| abstract |
PROBLEM TO BE SOLVED: To provide a refrigerating machine oil composition having good lubricating performance and sealability and capable of long-term stable use in a compression refrigeration cycle using a refrigerant containing CO 2 as a main component, and the composition. And a lubrication method using the same. SOLUTION: (1) A refrigerant mainly composed of CO 2 and a lubricating oil composition, wherein the lubricating oil composition mainly comprises an ester oil and has a kinematic viscosity at 40 ° C of 56 to 130 mm. A refrigerating machine oil composition comprising a base oil of 2 / s, wherein the ester oil is an ester compound of pentaerythritol and a fatty acid having 8 and / or 9 carbon atoms and / or a carbonate compound; 2) To provide a lubrication method using the refrigerating machine oil composition in a compression refrigeration cycle having an oil separator and / or a hot gas line. |