Investigation of phase change heat transfer in a rectangular case as function of fin placement for solar applications

This paper attempts to maximize solar energy utilization by employing a latent heat thermal energy storage (LHTES) unit integrated with a solar receiver of concentrating collectors or thermal management unit for photovoltaic panels. The study investigated an LHTES unit with a rectangular shape and equipped with a T-shaped fin subjected to heat flux. The paper examined the effect of eight T-fin positions under the applied heat flux on the thermal performance of phase change material (PCM). The PCM melting process was modeled using the enthalpy-porosity method using the finite element approach. The obtained numerical results revealed that PCM melting rate strongly depends on fin position, with superiority for fins located at the upper part of the chamber when heat flux is used as the primary heating source. Under applied heat flux, locating the fin at the upper section of the vertical LHTES unit enhanced the melting rate of the PCM, reaching 10 % better than the fin's middle and bottom positions, which is against the cases reported for the fixed temperature heating process that prefer bottom fins. Thus, these results recommend using T-shaped fins in the upper parts of PCM-based units used for solar collector receivers and thermal management of photovoltaic panels.