The present invention relates to a refrigerator oil for a mixed refrigerant containing less than 40% by mass of an unsaturated fluorinated hydrocarbon compound (HFO) on a basis of the whole amount of the mixed refrigerant, the refrigerator oil containing a base oil (P) including at least one selected from the group consisting of a polyvinyl ether (PVE), a polyalkylene glycol (PAG), a copolymer (ECP) of a poly(oxy)alkylene glycol or a monoether thereof and a polyvinyl ether, and a polyol ester (POE), with a hydroxy value of the base oil (P) being 15 mgKOH/g or less; and a refrigerator oil composition containing the foregoing refrigerator oil and a specified refrigerant.

The invention relates to a lubricating oil composition and a refrigerant composition containing a polyalkylene glycol having a terpenoid end group, such as a farnesol end group.

The lubricating oil composition for a refrigerator according to the present invention is a lubricating oil composition for a refrigerator containing a base oil containing a low-viscosity base oil component having added thereto a polyoxyalkylene glycol compound having a kinetic viscosity at 100° C. that is higher than the low-viscosity base oil component, and the base oil has a kinetic viscosity at 100° C. of 2.4 to 25 mm.sup.2/s and a ratio (Mw/Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn) of 1.3 to 13.

A compound of formula (I): wherein W is independently selected from the group consisting of H, F, CI, Br, and I; X is independently selected from the group consisting of H, F, CI, Br, and I; Y is independently selected from the group consisting of F, CI, Br, and I; Z is independently selected from the group consisting of H, F, CI, Br, and I; n is an integer from 1 to 8; and n′ is an integer from 1 to 12.

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A climate-control system can be used to heat or cool a space. The climate-control system may include first and second vessels between which refrigerant and co-fluid may be circulated. The refrigerant may be absorbed into the co-fluid within the first vessel at a first rate. The refrigerant may desorb from the co-fluid within the second vessel at a second rate. Ultrasonic energy may be used to adjust the second rate to substantially match the first rate.

A working fluid composition for a refrigerating machine comprises a refrigerant comprising monofluoroethane and a refrigerating machine oil comprising, as a base oil, at least one selected from a mineral oil having % C.sub.N in an n-d-M ring analysis of 10 to 60 and a pour point of −15° C. or lower and a synthetic hydrocarbon oil having a pour point of −15° C. or lower, and the refrigerating machine oil having a kinematic viscosity at 40° C. of 3 to 500 mm.sup.2/s.

The present invention provides a refrigerating machine oil comprising, as a base oil, a polymer having a structural unit represented by the following formula (1):

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wherein R.sup.1, R.sup.2 and R.sup.3, which may be the same as or different from each other, represent a hydrogen atom or a hydrocarbon group; and R.sup.4 represents a hydrocarbon group or an organic group containing an oxygen atom, and having a number average molecular weight Mn of 300 or more and 3000 or less and a ratio of a weight-average molecular weight Mw to a number average molecular weight Mn (Mw/Mn) of 1.10 or more and 2.00 or less, and the refrigerating machine oil being used with a refrigerant selected from the group consisting of difluoromethane, a mixture of difluoromethane and pentafluoroethane, a mixture of difluoromethane, pentafluoroethane and 1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane, 1,1,1,2-tetrafluoroethane and 1,1,1-trifluoroethane, unsaturated hydrofluorocarbons, hydrocarbons and carbon dioxide.

A lubricating oil composition for refrigerating machines contains a base oil and an additive in a form of a hydrocarbon compound having a biphenyl structure or a stilbene structure. When the present lubricating oil composition for refrigerating machines is used in refrigerating equipment such as an open-type automobile air-conditioner, an electric automobile air-conditioner, a gas heat pump, other air-conditioning equipment, a refrigerating machine, a vending machine, a showcase, a water-heating system and a refrigerating/heating system, it is possible to detect the leakage of a refrigerant with a long-lasting stability. Therefore, when an unsaturated chlorofluorocarbon refrigerant with a poor stability is used in the above-listed equipment, the present lubricating oil composition for refrigerating machines is significantly advantageous.

In an aspect, the present invention provides a refrigerating machine oil comprising a poly(meth)acrylate as a base oil, wherein the poly(meth)acrylate comprises a hydrogenated poly(meth)acrylate, a content of a unit having a carbon-carbon double bond present at a terminal in the poly(meth)acrylate is 6% by mole or less relative to total units constituting the poly(meth)acrylate, and a kinematic viscosity at 40° C. of the hydrogenated poly(meth)acrylate is 1 to 1000 mm2/s, the refrigerating machine oil being used with a refrigerant comprising a refrigerant selected from difluoromethane, a mixture of difluoromethane and pentafluoroethane, a mixture of difluoromethane, pentafluoroethane, and 1, 1, 1, 2-tetrafluoroethane, a mixture of pentafluoroethane, 1, 1, 1, 2-tetrafluoroethane, and 1, 1, 1-trifluoroethane, an unsaturated hydrofluorocarbon, a hydrocarbon, and carbon dioxide.

A compound of formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br, and I; X is independently selected from the group consisting of H, F, Cl, Br, and I; Y is independently selected from the group consisting of F, Cl, Br, and I; Z is independently selected from the group consisting of H, F, Cl, Br, and I; n is an integer from 1 to 8; and n′ is an integer from 1 to 12. ##STR00001##