Investigation of thermal energy storage capacities of phase change material embedded different bio-based materials converted into biochar

Abstract In recent years, latent heat thermal energy storage systems have emerged as a significant technique for addressing the variable nature of renewable energy sources, balancing energy demand, and enhancing energy efficiency. Additionally, phase change materials (PCMs) with high latent energy storage capabilities have become increasingly popular as the preferred materials for thermal energy storage applications. This study investigates the effects of using composite materials with phase change materials embedded in biochar pores through microencapsulation on improvements in latent energy storage capacity. To achieve this, various organic materials, including hazelnut shells, peanut shell, pine cone, and poplar sawdust, were converted into composite biochar through pyrolysis, thereby enhancing their porosity. The results obtained are given in comparison with the results of composite materials with phase change materials encapsulated in the pores of the raw material. The latent heats of the composites impregnated with phase change material (PCM) in their pores were compared to identify the most suitable composite biochar material. The best performance improvements in energy storage capacities compared to the raw material results were found to be 134.8% and 147.6% for RT-28/Peanut shell biochar and RT-28/Pine cone biochar composites, respectively. On the other hand, the highest energy storage capacity for both raw material and biochar was measured as 50.18 J g −1 and 75.1 J/g for poplar sawdust, respectively. The results indicated that poplar sawdust was the most appropriate base material.