Anisotropic porous skeleton for efficient thermal energy storage and enhanced heat transfer: Experiments and numerical models

The pore structure of the porous skeleton plays a decisive role in the performance of the shape-stabilized phase change materials (ss-PCM). For example, in the adsorption rate of the phase change material and the effect of heat transfer enhancement. In this paper, the anisotropic porous skeleton was prepared via ice-template method and used as supports for phase change materials (PCM). The coherent hierarchical pore structure not only made the adsorption of PCM more effectively, increasing the pore utilization rate to 98.22 % and realizing a satisfactory heat storage density of 94.17 J/g (50.42 wt%), but also achieved the prominent heat transfer enhancement in axial direction. Owing to this, the prepared anisotropic ss-PCM showed excellent thermal management capability, which reduced the chip surface temperature from 160 degrees C to 80 degrees C; even 20 degrees C lower than using aluminum heat sinks. The numerical model via Lattice-Boltzmann method was used to investigate the mechanism of enhanced heat transfer. It showed that the anisotropic porous skeleton strongly enhanced the convection in the melting process of PCM by reducing the tortuosity, which greatly compensated for the low thermal conductivity of the skeleton and fully demonstrated the importance of the design of the pore structures. Therefore, it provided useful suggestions for the preparation of high quality ss-PCMs.