A controller for a refrigeration system includes a processing circuit having one or more processors and memory. The processing circuit is configured to calculate a superheat of a gas refrigerant exiting a first side of a subcooler based on a measured temperature and a measured pressure of the gas refrigerant and compare the calculated superheat to a superheat threshold. In response to a determination that the calculated superheat is less than the superheat threshold, the processing circuit closes an expansion valve to restrict a flow of the gas refrigerant through a second side of the subcooler. In response to a determination that the calculated superheat is equal to or greater than the superheat threshold, the processing circuit operates the expansion valve to drive a temperature of a subcooled liquid refrigerant exiting the second side of the subcooler to a subcooled liquid temperature setpoint.

A refrigeration system includes an evaporator within which a refrigerant absorbs heat, a gas cooler/condenser within which the refrigerant rejects heat, a compressor operable to circulate the refrigerant between the evaporator and the gas cooler/condenser, a high pressure valve operable to control a pressure of the refrigerant at an outlet of the gas cooler/condenser, and a controller. The controller is configured to automatically generate a setpoint for a measured or calculated variable of the refrigeration system based on a measured temperature of the refrigerant at the outlet of the gas cooler/condenser. The setpoint is generated using a stored relationship between the measured temperature and a maximum estimated coefficient of performance (COP) that can be achieved at the measured temperature. The controller is configured to operate the high pressure valve to drive the measured or calculated variable toward the setpoint.

A diaphragm pressure regulator includes: a body defining a process surface and including: an exhaust port having a discharge opening, and at least one vent void interconnecting the process surface and the exhaust port; and an inlet port, and at least one process void communicating with the process surface and the inlet port; a reference housing including a cavity defining a reference surface and a reference port in fluid communication with the cavity; and a diaphragm disposed between the body and the reference housing, the diaphragm movable between a first position engaged with the vent voids, and a second position wherein the membrane is not engaged with at least one of the vent voids, wherein a dome is defined between the cavity and the reference side of the diaphragm; and wherein the reference housing includes a sump configured to segregate liquid from the reference side of the diaphragm.

A controller for a refrigeration system includes a processing circuit having one or more processors and memory. The processing circuit is configured to calculate a superheat of a gas refrigerant exiting a first side of a subcooler based on a measured temperature and a measured pressure of the gas refrigerant and compare the calculated superheat to a superheat threshold. In response to a determination that the calculated superheat is less than the superheat threshold, the processing circuit closes an expansion valve to restrict a flow of the gas refrigerant through a second side of the subcooler. In response to a determination that the calculated superheat is equal to or greater than the superheat threshold, the processing circuit operates the expansion valve to drive a temperature of a subcooled liquid refrigerant exiting the second side of the subcooler to a subcooled liquid temperature setpoint.

A controller for a refrigeration system includes a processing circuit having one or more processors and memory. The processing circuit is configured to calculate a superheat of a gas refrigerant exiting a first side of a subcooler based on a measured temperature and a measured pressure of the gas refrigerant and compare the calculated superheat to a superheat threshold. In response to a determination that the calculated superheat is less than the superheat threshold, the processing circuit closes an expansion valve to restrict a flow of the gas refrigerant through a second side of the subcooler. In response to a determination that the calculated superheat is equal to or greater than the superheat threshold, the processing circuit operates the expansion valve to drive a temperature of a subcooled liquid refrigerant exiting the second side of the subcooler to a subcooled liquid temperature setpoint.

Embodiments relate generally to subcooling control of a heating, ventilation, and air conditioning (HVAC) system. An HVAC system may include a first electronic expansion valve (EEV) fluidly coupled to an indoor coil, wherein the first EEV is adjacent to the indoor coil. The HVAC system may also include a second EEV fluidly coupled to an outdoor coil, wherein the second EEV is adjacent to the outdoor coil. A system controller may be configured to control the first and second EEVs to control a flow of refrigerant to control subcooling (SC) produced by the HVAC system. The second EEV remains open during a cooling mode, and the first EEV modulates during the cooling mode. The second EEV modulates during a heating mode, and the first EEV remains open during the heating mode.

Described is, among other things, a method and an apparatus for control of a cooling device. The cooling device comprise a circuit in which a refrigerant fluid is circulated in a fluid path where the circuit comprises a compressor and a condenser provided down streams the compressor. A fluid expansion device is provided down streams the condenser and an evaporator is provided between the fluid expansion device and the compressor. The circuit further comprises a valve provided in the fluid path between the condenser and the fluid expansion device. The method comprises to during an on-cycle of the compressor controlling the valve opening to provide a variable fluid mass flow of the refrigerant fluid circulated in the circuit where the valve opening is controlled to decrease during the on-cycle of the compressor.

The invention relates to a refrigeration installation (1), to a method for same, and to a refrigeration installation system for controlling the temperature of air, including at least one compressor (3), at least one expansion element (39), and at least one first (5) and a second (7) heat exchanger, each of which can be operated as a condenser or a gas cooler, wherein at least one of the heat exchangers can be operated as an evaporator or at least one additional heat exchanger is provided which can be operated as an evaporator. A refrigerant line is equipped with a first valve (11) downstream of at least one compressor (3) at or downstream of a branch (9) and upstream of or at the condenser or gas cooler inlet (15) of the first heat exchanger (5), and a second valve (19) is arranged at or downstream of the condenser or gas cooler outlet (17) of the first heat exchanger (5) and upstream of or as an expansion element. The refrigeration installation (1) contains at least one valve controller (13) for the first (11) and second valve (19) with at least one first and second possible valve set-up in order to displace the refrigerant, wherein the first valve (11) is open while the second valve (19) is closed at the same time in the first set-up and vice versa in the second set-up. The valve controller (13) comprises an automatic regulator which sets the first valve switch set-up for at least one heat exchanger (5, 7) which is not being used as a with refrigerant flowing through condenser or gas cooler at the moment when a specified refrigerant quantity is exceeded in the refrigerant circuit through which refrigerant is flowing.

A refrigerator includes a main body having a freezing chamber and a switchable chamber communicating with a refrigerating chamber through a duct, a compressor connected with a compressor suction path and a compressor discharging path, a condenser connected with the compressor discharging path and connected with a condenser discharging path, a switchable chamber evaporator, a freezing chamber evaporator connected with the switchable chamber evaporator through an evaporator connection path, a damper configured to control flow of cold air through the duct, a pair of switchable chamber capillary tubes connected with the switchable chamber evaporator, a bypass capillary tube connected with the evaporator connection path, a path switching device connected with the condenser discharging path, the pair of switchable chamber capillary tubes and the bypass capillary tube, and a controller for controlling the compressor, the damper and the path switching device.

In an under counter type refrigerator, when a defrosting period arrives, air of a storage compartment may be supplied towards an evaporator to perform a defrosting operation (natural defrosting operation) for removing frost generated on the evaporator, thereby improving defrosting efficiency and reducing power consumption.