Na 2 SO 4 ·10H 2 O/EG复合相变材料的制备与性能分析
摘要
Sodium sulfate decahydrate/expanded graphite composite phase-change material (Na<sub>2</sub>SO<sub>4</sub>·10H<sub>2</sub>O/EG) was prepared by vacuum adsorption method.The thermal properties of Na<sub>2</sub>SO<sub>4</sub>·10H<sub>2</sub>O/EG,such as melting-solidification,phase separation,supercooling and latent heat were tested and analyzed.The results show that with the addition of 2%(mass fraction) borax and 8% EG,the composite phase-change materials Na<sub>2</sub>SO<sub>4</sub>·10H<sub>2</sub>O/EG obtain ideal properties.The phase separation is eliminated,the supercooling degree of Na<sub>2</sub>SO<sub>4</sub>·10H<sub>2</sub>O is reduced from 13.6℃ to below 0.6℃,the latent heat and the energy storage density of the phase-change materials reach 225.77kJ·kg<sup>-1</sup> and 218.09MJ·m<sup>-3</sup> respectively.The thermal conductivity is also greatly improved.Compared with Na<sub>2</sub>SO<sub>4</sub>·10H<sub>2</sub>O with the addition of the nucleating agent borax only,the time for heat storage is shortened by 52.6%,and the time for heat release is shortened by 55.1%.Even after 500 times of rapid heating and cooling cycles,the performance of Na<sub>2</sub>SO<sub>4</sub>·10H<sub>2</sub>O/EG does not deteriorate.The novel composite phase-change material has better storage/exothermic properties.