Evaluating Loop Heat Pipes Performances Regarding Their Geometric Characteristics

This paper presents the performance tests of small-scale loop heat pipes (LHPs) that have being developed in order to perform the heat dissipation using acetone as working fluid. Two LHPs have being designed and built to accomplish the thermal management on power cycles of up to 80 W, where each LHP has a different set of compensation chamber/capillary evaporator, being one detached from the evaporator while the other is an integral part of it. Laboratory life tests have shown reliable operation with negligible non-condensable gas influence along time. The basic difference between tests with both LHPs is that the one with an integral compensation chamber showed higher operation temperatures due to the smaller thermal resistances between the evaporator and the compensation chamber. The life tests results show the potential in using acetone as an alternative working fluid in LHPs with reduced active lengths.