To prevent a drop in the cooling capacity by restricting retention of a refrigerant increased up to a liquid phase under a low outside air temperature in a natural circulation loop.
A refrigerant liquid reservoir 30 is provided and an excessive refrigerant liquid is distributed by a condenser 22 and the refrigerant liquid reservoir 30. As the refrigerant liquid reservoir 30 is made up of a container with a larger bottom area, the most of the excessive refrigerant liquid is stored into the refrigerant liquid reservoir 30, so that the level of the refrigerant liquid in the condenser 22 can be restricted sufficiently as compared with the case where the refrigerant liquid reservoir 30 is not used. Thus, a decrease in effective heat transfer area of the condenser 22 is prevented to secure a cooling capacity. In addition, the refrigerant liquid reservoir 30 is connected to the topmost point of a liquid piping 28 secure the height of the liquid column of the refrigerant, thereby assuring a refrigerant circulation drive force.
SAGARA TAIICHI
AOYAMA NOBORU
