三水合乙酸钠/蛭石复合相变蓄热材料性能优化研究  

Study on performance optimization of sodium acetate/vermiculite composite phase change thermal storage material

作　　者：朱宸皓 刘建伟 王翠苹[1] ZHU Chenhao;LIU Jianwei;WANG Cuiping(College of Mechanical and Electrical Engineering,Qingdao University,Qingdao 266071,China)

机构地区：[1]青岛大学机电工程学院,山东青岛266071

出　　处：《热科学与技术》2020年第5期451-458,共8页Journal of Thermal Science and Technology

摘　　要：采用真空浸渍法将三水合乙酸钠(sodium acetate trihydrate,SAT)吸附在膨胀蛭石(expanded vermiculite,EV)微孔内制备了复合相变材料,EV吸附SAT的质量比选择为1∶6。通过扫描电子显微镜(scanning electron microscopy,SEM)观察复合相变材料(composite phase change material,CPCM)的微观结构,EV微孔几乎完全被SAT填充。X射线衍射仪(X-ray diffraction,XRD)对热循环前后材料的测试表明,SAT与EV化学相容性较好,仅发生物理吸附作用的变化。通过差式扫描量热法(differential scanning calorimetry,DSC)测得复合相变材料的相变温度为57.6℃,相变潜热为238.8 kJ/kg;接近SAT理论相变温度58.1℃。热重分析(thermogravimetric analysis,TG)结果显示复合材料热稳定性良好,相变过程结晶水流失极少。SAT负载于EV孔隙中,可视为无数微单元;EV壁面较高的导热系数和连续性微单元SAT相变,有效改善SAT相变过程中过冷和相分离现象。实验研究制备的CPCM具有较好的热物性以及稳定的热循环性能,对推动冬季供暖用相变蓄热材料的开发具有指导意义。Sodium Acetate Trihydrate(SAT) was adsorbed and loaded into the micropores of Expanded Vermiculite(EV) by vacuum impregnationand the Composite Phase Change Material(CPCM) was prepared. The optimal mass ratio of EV adsorbing SAT was 1∶6. The microstructure of the CPCM was investigated by Scanning Electron Microscopy(SEM), showing that the micropores of EV were nearly completely filled with SAT. Chemical compatibility of SAT and EV was showed by X-ray Diffraction(XRD), only physical adsorptionoccurring. Under the maximum adsorption capacity of EV, the phase transition temperature of the CPCM was 57.6 ℃ measured by Differential Scanning Calorimetry(DSC), which was close to the theoretical temperature of 58.1 ℃ of SAT, and the latent heat of CPCM was 238.84 kJ/kg. The CPCM showed a good thermal stability from Thermogravimetric Analysis(TG) tests, and the crystal water lost little during the phase transition. The SAT was divided into innumerable cells in the EV interspace, locking water in the salt liquid phase, effectively improving the phase separation phenomenon, and depressing supercooling. The prepared CPCM is expected to guide the phase change material development for winter heating for the excellent thermal properties and cycle stability.

关 键 词：真空吸附 复合相变材料 过冷度 相分离 热循环性能 

分 类 号：TK02[动力工程及工程热物理]