A numerical and experimental study of solidification around axially finned heat pipes for high temperature latent heat thermal energy storage units

A numerical and experimental investigation was conducted on the thermal performance of latent heat thermal energy storage (LHTES) systems which use heat pipes (HPs) for solar thermal power generation. The aim of this study was to quantify the advantages of utilising axially finned HPs rather than bare HPs in LHTES systems. The numerical model uses the effective heat capacity formulation to simulate the solidification process in the phase change material (PCM) and adopts the thermal resistance network approach simulate the heat transfer phenomena through the HPs. The experimental measurements were conducted on a bare heat pipe and on an identical heat pipe with four axial fins. The numerical predictions and the experimental measurements were found to be in good agreement. The benefits of finning the HPs can be seen by considering the enhancement of the rate of energy extraction from the PCM as well as the HP effectiveness. The results have shown the energy extracted increased by 86% and the heat pipes effectiveness increased by 24%.