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用步冷曲线法和TGA-DSC联用研究了室温冷却开放体系和冰水浴冷却封闭体系两种工况下硼砂、SrCl2·6H2O、Ba(OH)2·8H2O等7种成核剂-CaCl2·6H2O复合体系的储热性能,探讨了工业级CaCl2·6H2O原料中主要杂质NaCl和MgCl2对成核剂成核作用的影响。研究结果表明:两种工况下,锶盐比其他成核剂的成核效果好,可使体系过冷度降低至3-4℃,但其热循环性能不稳定;钡盐为成核剂的复合储热体系循环性能明显优于其他体系,但其过冷现象严重。工业级CaCl2·6H2O中的主要杂质NaCA、MgCl2对PCM存在屏蔽成核效应,使体系储热性能恶化。
The nucleating agents such as borax, SrCl 2 · 6H 2 O, Ba (OH) 2 · 8H 2 O were studied under the conditions of open-cooled cooling system and closed cooling system in ice-water bath by step-cooling curve method and TGA- 6H2O composite system. The effects of NaCl and MgCl2, the main impurities in commercial CaCl2 · 6H2O feedstock, on the nucleation of nucleating agent were discussed. The results show that the nucleation effect of strontium salt is better than that of other nucleating agents under both conditions, and the undercooling of the system can be reduced to 3-4 ℃, but its thermal cycling performance is not stable. Barium salt as nucleating agent The composite thermal storage system has better cycling performance than other systems, but its overcooling is serious. Industrial grade CaCl2 · 6H2O in the main impurities NaCA, MgCl2 shielding effect exists on the PCM nucleation, the system deteriorated thermal storage performance.