MIXED REFRIGERANT BASED ON FLUOROCARBON

PURPOSE:To obtain the refrigerant which is chlorine- and bromine-free and can embody a temperature of -30 deg.C or lower in the inside of a freezing chamber, by mixing 1,1,1,2-tetrafluoroethane and hexafluoroethane. CONSTITUTION:A mixed refrigerant containing hydrofluorocarbon 134a (i.e., 1,1,1,2-tetrafluoroethane CH2FC3) and fluorocarbon 116 (i.e., hexafluoroethane CF3-CF3). When lower boiling point is desired, the ratio of fluorocarbon 116 is raised; when very low boiling point is not desired, the ratio of hydrofluorocarbon 134a is raised. Generally, the higher the ratio of fluorocarbon 116, the higher is the discharge pressure of a refrigerator and, as the result, the more often do mechanical problems tend to occur. To obtain a temperature of -50 deg.C or lower in the inside of a freezing chamber, it is desirable that the refrigerant contains 75+ or -15wt.% hydrofluorocarbon 134a and 25+ or -15wt.% fluorocarbon 116.