随着可再生能源的发展,熔盐相变储热技术备受关注.由陶瓷和熔盐复合形成的形态稳定的相变储热材料具有储热量大、工艺简单、成本低等优点,逐渐成为研究热点.然而,熔盐吸湿性高,熔盐/陶瓷复合相变储热材料在湿度环境下存在因熔盐泄漏而产生的相变潜热衰减问题.采用封装剂埋烧成膜的方法对K2CO3-Na2CO3/MgO/玻璃复合相变储热材料表面进行处理,使其表面形成不溶于水的涂层,以解决复合相变储热材料在高湿度环境下熔盐泄漏的问题.结果表明:在相对湿度为80%条件下放置72 h后,未封装材料的相变潜热由58 J/g衰减到28 J/g,材料底部玻璃纸吸盐增重1.32 g;封装后材料的相变潜热由55 J/g衰减至53 J/g,材料底部玻璃纸吸盐增重0.12 g.与未封装材料相比,封装后材料的相变潜热衰减率由51.72%降至3.63%,熔盐泄漏量显著降低,能够有效解决因高湿度导致的熔盐泄漏问题,进一步扩展了材料的应用范围.
With the rapid development of renewable energy,molten salt phase change heat storage technology has received high attention.Stable phase change heat storage materials composed of ceramics and molten salt have the advantages of large heat storage,simple process,and low cost,thus gradually becoming a research hotspot.However,due to the high hygroscopicity of molten salt,there is a problem of phase change latent heat attenuation caused by the loss of molten salt in the humidity environment of molten salt/ceramic phase change composite thermal storage materials.The surface of K2CO3-Na2CO3/MgO/glass phase change composite heat storage material was treated by encapsulating agent embedding and firing into a film,forming an insoluble coating on its surface,which solved the problem of molten salt leakage of phase change composite heat storage materials in high humidity environments.The results of humidity test showed that the latent heat of phase change of the unencapsulated materials was decreased from 58 J/g to 28 J/g,and the salt absorption weight of cellophane at the bottom of the materials was increased by 1.32 g.The phase change latent heat of the encapsulated materi-als was decreased from 55 J/g to 53 J/g,and the salt absorption weight of cellophane at the bottom of the materials was in-creased by 0.12 g.Compared with unencapsulated materials,the phase change latent heat decay rate of the encapsulated ma-terials was decreased from 51.72%to 3.63%,and the leakage of molten salt was significantly reduced,which could effec-tively solve the problem of molten salt leakage caused by high humidity and further expand the application range of the ma-terials.