Reheat operation for heat pump system

Abstract

A heat pump system includes a refrigerant circuit comprising a compressor, a reversing valve, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, and a three-way valve. The reversing valve is configured to receive refrigerant from the compressor and adjust between a first configuration to direct the refrigerant toward the three-way valve and a second configuration to direct the refrigerant toward the first heat exchanger. The three-way valve is configured to adjust between a first position to direct the refrigerant between the reversing valve and the second heat exchanger and a second position to direct the refrigerant from the reversing valve to the reheat heat exchanger.

1 . A heat pump system, comprising:
 a refrigerant circuit comprising a compressor, a reversing valve, a first heat exchanger, a second heat exchanger, a reheat heat exchanger, and a three-way valve,   wherein the reversing valve is configured to receive refrigerant from the compressor and adjust between a first configuration to direct the refrigerant toward the three-way valve and a second configuration to direct the refrigerant toward the first heat exchanger, and   wherein the three-way valve is configured to adjust between a first position to direct the refrigerant between the reversing valve and the second heat exchanger and a second position to direct the refrigerant from the reversing valve to the reheat heat exchanger.   
     
     
         2 . The heat pump system of  claim 1 , wherein the three-way valve is configured to block flow of the refrigerant from the reversing valve to the reheat heat exchanger in the first position, and the three-way valve is configured to block flow of the refrigerant between the reversing valve and the second heat exchanger in the second position. 
     
     
         3 . The heat pump system of  claim 1 , comprising a control system configured to:
 position the reversing valve in the second configuration and position the three-way valve in the first position to operate the heat pump system in a heating mode;   position the reversing valve in the first configuration and position the three-way valve in the first position to operate the heat pump system in a cooling mode; and   position the reversing valve in the first configuration and position the three-way valve in the second position to operate the heat pump system in a reheat mode.   
     
     
         4 . The heat pump system of  claim 1 , wherein the first heat exchanger is an indoor heat exchanger, and the second heat exchanger is an outdoor heat exchanger. 
     
     
         5 . The heat pump system of  claim 1 , wherein the three-way valve is a first three-way valve, and the refrigerant circuit comprises a second three-way valve configured to adjust between a third position to direct the refrigerant between the first heat exchanger and the second heat exchanger and a fourth position to block flow of the refrigerant between the first heat exchanger and the second heat exchanger. 
     
     
         6 . The heat pump system of  claim 5 , wherein the second three-way valve is configured to direct the refrigerant from the reheat heat exchanger to the first heat exchanger in the fourth position and to block flow of the refrigerant between the reheat heat exchanger and the first heat exchanger in the third position. 
     
     
         7 . The heat pump system of  claim 1 , wherein the refrigerant circuit comprises a first flow path and a second flow path arranged in parallel with one another and extending between the second heat exchanger and the first heat exchanger, wherein the first flow path comprises a check valve configured to enable flow of the refrigerant from the second heat exchanger toward the first heat exchanger, and the second flow path comprises a solenoid valve configured to adjust between a third position to direct the refrigerant between the first heat exchanger and the second heat exchanger and a fourth position to block flow of the refrigerant between the first heat exchanger and the second heat exchanger. 
     
     
         8 . The heat pump system of  claim 1 , wherein the refrigerant circuit comprises a check valve configured to block flow of the refrigerant from the first heat exchanger to the reheat heat exchanger. 
     
     
         9 . A tangible, non-transitory, computer-readable medium comprising instructions, wherein the instructions, when executed by processing circuitry, are configured to cause the processing circuitry to:
 position a reversing valve of a heat pump system in a first configuration to direct flow of refrigerant from the reversing valve toward a three-way valve of the heat pump system and position the three-way valve in a first position to direct flow of the refrigerant from the three-way valve to an outdoor heat exchanger of the heat pump system in a cooling mode of the heat pump system;   position the reversing valve in the first configuration to direct flow of the refrigerant from the reversing valve toward the three-way valve and position the three-way valve in a second position to direct flow of the refrigerant from the three-way valve to a reheat heat exchanger of the heat pump system in a reheat mode of the heat pump system; and   position the reversing valve in a second configuration to direct flow of the refrigerant from the reversing valve toward an indoor heat exchanger of the heat pump system in a heating mode of the heat pump system.   
     
