Enhanced Thermal Performance of Finned Heat Exchangers With Beeswax‐Based Phase Change Materials: Optimization and Comparative Analysis

ABSTRACT This study examines a compact latent heat thermal storage system featuring a finned‐tube helical heat exchanger and two phase change materials: pure beeswax and a beeswax–paraffin eutectic mixture. Experimental charging and discharging processes were performed at flow rates ranging from 40 to 100 L/h to evaluate the influence of operational parameters on the system's thermal behavior. The system would demonstrate high reliability, with temperature deviations below ±1.1%, and melting time would be cut by up to 50% at higher flow rates. Although faster melting would come at the cost of lower effectiveness, solidification would remain highly efficient, reaching up to 0.93. The study would also highlight a clear shift from convective limitations at low flow rates to PCM‐conductivity limitations at higher ones. Throughout all tests, natural beeswax would offer superior thermal stability and outlet‐temperature uniformity. With efficiencies near 0.9 and C‐factors around 0.019, the compact finned‐tube design would outperform conventional systems, suggesting that such enhanced geometries coupled with natural PCMs could offer a highly effective and sustainable solution for low‐temperature thermal energy storage.