Enhancing PCM thermal management in multi-cycle melting-solidification

We present a comprehensive study on heat transfer in phase-change materials (PCMs), focusing on both melting and solidification phases, different temperature scenarios, an assessment of practical implementation aspects, and Marangoni convection. The research examines heat transfer rates during the melting-solidification cycle, with a focus on gallium (Ga) and n-eicosane (C20), the latter being a candidate for the MarPCM project aboard the ISS [1]. The paper explores different temperature scenarios using Ga to optimize PCM performance. N-eicosane requires extensive computational resources due to its significant thermal time, whereas gallium allows for more efficient simulations. The most effective scenario involves switching temperatures between cold and hot walls at a certain moment, which occurs earlier than the full melting time or reaching steady state. This specific moment corresponds to the beginning of a decrease in heat extraction efficiency. The success of this scenario relies on the symmetric thermal boundary conditions and multi-cyclic temperature inversion. We suggest that the implementation of this scenario is similar to rotating the PCM body within its package while maintaining the temperature of the external walls constant. Extending the strategy to n-eicosane yields promising results. This study also highlights the importance of Marangoni convection in heat transfer mechanisms.