An air-conditioning apparatus is able to ensure an appropriate flow rate of refrigerant and an appropriate amount of oil returned to a compressor that match operation conditions regardless of an operating state of a refrigerant circuit and a change in an operation condition. The air-conditioning apparatus includes: a first detector configured to detect a refrigerant temperature within an accumulator; a storage unit configured to store information regarding a two-layer separation temperature of refrigerant and refrigerating machine oil; a determiner configured to compare the refrigerant temperature with the two-layer separation temperature and determine a two-layer separation state of the refrigerant and the refrigerating machine oil; a second detector configured to detect a state of the refrigerant sucked by the compressor; and a control unit configured to adjust an opening degree of a flow control valve on the basis of the two-layer separation state and a state of the sucked refrigerant.

An air conditioning system includes a storage medium and an air conditioning system, for a three-pipe air conditioning system, the three-pipe air conditioning system includes a compressor, an outdoor heat exchanger, an indoor heat exchanger, a gas-liquid separator, a first pipeline, a second pipeline and a third pipeline; the oil return control method comprises the following steps: controlling the compressor to operate at a first frequency in a refrigerating mode; judging whether the operation duration of the refrigerating mode reaches a first preset time or not; if so, the air conditioning system enters an oil return state, and the compressor, the third pipeline, the second pipeline and the gas-liquid separator are controlled to be communicated in sequence to form a refrigerant circulation loop.

A refrigeration cycle apparatus includes refrigerant circuits in which a high pressure shell compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are connected; a mixed refrigerant made up of a mixture of 1,1,2-trifluoroethylene, difluoromethane, and 2,3,3,3-tetrafluoropropene and configured to circulate through the refrigerant circuits, the mixed refrigerant containing less than 50 wt % of 1,2,2-trifluoroetylene and a mixing ratio of difluoromethane being between 0.7 times and two times (both inclusive) that of 1,2,2-trifluoroetylene in terms of weight ratio, in a state before the mixed refrigerant is enclosed in the refrigerant circuits; and a refrigerating machine oil enclosed in the refrigerant circuits and prepared such that difluoromethane is least soluble in the refrigerating machine oil.

An outdoor unit of the heat pump includes a compressor, an oil separator provided in a discharge path of the compressor, an outdoor-unit connecting pipe connecting an intake path of the compressor and an outdoor unit of an another heat pump for supplying a refrigerant to the outdoor unit of the another heat pump, an oil supply pipe extending from a predetermined position of the oil separator and connecting to the outdoor-unit connecting pipe, an on-off valve provided on the oil supply pipe, an expansion valve provided in a portion of the outdoor-unit connecting pipe between a connecting part connected to the intake path and a connecting part connected to the oil supply pipe, and a refrigerant filling port provided in a portion of the outdoor-unit connecting pipe between the connecting part and the expansion valve.

A temperature control apparatus (70) includes a heat exchanger (71) configured to exchange heat with the surroundings using a phase change of a refrigerant, a rotary pump (73) configured to receive the refrigerant from the heat exchanger (71) and fuse the refrigerant with oil contained inside the rotary pump, and an oil water separator (74) configured to receive the refrigerant fused with the oil from the rotary pump (73) and separate the refrigerant from the oil. The temperature control apparatus further includes a refrigeration cycle that implements a cooling function by circulating the refrigerant separated from the oil back to the heat exchanger (71).

An oil separator includes a separation container. The separation container has a side surface portion to which an inlet pipe is attached. The separation container has an upper surface portion to which an outlet pipe is attached. An oil reservoir is provided in a lower portion of the separation container. The separation container has a lower surface portion to which an oil return pipe is attached. The separation container has an inner wall surface provided with a liquid passage section. The liquid passage section is provided with a groove. The groove is disposed to extend in a direction of gravity toward the oil reservoir. The groove is formed to be gradually increased in depth from an upper portion of the groove toward a lower portion thereof.

A refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port.

A turbo compressor that has a pressure equalizing tube that circulates a gas from a gear unit accommodation space toward an IGV accommodation space, and an oil separation device that is provided in the gear unit accommodation space to separate lubricating oil that is contained in the gas, in which the oil separating device has a suction duct that communicates with the pressure equalizing tube, and the suction duct has a centrifugal separation portion provided with a first demister, a second demister provided on the downstream side of the first demister in relation to the suction direction, and a curved passage provided between the first demister and the second demister.

An air conditioning system capable of treating a conditioned space by treating outdoor air from outside the conditioned space and treating air returned from inside the conditioned space, and mixing the outdoor air with the returned air to form supply air for the conditioned space, the air conditioning system including: •an outdoor air latent cooling treatment stage and a return air sensible cooling treatment stage, and •an air mixer for mixing outdoor air with return air to form the conditioned space supply air; wherein the outdoor air latent cooling treatment stage includes a dehumidification evaporator and the return air sensible cooling treatment stage includes a sensible evaporator, both evaporators being coupled to a direct expansion refrigeration circuit, and wherein the dehumidification evaporator thermal capacity is regulated in response to conditioned space humidity and the sensible evaporator thermal capacity is regulated in response to conditioned space dry bulb temperature.

A refrigeration cycle device includes at least a condenser, an expansion valve, an evaporator and a plurality of compressors, a sealed casing of each of the compressors is disposed with a rotary compression mechanism part in communication with a low-pressure path and a motor part configured to drive the compression mechanism part, the low-pressure path is in communication with the evaporator, each of the compressors is further provided with an oil storage cavity, and a gas discharge path of at least one compressor is connected with the sealed casing of another compressor.