制备了4组不同浓度的醋酸钠水溶液。将纯三水醋酸钠分别在70℃、75℃、80℃、85℃不同加热温度中熔化后进行冷却,来研究加热温度对过冷度的影响。4组样品在85℃水槽中熔化后分别在10℃和0℃低温槽中冷却,手动播种三水醋酸钠晶粒触发结晶放热,来研究醋酸钠水溶液的稳定过冷和放热性能;并通过DSC测试醋酸钠水溶液的相变温度和潜热值。结果发现,过冷度随着加热温度的升高而增大,加热温度超过80℃时,三水醋酸钠可以实现稳定过冷。醋酸钠水溶液的相变温度与潜热值随着浓度的降低而降低,且过冷液体随浓度的降低过冷状态越稳定。其中60%浓度的醋酸钠水溶液相变温度为58.4℃,潜热值最大,达到265.4kJ/kg,无相分离,适合作为跨季节储热的相变材料。
Sodium acetate water solution with four different concentrations were prepared.The pure sodium trihydrate was cooled after melting in 70℃,75℃,80℃,85℃ four different heating temperatures to study the effect of heating temperature on the supercooling.Four groups of samples were melted in the water bath of 85℃ cooled in the low temperature bath of 10℃ and 0℃,and triggered crystallization exothermic by manual seeding sodium acetate trihydrate grains to study the stable supercooling and exothermic properties of sodium acetate water solution.And phase transition temperature and latent heat of sodium acetate solution was determined by DSC test.The results showed that supercooling degree increased with the increase of heating temperature,sodium acetate trihydrate can achieve stable undercooling when the heating temperature exceeded 80℃,and the phase transition temperature and latent heat of sodium acetate solution decreased with decreasing concentration,and the stability of the supercooled liquid state was greater.The phase transition temperature of 60% concentration of sodium acetate was 58.4℃,the latent heat was maximum,reaching 265.4kJ/kg,and no phase separation.It was more suitable for the phase change material of seasonal heat storage.
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基金资助
国家重点研发课题(2018YFD0401305);国家自然科学基金项目(51376115);上海市科委项目(16040501600)
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