Development and thermal analysis of novel thermal storage capsules for high-temperature latent heat storage based on cold-pressing and hot-sintering

Corrosion and leakage of molten salt pose significant challenges to the implementation of high-temperature packed-bed latent heat storage in concentrating solar power. This work proposes a novel material-system integrated solution for high-temperature (> 500 °C) packed-bed latent heat storage. Shape-stabilized phase change material (ss-PCM) made by cold-pressing and hot-sintering serves as the “core” of the thermal storage capsule, achieving high thermal stability and excellent corrosion resistance at high temperatures. By controlling the particle size of the SiC, ss-PCMs exhibit a high thermal conductivity of 1.81–5.45 W/(m·K). The effective thermal storage density is 1213.46 kJ/kg within the 50–700 °C range. Furthermore, the thermal performance and pressure drop of the five configurations are analyzed using a 3D model that accounts for radiation effects. The results indicate that reducing capsule height with staggered stacking significantly increases the average charging power (by 29.8% compared to Case 1) and shortens the charging time, but raises the pressure drop. Case 5 (with reduced diameter) is recommended as the optimal design, achieving a 21.8% power improvement (compared to Case 1) while maintaining a manageable pressure drop. This work offers a promising approach for scaling up high-temperature packed-bed thermal storage in renewable energy integration, contributing to enhanced renewable energy utilization.