Systems and methods of operating a refrigeration system including initiating a compressor shutdown operation (302), recording shutdown conditions (304), calculating one or more restart characteristics based on the recorded shutdown conditions (306), comparing the calculated restart characteristics with one or more compressor restart safety limits (308), when the calculated restart characteristics do not satisfy the restart safety limits, performing a temperature modulation pump down operation (310), and when the calculated restart characteristics satisfy the restart safety limits, completing the compressor shutdown operation (312).

A refrigeration apparatus, comprising: a compressor, the compressor being provided with an air exhaust opening and an air return opening; a condenser, a first end of the condenser being connected to the air exhaust opening; an evaporator, a first end of the evaporator being connected to the air return opening, a throttling element being connected in series between a second end of the evaporator and a second end of the condenser; a first control valve, the first control valve being connected in series between the evaporator and the compressor; an air suction device, a gas port of the air suction device being connected between the first control valve and the air return opening; and a control device, the control device being connected to the compressor, the first control valve, and the air suction device.

A method for controlling a refrigerator comprises: as a first refrigeration cycle for refrigeration of a first storage chamber is operated, operating a compressor and operating a first cold air supply; when the first refrigeration cycle has been operated for a first run time, converting to a second refrigeration cycle for refrigeration of a second storage chamber, and operating a second cold air supply; and if the second refrigeration cycle has been operated for a second run time, stopping the second refrigeration cycle. A first reference time is determined using a representative value obtained based on the temperature of the first storage chamber during a single run cycle, which includes a previous first refrigeration cycle and a previous second refrigeration cycle. A second reference time period is determined using a representative value obtained on the basis of the temperature of the second storage chamber during the single run cycle.

A control unit (19) that controls the operation of a refrigerant circuit (10) executes pump down operation in which a non-azeotropic refrigerant mixture is collected into a portion of the refrigerant circuit (10) within an outdoor unit (2), executes compositional ratio determination in which the compositional ratio of the non-azeotropic refrigerant mixture is determined based on the pressure and temperature of the non-azeotropic refrigerant mixture collected into the outdoor unit (2) by the pump down operation, and generates an alert when the compositional ratio of the non-azeotropic refrigerant mixture determined by the compositional ratio determination is outside an acceptable proportion range of a hydrofluorocarbon having the property of undergoing a disproportionation reaction.

An apparatus includes a flash tank that stores a refrigerant, a first load that uses the refrigerant to cool a first space, second and third loads, first and second compressors, and a high side heat exchanger configured to remove heat from the refrigerant. During a first mode of operation: the second load uses the refrigerant to cool a second space, the third load uses the refrigerant to cool a third space, the second compressor compresses the refrigerant from the second and third loads, and the first compressor compresses the refrigerant from the first load and the second compressor. During a second mode of operation, the second compressor compresses the refrigerant from the second load and directs the compressed refrigerant to the third load to defrost the third load.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a refrigeration system of a building; a leak module configured to diagnose that a leak is present in the refrigeration system based on the amount of refrigerant; and at least one module configured to take at least one remedial action in response to the diagnosis that the leak is present in the refrigeration system.

An apparatus includes a flash tank that stores a refrigerant, a first load that uses the refrigerant to cool a first space, second and third loads, first and second compressors, and a valve. During a first mode of operation: the second load uses the refrigerant to cool a second space, the third load uses the refrigerant to cool a third space, the second compressor compresses the refrigerant from the second and third loads, and the first compressor compresses the refrigerant from the first load and the second compressor. During a second mode of operation: the second compressor compresses the refrigerant from the second load and directs the compressed refrigerant to the third load to defrost the third load and the valve prevents the refrigerant at the third load from flowing to the flash tank until a pressure of the refrigerant at the third load exceeds a threshold.

A system for starting a refrigeration system includes a liquid line regulating valve, a liquid line charging valve, a suction line expansion valve, a suction line charging valve, and a controller. The controller is configured to override normal operation of the refrigeration system and transmit a demand signal to enable partial system operation. The controller is configured to operate the liquid line regulating valve and the liquid line charging valve to charge a receiver tank, gradually increase the demand signal to a predetermined level of partial system operation, and release the liquid line charging valve to normal operation. The controller is configured to operate the suction line expansion valve and the suction line charging valve to charge a suction line, gradually increase the demand signal to full system operation, and release the liquid line regulating valve, the suction line expansion valve, and the suction line charging valve to normal operation.

A refrigeration cycle apparatus capable of performing pump down operation while suppressing degradation in performance is provided. The refrigeration cycle apparatus includes an outdoor heat exchanger, a compressor including an inlet side and an outlet side, at least one indoor heat exchanger, a four-way valve, a check valve including an inlet side and an outlet side, a pipe serving as a first flow path connecting the outlet side of the check valve to the inlet side of the compressor, a first on-off valve, and a refrigerant leak detection device. The refrigeration cycle apparatus is configured such that, when a refrigerant leak is detected by the refrigerant leak detection device, pump down operation is performed as refrigerant transfer operation of transferring the refrigerant from the indoor heat exchanger to the outdoor heat exchanger.

Systems and methods for heating and cooling a vehicle are disclosed herein. In one embodiment, a method for heating and cooling the vehicle includes: running a compressor of an air-conditioning system; and sensing the temperature inside the cab of the vehicle. The method further includes, closing a path of refrigerant to the compressor by a solenoid valve, pumping-down refrigerant by the compressor, and deactivating the compressor when a lower set point of the temperature inside the cab is reached. The method also includes opening the path of refrigerant to the compressor by a solenoid valve, sensing pressure of refrigerant at an inlet of the compressor by a pressure sensor, and activating the compressor based on a signal from the pressure sensor when an upper set point of temperature inside cab is reached.