Evaluation of waste corn cob and copper slag for production of novel leakage-free composite phase change material with ımproved thermal energy storage

In this study, a leakage-free and thermally stable composite phase change material (PCM) was developed using waste corn cob (CC) and waste copper slag (CS) to evaluate renewable and waste biomass resources. MP-MS eutectic mixture was impregnated into a corn cob-derived carbon structure, and then, by adding CS at different ratios (1%, 3%, and 5%), the thermal performance was optimized. DSC analyses revealed that the melting temperature and melting enthalpy of the CC/MP-MS (35%) composite PCM were 22.9 °C and 81.4 J/g, respectively. Small changes were observed in these values ​​with the addition of CS, but only a 1–2% decrease in enthalpy was observed. Furthermore, after 650 cycles of thermal cycling testing, only a limited decrease in the thermal performance of the composite PCMs was observed, demonstrating high thermal stability and cyclic durability. Thermal conductivity values ​​increased significantly with the addition of CS. While the MP-MS eutectic mixture had a limited thermal conductivity of only 0.17 W/mK, this value reached 0.42 W/mK with the addition of 5% CS. IR thermal camera images demonstrate that increasing the CS content accelerates heat transfer and improves temperature distribution. Specifically, after a 25-minute heating period, the surface temperature of the composite PCM containing 5% CS was approximately 9 °C higher than that of the pure composite.