A refrigeration cycle apparatus includes: a refrigerant circuit; an oil reservoir; a first pipe that connects the oil separator and the oil reservoir, the first pipe being configured to send the refrigeration oil separated by the oil separator to the oil reservoir; a first valve provided at the first pipe; a second pipe that connects the oil reservoir and a suction side of the compressor; a second valve provided at the second pipe; a third pipe that connects the oil reservoir and the suction side of the compressor at a position lower than a position at which the second pipe is connected to the oil reservoir; and a third valve provided at the third pipe. The first to third valves are closed in a non-operational period of the compressor.

The present invention relates to a refrigerant composition, including difluoromethane (HFC-32), pentafluoroethane (HFC-125), and trifluoroiodomethane (CF.sub.3I) for use in a heat exchange system, including air conditioning and refrigeration applications and in particular aspects to the use of such compositions as a replacement of the refrigerant R-410A for heating and cooling applications and to retrofitting heat exchange systems, including systems designed for use with R-410A.

The present invention relates to heat transfer compositions comprising refrigerant, lubricant and stabilizer, wherein the refrigerant comprises 39 to 45% by weight difluoromethane (HFC-32), 1 to 4% by weight pentafluoroethane (HFC-125), and 51 to 57% by weight trifluoroiodomethane (CF.sub.3I), and wherein said lubricant comprises polyol ester (POE) lubricant and/or polyvinyl ether (PVE) lubricant, and wherein said stabilizer comprises an alkylated naphthalene and optionally but preferably an acid depleting moiety.

A technique that allows a plurality of series-connected compressors in a refrigerant circuit to have equal amounts of oil in a more versatile manner is provided. A compression apparatus according to an embodiment in the disclosure includes series-connected compressors 10, 20 in a refrigerant circuit 1 that is to circulate a refrigerant; an oil separator 30 is provided in a discharge passage 50 of the compressor 10 of the compressors 10, 20, and separates oil from the refrigerant discharged from the compressor 10 and causes the refrigerant separated from the oil to flow downstream (intake passage 80); an oil return passage 70 returns the oil separated by the oil separator 30 to the compressor 10 neighboring upstream; an oil discharge outlet 10A is provided in the compressor 10; and an oil discharge passage 60 connects the oil discharge outlet 10A to an inlet of the oil separator 30.

A refrigerant circuit includes a compressor, a high-pressure side heat exchanger, a decompressor, and a low-pressure side heat exchanger, which are annularly interconnected by a refrigerant pipe, and is configured to circulate refrigerant. The refrigerant circuit performs an oil recovery operation based on an operation history of the compressor ring a normal operation of the refrigerant circuit and an amount of oil in the compressor detected by an oil depletion sensor.

The present invention relates to heat transfer compositions comprising refrigerant, lubricant and stabilizer, wherein the refrigerant comprises 39 to 45% by weight difluoromethane (HFC-32), 1 to 4% by weight pentafluoroethane (HFC-125), and 51 to 57% by weight trifluoroiodomethane (CF.sub.3I), and wherein said lubricant comprises polyol ester (POE) lubricant and/or polyvinyl ether (PVE) lubricant, and wherein said stabilizer comprises an alkylated naphthalene and optionally but preferably an acid depleting moiety.

A rotary compressor includes a casing, a compression mechanism housed in the casing and having a suction port, a joint pipe fixed to the casing and formed into a cylindrical shape, a suction pipe arranged inside the joint pipe and communicating with the suction port of the compression mechanism, and an accumulator including an outlet pipe connected to an inlet end of the suction pipe. The suction pipe has a large diameter portion formed on an inlet side of the suction pipe and fixed to an inner peripheral surface of the joint pipe, and a small diameter portion formed on an outlet side of the suction pipe and having a smaller outside diameter than the large diameter portion. The joint pipe is made of an iron-based material. A clearance is formed between an outer peripheral surface of the small diameter portion of the suction pipe and the inner peripheral surface of the joint pipe.

A turbo chiller that has an oil-free configuration, which reduces the frequency of maintenance and maintenance-induced release of refrigerant, and can achieve a reduced environmental impact by utilizing the characteristics of the low-pressure refrigerant R1233zd(E) that reaches negative pressure at a saturation temperature of 18° C. or lower. The turbo chiller comprises a refrigeration cycle that includes a turbo compressor, a condenser, a decompression device, and an evaporator connected in sequence via piping and is filled with a refrigerant; wherein the refrigerant is a low-pressure refrigerant R1233zd(E) refrigerant with low global warming potential and low ozone depletion potential; the turbo compressor has a direct drive configuration in which a rotating shaft of impellers is directly joined to a motor; and the rotating shaft is supported by magnetic bearings.

Methods are directed towards dynamically determining refrigerant film thickness at the rolling-element bearing and for dynamically controlling refrigerant film thickness at the rolling-element bearing. Further, an oil free chiller system is configured for dynamically determining refrigerant film thickness at the rolling-element bearing of the oil free chiller system, wherein the oil free chiller system is also configured for dynamically controlling refrigerant film thickness at the rolling-element bearing of the oil free chiller system.

A refrigerant regenerating apparatus is disclosed. A refrigerant regenerating apparatus of the present disclosure includes: a regenerator into which a refrigerant flows and from which the refrigerant is discharged, the regenerator configured to separate and discharge oil contained in a refrigerant flowing in the regenerator; and a recoverer into which the refrigerant discharged from the regenerator flows, the recoverer including a compressor configured to compress a refrigerant flowing in the recoverer and a heat exchanger configured to condense a refrigerant discharged from the compressor, in which the regenerator includes: a charger configured to charge oil contained in the refrigerant flowing in the regenerator with positive ions or negative ions using corona discharge; and a collector configured to electrically collect the oil charged through the charger.