十二水磷酸氢二钠纳米复合相变材料的过冷特性

摘要

A low temperature phase change material with the disodium hydrogen phosphate (Na2HPO4·12H2O) as the main energy storage material was developed. The property of the Na2HPO4·12H2O was modified by adding nucleators, such as nano Al2O3, nano TiO2, nano-graphite powder, multi-walled carbon nanotubes (MWCNTs), and the polymer dispersant polyacrylic acid sodium (PAAS) . The results showed that the adding of MWCNTs would reduce the super-cooling degree of the Na2HPO4·12H2O while destroy its phase change characteristics. The super-cooling degree decreased by 40.7% after adding 3% (mass fraction) nano Al2O3,44.6% by adding 4% nano TiO2,and decreased by 62.3% after adding 4% nano-graphite powder. Compared with 3% (mass fraction) nano Al2O3 composite phase change material,the concentration of PAAS had no effect on the supercooling degree. Comepared with 4% nano TiO2 composite phase change material,the minimum supercooling degree was 3.2℃,which decreased by 76.1% by adding 4% PAAS. Comepared with 4% nano-graphite powder composite phase change material,the minimum supercooling degree was 1.2℃,which decreased by 90.7% by adding 2% PAAS. It was found that the three elements composite phase change material had good thermal reliability by the cyclic experiments.%研制了一种以十二水磷酸氢二钠(Na2HPO4·12H2O)为主储能材料的中低温相变材料.通过添加成核剂纳米Al2O3、纳米TiO2、纳米石墨粉、多壁碳纳米管和高分子分散剂聚丙烯酸钠(PAAS)对Na2HPO4·12H2O改性.结果表明,多壁碳纳米管减少过冷度的同时会破坏 Na2HPO4·12H2O 的相变特性,添加 3%(质量分数)的纳米Al2O3可以减少40.7%的过冷度,添加4%的纳米TiO2可以减少44.6%的过冷度,添加4%的纳米石墨粉可以减少62.3%的过冷度.对于添加3%纳米Al2O3的复合相变材料,PAAS浓度对过冷度无影响;对于4%纳米TiO2的复合相变材料,添加4%PAAS过冷度最低为3.2℃,减少了76.1%;对于4%纳米石墨粉的复合相变材料,2%PAAS过冷度最低为1.2℃,减少了90.7%;纳米石墨粉/PAAS/Na2HPO4·12H2O三元复合相变材料经过100次循环实验后,发现具有较好的热稳定性.