It is determined whether thermo-off postponement control is allowed or not on the basis of a current compressor operating frequency when a thermo-off condition is satisfied. If it is determined that thermo-off postponement control is allowed, the thermo-off postponement control in which a lowest operating frequency in an operating frequency range of a compressor is temporarily reduced within a range greater than or equal to a minimum operating frequency of the compressor in use so as to continue an operation. If it is determined that thermo-off postponement control is not allowed, thermo-off of stopping the compressor is performed.

An air conditioner which continues driving with a deteriorated gas leakage sensor is provided. An air conditioner of the present invention includes an outdoor unit including a compressor and an indoor unit connected with the outdoor unit and uses flammable refrigerant. The air conditioner includes: a refrigerant gas sensor; and a controlling unit configured to stop the compressor at occurrence of abnormality, when the refrigerant gas sensor detects refrigerant gas while the compressor is being driven. After the compressor is stopped as the refrigerant gas sensor detects the refrigerant gas, the controlling unit does not start driving of the compressor until an operation to cancel the abnormality is performed.

A method for controlling a vapour compression system (1) is disclosed, the vapour compression system (1) comprising an ejector (5). The method comprises controlling a compressor unit (2) in order to adjust a pressure inside a receiver (6), on the basis of a detected pressure of refrigerant leaving an evaporator (8). The portion of refrigerant leaving the evaporator (8) which is supplied to a secondary inlet (15) of the ejector is maximised and the portion of refrigerant supplied directly to the compressor unit (2) is minimised, while ensuring that the pressure of refrigerant leaving the evaporator (8) does not decrease below an acceptable level.

Methods of operation for refrigerator appliance configurations with a controller, a condenser, at least one evaporator, a compressor, and two refrigeration compartments. The configuration may be equipped with a variable-speed or variable-capacity compressor, variable speed evaporator or compartment fans, a damper, and/or a dual-temperature evaporator with a valve system to control flow of refrigerant through one or more pressure reduction devices. The methods may include synchronizing alternating cycles of cooling each compartment to a temperature approximately equal to the compartment set point temperature by operation of the compressor, fans, damper and/or valve system. The methods may also include controlling the cooling rate in one or both compartments. Refrigeration compartment cooling may begin at an interval before or after when the freezer compartment reaches its lower threshold temperature. Freezer compartment cooling may begin at an interval before or after when the freezer compartment reaches its upper threshold temperature.

Systems, apparatus and methods for operating a chiller plant while minimizing or eliminating the occurrence of centrifugal compressor surge. Taking into account chiller design specifications and current operating conditions, a compressor lift point at which surge is predicted to occur is established. Minima and maxima for various chiller setpoints that avoid or eliminate the occurrence of compressor surge are imposed on setpoints provided by a conventional optimizing chiller controller. The chiller system is operated in accordance with the resultant anti-surge setpoints. Coolant tower flow is modulated to enable the compressor to operate at near-surge conditions while preventing the onset of actual surge.

An outdoor HVAC unit includes a housing. A compressor is located within the housing. A heat exchanger is located within the housing and is in fluid communication with the compressor. At least one expansion device is located within the housing and is in fluid communication with the heat exchanger.

A freezing device including a compressor that compresses sucked refrigerant using a compression mechanism and discharges compressed refrigerant includes a compressor, an inverter, and a controller. The compressor includes a motor, a low pressure unit, a compression space, a high pressure unit, a communication flow path, and a flow control valve. The inverter drives or stops the motor. The controller controls the inverter and the flow control valve. The controller performs, in stop control in which an operation of the compressor is stopped, braking control in which driving of the compression mechanism is prevented or suppressed, and pressure equalization control in which pressure in the high pressure unit is equalized with pressure in the low pressure unit.

A heating, ventilation, air conditioning, and refrigeration (HVACR) protection system can include a pressure sensor operable to sense a pressure within a refrigerant line operably coupled to a compressor; a timer; and a protection system controller. The protection system controller can be in communication with the pressure sensor, the timer, and a compressor controller operable to control operation of the compressor. The protection system controller can disable the compressor controller from operating the compressor until successful completion of a vacuum test of at least the refrigerant line. The protection system controller can be configured to initiate the vacuum test upon the pressure sensor sensing the pressure of the refrigerant line less than or equal to a vacuum test pressure, at which point the timer begins timing for a vacuum test time period. The vacuum test can be successfully completed upon expiration of the vacuum test time period and the pressure of the refrigerant line remained less than or equal to the vacuum test pressure for the duration of the vacuum test time period. Additionally, the protection system controller can be configured to enable operation of the compressor controller to operate the compressor upon successful completion of the vacuum test.

A cooling system is designed to generally allow for one or more compressors to be bypassed when ambient temperatures are low. The system includes a bypass line and valve that opens when ambient temperatures are low and/or when the pressure of the refrigerant in the system is low. In this manner, the refrigerant can flow through the bypass line instead of through one or more compressors. These compressors may then be shut off. To supply any needed pressure to cycle the refrigerant, the system may include a pump that turns on when the bypass line is open. When ambient temperatures are extremely low, thermosiphon may be used to cycle the refrigerant.

A method of controlling a transport climate control system includes detecting for leaking of working fluid from a climate control circuit. The method also includes isolating a high-pressure side of the climate control circuit when leaking of the working fluid is detected. A method of controlling a transport climate control circuit includes detecting for overcharge and/or an undercharge of the climate control circuit. A transport climate control system includes a climate control circuit and a climate controller that is configured to detect for working fluid leaking from the climate control circuit. The climate controller configured to isolate a high-pressure side of the climate control circuit when leaking of the working fluid is detected.