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.

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.

An integrated valve includes a connecting member including a first valve element and a second valve element. The first valve element is disposed in a pressure reducing chamber of a body of the integrated valve and forms a pressure reducing valve that reduces the pressure of the refrigerant discharged from a compressor. The second valve element is disposed in an on-off valve chamber of the body and forms an on-off valve for adjusting a flow rate of the refrigerant flowing into an intermediate-pressure port of the compressor. The on-off valve is in a fully opened state when the pressure reducing valve is in a throttling state, the on-off valve is in an opened state when the pressure reducing valve is in an opened state, and the on-off valve is in a closed state when the pressure reducing valve is in a fully opened state.

A cooling system drains oil from low side heat exchangers to vessels and then uses compressed refrigerant to push the oil in the vessels back towards a compressor. Generally, the cooling system operates in three different modes of operation: a normal mode, an oil drain mode, and an oil return mode. During the normal mode, a primary refrigerant is cycled to cool one or more secondary refrigerants. As the primary refrigerant is cycled, oil from a compressor may mix with the primary refrigerant and become stuck in a low side heat exchanger. During the oil drain mode, the oil in the low side heat exchanger is allowed to drain into a vessel. During the oil return mode, compressed refrigerant is directed to the vessel to push the oil in the vessel back towards a compressor.

A refrigerant circuit includes a first compressor connected to a first suction pipe and a first discharge pipe and configured to compress a refrigerant, a second compressor connected to a second suction pipe and a second discharge pipe and configured to compress the refrigerant discharged from the first compressor, a radiator, and a high-pressure passage connecting the second discharge pipe and the radiator. A first oil drain passage guides an oil in the second compressor to one of the first suction pipe and an intermediate port of the first compressor, without via the high-pressure passage.

An intermediate plate is supported by a bottom member through a plurality of second elastic members. A first compressor is supported by the intermediate plate through a plurality of first elastic members. A second compressor is supported by the same intermediate plate through a plurality of first elastic members.

A heat pump system and control method thereof. The heat pump system includes: a main flow path with a compressor, a reversing valve, a first heat exchanger, a first throttling device and a second heat exchanger; the heat pump system further includes an ejector comprising a high-pressure fluid inlet, a fluid suction inlet and a fluid outlet, the high-pressure fluid inlet of the ejector is connected between the second heat exchanger and the first throttling device on the main flow path through a second throttling device, the fluid suction inlet of the ejector is connected to the reversing valve, and the fluid outlet of the ejector is connected to a separator, and a gas phase outlet of the separator is connected to the compressor, and a liquid phase outlet of the separator is connected between the first heat exchanger and the first throttling device on the main flow path.

A test chamber and a method for conditioning air in a temperature-insulated test space of a test chamber, which is sealable against an environment and serves for receiving test material, a temperature ranging from −20° C. to +180° C. being produced within the test space by means of a cooling device of a temperature control device of the test chamber, using a cooling circuit with carbon dioxide (CO.sub.2) as a cooling agent, using a heat exchanger in the test space, using a low-pressure compressor and using a high-pressure compressor downstream of the low-pressure compressor, using a gas cooler, using a storage means for the cooling agent and using an expansion valve, the temperature in the test space being controlled and/or regulated by means of a control device of the test chamber. A gaseous and/or liquid cooling agent is dosed in the storage means by means of a high-pressure valve of the cooling circuit downstream of the gas cooler, the storage means being connected to a medium-pressure side of the cooling circuit upstream of the high-pressure compressor and downstream of the low-pressure compressor via a medium-pressure bypass of the cooling circuit, the gaseous cooling agent being dosed in the medium-pressure side from the storage means by means of a medium-pressure valve when the low-pressure compressor is switched off.

A first intermediate plate and a second intermediate plate are supported by a bottom member through a plurality of second elastic members. The first compressor and the second compressor are supported by the first intermediate plate and the second intermediate plate, respectively, through a plurality of first elastic members.

A refrigeration apparatus includes a refrigerant circuit switchable between a first operation of performing a refrigeration cycle in which a first compressor is stopped and a second compressor is driven and a second operation of performing a refrigeration cycle in which the first and second compressors and are driven. The refrigeration apparatus further includes a reduction mechanism configured to reduce a refrigerant flowing into the first compressor while a first condition is satisfied during the first operation. The first condition indicates that an internal pressure of the first compressor is lower than an evaporation pressure of an evaporator.