Study on formation of high-performance ice slurry made from W/O type emulsion in ice storage system

本文主要研究了乳状液作为一种新型的蓄冰材料。使用含有少量添加剂的油水混合物形成两种类型的乳状液。使用了硅胶、光油和块状油。乳液的含水率分别为70%、80%和90%。添加剂为氨基改性硅油。由于乳液的疏水性，没有观察到凝固点的降低。为了确定乳液的结构，测量了它们的电阻。此外，还分析了从乳状液中分离出的液体的组成。结果表明，一种乳液为W/O型乳液，另一种为O/W型乳液。最后讨论了两种乳状液对冰蓄冷的适应性，得出了W/O型乳状液可以形成高性能冰浆的结论，其中硅油(7：3)、轻质油(7：3)和块状油(9：1)乳状液的结冰效果最好，但对于含水率超过70%的W/O乳状液，过冷溶解过程是非常独特的。因此，从温度历史和过冷溶解速度的角度对这一过程进行了研究，发现乳状液的过冷溶解速度要慢得多。此外，还测量了溶解过冷所需的时间，改变了水与硅油的组成比。从实验结果可以看出，粘度较高的(8：2)比粘度较低的(7：3)需要更长的时间来溶解过冷。在(9：1)粘度最高的情况下，冰与冷却壁发生粘连。

This study is focuses on an emulsion as a new thermal storage material for ice storage. Two types of emulsions were formed using an oil-water mixture with a small amount of additive. A silicone, light and lump oils were used. The water contents of the emulsions were 70, 80 and 90%. The additive was an amino group modified silicone oil. No depression of freezing point was observed for the emulsions because of their hydrophobic properties. In order to determine the structure of the emulsions, their electrical resistances were measured. Moreover, components of the liquids separating from the emulsions were analyzed. The results indicated that one emulsion was a W/O type emulsion, while the other was the O/W type. Finally, adaptability of the two emulsions to ice storage was discussed, it was concluded that a high performance ice slurry could be formed by the W/O type emulsion and the W/O emulsions silicone oil(7:3), light oil(7:3) and lump oil(9:1) exhibited the best ice formation.However, for the W/O emulsion with over 70% water content the dissolution process of supercooling was very unique. Therefore, the process was investigated from the view of temperature history and dissolution rate of supercooling, and it was found that dissolution rate of supercooling of the emulsion was much slower. Moreover, the time required to dissolve supercooling was measured, varying the composition ratio water to silicone oil. From the experimental results, it was found that longer time to dissolve supercooling in the case of (8:2) with higher viscosity was required compared with the case of (7:3) with lower viscosity. In the case of (9:1) with the highest viscosity ice adhesion to the cooling wall occurred.