Abstract: There is disclosed a controller for a refrigeration circuit, configured to monitor a set of prevailing conditions relating to the refrigeration circuit including a space temperature of a temperature-controlled space associated with the refrigeration circuit. The controller has a simulation module configured to determine a limit setting of a control variable for the refrigeration circuit by an iterative optimisation procedure based on a model corresponding to the refrigeration circuit. The objective function for the optimisation relates to an operating efficiency. The controller further comprises a dynamic control module configured to: adjust an operating setting of the control variable within an operating range to target a performance threshold for a monitored performance parameter, based on monitoring of the performance parameter during operation of the refrigeration circuit; and apply the limit setting received from the simulation module as a limit to the operating range.

Abstract: 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.

Abstract: There is disclosed an environmental control system for thermally conditioning air within an enclosed space, the system comprising: a refrigerant circuit having a compressor, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger. The system comprises an exhaust flowpath having a first inlet for receiving an exhaust flow of thermally conditioned air from the enclosed space and an outlet for discharging the exhaust flow to an external environment. A heat transfer section of the outdoor heat exchanger is located in the exhaust flowpath, wherein the exhaust flowpath is for directing the exhaust flow of thermally conditioned air through the heat transfer section of the outdoor heat exchanger.

Abstract: There is disclosed an environmental control system for thermally conditioning air within an enclosed space comprising: a refrigerant circuit having a compressor, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger. The system further comprises an intake flowpath for directing an intake flow of fresh air to the enclosed space, wherein a heat-transfer section of the indoor heat exchanger is located within the intake flowpath to thermally condition the intake flow of fresh air before entering the enclosed space. The system further comprises an exhaust flowpath for directing an exhaust flow of thermally conditioned air to an external environment. A recovery heat exchanger is provided to transfer thermal energy between the exhaust flow and the intake flow at a location within the intake flowpath that is upstream of the heat-transfer section of the indoor heat exchanger.

Abstract: An evaporator apparatus for a refrigeration cycle of an HVAC system or a refrigeration system is disclosed that includes: a primary evaporator pathway for a working fluid of the refrigeration cycle extending through a primary expansion device and a primary evaporator; a secondary evaporator pathway for the working fluid in parallel with the primary evaporator pathway and extending through a secondary expansion device and a secondary evaporator; a coolant circuit for cooling a device, the secondary evaporator configured for heat exchange between the working fluid and process fluid of the coolant circuit; and a controller configured to control: the primary expansion device to maintain a target superheat of working fluid at a primary control location downstream of the primary evaporator; and the secondary expansion device based on monitoring a temperature of process fluid to maintain a target temperature of process fluid at a coolant control location in the coolant circuit.

Abstract: There is disclosed an environmental control system for heating at least one enclosed space. The system comprises a heat-pump circuit that includes a compressor, a heat-output stage, an expansion device and an evaporator arranged in series along a flow path for a refrigerant. The heat-output stage comprises a primary heat exchanger and a secondary heat exchanger that are both configured to transfer heat from the refrigerant to one or more external mediums in thermal communication with the at least one enclosed space. The primary heat exchanger and the secondary heat exchanger are connected in series along the flow path, such that the secondary heat exchanger will transfer excess heat energy remaining within the refrigerant after passing through the primary heat exchanger to the one or more external mediums.

Abstract: A method for defrosting a heat exchanger of a refrigeration circuit is provided. The method includes monitoring a compressor suction parameter at a suction line to a compressor of the refrigeration circuit. The method also includes determining a compressor suction parameter threshold. Also, the method includes initiating a defrost mode of the refrigeration circuit when the compressor suction parameter is less than or equal to the compressor suction parameter threshold.