Simulation on PCM melting improvement with triple-finned horizontal shell-tube latent-heat thermal energy storage unit: Effect of fin size and distribution
S. R. Pal, Dipankar Bhanja, Rahul Dev Misra
Abstract
Due to their high latent heat storage capacity, phase change materials (PCMs) offer great potential in latent heat thermal energy storage (LHTES) devices. However, the primary drawback is their inherently poor thermal conductivity. Fins are very useful to accelerate the melting process and maximize energy storage efficiency. This study investigates the enhancement of heat transfer in a shell-and-tube latent heat thermal energy storage (LHTES) system by incorporating angled fins to improve the thermal conductivity of the phase change material (PCM). The study analyses the effect of fin angular position (20°, 40°, 60°, and 80°) and fin length (L = 6.25 mm, 9.375 mm, and 12.5 mm) on the melting dynamics of the PCM. Numerical simulations were conducted using the finite element method (FEM) in COMSOL, assuming an adiabatic boundary condition on the shell. The results demonstrate that fins can significantly reduce the melting time compared to the no-fin case, with performance strongly dependent on fin length and angular orientation. For shorter fins (L = 6.25 mm), the lower angular positions (20° and 40°) provided the fastest melting rates, whereas for longer fins (L = 12.5 mm), higher angular positions (60° and 80°) exhibited better performance. The most significant reduction in melting time compared to the no-fin case was 31.13 % for 80° fins at L = 6.25 mm, 37.12 % for 40° and 80° fins at L = 9.375 mm, and 41.31 % for 80° fins at L = 12.5 mm. The study introduces a novel approach by strategically positioning fins in downward orientations to enhance convection-driven heat transfer in LHTES systems. The optimized fin arrangement significantly improves thermal performance, offering valuable insights for increasing the efficiency of thermal energy storage in renewable energy applications, especially where heat absorption and release fast are essential. Additionally, the study compares the performance of two-fin, three-fin, four-fin and no-fin configurations.