Incorporating phase change material (PCM) into construction materials is an effective method for modifying building energy regulations throughout their service life. However, the effectiveness of PCM is constrained by its low thermal conductivity, highlighting the need for efficient enhancement methods. This study introduces thermally conductive carbon-based additions at both the nano-scale and meso-scale with different shapes, including carbon nano-tube (CNT), carbon black nano-particle (CB), and carbon fibre (CF) in PCM mortar. The mixed hydrated inorganic salt serves as the core PCM, while expanded perlite acts as the supporting material for the stable PCM composite, based on the presented research. The multi-scale additions establish thermal conduction pathways that improve temperature regulation performance. The modified samples exhibited a temperature difference of 2.2 °C and a time lag of up to 20 min under natural cooling conditions. Notably, CB positively influenced thermal conductivity, while CNT demonstrated an unexpected minor reduction. The enhancement in thermal conductivity increased with the content of CB, reaching an optimal enhancement of 18 %, except at a CNT content of 0.5 %. Conversely, both CB and CNT consistently improved thermal diffusivity. Furthermore, the compressive strength of the modified samples was significantly enhanced by up to 24 % compared to PCM mortar without carbon modifications. The modification method proposed in this study significantly improves both the thermal and mechanical properties of PCM mortar.

中文翻译：

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使用多尺度碳基材料增强相变砂浆的热性能


在建筑材料中加入相变材料 （PCM） 是在整个使用寿命期间修改建筑能源法规的有效方法。然而，PCM 的有效性受到其低导热率的限制，这凸显了对高效增强方法的需求。本研究介绍了纳米级和介级不同形状的导热碳基添加剂，包括相变材料砂浆中的碳纳米管 （CNT）、炭黑纳米颗粒 （CB） 和碳纤维 （CF）。基于本研究，混合水合无机盐作为核心 PCM，而膨胀珍珠岩作为稳定 PCM 复合材料的支撑材料。多尺度添加建立了提高温度调节性能的热传导路径。改性样品在自然冷却条件下表现出 2.2 °C 的温差和长达 20 min 的时间滞后。值得注意的是，CB 对热导率产生了积极影响，而 CNT 则表现出意想不到的小幅降低。导热系数的增强随着 CB 含量的增加而增加，达到 18% 的最佳增强，除了 CNT 含量为 0.5 %。相反，CB 和 CNT 都持续提高了热扩散率。此外，与没有碳改性的 PCM 砂浆相比，改性样品的抗压强度显著提高了 24%。本研究提出的改性方法显著提高了 PCM 砂浆的热性能和力学性能。