A heat source unit and a refrigeration cycle apparatus that are able to reduce damage to a connection pipe when a refrigerant containing at least 1,2-difluoroethylene is used are provided. An outdoor unit (20) that is connected via a liquid-side connection pipe (6) and a gas-side connection pipe (5) to an indoor unit (30) including an indoor heat exchanger (31) and that is a component of an air conditioner (1) includes a compressor (21) and an outdoor heat exchanger (23). A refrigerant containing at least 1,2-difluoroethylene is used as a refrigerant. A design pressure of the outdoor unit (20) is lower than 1.5 times a design pressure of each of the liquid-side connection pipe (6) and the gas-side connection pipe (5).

A refrigerant for a cooling device including a cooling circuit with at least one heat exchanger, the refrigerant undergoing a phase transition in the heat exchanger, the refrigerant being a refrigerant mixture composed of a mass fraction of carbon dioxide, a mass fraction of pentafluoroethane, a mass fraction of difluoromethane and a mass fraction of at least one other component, wherein the mass fraction of carbon dioxide in the refrigerant mixture is 28 to 51 mass percent, the mass fraction of pentafluoroethane being 14.5 to 32 mass percent, the mass fraction of difluoromethane being 14.5 to 38 mass percent, the other component being fluoromethane.

A lubricating oil composition excellent in the wear resistance and a refrigerator oil composition excellent in the oxidation stability using the lubricating oil composition are provided by a lubricating oil composition containing a base oil (A) and a phosphine derivative (B) having one or more oxygen atom in a molecule.

A refrigerant for a cooling device (10) comprising a cooling circuit (11) with at least one heat exchanger, in which the refrigerant undergoes a phase transition, the refrigerant being a refrigerant mixture composed of a mass fraction of carbon dioxide and a mass fraction of at least one other component, wherein the mass fraction of carbon dioxide in the refrigerant mixture is 10 to 50 mass percent, preferably 30 to 50 mass percent, the other component being pentafluoroethane and/or difluoromethane.

The present invention provides a refrigerating machine oil comprising: a lubricating base oil; and 40 mass % or less of a polymer, based on a total amount of the refrigerating machine oil, the polymer having a structural unit represented by the following formula (I) and a weight average molecular weight of from 500 to 100000. ##STR00001## [In formula (I), R.sup.a, R.sup.b and R.sup.c each independently represents a hydrogen atom or a hydrocarbon group, and R.sup.d represents an oxygen-containing organic group or a C.sub.1-18 hydrocarbon group.]

A test chamber (10) for conditioning air has a test space (12), and a temperature control device (11) for controlling the temperature of the test space and allowing a temperature in a range of 80 C. to +180 C., preferably 100 C. to +200 C., to be established within the test space, the temperature control device having a cooling device (16) with a cooling circuit (17), a heat exchanger (18), a compressor (19), a condenser (20), and an expansion element (21), wherein the refrigerant is a nearly azeotropic and/or zeotropic refrigerant mixture of a mass percentage of carbon dioxide and a mass percentage of at least one of the components ethane, ethene, hexafluoroethane, pentafluoroethane, monofluoro-ethane, 1,1-difluoroethene, fluoromethane and/or propane and/or xenon, the refrigerant having a relative CO2 equivalent of <3000, preferably <500, in particular preferably <10, with respect to 20 years.

The present disclosure provides a composition comprising a refrigerant characterized by having a GWP lower than that of R410A and a COP equivalent to that of R410A. Specifically, the present disclosure provides a composition comprising a refrigerant, the refrigerant comprising CO.sub.2 (R744) and at least one compound A selected from the group consisting of trans-1,2-difluoroethylene [(E)-HFO-1132], cis-1,2-difluoroethylene [(Z)-HFO-1132], fluoroethylene (HFO-1141), and 3,3,3-trifluoropropyne (TFP).

The present disclosure provides a composition comprising a refrigerant characterized by having a low GWP, low flammability, a COP equivalent to that of R410A, and a refrigerating capacity almost equivalent to that of R410A. Specifically, the present disclosure provides a composition comprising a refrigerant, the refrigerant comprising CO.sub.2 (R744), hexafluoropropene (FO-1216), and at least one compound A selected from the group consisting of trifluoroethylene (HFO-1123), trans-1,2-difluoroethylene [(E)-HFO-1132], cis-1,2-difluoroethylene [(Z)-HFO-1132], fluoroethylene (HFO-1141), and 3,3,3-trifluoropropyne (TFP).

In accordance with the present invention refrigerant compositions are disclosed. The compositions comprise HFC-32, HFC-125, HFO-1234yf, HFC-134a, and CO.sub.2. The refrigerant compositions are useful in processes to produce cooling and heating, in methods for replacing refrigerant R-410A or R-22, and in refrigeration, air conditioning or heat pump systems. These inventive compositions are non-flammable and match cooling performance for R-22 and R-410A within 15%. Additionally, these compositions may serve as replacements for R-404A, R-507, R407A, R407C and/or R-407F in refrigeration, air conditioning or heat pump systems. The compositions as described herein have unexpected flammability properties.

Refrigerant compressor includes electromotive element, and compression element that is driven by electromotive element, includes a slider, and compresses a refrigerant. Freezer oil that lubricates the slider is added with fullerene having a diameter that ranges from 100 pm to 10 nm.