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

Abstract

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 degrees 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 degrees C higher than that of the pure composite.