Numerical study on the thermal performance of high-temperature latent heat packed-bed with a rectangular heat storage unit

As one of the most effective methods of thermal energy storage, packed-bed (PB) systems using phase change material (PCM) as heat storage media have been vigorously developed. To obtain the thermal performance of brick structure heat storage unit (HSU) in hightemperature latent heat PB, a 3-D PBsystem based on Navier-Stokes equations for heat transfer fluid, phase change model for PCM, and surface-to-surface (S2S) radiation model is established. The idea of changing the geometric structure of the brick HSU is proposed to improve the thermal performance of PB system. The influence of three-dimensional size of carbonate-based composite PCM with brick structure on the thermal performance of high-temperature PB is studied systematically. The numerical analyses show that the influence of three-dimensional size of brick-type HSU in different directions on the thermal performance of the PB system is independent. And the system has a higher energy efficiency (66.5%) and lower heat loss when the width and height of HSU are around 25 mm. The research results can guide the optimization of high-temperature composite PCM PB system.