Preparation and thermal characterization of expanded graphite/paraffin composite phase change material
Preparation and thermal characterization of expanded graphite/paraffin composite phase change material
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DOI：
10.1016/j.carbon.2010.03.030
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发表时间：
2010-08-01
期刊：
影响因子：
10.9
通讯作者：
Wang, R. Z.
中科院分区：
文献类型：
--
作者：
Xia, L.;Zhang, P.;Wang, R. Z.
膨胀石墨（EG）/石蜡复合相变材料（PCM），EG质量分数为0 ~ 10wt%，制备并表征。偏光显微镜研究表明，随着EG质量分数的增加，EG网络逐渐形成。这些网络提供了热传导路径，其增强了复合PCM的热导率，例如，添加10重量% EG导致导热系数比纯石蜡增加10倍以上。利用差示扫描量热仪（DSC）对复合相变材料进行了热分析，研究了多孔EG对石蜡相变行为的影响。观察到相变温度的变化。复合相变材料的熔点/凝固点与纯石蜡的熔点/凝固点的最大偏差为1.2 ℃，而峰值熔点/凝固点的最大偏差为5.6 ℃。DSC研究还表明，在复合PCM中的石蜡的潜热的异常，它首先增加，然后随着EG馏分的增加而减少。复合相变材料在潜热储能系统中的储放热试验表明，EG（10）/石蜡（90）复合相变材料的储放热时间比纯石蜡分别缩短了48.9%和66.5%，系统的储放热率有较大提高。(C)2010爱思唯尔有限公司版权所有。
Expanded graphite (EG)/paraffin composite phase change materials (PCMs), with mass fraction of EG varying from 0 to 10 wt.%, were prepared and characterized. Polarizing optical microscope investigation showed that compact EG networks formed gradually with increase in the mass fraction of EG. These networks provided thermal conduction paths which enhanced the thermal conductivity of the composite PCMs, e.g., an addition of 10 wt.% EG resulting in a more than 10-fold increase in the thermal conductivity compared to that of pure paraffin. Thermal characterization of the composite PCMs with a differential scanning calorimeter (DSC) revealed the effect of the porous EG on the phase change behavior of paraffin. The shifts in the phase change temperatures were observed. The maximum deviation of the melting/freezing points of the composite PCMs from that of pure paraffin was 1.2 degrees C whereas that of the peak melting/freezing temperature was 5.6 degrees C. The DSC investigation also showed an anomaly in the latent heat of the paraffin in the composite PCMs in that it first increased and then decreased with increase in the EG fraction. Heat storage/retrieval tests of the composite PCMs in a latent thermal energy storage system showed that the heat storage/retrieval durations for EG(10)/paraffin(90) composite were reduced by 48.9% and 66.5%, respectively, compared to pure paraffin, which indicated a great improvement in the heat storage/retrieval rates of the system. (C) 2010 Elsevier Ltd. All rights reserved.