Development and Study of a Loop Heat Pipe with Several Heat Sources of Different Power

Abstract

The results of the development and experimental studies of a loop heat pipe designed for the simultaneous cooling of several heat sources that dissipate different power amounts is presented. The pipe has a cylindrical evaporator and a serpentine-shaped condenser that is connected via the vapor and liquid lines. The evaporator was in thermal contact with the main heat source. Two additional, less powerful heat sources were in contact with the heat exchangers located on the vapor line and liquid lines. Freon-152a and ammonia were used as the working fluids. The efficiency of the loop heat pipe is estimated according to the ratio of the maximum heat load on the additional sources to the heat load of the main source. A temperature of 90°C was the limiting condition for each source. The tests were performed at a condenser coolant temperature of 20°C. The maximum power of the pipe with ammonia, without additional heat sources, was equal to 350 W, and that with freon-152a was130 W. We show that the maximum load on the additional source located on the liquid line was 34 W (57%) for a freon pipe under a nominal heat load on the main source of 60 W and 10 W (16%) on the source located on the vapor line. For an ammonia loop heat pipe under a nominal load on the main source of 220 W, the respective values for the additional sources were 60 W (27%) and 13 W (6%).