A review of nanomaterial incorporated phase change materials for solar thermal energy storage

Phase Change Materials (PCMs) have being used in different solar energy systems for thermal energy storage and performance enhancement. Improving heat transfer from PCMs leads to reductions in charge and discharge durations, which makes them more favorable as storage units. Dispersion of conductive solid materials with nano dimensions is a practical approach to enhance their thermal features. Several nano-sized materials have been added to PCMs to improve their heat/cool storage abilities. The studies in this field reveal that employing nanotechnology is an efficient method for heat transfer improvement. In the current article, studies concerning applications of nanotechnology in PCMs are reviewed. According to the results, employing nanotechnology can noticeably enhance the heat transfer rate, which results in a reduction of charge and discharge times of the storage units equipped with the PCMs. The enhancement in the melting process of nano PCMs, which indicates the storage performance, depends on several factors such as concentration and kind of solid nano-sized particles, type of base PCM and the parameters related to operating conditions such as Rayleigh and Darcy numbers. The improvement in thermal performance due to nano PCMs is mainly attributable to the increased thermal conductivity and decrease in latent heat of fusion, which accelerates the melting/solidification processes.