Experimental investigation of the performance of a phase change material thermal management module under vacuum and atmospheric pressure conditions

High computational power and miniaturisation of modern electronics lead to high heat generation, compounded by the decreased available area for heat dissipation. This challenge is exacerbated in space environments due to the lack of convection. Phase change materials (PCM) are a strong option for the passive thermal management of satellites. However, their behaviour in vacuum is unclear. This study experimentally investigates and compares the performance of non-PCM and PCM-based thermal control modules under atmospheric pressure and vacuum conditions. A stainless steel heat sink with internal planar fins was tested using a printed circuit board (PCB) to produce three input power levels, simulating the heat dissipated by satellite electronics. Paraffin wax was used as the PCM. The thermal performance is reported and analysed for both pressure conditions. A reduced-order numerical model was established to predict performance with low required computational effort. This work finds that electronics operating in vacuum displayed temperatures as much as 32.8% higher compared to those in atmosphere due to decreased heat dissipation resulting from the lack of convective heat transfer. In addition, PCM had a greater impact in reducing the electronics temperature in vacuum than at atmospheric pressure. The presence of 6 g of PCM lowered the electronics temperatures by up to 18.0 °C in vacuum, and by up to 12.3 °C in atmospheric pressure. That amount of PCM doubled the electronics operating time under both pressure conditions at high power. The findings of this work contribute to understanding the performance variances of non-PCM and PCM-based heat sinks under different pressure conditions to further improve the design of thermal management modules for satellites.