     
         10 . The tangible, non-transitory, computer-readable medium of  claim 9 , wherein the instructions, when executed by the processing circuitry, are configured to cause the processing circuitry to position the three-way valve in the first position to direct flow of the refrigerant from the outdoor heat exchanger to the reversing valve via the three-way valve in the heating mode of the heat pump system. 
     
     
         11 . The tangible, non-transitory, computer-readable medium of  claim 9 , wherein the instructions, when executed by the processing circuitry, are configured to cause the processing circuitry to position the three-way valve in the second position to block flow of the refrigerant from the three-way valve to the outdoor heat exchanger in the reheat mode. 
     
     
         12 . The tangible, non-transitory, computer-readable medium of  claim 9 , wherein the instructions, when executed by the processing circuitry, are configured to cause the processing circuitry to operate a fan in the cooling mode to direct an air flow across the outdoor heat exchanger to maintain flow of the refrigerant from the outdoor heat exchanger toward the indoor heat exchanger above a threshold flow rate. 
     
     
         13 . The tangible, non-transitory, computer-readable medium of  claim 12 , wherein the instructions, when executed by the processing circuitry, are configured to cause the processing circuitry to operate the fan based on a pressure of the refrigerant, a temperature of the refrigerant, a detected flow rate of the refrigerant, a temperature of outdoor air, or any combination thereof. 
     
     
         14 . The tangible, non-transitory, computer-readable medium of  claim 9 , wherein the three-way valve is a first three-way valve, and the instructions, when executed by the processing circuitry, are configured to cause the processing circuitry to:
 position a second three-way valve of the heat pump system in a third position in the heating mode and in the cooling mode of the heat pump system to enable flow of the refrigerant between the indoor heat exchanger and the outdoor heat exchanger; and   position the second three-way valve in a fourth position in the reheat mode of the heat pump system to block flow of the refrigerant between the indoor heat exchanger and the outdoor heat exchanger.   
     
     
         15 . The tangible, non-transitory, computer-readable medium of  claim 9 , wherein the instructions, when executed by the processing circuitry, are configured to cause the processing circuitry to:
 operate a fan in the cooling mode and in the heating mode to direct an air flow across the outdoor heat exchanger; and   suspend operation of the fan in the reheat mode.   
     
     
         16 . A heat pump system, comprising:
 a refrigerant circuit comprising a compressor, a reversing valve, a three-way valve, an indoor heat exchanger; and   a control system configured to adjust the reversing valve and the three-way valve based on an operating mode selected from a heating mode, a cooling mode, and a reheat mode,   wherein the reversing valve is configured to receive refrigerant from the compressor and adjust between a first configuration to direct the refrigerant from the compressor toward the three-way valve and a second configuration to direct the refrigerant from the compressor toward the indoor heat exchanger, and   wherein the three-way valve is configured to adjust between a first position to direct the refrigerant between the reversing valve and the outdoor heat exchanger and a second position to direct the refrigerant from the reversing valve to the reheat heat exchanger.   
     
     
         17 . The heat pump system of  claim 16 , wherein the control system is configured to:
 position the reversing valve in the second configuration and position the three-way valve in the first position based on operation of the heat pump system in the heating mode;   position the reversing valve in the first configuration and position the three-way valve in the first position based on operation of the heat pump system in the cooling mode; and   position the reversing valve in the first configuration and position the three-way valve in the second position based on operation of the heat pump system in the reheat mode.   
     
     
         18 . The heat pump system of  claim 16 , wherein the refrigerant circuit comprises an accumulator configured to direct the refrigerant to the compressor. 
     
     
         19 . The heat pump system of  claim 16 , wherein the three-way valve is configured to block refrigerant flow to the reheat heat exchanger via the three-way valve in the first position, and the three-way valve is configured to block refrigerant flow to the outdoor heat exchanger via the three-way valve in the second position. 
     
     
         20 . The heat pump system of  claim 15 , comprising a fan configured to direct an air flow across the indoor heat exchanger and a reheat heat exchanger.