Publication
In the present paper, a closed-loop thermosyphon cooling system for power electronics has been developed and tested. The evaporator is a multi-microchannel heat sink designed for high heat fluxes. The power electronics module is emulated by four independent electrical heaters, which can generate a non-uniform heat flux on the evaporator. The condenser is air-cooled and is tested in both natural convection and forced convection modes. R1234ze has been selected as the working fluid. Although in natural convection mode the cooling system experiences a maximum thermal resistance of approximately 0.6 K/W, the complete passiveness makes such a system very attractive. With values of heat fluxes of 107 W/cm(2) and 25 W/cm(2) equally distributed on the four heaters, the maximum heater temperature measured is 53 degrees C at a saturation temperature of 45 degrees C. In forced convection mode, two different values of air flow have been tested. A reduction of 50% on the overall thermal resistance has been measured with an imposed air flow rate of 87.8 m(3)/h, consuming only 5.29 W to drive the fan for dissipating 70.2 W. At this condition, the maximum heater temperature is reduced to 36 degrees C. In summary, it has been demonstrated that a thermosyphon coupled with air cooling can dissipate high heat fluxes of power electronics with no or little energy consumption. (C) 2017 Elsevier Ltd. All rights reserved.
Dolaana Khovalyg, Mohammad Rahiminejad
Christian Leinenbach, Rafal Wróbel, Thomas Mayer