| 摘要 |
PROBLEM TO BE SOLVED: To provide a cascade refrigeration system using refrigerant compositions low in global warming potential (GWP) and earth-friendly, capable of achieving a temperature as low as -80°C, and excellent in refrigeration capability and other performances.SOLUTION: A cascade refrigeration system comprises: a high-temperature-side refrigeration circuit and a low-temperature-side refrigeration circuit, and condenses a refrigerant in the low-temperature-side refrigeration circuit by a refrigerant passing through a cascade condenser in the high-temperature-side refrigeration circuit. As the refrigerant in the low-temperature-side refrigeration circuit, a refrigerant composition containing azeotropic mixture that is a mixture of ethane (R170) and pentafluoroethane (R116) is used, 50 mass% or higher and 60 mass% or lower of the pentafluoroethane (R116) relative to the refrigerant composition being added. |
