Experimental and numerical study on transient thermal energy storage of microencapsulated phase change material particles in an enclosure

This work aims to examine, via a complementary approach of experimental measurement and numerical simulation, transient characteristics of thermal energy storage in an enclosure filled with microencapsulated phase change material (MEPCM) particles. The core phase change material of the MEPCM is n-octadecane with melting temperature about TM = 24 °C. The two vertical surfaces of the enclosure are, respectively, maintained at hot and cold temperatures, while the horizontal surfaces are kept thermally insulated. The study has been performed for nine sets of the hot and cold wall temperatures with the corresponding dimensionless parameters ranges: Stefan number Stem = 0.063-0.251; subcooling factor Sbc = 0.0-0.75. To further elucidate the relevant heat transfer characteristics, numerical simulations have been carried out based on a mathematical modeling of the experimental configuration considered. The results disclosed that the faster melting is experienced for the system with higher Stefan number and the subcooling number is the main parameter to dominate the thermal latent heat storage of the MEPCM system. Besides, the dimensionless accumulated energy through the hot wall Qh∗ is well correlated with the relevant parameters, including the Stefan number Stm, the subcooling parameter Sbc, and the Fourier number Fo.