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水合盐作为一种固-液相变材料因具有高的能量储存密度而备受关注。然而,其过冷和相分离的缺陷限制了它的应用。为了解决过冷及相分离问题,文章提出了采用在硫酸钠饱和溶液中原位聚合的方法制备硅胶。根据实验结果,硅胶中饱和硫酸钠水溶液的潜热为238.1 J/g,相变温度为30℃。通过添加这种添加剂,它可以在亚热带春夏季时期承受长达五个月以上的冷热循环。通过扫描电子显微镜和傅里叶变换红外光谱检测发现,实验制备的硅胶是无定型结构,并有一些小的晶体分布其中。实验推断,硅胶的添加提供了一种多孔结构,有助于硫酸钠水合盐晶体的生长,因此,它可以抑制过冷和相分离的发生。
Hydrated salts as a solid-liquid phase change material have attracted much attention for their high energy storage density. However, the defects of its subcooling and phase separation limit its application. In order to solve the problem of subcooling and phase separation, the article proposes the preparation of silica gel by in-situ polymerization in a saturated sodium sulfate solution. According to the experimental results, the latent heat of the saturated sodium sulfate aqueous solution in silica gel is 238.1 J / g and the phase transition temperature is 30 ℃. By adding this additive, it can withstand hot and cold cycles of up to five months in subtropical spring and summer. By scanning electron microscopy and Fourier transform infrared spectroscopy, we found that the experimental preparation of silica gel is amorphous structure, and there are some small crystal distribution. Experiments concluded that the addition of silica gel provides a porous structure that is conducive to the growth of sodium sulfate hydrated salt crystals, therefore, it can inhibit the occurrence of supercooling and phase separation.