Performance Assessment of Biocomposite Phase Change Materials for Sustainable Thermal Energy Storage

This study presents a novel, cost‐effective composite phase change material (PCM) using cetyl alcohol (CAL) and shape‐stabilizing biochar derived from industrial waste wood carbon (WWC) for low‐temperature thermal energy storage, and the simultaneous use of Kissinger and Ozawa techniques to assess the kinetics and activation energies of PCM samples. Biochar content was varied from 0 to 3 g per 10 g CAL to synthesize various composite PCM samples. The morphological studies confirmed the encapsulation of molten PCM into biochar. FTIR and XRD investigations confirmed the chemical stability of the synthesized PCM samples, ascribing to the absence of extra peaks/bands. TGA studies divulged the enhanced thermal stability of the CAL4 sample. CAL4 sample has exhibited suitable thermal properties comprising a latent heat of 184.83 J/g, an encapsulation efficiency of 76.76%, and a thermal energy storage capacity of 99.62%. The activation energy of CAL4 calculated by both models, i.e., 551.118 and 531.827 kJ/mol, is superior compared to that of the pure PCM, which is due to the porous matrix of the CAL4 sample. Even after 100 thermal cycles, CAL4 showed negligible thermal property changes and zero leakage, proving it as a cost‐effective leak‐proof solution for long‐term low‐temperature thermal energy storage applications.