Waste polyvinyl chloride derived latent thermal energy storage composites for waste heat recovery via packed bed system

Latent thermal energy storage (TES) techniques utilizing phase change materials (PCMs) provide a promising way to mitigate the discrepancy between the intermittent nature of solar energy supply and consistent demand for human society. However, the development is hindered by the slow charging/discharging rates of the low thermal conductivity PCMs. Meanwhile, the high value-added utilization of waste plastic is receiving increasing attention as an environmentally sustainable strategy. In this regard, waste polyvinyl chloride (PVC) is recovered as SiC skeletons to obtain green phase change composites (PCCs) for waste heat recovery. After being infiltrated with paraffin wax (OP44E), proposed PCCs demonstrate a high retention ratio of latent heat up to 91.1% and a thermal conductivity of 2.4 W·m⁻¹·K⁻¹, which is benefitted from limited expansion and impurity remove process, respectively. With the elevated thermal conductivity and spectral absorptance, proposed PCCs exhibit superior solar-thermal energy storage rates. Furthermore, numerical simulation of the thermal charging/discharging performance and flow characteristics is carried out for the packed bed TES system. The results reveal a reduction in charging and discharging time by 21% and 41.1% for proposed PCCs, respectively. This work introduces a novel strategy for recycling waste heat via high-performance TES and repurposing waste plastics simultaneously.