Thermal energy storage characteristics in an enclosure packed with MEPCM particles: An experimental and numerical study

This work aims to examine, via a complementary approach of experimental measurement and numerical simulation, transient thermal energy storage characteristics across an air-saturated enclosure packed with microencapsulated phase change material (MEPCM) particles. The core phase change material of the MEPCM particles is n-octadecane with melting temperature about TM = 24 °C. The square enclosure has a cross-section dimension of 25 by 25 mm and it was 60 mm long. The vertical side walls of the enclosure were differentially heated isothermally while the remaining side walls were thermally insulated. Experiments have been undertaken for the air-saturated enclosure filled with MECPCM particles of volumetric fraction of 0.55 with the relevant parameters in the following ranges: the Darcy number, Da = 1.42 × 10−9; the Rayleigh number, Raf = 1.71 × 106-5.67 × 107; the Stefan number, Stem = 0.125-0.23; and the subcooling parameter, Sbc = −0.375 to 0.25. Meanwhile, numerical simulations have been performed based on a mathematical modeling mimicking the experimental configuration considered to further elucidate the transient heat transfer characteristics across as well as the thermal energy storage efficiency of the enclosure.