A method for operating a refrigerant circulation system comprising a compressor, a condenser, an expansion mechanism, and an evaporator connected in this order with piping, wherein a refrigerant comprising trifluoroiodomethane is used as a refrigerant; a refrigerating machine oil comprising, as a base oil, a polyolester synthesized from a polyhydric alcohol and fatty acids, with a proportion of a fatty acid having 9 carbon atoms in the fatty acids being 65 mol % or less is used as a refrigerating machine oil; and a temperature of an entire area of the refrigerant circulation system is kept at 160° C. or lower.

A method for operating a refrigerant circulation system comprising a compressor, a condenser, an expansion mechanism, and an evaporator connected in this order with piping, wherein a refrigerant comprising trifluoroiodomethane is used as a refrigerant; a refrigerating machine oil comprising, as a base oil, a polyolester synthesized from a polyhydric alcohol and fatty acids, with a proportion of a fatty acid having 9 carbon atoms in the fatty acids being 65 mol % or less is used as a refrigerating machine oil; and a temperature of an entire area of the refrigerant circulation system is kept at 160° C. or lower.

Low transition temperature mixtures (LTTMs) comprising a eutectic mixture of a quaternary amine and a polyol such as glycol are provided. The LTTMs can provide various beneficial properties, such as highly desirable viscosity index, low glass transition temperatures, and/or high kinematic viscosities relative to the molecular weight of the mixture components. The mixtures can be advantageously used as co-base stocks in lubricating oil compositions.

Low transition temperature mixtures (LTTMs) comprising a eutectic mixture of a quaternary amine and a polyol such as glycol are provided. The LTTMs can provide various beneficial properties, such as highly desirable viscosity index, low glass transition temperatures, and/or high kinematic viscosities relative to the molecular weight of the mixture components. The mixtures can be advantageously used as co-base stocks in lubricating oil compositions.

Low transition temperature mixtures (LTTMs) comprising a eutectic mixture of a quaternary amine and a polyol such as glycol are provided. The LTTMs can provide various beneficial properties, such as highly desirable viscosity index, low glass transition temperatures, and/or high kinematic viscosities relative to the molecular weight of the mixture components. The mixtures can be advantageously used as co-base stocks in lubricating oil compositions.

Low transition temperature mixtures (LTTMs) comprising a eutectic mixture of a quaternary amine and a polyol such as glycol are provided. The LTTMs can provide various beneficial properties, such as highly desirable viscosity index, low glass transition temperatures, and/or high kinematic viscosities relative to the molecular weight of the mixture components. The mixtures can be advantageously used as co-base stocks in lubricating oil compositions.