Refrigeration cycle

Abstract

In a refrigeration cycle comprising a compressor, a condenser, a pressure reduction and expansion means, and an evaporator, R1234yf is used as the refrigerant, the refrigerant at the exit side of the evaporator is controlled in a superheated condition, and the refrigeration cycle is operated in a range of 5 to 16 degrees of superheat, and preferably in a range of 10 to 16 degrees of superheat. When the refrigerant used is changed to the new refrigerant R1234yf, while high advantage for improving the coefficient of performance can be achieved, the rise in temperature of the discharged refrigerant is appropriately suppressed so that deterioration of refrigerating machine oil in the refrigerant can be prevented, and a high-efficiency operation can be realized as the entirety of the refrigeration cycle.

1 . A refrigeration cycle comprising a compressor for compressing refrigerant, a condenser for condensing compressed refrigerant, a pressure reduction and expansion means for reducing in pressure and expanding condensed refrigerant, and an evaporator for evaporating pressure-reduced and expanded refrigerant, characterized in that R1234yf is used as refrigerant for said refrigeration cycle, and said refrigeration cycle is operated so that said refrigerant at an exit side of said evaporator is controlled in a superheated condition, and said superheated condition is controlled in a range of 5 to 16 degrees of superheat. 
     
     
         2 . The refrigeration cycle according to  claim 1 , wherein said refrigeration cycle is operated at said superheated condition in a range of 10 to 16 degrees of superheat of said refrigerant at said exit side of said evaporator. 
     
     
         3 . The refrigeration cycle according to  claim 1 , wherein said refrigeration cycle comprises means for elevating said degree of superheat of said refrigerant at said exit side of said evaporator, as compared with a case where R134a is used as refrigerant for said refrigeration cycle. 
     
     
         4 . The refrigeration cycle according to  claim 1 , wherein said refrigeration cycle is used in an air conditioning system for vehicles.