石墨烯气凝胶导热定形相变材料的制备及性能研究

发布时间：2018-01-17 15:22

本文关键词：石墨烯气凝胶导热定形相变材料的制备及性能研究　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：相变储能技术是一项利用相变材料在相变过程中吸收或释放潜热来储存或释放热能的能量储存技术。一些有机相变材料(如:石蜡、硬脂酸等)具有高的相变潜热、良好的热稳定性、宽的相变温度范围、无毒无害、无过冷和相分离现象等特点,使其在建筑节能、太阳能储能、电子设备、纺织等领域有着广阔的应用前景。然而,在实际应用过程中发现相变材料存在热导率低以及易渗漏等问题,严重限制了相变材料的应用。为了解决这些问题,于是对相变材料进行封装定形以及增强其导热性是一种有效的解决方案。本文采用原位自组装法,通过配制不同浓度的氧化石墨烯(GO)分散液和控制不同反应温度制备了不同形貌的石墨烯气凝胶(GA),接着用真空浸渍法制备了石蜡/GA、EVA/石蜡/GA和硬脂酸/GA定形相变材料。以GA作为导热骨架,研究了GA以及不同形貌GA对石蜡/GA、EVA/石蜡/GA和硬脂酸/GA定形相变材料的热性能、渗漏率、热导率、光热储能的影响,研究表明GA能够提高定形相变材料的热导率,在一定程度上能够包覆相变材料,而且还能影响其相变焓值(除了硬脂酸/GA);对于不同形貌的GA而言,其孔径越小,孔隙越规整,其定形相变材料的热导率越高、对相变材料的包覆性越高、渗漏率越低、能量储存效率(?)越高。以GA和少量的EVA作为双重支撑材料,使定形相变材料的渗漏现象得到明显的好转,但由于EVA的加入,定形相变材料的相变焓值随EVA含量的增强而减少,且低于石蜡/GA定形相变材料。以硬脂酸作为相变材料时,由于硬脂酸自身的特性,使得硬脂酸/GA定形相变材料的相变焓值、热导率、光热储能性能都低于石蜡体系,而且发现硬脂酸与GA相结合时,不能影响其相变焓值。
[Abstract]:Phase change energy storage (PCE) is a kind of energy storage technology which can store or release heat by absorbing or releasing latent heat during phase change. Some organic phase change materials (such as paraffin wax) are used to store or release heat. Stearic acid) has the characteristics of high latent heat of phase change, good thermal stability, wide range of phase change temperature, non-toxic and harmless, no supercooling and phase separation, etc., which makes it energy saving in building, solar energy storage, electronic equipment and so on. Textile and other fields have broad application prospects. However, in the practical application process, it is found that phase change materials have the problems of low thermal conductivity and easy leakage, which seriously limit the application of phase change materials. In order to solve these problems. So it is an effective solution to encapsulate phase change material and enhance its thermal conductivity. In this paper, in situ self-assembly method is used. Graphene aerogels with different morphologies were prepared by preparing different concentrations of graphene oxide (GOO) dispersions and controlling different reaction temperatures. Then paraffin / GA was prepared by vacuum impregnation. EVA / paraffin / GA and stearic acid / GA were used as phase transition materials. The effects of GA and different morphologies of GA on paraffin / GA were studied using GA as the heat conduction skeleton. The effects of EVA / paraffin / GA and stearic acid / GA on the thermal properties, leakage, thermal conductivity and photothermal energy storage of PCMs were investigated. The results show that GA can improve the thermal conductivity of PCMs. To some extent, the phase change material can be coated and the enthalpy of phase transition can be affected (except stearic acid / GAN; For GA with different morphologies, the smaller the pore size and the more regular the pore size, the higher the thermal conductivity, the higher the encapsulation, the lower the leakage rate and the energy storage efficiency. Using GA and a small amount of EVA as double support materials, the leakage of the amorphous phase change material was improved obviously, but due to the addition of EVA. The enthalpy of phase transition decreases with the increase of EVA content, and is lower than that of paraffin / GA phase change material. When stearic acid is used as phase change material, the stearic acid has its own characteristics. The results show that the enthalpy of phase transition, thermal conductivity and photothermal energy storage of stearic acid / GA are lower than those of paraffin system, and it is found that stearic acid combined with GA can not affect the enthalpy of phase transition.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34

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