve is configured to receive the refrigerant from the source heat exchanger,   the space heat exchanger is configured to operate as an evaporator and receive the refrigerant from the bi-directional expansion valve, and   the reversing valve is configured to receive, via the third port, the refrigerant from the space heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         13 . The heat pump system of  claim 8 , wherein to operate in the space heating mode,
 the 3-way valve is configured to direct the refrigerant from the compressor to the reversing valve via the liquid heat exchanger bypass circuit;   the reversing valve is configured to direct the refrigerant, via the first port and the third port, to the space heat exchanger that is configured to operate as a condenser,   the bi-directional expansion valve is configured to receive the refrigerant from the space heat exchanger,   the source heat exchanger is configured to operate as an evaporator and receive the refrigerant from the bi-directional expansion valve, and   the reversing valve is configured to receive, via the fourth port, the refrigerant from the source heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         14 . The heat pump system of  claim 8 , wherein to operate in the space heating and liquid heating mode,
 the 3-way valve is configured to direct the refrigerant from the compressor to the liquid heat exchanger,   the reversing valve is configured to receive, via the first port, the refrigerant from the liquid heat exchanger and direct, via the third port, the refrigerant to the space heat exchanger that is configured to operate as a condenser,   the bi-directional expansion valve is configured to receive the refrigerant from the space heat exchanger,   the source heat exchanger is configured to operate as an evaporator and receive the refrigerant from the bi-directional expansion valve,   the reversing valve is configured to receive, via the fourth port, the refrigerant from the source heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         15 . The heat pump system of  claim 8 , wherein to operate in the primary liquid heating mode,
 the 3-way valve is configured to direct the refrigerant from the compressor to the liquid heat exchanger that is configured to operate as a desuperheater, condenser, and subcooler,   the reversing valve is configured to receive, via the first port, the refrigerant from the liquid heat exchanger and direct, via the third port, the refrigerant toward the space heat exchanger,   the bi-directional expansion valve is configured to subsequently receive the refrigerant,   the source heat exchanger is configured to operate as an evaporator and receive the refrigerant from the bi-directional expansion valve, and   the reversing valve is configured to receive, via the fourth port, the refrigerant from the source heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         16 . The heat pump system of  claim 9 , wherein to operate in the space cooling and liquid heating mode,
 the 3-way valve is configured to direct the refrigerant from the compressor to the liquid heat exchanger configured to subcool the refrigerant,   the reversing valve is configured to receive, via the first port, the refrigerant from the liquid heat exchanger and direct, via the fourth port, the refrigerant to the second 3-way valve,   the second 3-way valve is configured to direct the refrigerant to the source heat exchanger bypass circuit,   the bi-directional expansion valve is configured to receive the refrigerant from the source heat exchanger bypass circuit,   the space heat exchanger is configured to operate as an evaporator and receive the refrigerant from the bi-directional expansion valve, and   the reversing valve is configured to receive, via the third port, the refrigerant from the space heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         17 . The heat pump system of  claim 9 , wherein to operate in the space cooling and liquid heating mode,
 the 3-way valve is configured to direct a first portion of the refrigerant from the compressor to the liquid heat exchanger and a second remainder portion of the refrigerant from the compressor to the liquid heat exchanger bypass circuit,   the reversing valve is configured to receive, via the first port, the first portion and the second remainder portion of the refrigerant from the liquid heat exchanger and the liquid heat exchanger bypass circuit, respectively, and direct, via the fourth port, all of the refrigerant to the second 3-way valve,   the second 3-way valve is configured to direct a third portion of the refrigerant to the source heat exchanger and a fourth remainder portion of the refrigerant to the source heat exchanger bypass circuit,   the bi-directional expansion valve is configured to receive the third portion of the refrigerant from the source heat exchanger and the fourth remainder portion of the refrigerant from the source heat exchanger bypass circuit,   the space heat exchanger is configured to operate as an evaporator and receive all of the refrigerant from the bi-directional expansion valve, and   the reversing valve is configured to receive, via the third port, the refrigerant from the space heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         18 . The heat pump system of  claim 10 , wherein to operate in the space heating and liquid heating mode,
 the 3-way valve is configured to direct the refrigerant from the compressor to the liquid heat exchanger,   the reversing valve is configured to receive, via the first port, the refrigerant from the liquid heat exchanger and direct, via the third port, the refrigerant to the third 3-way valve,   the third 3-way valve is configured to direct a fifth portion of the refrigerant to the space heat exchanger and a sixth remainder portion of the refrigerant to the space heat exchanger bypass circuit,   the bi-directional expansion valve is configured to receive the fifth portion of the refrigerant from the space heat exchanger and the sixth remainder portion of the refrigerant from the space heat exchanger bypass circuit,   the source heat exchanger is configured to operate as an evaporator and receive all of the refrigerant from the bi-directional expansion valve,   the reversing valve is configured to receive, via the fourth port, the refrigerant from the source heat exchanger and direct, via the second port, the refrigerant to the compressor.   
     
     
         19 . The heat pump system of  claim 10 , wherein to operate in the space heating and liquid heating mode,
 the 3-way valve is configured to direct a seventh portion of the refrigerant from the compressor to the liquid heat exchanger and an eighth remainder portion of the refrigerant from the compressor to the liquid heat exchanger bypass circuit,   the reversing valve is configured to receive, via the first port, the seventh portion and the eighth remainder portion of the refrigerant from the liquid heat exchanger and the liquid heat exchanger bypass circuit, respectively, and direct, via the third port, all of the refrigerant to the third 3-way valve,   the third 3-way valve is configured to direct a fifth portion of the refrigerant to the space heat exchanger and a sixth remainder portion of the refrigerant to the space heat exchanger bypass circuit,   the bi-directional expansion valve is configured to receive the fifth portion of the refrigerant from the space heat exchanger and the sixth remainder portion of the refrigerant from the space heat exchanger bypass circuit,   the source heat exchanger is configured to operate as an evaporator and receive all of the refrigerant from the bi-directional expansion valve,   the reversing valve is configured to receive, via the fourth port, the refrigerant from the source heat exchanger and direct, via the second port, the refrigerant to the compressor.