Numerical Investigation on PCM-Based Enclosure: Effect of Pin Height and Count

One of the challenges in energy storage is the reduced thermal conductivity coefficient of phase-change materials (PCMs), which presents a barrier to efficient energy storage. Fins can be used as thermal conductivity enhancers to help overcome this problem. The PCM is meant to melt by heat transfer from high-temperature water, and this numerical study examined the impacts of pin-fin height and number on the heat transfer rate and melting time. The PCM enclosure had dimensions of [Formula: see text]. It was equipped with four sets containing 21, 35, 49, and 63 cylindrical pin fins, each with a diameter of 10 mm. The fins were arranged at heights of 30, 42, and 56 mm. The material for the pin fins and the plate between the water and PCM on which the pin fins are mounted is St37. The findings show that, compared to the design without fins, installing pin fins at a height of 56 mm and with a count of 63 may enhance the heat transfer rate from water to PCM by 59.65%. Additionally, it decreases the melting time by 36.6% for 1 kg of PCM. Increasing the number of pin fins was shown to reduce the melting time more effectively than increasing the fin height. It was shown that the larger heat transfer surface area and improved natural convection from flow vortices inside the PCM enclosure account for the higher heat transfer rate in designs with pin fins compared to those without.