A vehicle air-conditioning apparatus is provided which is capable of expanding an effective range of a dehumidifying and heating mode to achieve comfortable vehicle interior air conditioning. A control device (controller) executes a dehumidifying and heating mode to let a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, let a part of the refrigerant flow from a bypass circuit (refrigerant pipe 13F) to an indoor expansion valve 8, and let the residual refrigerant flow through an outdoor expansion valve 6. In the dehumidifying and heating mode, the control device has a state of controlling the operation of the compressor 2, based on a heat absorber temperature Te and executes a radiator temperature priority mode which enlarges a capability of the compressor when heat radiation in the radiator is insufficient.

A vehicle air-conditioning apparatus is provided which is capable of expanding an effective range of a dehumidifying and heating mode to achieve comfortable vehicle interior air conditioning. A control device (controller) executes a dehumidifying and heating mode to let a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, let a part of the refrigerant flow from a bypass circuit (refrigerant pipe 13F) to an indoor expansion valve 8, and let the residual refrigerant flow through an outdoor expansion valve 6. In the dehumidifying and heating mode, the control device has a state of controlling the operation of the compressor 2, based on a heat absorber temperature Te and executes a radiator temperature priority mode which enlarges a capability of the compressor when heat radiation in the radiator is insufficient.

A refrigeration cycle cools a battery. A controller controls a refrigerant flow rate flowing through a battery cooling system so as to adjust a temperature of the battery. The controller adjusts the refrigerant flow rate flowing in the battery cooling system so that the oil retained in the battery cooling system is flushed toward the compressor. The battery cooling system has a plurality of parallel systems. Electric expansion valves as flow adjusting valves are controlled so as to intermittently provide an oil-back operation. In the oil-back operation, the flow rate of the refrigerant flowing through a part among the plurality of parallel systems is increased more than a flow rate of the refrigerant flowed by a temperature control unit.

A refrigerating cycle device includes a compressor, a motor, and a wiring switch part. The compressor compresses a refrigerant. The motor generates power for compressing the refrigerant by rotating a rotor with voltage applied to a plurality of wirings. The motor is disposed in the compressor. The wiring switch part switches between a plurality of wiring states by changing connection between the plurality of wirings. When a rotational speed of the rotor exceeds a predetermined value, the wiring switch part switches to a first wiring state of the plurality of wiring states. The first wiring state differs from a second wiring state of the plurality of wiring state. Efficiency of the second wiring state is highest at the rotational speed.

A refrigeration cycle apparatus includes a refrigerant circuit including a compressor, a condenser, a pressure reducing device, and an evaporator connected by a refrigerant pipe. A refrigerant including a refrigerant having flammability is used as refrigerant circulating in the refrigerant circuit. The evaporator and the pressure reducing device are accommodated in a unit. The evaporator is disposed in the unit in such a manner that a linear distance between a refrigerant inlet of the evaporator and a refrigerant outlet of the pressure reducing device is shorter than a linear distance between a refrigerant outlet of the evaporator and the refrigerant outlet of the pressure reducing device.

A refrigeration cycle device includes a heating unit, an air-heating expansion valve, an outdoor heat exchanger, an air-cooling expansion valve, an indoor evaporator, and a cooler-unit expansion valve, a cooler unit, and a refrigerant circuit switching unit. In a heating series cooler-unit mode, refrigerant is circulated in order of the heating unit, the air-heating expansion valve, the outdoor heat exchanger, the cooler-unit expansion valve, and the cooler unit. In a heating parallel cooler-unit mode, refrigerant is circulated in order of the heating unit, the air-heating expansion valve, and the outdoor heat exchanger, and refrigerant is circulated in order of the heating unit, the cooler-unit expansion valve, and the cooler unit.

An air-conditioning device includes a refrigerant circuit including a compressor, a heat source-side heat exchanger, an expansion unit, and an intermediate heat exchanger connected by a refrigerant pipe, through which refrigerant circulates; and a heat medium circuit including a pump, the intermediate heat exchanger, and a load-side heat exchanger connected by a heat medium pipe, through which heat medium circulates. A discharge unit connected downstream of the intermediate heat exchanger in the heat medium circuit discharges fluid flowing through the heat medium pipe, depending on pressure of the fluid. A refrigerant concentration detector detects concentration of the refrigerant contained in the fluid discharged from the discharge unit. A notification device notifies leakage of the refrigerant. A controller activates the notification device depending on the concentration of the refrigerant detected.

An air conditioning unit capable of performing a refrigeration cycle using a small-GWP refrigerant is provided. A refrigeration cycle apparatus (1, 1a to 1m) includes a refrigerant circuit (10) including a compressor (21), a condenser (23, 31, 36), a decompressing section (24, 44, 45, 33, 38), and an evaporator (31, 36, 23), and a refrigerant containing at least 1,2-difluoroethylene enclosed in the refrigerant circuit (10).

An air conditioning unit capable of performing a refrigeration cycle using a small-GWP refrigerant is provided. A refrigeration cycle apparatus (1, 1a to 1m) includes a refrigerant circuit (10) including a compressor (21), a condenser (23, 31, 36), a decompressing section (24, 44, 45, 33, 38), and an evaporator (31, 36, 23), and a refrigerant containing at least 1,2-difluoroethylene enclosed in the refrigerant circuit (10).

The reversed single-working-medium vapor combined cycle of the present invitation belongs to the field of thermodynamics, refrigeration and heat pump, which are consists of ten processes: a heat-absorption and vaporization process 1-2 of the M.sub.1 kg of working medium, a pressurization process 2-3 of the M.sub.1 kg of working medium, a heat-absorption process 3-4 of the (M.sub.1+M.sub.2) kg of working medium, a pressurization process 4-5 of the (M.sub.1+M.sub.2) kg of working medium, a heat-releasing process 5-6 of the (M.sub.1+M.sub.2) kg of working medium, a depressurization process 6-3 of the M.sub.2 kg of working medium, a heat-releasing process 6-7 of the M.sub.1 kg of working medium, a pressurization process 7-8 of the M.sub.1 kg of working medium, a heat-releasing and condensation process 8-9 of the M.sub.1 kg of working medium, a depressurization process 9-1 of the M.sub.1 kg of working medium.