Comparative Study of the Thermal Enhancement for Spacecraft PCM Thermal Energy Storage Units

Abstract

To access the enhancement effect of the topology optimization and porous foam structure, numerical studies were conducted to investigate the heat conduction enhancement (by metal foam, graphite foam, topologically optimized fins, and combinations of metal foam and topologically optimized fins) of phase change material (PCM (n-octadecane)) based tubular thermal energy storage unit for spacecraft. The results showed that metal foam performed better than topologically optimized fins and a combination of metal foam and topology optimized fins, of which conductive material, unit mass, and volume fraction of PCM were the same. Graphite foam (140 W/(m·K)) had the best heat transfer enhancing effect, making PCM melt much faster than other enhancing methods investigated. A multi-criteria decision-making (MCDM) method integrated with the combined weight and TOPSIS method was introduced to evaluate the preferred alternatives’ performance based on the energy storage time, equivalent density, and energy storage. The evaluation pointed out that 3% topologically optimized aluminum fins with 98% copper foam had the best comprehensive performance. This study guided the optimal design of latent heat thermal energy storage units for spacecraft under microgravity.