Abstract Solar storage tanks are key to ensuring the high efficiency of concentrated solar power plants, and phase change materials are the most important storage energy media influencing system efficiency. Therefore, as energy storage or release mechanisms are a focus of related research. In this study, numerically analysed the thermal performance of a small capsule of three different phase change materials for a packed bed solar energy storage system. Air and molten salt are used as the heat transfer fluid (HTF) and the phase change material (PCM), respectively. A model based on a concentric-dispersion model and the enthalpy method was used to analyse the phase transition of the PCM. The equation was solved using the finite-difference method, and the results were verified using previous experimental data. The influence of particle diameter, porosity, and height-to-diameter ratio of the storage tank on the total storage energy, storage capacity ratio, axial temperature curve, and utilization ratio of the PCM were studied. It was found that he storage capacity and utilization rate of 3-PCM energy storage tanks are relatively high. And that increase from 86.07% to 86.65% and 86.07%–86.67%, respectively, when the porosity is reduced from 0.6 to 0.1. This results in an increase in the total storage energy of 5.2 × 1012 Wh to 1.3 × 1013 Wh. Similarly, when the particle diameter decreases from 0.6 to 0.1, the storage capacity ratio and utilization rate increase from 85.8% to 87.3% and 85.6%–87.4%, respectively. However, although these increases are larger, the increase in total energy storage is small. Finally, it was found that the shape of the tank has no effect on the storage capacity at a fixed tank volume. The proposed model provides a reference value for energy storage in a concentrating solar thermal power (CSP) system.

中文翻译：

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高温填充床系统中三相复合材料梯级储罐的蓄热性能

摘要 太阳能储罐是保证聚光太阳能电站高效运行的关键，而相变材料是影响系统效率的最重要的储能介质。因此，作为能量储存或释放机制是相关研究的重点。在这项研究中，数值分析了用于填充床太阳能存储系统的三种不同相变材料的小胶囊的热性能。空气和熔盐分别用作传热流体 (HTF) 和相变材料 (PCM)。使用基于同心色散模型和焓法的模型来分析 PCM 的相变。使用有限差分法求解方程，并使用先前的实验数据验证结果。粒径的影响，研究了储罐孔隙率、高径比对相变材料总储能、储量比、轴向温度曲线和利用率的影响。发现3-PCM储能罐的存储容量和利用率较高。当孔隙率从 0.6 减少到 0.1 时，分别从 86.07% 增加到 86.65% 和 86.07%–86.67%。这导致总存储能量从 5.2 × 1012 Wh 增加到 1.3 × 1013 Wh。同样，当粒径从 0.6 减小到 0.1 时，存储容量比和利用率分别从 85.8% 增加到 87.3% 和 85.6%–87.4%。然而，虽然这些增幅较大，但总储能的增幅很小。最后，结果表明，在固定的储罐容积下，储罐的形状对存储容量没有影响。所提出的模型为聚光太阳能热发电 (CSP) 系统中的能量存储提供了参考值。