Hydrated salt phase change materials (PCMs) can play an important role in the temperature regulation of buildings by storing and releasing latent heat. However, hydrated salt PCMs are affected by phase separation, supercooling, and leakage, which greatly limit their application. In this study, an innovative modified calcium chloride hexahydrate (CaCl₂·6H₂O) PCM was prepared with potassium chloride (KCl) as the temperature regulator and strontium hydroxide octahydrate (Sr(OH)₂·8H₂O) as the nucleating agent. Subsequently, 15 wt% expanded graphite (EG) was immersed into 85 wt% modified PCM to prepare form-stable composite PCM, which is suitable for space thermal regulation with a phase transition temperature of 26.25 °C, phase change enthalpy of 153.03 J/g and a thermal conductivity of 4.3893 W/(mK). After 500 heating–cooling cycles, the phase change temperature changed little, and enthalpy lost only 5.95%. The test chamber prepared with a composite PCM and polyvinyl chloride (PVC) board was studied to evaluate its temperature regulation performance. In the heating and cooling process, the indoor temperature is maintained at 24.5–27.5 °C for 180 to 652 min. Therefore, the prepared composite PCM can have a good application in the temperature management of buildings.

Graphical abstract

中文翻译：

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一种创新的改性六水氯化钙基复合相变材料，用于热能储存和室内温度调节

水合盐相变材料 (PCM) 通过储存和释放潜热在建筑物的温度调节中发挥重要作用。然而，水合盐相变材料存在相分离、过冷和泄漏等问题，极大地限制了其应用。本研究以氯化钾_（ KCl ）为温度调节剂，以氢氧化锶八水合物（Sr(OH) _{2 ·} 8H ₂O)作为成核剂。随后，将15 wt%的膨胀石墨（EG）浸入85 wt%的改性PCM中制备形态稳定的复合PCM，其相变温度为26.25 °C，相变焓为153.03 J/，适用于空间热调节。 g 和 4.3893 W/(mK) 的热导率。500次加热-冷却循环后，相变温度变化不大，热损失仅5.95%。研究了用PCM和聚氯乙烯（PVC）复合板制备的试验箱，以评估其温度调节性能。在加热和冷却过程中，室内温度保持在24.5-27.5℃，持续180-652分钟。因此，所制备的复合PCM可以在建筑物的温度管理方面有很好的应用。

图形概要