There is disclosed an air conditioning device for vehicle in which in a defrosting mode to defrost an outdoor heat exchanger, the defrosting of the outdoor heat exchanger can be achieved without hindrance while maintaining heating of a vehicle interior. A refrigerant discharged from a compressor 2 radiates heat in a radiator 4 and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in an outdoor heat exchanger 7 to heat the vehicle interior. The air conditioning device for vehicle includes an injection circuit 40 which distributes a part of the refrigerant flowing out from the radiator 4 to return the part to the compressor 2. When a controller 32 passes the high-temperature refrigerant through the outdoor heat exchanger 7 to perform defrosting, the controller operates the injection circuit 40 to return the refrigerant to the compressor 2.

An exterior heat exchanger is provided with paths P1-P4. The flow rate of the air being blown by an exterior blower to pass through the path P4 closer to a refrigerant outlet of the exterior heat exchanger is set to be higher than that of the air being blown by the exterior blower to pass through the path P1 closer to a refrigerant inlet of the exterior heat exchanger. An air-conditioning controller activates cooling fans during a defrosting mode of operation.

During a normal operation, a refrigeration cycle device is switched to a refrigerant circuit in which heat contained in a high-pressure refrigerant flowing out of an interior radiator is stored in a heat storage member. When frost is formed on an evaporator, the refrigeration cycle device is switched to another refrigerant circuit in which the exterior heat exchanger is heated and defrosted using heat stored in the heat storage member as a heat source. The heat storage member uses a material formed by adding W (tungsten) as an additive to VO.sub.2 (vanadium dioxide) which is a transition metal oxide having a property of a phase transition between a metal and an insulator. The heat storage member effectively stores or dissipates heat depending on a temperature zone of the refrigerant, thereby suppressing an increase in energy consumption of a compressor.

A heat pump system includes a heat pump cycle, a heat medium circulation circuit, and a refrigeration cycle device. The refrigeration cycle device is configured to perform a defrosting operation when a frost formation determiner determines that frost is formed. A throttle opening degree controller is configured to increase an opening degree in the defrosting operation. A pumping capacity controller is configured to increase a pumping capacity in the defrosting operation with increase of a required heating capacity required for heating a heating target fluid, the pumping capacity controller increasing the pumping capacity such that heat of refrigerant discharged from a compressor is transferred to heat medium in a first heat exchanger within a range in which a temperature of the refrigerant flowing into an outside heat exchanger is capable of melting the frost formed on the outside heat exchanger.

A heat pump device includes an air conditioning control device configured to switch the heat pump device among a plurality of operation modes including an air-heating operation mode in which an indoor heat exchanger serves as a radiator and an outdoor heat exchanger serves as a heat absorber, and an air-cooling operation mode in which the indoor heat exchanger serves as a heat absorber and the outdoor heat exchanger serves as a radiator. The air conditioning control device switch a refrigerant pipe such that refrigerant is, in the air-cooling operation mode, supplied to part of the outdoor heat exchanger serving as a refrigerant inlet in the air-heating operation mode.

Methods and systems for reducing the possibility of heat pump evaporator fin freezing are described. Evaporator fin temperature is compared to a threshold temperature that varies with vehicle operating conditions. Actions to mitigate evaporator fin freezing may be taken if evaporator fin temperature is less than the threshold temperature.

A transport refrigeration system is configured to set a first path, a second path, a third path, and fourth path selectively. The first path connects compressors in series. In the first path, interior heat exchangers each serve as an evaporator. The second path connects the compressors in series. In the second path, the interior heat exchangers each serve as a condenser. The third path connects the compressors in parallel. In the third path, at least one of the interior heat exchangers serve as the evaporator and the rest of the interior heat exchangers serve as the condenser. The fourth path connects the compressors in parallel. In the fourth path, the interior heat exchangers each serve as the condenser.

A method for controlling an air condition arrangement of a vehicle. The air condition arrangement includes a heat pump system having a compressor, a condenser, and an evaporator. An air distribution unit is arranged in the vehicle for providing air to a vehicle compartment of the vehicle. The method includes directing a flow of air heated by the condenser by work from the compressor to the evaporator.

There is disclosed a vehicle air-conditioning device in which a heating qualification by gas injection can sufficiently be obtained. The vehicle air-conditioning device comprises a compressor 2 which compresses a refrigerant, an air flow passage 3 through which air to be supplied into a vehicle interior flows, a radiator 4 disposed in the air flow passage to let the refrigerant radiate heat, a heat absorber 9 disposed in the air flow passage to let the refrigerant absorb heat, an outdoor heat exchanger 7 disposed outside the vehicle interior to let the refrigerant radiate or absorb heat, and a controller. The controller executes a heating mode in which the refrigerant discharged from the compressor 2 radiates heat in the radiator 4 and the refrigerant by which heat has been radiated is decompressed and then absorbs heat in the outdoor heat exchanger 7. The vehicle air-conditioning device comprises an injection circuit 40 which distributes a part of the refrigerant flowing out from the radiator 4 to return the refrigerant to the middle of compression by the compressor 2, and the injection circuit 40 has an expansion valve 30, and a discharge side heat exchanger 35 which performs heat exchange between the refrigerant decompressed by the expansion valve 30 and the refrigerant discharged from the compressor 2 before flowing into the radiator 4.

A refrigeration cycle device includes: a high-pressure side heat exchanger; a low-pressure side heat exchanger; a vehicle-mounted device that supplies heat to the heat medium; a heat-medium air heat exchanger that exchanges heat between the heat medium and air; a switching portion that switches between a state in which the heat medium circulates through the high-pressure side heat exchanger and a state in which the heat medium circulates through the low-pressure side heat exchanger with respect to each of the vehicle-mounted device and the heat-medium air heat exchanger; and a controller that drives the compressor, while controlling an operation of the switching portion to switch to a defrosting mode in which the heat medium circulates between the low-pressure side heat exchanger and the vehicle-mounted device, and the heat medium circulates between the high-pressure side heat exchanger and the heat-medium air heat exchanger, when defrosting of the heat-medium air heat exchanger is necessary.