| 摘要 |
PROBLEM TO BE SOLVED: To prevent the damage of a compressor and the deterioration of a performance coefficient in a CO2 cycle. SOLUTION: Lubricant where compatibility to CO2 in the case of critical pressure Pc or less is lower than that in the case of at least the critical pressure Pc is used in a compressor 1, thus separating the lubricant of a liquid phase from the CO2 of the liquid phase at the low-pressure side of an evaporator side, preventing the CO2 of the liquid phase from being inhaled to the compressor 1, and at the same time easily leading only the lubricant to the intake side of the compressor 1. Therefore, the damage of the compressor 1 can be prevented without deteriorating the performance coefficient of a CO2 cycle. |
