Abstract
In recent years, ebullient cooling and forced-circulation cooling is applied to cooling system for power conversion equipment of high capacity. However, problems of precipitous temperature fluctuation, correspondence to large area, and usage restrictions of the coolant are held in cooling system for the power conversion equipment. This study examined the natural circulation cooling system which canceled the demerit of both the above-mentioned cooling system for the coolant of high environmental performance. The objects of coolant are HFE-7200 and PFK-649. Heat transfer characteristics and natural circulation flow characteristics of the coolant concerned were verified by changing heat flux using an experimental apparatus. Moreover, the effect installed check-valve in the test loop was also made applicable to verification. As a result, we found that flow fluctuation can be reduced from 30 to 50% by the effect of check-valve in any of two kinds of coolants case.
