Abstract This paper presents a colloidal binary composite phase change storage material prepared using inorganic–organic phase-change materials (PCMs) to improve the thermal conductivity of the organic PCM and solve the supercooling and phase separation problems associated with inorganic PCMs. Samples of disodium hydrogen phosphate dodecahydrate (DHPD)/capric acid (CA) were prepared using a sol-gel method. These samples were characterized by differential scanning calorimetry (DSC), thermal conductivity analyses, Fourier transform infrared (FTIR) spectroscopy, and X-Ray diffraction (XRD). First, the eutectic mixture ratio for a DHPD-CA binary system was theoretically predicted. An analysis of the DSC curve and the two-phase diagram of the eutectic system reveals that the colloidal mixture is close to the eutectic state when the DHPD/CA ratio is 7:3. The results of FTIR spectroscopy and XRD revealed that DHPD and CA in the colloidal mixture did not undergo a chemical reaction, indicating the occurrence of physical mixing. Second, the melting temperature of the composite material was 33.8 °C, the degree of supercooling was 0.9 °C, the melting enthalpy of phase change was 168.8 J g−1, and the thermal conductivity was 0.468 W m−1K−1 at 15 °C. Moreover, after 300 accelerated cold–hot cycles, the thermal properties and morphology of the colloidal binary composite were stable. The addition of CA reduced the degree of supercooling of the DHPD. Furthermore, the addition of DHPD improved the phase-change latent heat and thermal conductivity of CA, thereby reducing the cost of the composite material. The material presented can be used in passive solar energy applications.

中文翻译：

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癸酸和Na2HPO4·12H2O胶体混合物作为储能相变材料的制备及热性能

摘要 本文提出了一种使用无机-有机相变材料（PCMs）制备的胶体二元复合相变存储材料，以提高有机相变材料的热导率并解决与无机相变材料相关的过冷和相分离问题。使用溶胶-凝胶法制备十二水磷酸氢二钠 (DHPD)/癸酸 (CA) 的样品。这些样品通过差示扫描量热法 (DSC)、热导率分析、傅里叶变换红外 (FTIR) 光谱和 X 射线衍射 (XRD) 进行表征。首先，理论上预测了 DHPD-CA 二元系统的共晶混合比。DSC曲线和共晶体系的两相图分析表明，当DHPD/CA比为7:3时，胶体混合物接近共晶状态。FTIR光谱和XRD结果表明胶体混合物中的DHPD和CA没有发生化学反应，表明发生了物理混合。其次，复合材料的熔化温度为 33.8 ℃，过冷度为 0.9 ℃，相变熔化焓为 168.8 J g-1，15 ℃时的热导率为 0.468 W m-1K-1 ℃。此外，经过 300 次加速冷热循环后，胶体二元复合材料的热性能和形态是稳定的。CA 的加入降低了 DHPD 的过冷度。此外，DHPD的加入提高了CA的相变潜热和导热系数，从而降低了复合材料的成本。所提供的材料可用于被动太阳能应用。