A novel stearic acid (SA)‐based phase change material (PCM) was developed by incorporating magnetic dust, an iron‐rich industrial byproduct, to enhance solar water heating performance. SA/magnetic dust composites containing 1–5 wt % filler were synthesized and characterized. Structural analyses identified magnetite (Fe 3 O 4 ), metallic iron (α‐Fe), and iron carbides (Fe 3 C) with hierarchical morphology, while FTIR confirmed stable Fe 3+ –carboxylate interactions. The optimal composite (SA/D3%, 3% wt) exhibited uniform filler dispersion, resulting in accelerated heating and cooling rates (evidenced by steeper heating/cooling slopes in solar‐thermal tests) while retaining high latent heat (177.4 J g −1 melting; 186.7 J g −1 freezing) and a narrow hysteresis (10.2°C). In solar water heating tests, SA/D3% achieved 64% efficiency and a maximum temperature of 56.8°C, outperforming pure SA (45%, 47.8°C) and higher loading composites. The composite demonstrated excellent thermal stability with <1.5% enthalpy loss after five cycles. These results highlight SA/D3% as a cost‐effective, sustainable, and high‐performance PCM for solar‐thermal energy systems.
Almorshedi et al. (Tue,) studied this question.