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浙江大学学报(工学版)
Journal of ZheJiang University (Engineering Science)  2019, Vol. 53 Issue (7): 1291-1297    DOI: 10.3785/j.issn.1008-973X.2019.07.007
Mechanical and Energy     
Preparation and properties of CaCl2?6H2O/ expanded graphite composite phase change materials
Xuan LIU(),Jiang-hong WU*(),Ting XIAN,Ye FENG
School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China
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Abstract  

A composite phase change materials (PCM) was prepared by physical adsorption method with CaCl2·6H2O as PCM, expanded graphite (EG) as carrier and SrCl2·6H2O as nucleating agent in order to improve the heat storage-release property of CaCl2·6H2O. The thermophysical properties of the PCM were analyzed. The cooling curve was used to analyze the degree of supercooling, the heat storage-release property and thermal cycling stability of the composite PCM. The composite material’s micromorphology, latent heat, phase transition temperature, specific heat and thermal conductivity were measured by using scanning electron microscopy, differential scanning calorimeter and thermal conductivity meter. The experimental results showed that phase change latent heat of the composite PCM was 151.6 J/g by adding 10% mass fraction of EG and 2% mass fraction of SrCl2·6H2O into CaCl2·6H2O, thermal conductivity increased to 3.328 W/(m·K), and the degree of supercooling kept within 2 °C. The thermal conductivity and supercooling of the PCM were significantly improved.

Key words： CaCl2·6H2O      expanded graphite (EG)      phase change material (PCM)      supercooling      thermal conductivity     
Received: 28 May 2018      Published: 25 June 2019
CLC:  TK 02  
Corresponding Authors: Jiang-hong WU     E-mail: 986347431@qq.com;pmjhwu@scut.edu.cn
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Xuan LIU
Jiang-hong WU
Ting XIAN
Ye FENG
Cite this article:

Xuan LIU,Jiang-hong WU,Ting XIAN,Ye FENG. Preparation and properties of CaCl2?6H2O/ expanded graphite composite phase change materials. Journal of ZheJiang University (Engineering Science), 2019, 53(7): 1291-1297.

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http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2019.07.007     OR     http://www.zjujournals.com/eng/Y2019/V53/I7/1291


CaCl2·6H2O/EG复合相变材料的制备与性能研究

为了改善六水氯化钙的蓄放热性能，以六水氯化钙为相变材料（PCM）、膨胀石墨（EG）为载体、六水氯化锶为成核剂，采用物理吸附法制备六水氯化钙/膨胀石墨复合相变材料，研究复合相变材料的热物理特性. 采用步冷曲线法，研究复合相变材料的过冷度、蓄/放热性能和热循环稳定性；采用扫描电镜、差示扫描量热法、热流计导热仪，对复合相变材料的显微形貌、相变潜热、相变温度、比热容和导热系数进行测定. 结果表明：在六水氯化钙中添加质量分数为10%的膨胀石墨和质量分数为2%的六水氯化锶，复合相变材料的相变潜热为151.6 J/g，导热系数提升至3.328 W/(m·K)，过冷度保持在2 °C以内. 相变材料的导热系数及过冷度得到显著改善.


关键词： 六水氯化钙,  膨胀石墨(EG),  相变材料(PCM),  过冷,  导热系数 
Fig.1 Schematic diagram of experimental system
Fig.2 Photos of expanded graphite adsorption capacity
Fig.3 SEM photographs of EG and composite PCM (x500)
Fig.4 Cooling curve of pure CaCl2•6H2O
Fig.5 Cooling curve of EG-CaCl2·6H2O-SrCl2·6H2O system
Fig.6 DSC curve of CaCl2•6H2O and CaCl2·6H2O/EG composite PCM
Fig.7 Specific heat capacity curve of CaCl2·6H2O/EG composite PCM
Fig.8 Temperature dependent thermal conductivities of CaCl2·6H2O/EG composite PCM
Fig.9 Temperature dependent thermal diffusivities of CaCl2·6H2O/EG composite PCM
Fig.10 Heat storage-release process curves of PCMs
Fig.11 Thermal stability curves of composite PCM
n θn/°C θm/°C θc/°C
1 26.6 27.4 0.8
20 25.9 27.1 1.2
40 25.5 27.5 2.0
60 26.7 27.2 0.5
80 25.6 27.3 1.7
100 26.5 27.2 0.7
Tab.1 Cooling phase change characteristics of CaCl2·6H2O/EG composite PCM for 100 cycles
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