Upon detection of a leakage of refrigerant, a refrigerant recovery operation is performed for operating a compressor in a state where an outdoor expansion valve is closed. The refrigerant suctioned from an indoor unit passes through an outdoor heat exchanger so as to be liquefied and accumulated in an outdoor unit. When a low-pressure detection value by a pressure sensor decreases below a reference value, a termination condition for the refrigerant recovery operation is satisfied, and the compressor is stopped. Furthermore, when an abnormality in the refrigerant recovery operation is detected based on a behavior of the low-pressure detection value obtained until the termination condition is satisfied, the compressor is stopped to thereby end the refrigerant recovery operation. Also, guidance information for notification about an abnormality is output to a user.

When a controller receives an instruction for a heating operation, the controller switches an operation mode of a refrigeration cycle apparatus between a heating operation mode and an oil recovery operation mode. The heating operation mode is a mode to circulate refrigerant in a refrigerant circuit such that the refrigerant flows through a gas extension pipe in a gas phase state. The oil recovery operation mode is a mode to circulate the refrigerant in the refrigerant circuit such that the refrigerant flows in the gas extension pipe in a gas-liquid two-phase state. The direction in which the refrigerant flows in the gas extension pipe in the oil recovery operation mode is opposite to that in which the refrigerant flows in the gas extension pipe in the heating operation mode.

A method for diluting a leaked refrigerant in a refrigeration system according to an example of the present disclosure includes operating the refrigeration system in a purge mode based on at least one purge condition prior to initiating a compressor of the refrigeration system. A refrigeration system according to an example of the present disclosure includes a compressor configured to compress refrigerant in a refrigerant line, a heat exchanger configured to exchange heat with the refrigerant line in a heat exchange mode, a fan configured to pass air through the heat exchanger to an indoor space, and a controller configured to operate the refrigeration system in a purge mode based on at least one purge condition prior to initiating the compressor.

Disclosed are climate systems and methods for control the climate systems. A climate system includes a refrigerant circuit, a first compressor, a second compressor, a first refrigerant-to-air heat exchanger, a second refrigerant-to-air heat exchanger, and a controller communicatively coupled to the first and second compressors. Respective outlets of the first and second compressors are fluidically coupled to the first refrigerant-to-air heat exchanger, the first refrigerant-to-air heat exchanger is fluidically coupled to the second refrigerant-to-air heat exchanger, and the second refrigerant-to-air heat exchanger is fluidically coupled with respective inlets of the first and second compressors. The fluidic connection between the second refrigerant-to-air heat exchanger and the first and second compressors includes a vertical split that is configured to mitigate or reduce the amount of compressor oil that migrates to dormant components.

A defrost method for a heat pump system includes running the heat pump system in a heating mode to provide heat to an enclosed space and determining if an outdoor temperature is less than an outdoor threshold temperature. Responsive to a determination that the outdoor temperature is below the outdoor threshold temperature, determining if a calibration state has been previously run. Responsive to a determination that the calibration state has not been previously run, running the heat pump system in the calibration state. Responsive to a determination that the calibration state has been previously run, determining if a temperature difference between a temperature of an evaporator coil of the heat pump system and the outdoor temperature exceeds a temperature threshold value. Responsive to a determination that the temperature difference between the evaporator coil and the outdoor temperature is greater than the temperature threshold value, running the heat pump system in a defrost state.

A refrigeration cycle apparatus includes: a refrigerant circuit which includes a compressor; a communication device that receives control information from a cloud server; and a controller having a storage unit for storing the control information received by the communication device. The controller controls the compressor, using the control information stored in the storage unit. As the communication device starts receiving, from a cloud server, updated control information that is newer than the control information before the update stored in the storage unit, the controller continues a pre-update control of causing the compressor to operate, using the already-received control information before the update, without forcibly stopping the operation of the compressor, until writing of the updated control information to the storage unit is completed.

A control device for a refrigerator system for cooling a load by using a plurality of refrigerators, said control device comprising a unit to control the number of operating units that changes the number of operating refrigerators according to the load rate, and a cold water temperature acquisition unit that acquires, via a temperature sensor, the temperature of cold water affected by the refrigerators. After a prescribed standby time from when the number of operating refrigerators was changed has elapsed, the unit to control the number of operating units changes the number of operating units and reduces the prescribed standby time when at least one of the cold-water temperature and the rate of change in the cold-water temperature satisfies a prescribed condition.

An air-conditioning apparatus includes a refrigerant circuit including a compressor, a strainer, and an expansion valve, and a controller configured to control the expansion valve in the refrigerant circuit. In the air-conditioning apparatus, in a case where the expansion valve is closed, the controller performs control to close the expansion valve after opening the expansion valve to cause an opening port diameter of the expansion valve to be greater than a mesh diameter of the strainer.

A method for controlling a vapour compression system, in particular an opening degree of an expansion valve. According to a first control strategy, the expansion valve is closed until the superheat value has increased above a lower threshold superheat value. According to a second control strategy, the expansion valve is kept open until the suction pressure has increased above a lower threshold suction pressure value. In the case of low superheat value as well as low suction pressure, the second control strategy is selected for a limited period of time.

A refrigeration system includes a receiver, a gas bypass valve, a parallel compressor, and a controller. The gas bypass valve and the parallel compressor are fluidly coupled to an outlet of the receiver in parallel and configured to control a pressure of a gas refrigerant in the receiver. The controller is configured to switch from operating the gas bypass valve to operating the parallel compressor to control the pressure of the gas refrigerant in the receiver in response to a value of a process variable crossing a switchover setpoint. The value of the process variable depends on an amount of the gas refrigerant produced by the refrigeration system. The controller is configured to automatically adjust the switchover setpoint in response to the amount of the gas refrigerant produced by the refrigeration system being insufficient to sustain operation of the parallel compressor.