There is disclosed heat pump, comprising: an internal heat exchanger configured to transfer heat from refrigerant in a liquid line pathway to refrigerant in a suction line pathway, to superheat the refrigerant upstream of a compressor; and a controller configured to: control an expansion valve to maintain a target superheat of refrigerant at a control location. The target superheat is variable and is determined based on one or more operating conditions of the heat pump. There is also disclosed a method of operating a heat pump and a simulation method to determine a variable superheat.

A thermal management system includes a refrigerant receiver configured to store a refrigerant fluid, an evaporator arrangement that removes heat from a heat load converting a portion of the refrigerant fluid to refrigerant vapor and a liquid separator having an inlet, a liquid side outlet, and a vapor side outlet. The system also includes a pump that pumps refrigerant liquid received from the liquid side outlet of the liquid separator and a closed-circuit refrigeration system having a closed-circuit fluid path that includes the refrigerant receiver, the liquid separator, the pump, and the evaporator arrangement, the closed-circuit refrigeration system further including a compressor and a condenser. The system also including an open-circuit refrigeration system having an open-circuit fluid path that includes the refrigerant receiver, the liquid separator, the pump, and the evaporator arrangement, and further including a back-pressure regulator configured to receive refrigerant vapor from the vapor side outlet of the liquid separator and an exhaust line coupled to the outlet of the back-pressure regulator, with refrigerant vapor from the exhaust line not returning to the refrigerant receiver.

A thermal management system includes a refrigerant receiver configured to store a refrigerant fluid, an evaporator arrangement that removes heat from a heat load converting a portion of the refrigerant fluid to refrigerant vapor and a liquid separator having an inlet, a liquid side outlet, and a vapor side outlet. The system also includes a pump that pumps refrigerant liquid received from the liquid side outlet of the liquid separator and a closed-circuit refrigeration system having a closed-circuit fluid path that includes the refrigerant receiver, the liquid separator, the pump, and the evaporator arrangement, the closed-circuit refrigeration system further including a compressor and a condenser. The system also including an open-circuit refrigeration system having an open-circuit fluid path that includes the refrigerant receiver, the liquid separator, the pump, and the evaporator arrangement, and further including a back-pressure regulator configured to receive refrigerant vapor from the vapor side outlet of the liquid separator and an exhaust line coupled to the outlet of the back-pressure regulator, with refrigerant vapor from the exhaust line not returning to the refrigerant receiver.

A combined heat exchanger, a heat exchange system, and an optimization method thereof are provided. The heat exchange system includes: an enhanced vapor injection compressor, a condenser, an expansion valve and an evaporator, which are located in a main circuit; wherein the heat exchange system further includes a first branch branched from the main circuit to an vapor injection port of the compressor at a branch point P downstream of the condenser, and a first heat exchange unit and a second heat exchange unit are further provided in the main circuit between the branch point P and the expansion valve; and wherein a refrigerant leaving the condenser is divided at the branch point P into a first portion passing through the first heat exchange unit and the second heat exchange unit from the main circuit, and a second portion passing through the first branch to the vapor injection port.

A combined heat exchanger, a heat exchange system, and an optimization method thereof are provided. The heat exchange system includes: an enhanced vapor injection compressor, a condenser, an expansion valve and an evaporator, which are located in a main circuit; wherein the heat exchange system further includes a first branch branched from the main circuit to an vapor injection port of the compressor at a branch point P downstream of the condenser, and a first heat exchange unit and a second heat exchange unit are further provided in the main circuit between the branch point P and the expansion valve; and wherein a refrigerant leaving the condenser is divided at the branch point P into a first portion passing through the first heat exchange unit and the second heat exchange unit from the main circuit, and a second portion passing through the first branch to the vapor injection port.

A method of detecting electrical failure in a refrigeration system is provided. The method includes determining whether a present superheat of the refrigeration system is between a maximum superheat and a minimum superheat for the refrigeration system, the maximum superheat and the minimum superheat defining a normal operating range. The method also includes detecting an electrical property of an expansion valve assembly of the refrigeration system responsive to the superheat being outside the normal operating range. The method further includes determining whether the expansion valve assembly as experienced an electrical failure based on at least the electrical property. A signal indicating that the expansion valve has experienced an electrical failure is generated based on a determination that the expansion valve assembly has experienced the electrical failure.

A method of detecting electrical failure in a refrigeration system is provided. The method includes determining whether a present superheat of the refrigeration system is between a maximum superheat and a minimum superheat for the refrigeration system, the maximum superheat and the minimum superheat defining a normal operating range. The method also includes detecting an electrical property of an expansion valve assembly of the refrigeration system responsive to the superheat being outside the normal operating range. The method further includes determining whether the expansion valve assembly as experienced an electrical failure based on at least the electrical property. A signal indicating that the expansion valve has experienced an electrical failure is generated based on a determination that the expansion valve assembly has experienced the electrical failure.

A refrigeration system configured for controlling operation of a compressor is disclosed. The refrigeration system comprises an electronic expansion device operatively coupled with the compressor. The refrigeration system comprises a controller operatively coupled with the electronic expansion device. The controller is configured to control the electronic expansion valve based on a superheat setpoint range. The controller is further configured to adjust the superheat setpoint range in response to an operating point of the compressor being within a threshold distance from a boundary of an operational envelope for the compressor.

A refrigeration system configured for controlling operation of a compressor is disclosed. The refrigeration system comprises an electronic expansion device operatively coupled with the compressor. The refrigeration system comprises a controller operatively coupled with the electronic expansion device. The controller is configured to control the electronic expansion valve based on a superheat setpoint range. The controller is further configured to adjust the superheat setpoint range in response to an operating point of the compressor being within a threshold distance from a boundary of an operational envelope for the compressor.

A method of operating a heat pump system comprising: operating the heat pump system in a demand operation heating mode, wherein the demand operation heating mode comprises controlling an opening amount of an expansion valve based on a superheat difference between a compressor inlet superheat value and a target compressor inlet superheat value, and controlling a flowrate of the refrigerant through a compressor based on a thermal demand difference between a thermal output of the indoor heat exchanger and a customer thermal demand; monitoring with the one or more controllers a parameter of the refrigerant cycle indicative of a charge imbalance condition; and transitioning operation with the one or more controllers to a charge compensation mode when the parameter satisfies a first threshold condition, wherein the charge compensation mode comprises performing with the one or more controllers a charge imbalance mitigation strategy.