Heat Pump System Defrosting Operations

Abstract

A heat pump system including a charge compensator having a liquid line port for an inflow of a refrigerant into the charge compensator and for an outflow of the refrigerant from the charge compensator. The heat pump system further includes an isolation valve configured to control flows of the refrigerant to and from the charge compensator through a liquid line piping of the heat pump system based on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode, where the liquid line port is fluidly coupled to the liquid line piping of the heat pump system.

1 - 20 . (canceled) 
     
     
         21 . A heat pump system comprising:
 a charge compensator configured to be in selective fluid communication with a system circulation flow path of the heat pump system; and   an isolation valve configured to selectively permit a refrigerant to flow between the charge compensator and the system circulation flow path based at least in part on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode,   wherein during the defrost mode, the isolation valve is configured to prevent the refrigerant from flowing between the charge compensator and the system circulation flow path.   
     
     
         22 . The heat pump system of  claim 21 , wherein during the cooling mode, the isolation valve is configured to permit the refrigerant to flow from the charge compensator to the system circulation flow path. 
     
     
         23 . The heat pump system of  claim 21 , wherein during the heating mode, the isolation valve is configured to permit the refrigerant to flow from the system circulation flow path to charge compensator. 
     
     
         24 . The heat pump system of  claim 23 , wherein:
 during a first duration of the heating mode, the isolation valve is configured to permit the refrigerant to flow from the system circulation flow path to the charge compensator, and   during a second duration of the heating mode that is after the first duration, the isolation valve is configured to prevent the refrigerant from flowing from the charge compensator to the system circulation flow path.   
     
     
         25 . The heat pump system of  claim 24 , wherein the first duration is based at least in part on an amount of time associated with a flow of refrigerant to fill the charge compensator. 
     
     
         26 . The heat pump system of  claim 23 , wherein the isolation valve is in an open configuration during an entirety of the heating mode. 
     
     
         27 . The heat pump system of  claim 21 , wherein the charge compensator has a liquid line port configured to selectively receive an inflow of the refrigerant from the system circulation flow path and discharge an outflow of the refrigerant to a liquid line portion of the system circulation flow path. 
     
     
         28 . The heat pump system of  claim 21 , wherein the charge compensator comprises a refrigerant passageway configured to permit a portion of the system circulation flow path to pass therethrough. 
     
     
         29 . The heat pump system of  claim 21  further comprising:
 a controller configured to output instructions for the isolation valve based at least in part on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode. 
 
     
     
         30 . The heat pump system of  claim 29  further comprising:
 a reversing valve in fluid communication with the system circulation flow path, 
 wherein the controller is further configured to output instructions for the reversing valve to direct the refrigerant through the system circulation flow path based at least in part on whether heat pump system is operating in a cooling mode, a defrost mode, or a heating mode. 
 
     
     
         31 . The heat pump system of  claim 21  further comprising:
 a relief valve in communication with the charge compensator and the system circulation flow path, the relief valve being configured to open and permit a bypass flow of the refrigerant from the charge compensator to the system circulation flow path if a pressure across the relief valve exceeds a safety threshold. 
 
     
     
         32 . A non-transitory, computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause a computing device to:
 output instructions for an isolation valve of a heat pump system to selectively permit a refrigerant of the heat pump system to flow between a charge compensator of the heat pump system and a system circulation flow path of the heat pump system, based at least in part on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode; and   output instructions for the isolation valve to prevent the refrigerant from flowing between the charge compensator and the system circulation flow path when the heat pump is in the defrost mode.   
     
     
         33 . The non-transitory, computer-readable medium of  claim 32 , wherein the instructions, when executed by the one or more processors, further cause the computing device to:
 output instructions for the isolation valve to permit the refrigerant to flow from the charge compensator to the system circulation flow path during the cooling mode.   
     
     
         34 . The non-transitory, computer-readable medium of  claim 32 , wherein the instructions, when executed by the one or more processors, further cause the computing device to:
 output instructions for the isolation valve to permit the refrigerant to flow from the system circulation flow path to charge compensator during the heating mode.   
     
     
         35 . The non-transitory, computer-readable medium of  claim 34 , wherein the instructions for the isolation valve to permit the refrigerant to flow from the system circulation flow path to charge compensator during the heating mode further comprise:
 instructions for the isolation valve to permit the refrigerant to flow from the system circulation flow path to the charge compensator during a first duration of the heating mode; and   instructions for the isolation valve to prevent the refrigerant from flowing from the charge compensator to the system circulation flow path during a second duration of the heating mode that is after the first duration   
     
     
         36 . The non-transitory, computer-readable medium of  claim 35 , wherein the first duration is based at least in part on an amount of time associated with a flow of refrigerant to fill the charge compensator. 
     
     
         37 . The non-transitory, computer-readable medium of  claim 34 , wherein the isolation valve is in an open configuration during an entirety of the heating mode. 
     
     
         38 . The non-transitory, computer-readable medium of  claim 32 , wherein the instructions, when executed by the one or more processors, further cause the computing device to:
 output instructions for one or more a reversing valves of the heat pump system to direct the refrigerant through the system circulation flow path based at least in part on whether heat pump system is operating in a cooling mode, a defrost mode, or a heating mode.   
     
     
         39 . The non-transitory, computer-readable medium of  claim 32 , wherein the instructions, when executed by the one or more processors, further cause the computing device to:
 receive temperature data from a temperature sensor of the heat pump system,   wherein outputting the instructions for the isolation valve to selectively permit the refrigerant to flow between the charge compensator and the system circulation flow path is further based at least in part on the temperature data.