Heat transfer enhanced by angle-optimized fan-shaped porous medium in phase change thermal energy storage system at pore scale

High-thermal-conductivity porous medium can effectively improve the heat transfer rate of solid-liquid phase change in thermal energy storage system, enhancing the usage efficiency of renewable energy. In this paper, the fan-shaped porous medium was applied to accelerate heat transfer rate of phase change material in thermal energy storage, and the corresponding heat transfer performance affected by Rayleigh number, porosity and angle of porous medium during melting and solidification process was investigated. The results showed that the porous medium can reduce heat accumulation and improve heat transfer rate. Compared with the pure PCM, the complete melting time was shortened by 51.2% after inserting 150° porous medium with porosity of 0.5, when the Rayleigh number was 105. In addition, there was an optimal angle according to the melting rate and energy storage density. When the Rayleigh number was 5 × 105, the optimal angle of porous medium is 180°. Besides, the heat transfer effect was significantly improved by the porous medium with larger angle during solidification process.