▎ 摘　　要

The substitution of fossil fuels with renewable energies is a meaningful way to mitigate global warming and air pollution. Phase change materials could store and release a high amount of energy. The solidification phenomenon is an essential factor that should be considered for choosing Phase Change Materials (PCMs). In this work, attempts have been made to improve the thermophysical properties of paraffin as a PCM during the solidification process. 1-3 wt.% of Al2O3, CuO, TiO2, and graphene nanoparticles were used during the solidification process. No reports had yet been made on the effect of graphene nanoparticles versus metal oxide nanoparticles on the thermal properties of Nanoparticle-Enhanced Phase Change Materials (NEPCMs). The DSC, TGA, SEM, and FT-IR analyses were done to investigate the transition temperature, nanoparticle distribution, and nanocomposites morphology, respectively. It was seen that the addition of nanoparticles could effectively increase the thermal conductivities of paraffin. The maximum and minimum increases were in thermal conductivities were recorded in samples with 3wt.% of graphene and lwt.% of TiO2. The results showed that selecting suitable nanocomposites depended on various parameters, such as the type of nanoparticles and the weight percentage of nanoparticles. The PCM nanocomposites can be used to control the thermal management of different systems. The results can be applied in thermal design and management concepts, especially in the solidification process.