Abstract
This study investigates the optimization of heat transfer in a thermal battery system using phase change material (PCM) to enhance energy storage efficiency. A 2D model with 28,500 elements is developed, utilizing paraffin wax as the PCM and polystyrene (EPS) for insulation. Four fin configurations are analyzed: Case 1 features straight fins; Case 2 incorporates 30° inclined branches; Case 3 includes a top branch; and Case 4 combines two branches at the body and top. Compared to the baseline (Case 1), fin-enhanced designs - particularly Cases 3 and 4 -significantly accelerate PCM melting, reduce thermal equilibrium time, and increase total heat absorption by 16% to 20%. These configurations also achieve a higher average PCM temperature, improving overall heat transfer efficiency. The findings provide valuable insights for advancing thermal storage systems in solar energy and HVAC applications while highlighting opportunities for further optimization through dynamic temperature control strategies.