A refrigeration apparatus includes a heat source-side unit and a utilization-side unit that are connected to each other, and performs a refrigeration cycle in which a high pressure of a refrigerant reaches or exceeds a critical pressure. The refrigeration apparatus also includes a control unit configured to perform a first action of returning the refrigerant to the heat source-side unit when a stop condition of the utilization-side unit is satisfied, and a second action of prohibiting the first action when a pressure at the heat source-side unit is equal to or more than the critical pressure of the refrigerant. This configuration suppresses damage to a refrigerant storage reservoir and the like in returning the refrigerant to the heat source-side unit.

A preheater for a compressor that is capable of heating a lubricant oil efficiently with smaller power is provided. A preheater for a compressor includes: a capacitive oil surface sensor that is provided at a compressor used in a refrigerating cycle, and detects an oil surface of a lubricant oil A in the compressor; and a power supply unit that applies high-frequency voltage to the oil surface sensor.

An air-conditioning apparatus includes a compressor, a four-way valve, expansion means, and an indoor heat exchanger, and further includes a check valve disposed between a discharge side of the compressor and the four-way valve, a first solenoid valve disposed between the expansion means and the indoor heat exchanger, and a controller. Opening and closing of the first solenoid valve are controllable. The controller switches the four-way valve and switches the first solenoid valve between open and closed states. When a heating operation is stopped, the controller switches the four-way valve from connection for the heating operation to connection for a cooling operation, closes the first solenoid valve, and then stops the compressor.

The refrigeration cycle apparatus includes: liquid-side connection piping that extends from liquid-side refrigerant piping; gas-side connection piping that extends from gas-side refrigerant piping; a refrigerant storage tank that stores refrigerant, an intake side thereof being connected to the liquid-side connection piping, and a discharge side thereof being connected to the gas-side connection piping; an inlet-side electromagnetic valve that is disposed on the liquid-side connection piping, and that is opened when there is no passage of electric current; an inlet-side check valve that is disposed on the liquid-side connection piping, and that allows the refrigerant to flow only toward the refrigerant storage tank; and a valve apparatus that is disposed on the gas-side connection piping, that is opened during passage of electric current to the inlet-side electromagnetic valve, and that is delayed before being shut off after passage of electric current to the inlet-side electromagnetic valve is stopped.

A high pressure compressor according to the present disclosure and a refrigerating cycle device to which the high pressure compressor is applied may include a casing having a sealed inner space; drive motor provided in the inner space of the casing; a compression unit provided in the inner space of the casing, and provided with a compression space for compressing refrigerant, and provided with a suction port for guiding refrigerant into the compression space, and provided with a discharge port for guiding refrigerant compressed in the compression space into the inner space of the casing a discharge valve provided in the compression unit to selectively open or close the discharge port according to a difference between a pressure of the inner space of the casing and a pressure of the compression space of the compression unit; a first valve configured to suppress refrigerant discharged from the inner space of the casing from flowing backward into the inner space of the casing; a bypass pipe connected between a discharge side and a suction side of the compression unit based on the compression unit; and a second valve provided at the bypass pipe to selectively open or close the bypass pipe.

An air conditioner includes an outdoor unit, a plurality of indoor units, a plurality of expansion valves which are provided upstream of indoor heat exchangers, a plurality of on-off valves which are provided upstream of the expansion valves, and control unit wherein when the indoor units include a stopping indoor unit and an operating indoor unit currently operating, and when a stopping of the stopping unit is due to thermostat-off operation, the control unit performs a procedure to stop the stopping unit, the procedure including closing an on-off valve that corresponds to the stopping unit and driving an indoor fan in the stopping unit until pressure in a part between the on-off valve and an expansion valve that corresponds to the stopping unit and pressure in a part downstream of the first expansion valve are equalized, fully opening the expansion valve, and stopping the indoor fan.

A refrigeration cycle apparatus includes a refrigeration cycle in which refrigerant circulates, the refrigeration cycle including a compressor, an outdoor heat exchanger, expansion valves, and indoor heat exchangers, which are connected to each other via a refrigerant pipe, a heat source unit accommodating the outdoor heat exchanger, use-side units accommodating the indoor heat exchangers, and a control unit that controls at least turning on and off of the refrigeration cycle. The control unit detects abnormality of the refrigeration cycle based on the pressure or temperature of the refrigeration cycle in an off time of the refrigeration cycle.

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 refrigeration system and a start control method for a refrigeration system. The refrigeration system includes: a refrigeration loop having an exhaust port of a compressor, a condenser, a throttle element, an evaporator, and a suction port of the compressor connected in sequence by using a flow path; wherein a first valve is disposed between the throttle element and the condenser, and the first valve is at least capable of cutting off a refrigerant flow from the throttle element to the condenser; and a second valve is disposed close to the suction port of the compressor, and the second valve is used to control on/off of a flow path between the evaporator and the compressor. Starting load of the refrigeration system according to the present invention can be effectively reduced, so that the power and size of a drive component for providing power can also be reduced.

The present application provides a vacuum pump (15) for use during maintenance or commissioning of an HVAC-R system (1). The vacuum pump (15) has a pump (17) having a pump intake (22) for connection to the HVAC-R system (1), in particular one or more of a high pressure service port (14) and a low pressure service port (13) of the HVAC-R system (1). The vacuum pump (15) also includes a communications unit (19) that is configured to connect to a mobile communications network. The vacuum pump (15) also includes a pressure sensor arranged to detect a pressure in the HVAC-R system (1). The vacuum pump (15) also includes a control unit (18) configured to receive pressure data from the pressure sensor (21), control operation of the pump (17), and communicate with a remote device via the communication unit (19) and the mobile communications network. In examples, the remote device (20) may be a mobile phone or a tablet computer, or any device that can connect to a mobile communications network. Therefore, the vacuum pump (15) can remotely communicate updates to the remote device (20) over a mobile communications network, and can optionally also receive instructions or requests from the remote device (20) over a mobile communications network.