Thermal storage performance of sodium acetate trihydrate/expanded graphite composite phase change material

doi:10.16085/j.issn.1000-6613.2017-2531

Abstract

Abstract: The composite phase change material was formed by expanded graphite (EG) with porous mesh structure and sodium acetate trihydrate (SAT) as the substrate. The effects of EG on the properties of SAT were studied by using scanning electron microscope, temperature data logger, differential scanning calorimeter, and Hot Disk thermal constant analyzer etc. The results showed that the EG could not reduce the degree of supercooling of SAT, but it could largely improve the thermal conductivity of the material. EG had little effect on the latent heat value and phase transition temperature of SAT. EG could reduce the phase separation of SAT and improve its durability. Compared to the pure SAT, the degree of supercooling of composite PCM (7% EG+1% disodium hydrogen phosphate + SAT) was reduced by 49℃. Thermal conductivity of the composite PCM was doubled. Latent heat and phase transition temperature of the composite PCM were basically the same. After 50 cycles, the change of latent heat of composite PCM was kept within 1.4%, which had great potential in thermal storage.

Key words: phase change, thermal conductivity, nucleation, expanded graphite, sodium acetate trihydrate, latent heat

摘要： 以三水乙酸钠（SAT）为基材，添加具有多孔网状结构的膨胀石墨（EG）制备复合相变材料。使用扫描电子显微镜、温度数据采集仪、差示扫描量热仪、Hot Disk热常数分析仪等对材料进行结构观察及相关热物性测试，研究膨胀石墨对三水乙酸钠的热物性影响。结果表明，膨胀石墨不能减小三水乙酸钠的过冷度，但可大幅提高材料热导率，对材料潜热值、相变温度影响较小，能减轻三水乙酸钠的相分离现象且能提高其循环稳定性。对于基材为三水乙酸钠的相变材料，膨胀石墨添加量为7%时，复合材料吸附情况最好。当复合材料配比为7% EG+1%十二水磷酸氢二钠+SAT时，相比于纯SAT相变材料，过冷度减小约49℃，热导率提高将近1倍，相变潜热影响幅度3.14%，相变温度基本不变；50次循环后，相变潜热影响幅度保持在1.4%以内，循环稳定性较好，具有较好的应用前景。

关键词: 相变, 热导率, 成核, 膨胀石墨, 三水乙酸钠, 潜热

CLC Number:

TK02

YUAN Weiye, ZHANG Xuelai, HUA Weisan, HAN Xingchao, LI Yuyang, WANG Xiang. Thermal storage performance of sodium acetate trihydrate/expanded graphite composite phase change material[J]. Chemical Industry and Engineering Progress, 2018, 37(11): 4405-4411.

袁维烨, 章学来, 华维三, 韩兴超, 李玉洋, 汪翔. 膨胀石墨/三水乙酸钠复合相变材料储热的性能[J]. 化工进展, 2018, 37(11): 4405-4411.

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