Abstract A mixed polymeric emulsifier consisting of polyvinyl alcohol (PVA) and polyethylene glycol-600 (PEG-600) was explored for preparing high-performance phase change material emulsions (PCMEs) containing the paraffin with a melting point of 62–64 °C. After the effects of the mass ratio of PVA to PEG-600, the mass ratio of the mixed emulsifier to the paraffin and the homogenization rate on the size distribution, viscosity and dispersion stability of the PCMEs containing 20 wt% paraffin were systematically investigated, the optimal emulsifying process parameters have been determined to be the mass ratio of PVA to PEG-600 of 50:50, the mass ratio of the mixed emulsifier to paraffin of 1:5 and the homogenization rate of 10,000 rpm. Accordingly, the PCMEs with the paraffin mass fractions varying from 10 wt% to 30 wt% were prepared. It is found that the paraffin has been well dispersed in water in the form of sphere-like droplets with average diameters ranging from 3 µm to 11 µm in the obtained PCMEs. Significantly, the PCMEs with different mass fractions of the paraffin exhibit no supercooling, owing to the function of the mixed polymeric emulsifier as a nucleating agent. The apparent specific heat of PCMEs are 1.51–2.18 times as high as that of water at the phase transition temperature region, due to the existent of the paraffin in them. Their apparent thermal conductivity gradually decreases with an increase in the mass fraction of the paraffin, while the viscosity increases significantly with mass fraction of the paraffin at the same temperatures. Furthermore, the pumping power consumption of the PCMEs shows a drastic reduction as compared to that of water at the same heat storage capacity. It is revealed that the PCMEs show great potential for use as a novel heat transfer fluid (HTF) in thermal energy storage (TES) systems.

中文翻译：

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用混合聚合物乳化剂储存热能制备稳定性好、过冷度小的相变材料乳液

摘要 探索了一种由聚乙烯醇 (PVA) 和聚乙二醇-600 (PEG-600) 组成的混合聚合物乳化剂，用于制备含有熔点为 62–64 °C 的石蜡的高性能相变材料乳液 (PCMEs)。系统研究了 PVA 与 PEG-600 的质量比、混合乳化剂与石蜡的质量比和均质率对含 20 wt% 石蜡的 PCMEs 的粒径分布、粘度和分散稳定性的影响后,最佳乳化工艺参数确定为PVA与PEG-600的质量比为50:50，混合乳化剂与石蜡的质量比为1:5，均质速率为10,000 rpm。因此，制备了石蜡质量分数从 10 wt% 到 30 wt% 不等的 PCME。发现石蜡在获得的 PCME 中以平均直径为 3 µm 至 11 µm 的球形液滴形式很好地分散在水中。值得注意的是，由于混合聚合物乳化剂作为成核剂的作用，具有不同质量分数的石蜡的 PCME 没有表现出过冷。由于其中存在石蜡，PCMEs 在相变温度区域的表观比热是水的 1.51-2.18 倍。它们的表观热导率随着石蜡质量分数的增加而逐渐降低，而在相同温度下，粘度随着石蜡质量分数的增加而显着增加。此外，PCME 的泵送功率消耗与相同蓄热容量的水相比显着降低。结果表明，PCMEs 在热能储存 (TES) 系统中作为一种新型传热流体 (HTF) 显示出巨大的潜力。