Abstract: On a single-stage type refrigerating system using non-azeotropic refrigerant, composing with a compressor (1), a condenser (2), and an evaporator (10), heat exchanging between returned-refrigerant from evaporator and high-pressure refrigerant toward evaporator, electromagnetic valves (5-1 to 5-4) of capillary tubes (6-1 to 6-4) as expansion valves of evaporator are fully open, at moments of large load needed such as at starting up, the system is controlled flux of refrigerant gas and pressure of it by closing them one by the other corresponding to going down of interior room temperature. As the state of interior room temperature is high and low boiling point constituent is not condensed, cooling capability of high boiling point refrigerant performs in maximum.

Abstract: A mixed refrigerant comprising one member selected from R-23, R-116 and a mixture thereof and one member selected from propane, butane and a mixture thereof. The mixed refrigerant allows cooling the inside of a freezer to a super low temperature, particularly to a temperature of −60° C. or lower, with a compressor of a conventional freezer. The mixed refrigerant not only has a low boiling point similar to those of R-23 and R-116, but also can be liquefied in a room temperature surrounding due to propane or butane contained therein, and further has good miscibility with a lubricating oil or the like so that a freezer unit using the refrigerant is free from the problem of clogging therein. Additionally, the mixed refrigerant has no ability to deplete ozone and is significantly low with respect to greenhouse effect.

Abstract: A mixed fluorocarbon refrigerant comprising 1,1,1,2-tetrafluoroethane and trifluoromethane provides a refrigeration temperature of −30° C. or less. The composition can also contain a refrigerator oil and an additive. The additive is selected from the group consisting of saturated hydrocarbons, unsaturated hydrocarbons and aromatic hydrocarbons.