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.

An electric compressor includes a compression portion discharging a high pressure refrigerant by compressing a low-pressure drawn refrigerant, an electric motor driving the compression portion with a rotation of a rotor, a motor drive circuit driving the electric motor, an intermediate pressure port through which an intermediate pressure refrigerant is introduced into the compression portion, and a controller performing a rotation control of the rotor. When the controller stops the electric motor in a two-step compression mode in which the intermediate pressure refrigerant is introduced into the compression portion, the controller stops the rotor rotating by performing short-circuit braking on the electric motor and then fixes a rotational position of the rotor at a predetermined rotational position by performing direct current excitation on the electric motor.

A heat-pump air-conditioning hot-water supply device includes a first refrigerant passage connecting a compressor and a decompressor, a second refrigerant passage branching from between the compressor and a first solenoid valve and connecting a second solenoid valve, a hot-water supply heat exchanger, and the decompressor, a pressure sensor configured to measure discharge pressure of the compressor, and a control device configured to adjust an operational frequency of the compressor and adjust an opening degree of a valve of the decompressor. The control device is configured to calculate a condensing temperature from the discharge pressure, and perform operation in one of an air conditioning prioritized mode in which a preset operational frequency of the compressor is changed, and an energy saving prioritized mode in which the opening degree of the valve of the decompressor is changed, when the condensing temperature is not lower than a set condensing temperature.

A domestic refrigeration appliance has a heat-insulated housing with a coolable inner container delimiting a coolable interior for storing foods. The interior is cooled with a coolant circuit that includes a compressor with a three-phase motor operated by an actuator via electrically powered motor windings. The actuator is actuated at least indirectly to operate the compressor in a switched-on state with a rotational speed of the three-phase motor at least approximately equal to a predetermined rotational speed. The actuator is caused to switch off the compressor such that the rotational speed of the three-phase motor decreases to a predetermined minimum rotational speed, and thereafter to switch off the three-phase motor for at least a predetermined period of time by de-energizing the motor windings. The period of time is selected long enough to reduce the speed of the motor, beginning from the minimum rotational speed, to reach standstill.

An air conditioner for a vehicle has a compressor, a radiator, a first pressure reducer, a gas-liquid separator, a second pressure reducer, an exterior heat exchanger, an intermediate pressure refrigerant passage, a switching device, and a controller. The controller operates the switching device to switch from a refrigerant circuit of a two-stage compression mode to a refrigerant circuit of a single-stage compression mode when a compressor stop signal is output in the two-stage compression mode. The single-stage compression mode is a mode that blocks at least a flow of an intermediate-pressure refrigerant into the intermediate pressure refrigerant passage and makes refrigerant remained in the intermediate pressure refrigerant passage to flow out of the intermediate pressure refrigerant passage. The controller stops the compressor after controls the compressor to continue operating for a specified time in the single-stage compression mode. The controller restarts the compressor when the compressor stop signal is canceled.

Provided is a heat pump system that can appropriately manage the number of heat pumps in operation even when any of the heat pumps is defrosting, and that can always operate at a capacity that corresponds to a load. Also provided is an operation method for the heat pump system. A heat pump system (1) wherein a plurality of heat pumps (10A-10C (13A-13D)) are connected to a system load and wherein a system management unit (27) successively calculates the capacity that can be output by the heat pumps (10A-10C (13A-13D)) in operation, compares the calculated capacity value, as a threshold value, to the thermal load of the system load, and manages the number of heat pumps (10A-10C (13A-13D)) in operation.

A refrigeration device includes a blow-out temperature detector that detects the blow-out temperature of air blown out into the interior of the device, a cargo temperature detector that detects the temperature of a cargo, an operation controller that performs cooling control of the interior on the basis of the detection temperature from the blow-out temperature detector and the detection temperature from the cargo temperature detector, a storage unit that stores a first set temperature as a control target value for the blow-out temperature and a cargo target temperature as a target value for the temperature of the cargo, and a time measurement unit that measures a treatment time elapsed for low-temperature treatment of the cargo. The operation controller is configured to control the refrigerant circuit so that the blow-out temperature approaches the first set temperature. The time measurement unit is configured to start measuring the treatment time when the temperature of the cargo is lower than the cargo target temperature.

A purging device equipped with: a purging pipe for purging a gas mixture containing a coolant and a non-condensable gas from a chiller; a purging tank for storing the gas mixture purged from the purging pipe; a cooling device which cools the interior of the purging tank and condenses the coolant in the gas mixture; a drainage pipe for discharging the liquid coolant inside the purging tank to the chiller; an exhaust pipe for discharging the non-condensable gas in the gas mixture inside the purging tank to the exterior; and a control unit which stops operation of the purging device when the discharged non-condensable gas amount discharged from the exhaust pipe exceeds the introduced non-condensable gas amount introduced into the chiller.

In order to improve a method for selecting a frequency converter for a refrigerant compressor unit that includes a refrigerant compressor and an electric drive motor such that the frequency converter is selected in a manner for optimized use, it is proposed that a working state suitable for operation of the refrigerant compressor unit should be selected within an application field of an application graph of the refrigerant compressor, that an operating frequency for this selected working state should be selected, and that a working state operating current value that corresponds to the selected working state and the selected operating frequency should be determined from drive data, for operation of the refrigerant compressor unit.

A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identified if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.