Abstract: A refrigerant compressor is configured such that a compressor unit is installed in a hermetically sealed container, an HFC type refrigerant or a mixture thereof and a refrigerator oil having compatibility with the refrigerant are charged into the hermetically sealed container, and the refrigerator oil essentially comprises a polyvinyl ether type compound having structural units represented by the following general formula (1): ##STR1## wherein n is an integral number in the range of 1 or more, R1 to R3 are each a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms and may be the same or different, R4 is an alkyl group having 1 to 4 carbon atoms, and units in which R4 is an alkyl group having 1 to 2 carbon atoms are 40 to 100% and units in which R4 is an alkyl group having 3 to 4 carbon atoms are 0 to 60%.

Abstract: A refrigerant compressor is configured such that a compressor unit is installed in a hermetically sealed container, an HFC type refrigerant or a mixture thereof and a refrigerator oil having compatibility with the refrigerant are charged into the hermetically sealed container, and the refrigerator oil essentially comprises a polyvinyl ether type compound having structural units represented by the following general formula (1): ##STR1## wherein n is an integral number in the range of 1 or more, R1 to R3 are each a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms and may be the same or different, R4 is an alkyl group having 1 to 4 carbon atoms, and units in which R4 is an alkyl group having 1 to 2 carbon atoms are 40 to 100% and units in which R4 is an alkyl group having 3 to 4 carbon atoms are 0 to 60%.

Abstract: There are provided a highly durable and efficient refrigerating apparatus and a lubricating oil composition that uses an HFC type refrigerant and is still free from the problem of thermal hydrolysis of polyol-ester type oil and resulting generation of carboxylic acid and sludge so that the refrigerating apparatus and the lubricating oil composition may be used stably for a prolonged period of time. A lubricating oil composition according to the invention comprises as base oil components a polyol-ester type oil formed by reacting specific polyhydric alcohol with a fatty acid, to which tricresylphosphate and epoxy compound comprising glycidyl ether or carbodiimide are added at respective specific rates.