PEG/EG复合相变储能材料蓄冷性能的实验研究

摘要

制备了以相对分子质量不超过1 000的聚乙二醇(PEG)为相变基质、膨胀石墨(EG)为导热强化相的PEG/EG低温复合相变储能材料,并分析了不同EG含量时各种因素对这种相变储能材料的蓄冷性能的影响.利用闪光导热分析法研究了EG含量和加压程度对这种复合材料的导热性能的影响,用电子显微镜观察法比较了不同EG含量和加压条件下这种复合材料导热性能差异的微观机理,用工程测量法分析了这种复合材料的蓄冷性能及其相变曲线.结果表明,EG含量和加压程度对这种低温复合材料导热性能的影响是通过改变EG内部导热网络结构而实现的;随着EG含量的增加,复合材料的蓄冷性能呈提升趋势;EG能够减少冷媒温度、蓄冷剂本身质量对蓄冷过程的影响.%Composite phase change materials (PCMs) were prepared by melt mixing poly(ethylene glycol) (PEG,molecular weight＜1 000) with expanded graphite (EG) as a thermally conductive enhancer,and various effects on the cool storage performance of the PEG/EG composite PCMs were analyzed.The influences of EG content and pressing level on the thermal conductivity of PCMs were investigated by a flash thermal analysis method,their microstructures were determined by scanning electron microscopy,and their cool storage performance was characterized by an engineering survey method to obtain phase transition curves.The results indicated that the effects of EG content and pressing level on the thermal conductivity of PCMs were caused by changing the internal structure of thermally conductive network in the PEG matrix.The cool storage performance was improved with the increase of EG content,and EG also could weaken the influences of coolant content and coolant temperature on the cool storage process.