Abstract Phase change materials (PCMs) with paraffin waxes have been widely used in solar energy systems attributed to their favorable latent heat thermal energy storage (LHTES) properties. However, long-standing drawbacks of serious leakage in the melting state and low heat transfer property significantly limit their practical application in TES. Herein, we report a novel expanded perlite/paraffin/graphite powder (EP/P50/GP) composite form-stable PCM (FSPCM) with enhanced thermal conductivity overcoming the drawbacks of paraffin. The effects of graphite particle (GP) size on the properties of composite FSPCM were investigated by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM). XRD and FTIR analysis suggested that there was favorable chemical compatibility among the composite FSPCMs. GP addition exhibited a positive influence on the thermal stability of EP/P50/GP composite FSPCMs. The smaller the GP size is, the better the dispersion of GP in the composite FSPCMs is. The thermal energy storage capacity per unit volume and cost of EP/P50/GP80 composite were also calculated as 1.95 × 107 kJ/m3 and 23.49 $/kJ. The thermal conductivity of EP/P50/GP80 composite FSPCM was determined as 1.34 W/m∙K, which showed the highest heat transfer rate in the all EP/P50/GP composite FSPCMs and was 4.15 times higher than that of P50 (0.26 W/m∙K). After the thermal cycling tests, the prepared samples exhibited good thermal reliability, and the thermal conductivities were also further improved. Overall, GP showed apparent effects on the heat transfer rate and thermal behavior of the composite FSCPMs. The as-synthesized FSPCMs could have considerable promising in the solar energy systems.

中文翻译：

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石墨杂化膨胀珍珠岩/石蜡提高形状稳定复合相变材料的热导率

摘要 含石蜡的相变材料 (PCM) 因其良好的潜热热能储存 (LHTES) 特性而被广泛应用于太阳能系统。然而，长期存在的熔融态泄漏严重和传热性能低的缺点极大地限制了它们在 TES 中的实际应用。在此，我们报告了一种新型膨胀珍珠岩/石蜡/石墨粉 (EP/P50/GP) 复合形状稳定的 PCM (FSPCM)，其具有增强的导热性，克服了石蜡的缺点。通过X射线衍射（XRD）、傅里叶变换红外（FTIR）光谱、扫描电子显微镜（SEM）研究石墨颗粒（GP）尺寸对复合FSPCM性能的影响。XRD 和 FTIR 分析表明复合 FSPCMs 之间存在良好的化学相容性。添加GP对EP/P50/GP复合FSPCM的热稳定性有积极影响。GP 尺寸越小，GP 在复合 FSPCM 中的分散性越好。EP/P50/GP80 复合材料的单位体积热储能容量和成本也计算为 1.95 × 107 kJ/m3 和 23.49 $/kJ。EP/P50/GP80 复合 FSPCM 的热导率确定为 1.34 W/m∙K，在所有 EP/P50/GP 复合 FSPCM 中表现出最高的传热率，是 P50 的 4.15 倍（0.26 W /m∙K)。经过热循环测试，制备的样品表现出良好的热可靠性，热导率也进一步提高。总体而言，GP 对复合 FSCPM 的传热速率和热行为表现出明显的影响。