Abstract Phase change materials are widely used as thermal capacitors in solar thermal systems. The phase change materials with carbon materials could directly absorb the solar energy and transfer to water for building heating, while are rarely reported. In this work, an Ethylene-Propylene-Diene Monomer based phase change material with expanded graphite is prepared. The photo-thermal performance of the phase change material is investigated with combined experimental and numerical method. The SiO2 aerogel is first used as the thermal insulator in the solar thermal systems with the high transmittance and low thermal conductivity. The effect of the phase change material height and tube passes number on the photo-thermal performance of the phase change materials are calculated. The results show that the new material has a tensile strength of 3.6 MPa, enthalpy of 126.8 J g−1，and thermal conductivity of 1.106 W m−1 K−1. The phase change material with SiO2 aerogel could resist heat lost on the surface. The phase change material has good photo-thermal performance in solar thermal systems, could heat more than 200 L of hot water at daytime.

中文翻译：

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用于光热利用的聚合物基相变材料

摘要 相变材料在太阳能热系统中被广泛用作热电容器。含碳材料的相变材料可以直接吸收太阳能并转移到水中用于建筑供暖，但鲜见报道。在这项工作中，制备了一种基于乙烯-丙烯-二烯单体的膨胀石墨相变材料。结合实验和数值方法研究了相变材料的光热性能。SiO2气凝胶首先被用作太阳能热系统中的绝热体，具有高透光率和低热导率。计算了相变材料高度和管程数对相变材料光热性能的影响。结果表明，新材料的抗拉强度为3.6 MPa，126.8 J g-1 的焓，以及 1.106 W m-1 K-1 的热导率。带有SiO2气凝胶的相变材料可以抵抗表面的热量损失。该相变材料在太阳能热系统中具有良好的光热性能，白天可加热200L以上的热水。