Improved design for heat transfer performance of a novel phase change material (PCM) thermal energy storage (TES)

This study evaluates numerically various configurations of PCM thermal energy storage devices, e.g., U-tube, U-tube with in-line fins, U-tube with staggered fins and a novel festoon design. The conjugate heat transfer between the heat transfer fluid (HTF) and PCM, which undergoes a cyclic melting and freezing process, is solved numerically using the computational fluid dynamic approach utilizing enthalpy-porosity formulation. The results indicate that our novel festoon channel design yields improved heat transfer rate for both charging and discharging stages. To further enhance heat transfer performance, we introduce use of multiple PCMs with various configurations of different PCM arrangement. Advantages and limitations of each design are evaluated with respect to their heat transfer performance vis-à-vis heat storage capacity. Further R&D and experimentation is needed to arrive at commercially viable designs of PCM heat storage units.