CIESC Journal ›› 2019, Vol. 70 ›› Issue (9): 3553-3564.DOI: 10.11949/0438-1157.20190179

• Material science and engineering, nanotechnology • Previous Articles     Next Articles

Preparation and thermal energy storage properties of high heat conduction expanded graphite/palmitic acid form-stable phase change materials

Shaofei WU(),Ting YAN(),Zihan KUAI,Weiguo PAN()   

  1. College of Energy and Mechanical Engineering, Shanghai University of Electric Power, Shanghai 200090, China
  • Received:2019-03-03 Revised:2019-05-24 Online:2019-09-05 Published:2019-09-05
  • Contact: Ting YAN,Weiguo PAN

高导热膨胀石墨/棕榈酸定形复合相变材料的制备及储热性能研究

吴韶飞(),闫霆(),蒯子函,潘卫国()   

  1. 上海电力大学能源与机械工程学院,上海 200090
  • 通讯作者: 闫霆,潘卫国
  • 作者简介:吴韶飞(1993—),男,硕士研究生,wshaofei1217@163.com
  • 基金资助:
    国家自然科学基金项目(21546014);上海市科委科技攻关项目(18DZ1202502)

Abstract:

A kind of composite phase change materials (PCMs) was prepared by the process of “melting blend - solidification and form-stable” to improve the comprehensive performance of PCMs. Palmitic acid (PA) is used as PCM and expanded graphite (EG) is used for the supporting material. Twenty-one kinds of form-stable composite PCMs were prepared with different contents of EG. The morphologies and structures were characterized microscopically by SEM. On this basis, heat transfer performance analysis, thermophysical test, thermal stability test and heat storage performance analysis were conducted. SEM morphological characterization showed that PA could be absorbed into the pores of EG and the distribution was uniform. DSC test results revealed that the melting enthalpy of PCMs is 193.01 J/g with the 70%(mass) PA corresponding to the melting point of 61.08℃. The melting enthalpy of pure PA is 275.35 J/g corresponding to the melting point of 59.53℃. The thermal conductivity of the PCMs is significantly improved by the addition of EG. When the sample density was 900 kg/m3 and the content of EG was 30%(mass), the thermal conductivity of the composite PCM is 14.09 W/(m·K), which is about 87 times higher than that of pure PA. Cycle stability tests were carried out, the results suggest the samples with 24% and 30% EG content have no any change in shape, and therefore show excellent cycle stability in repeating charging and discharging processes.

Key words: palmitic acid, expanded graphite, form-stable, phase change materials (PCMs), preparation, thermal energy storage performance

摘要:

采用棕榈酸(palmitic acid, PA)作为相变材料,膨胀石墨(expanded graphite, EG)作为添加基质,通过“熔融共混-凝固定形”工艺制备了PA/EG定形复合相变材料以提高相变材料的综合性能。预测并制备了21种不同配比的定形复合相变材料,对其形貌结构和孔隙率进行了微观表征与理论分析,并在此基础上对样品进行了传热性能分析、热物性测试、热稳定性研究和储热性能分析。SEM形貌分析显示所使用工艺可使棕榈酸能较好地被吸附于膨胀石墨的孔隙结构并使之均匀分布;DSC测试结果表明定形复合相变材料[70%(质量) PA]的焓值为193.01 J/g,纯PA的焓值为275.35 J/g,对应于熔点分别为61.08℃和59.53℃。EG的添加,可有效提高相变材料的热导率。当样品密度为900 kg/m3,EG含量为30%(质量)时,定形复合相变材料的热导率为14.09 W/(m·K),相比于纯PA[0.162 W/(m·K)]提高约87倍;对制备的样品进行50次循环稳定性实验,EG含量为24%(质量)和30%(质量)的样品形态均未出现明显变化,表现出良好的充放热循环稳定性。

关键词: 棕榈酸, 膨胀石墨, 定形, 相变材料, 制备, 储热性能

CLC Number: