Supercritical refrigerant cycle system

Abstract

An object of the present invention is to improve a heat exchanging capability in an evaporator in a refrigerant cycle system in which a high pressure side is operated at a supercritical pressure. The refrigerant cycle system is a refrigerant cycle system in which a compressor, a gas cooler, an expansion valve and an evaporator are sequentially connected in a cyclic form and a high pressure side is operated at a supercritical pressure, wherein the degree of opening of the expansion valve is adjusted based on the temperature and pressure of a refrigerant at an outlet of the evaporator so as to control the degree of superheat at the outlet of the evaporator. An abstract of the present invention is to make large the degree of superheat at the outlet of the evaporator by means of the expansion valve.

What is claimed is:  
     
         1 . A supercritical refrigerant cycle system in which a compressor, a gas cooler, throttle means and an evaporator are sequentially connected in a cyclic form and a high pressure side is operated at a supercritical pressure, wherein the degree of opening of the throttle means is adjusted based on the temperature and pressure of a refrigerant at an outlet of the evaporator so as to control the degree of superheat at the outlet of the evaporator.  
     
     
         2 . The system of  claim 1 , wherein the degree of superheat at the outlet of the evaporator is increased by the throttle means.  
     
     
         3 . A supercritical refrigerant cycle system in which a compressor, a gas cooler, throttle means and an evaporator are sequentially connected in a cyclic form and a high pressure side is operated at a supercritical pressure, wherein the degree of opening of the throttle means is adjusted based on heat load conditions so as to control the degree of superheat at an outlet of the evaporator.  
     
     
         4 . The system of  claim 3 , wherein the degree of superheat at the outlet of the evaporator is decreased when a heat load is high and increased when the heat load is low.  
     
     
         5 . The system of  claim 1 ,  2 ,  3  or  4 , which further comprises an intermediate heat exchanger for allowing a refrigerant that has come out of the gas cooler to exchange heat with a refrigerant that has come out of the evaporator and a receiver tank for temporarily reserving a refrigerant to be sucked into the compressor and causes a refrigerant which has come out of the evaporator and passed through the intermediate heat exchanger to flow into the receiver tank.  
     
     
         6 . The system of  claim 1 ,  2 ,  3 ,  4  or  5 ,wherein a CO 2  refrigerant is used.