Experimental and numerical characterization of sub-zero phase change materials for cold thermal energy storage
Experimental and numerical characterization of sub-zero phase change materials for cold thermal energy storage
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DOI：
10.1016/j.apenergy.2020.115131
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发表时间：
2020-10-01
期刊：
影响因子：
11.2
通讯作者：
Comodi, Gabriele
中科院分区：
文献类型：
--
作者：
Borri, Emiliano;Sze, Jia Yin;Comodi, Gabriele
潜热热能存储系统由于其高能量密度和在近等温温度下放电的能力而获得越来越多的关注。对这些系统中使用的相变材料（PCM）的热行为的良好理解以及因此用于表征存储介质在充电和放电阶段期间的相变行为的方法对于优化存储设计是重要的。在这项工作中，在一个圆柱形容器的实验装置设计，以获得不同类别的低温相变材料的热分布。首先使用去离子水（冰）的实验测量来校准和验证数值1-D模型。进一步测试了三种类型的零度以下PCM，包括氯化钠水溶液、乙二醇水溶液和癸烷。数值结果表明，乙醇水溶液与实验结果吻合最好。在石蜡和氯化钠水溶液的情况下，数值计算和实验结果之间的差异被发现，特别是在熔化阶段，差异是由于自然对流的影响，而在凝固阶段，它是由于过冷的影响。这突出了正确估计这些影响对准确预测的重要性。然而，由于其简单性，1-D模型可以被认为是一种有效的方法来近似不同PCM的行为，并比较不同材料的热分布。
Latent heat thermal energy storage systems are gaining increasing attention due to their high energy density and ability to discharge at near isothermal temperatures. A good understanding of the thermal behaviour of phase change materials (PCMs) used in these systems and therefore, a methodology for the characterisation of the phase change behaviour of storage media during charge and discharge phases is important for an optimised storage design. In this work, an experimental rig in a cylindrical shape container was designed to obtain the thermal profiles of different category of sub-zero PCMs. The experimental measurement of deionised water (ice) was first used to calibrate and validate a numerical 1-D model. Three types of sub-zero PCMs were further tested including aqueous sodium chloride, aqueous ethylene glycol and decane. The numerical results showed that aqueous alcohol had the best agreement with the experiments. In the case of paraffin and aqueous sodium chloride, a discrepancy between numerical and experimental results was found. In particular, during the melting phase, the discrepancy was due to the effect of natural convection while, during the solidification phase, it was due to the effect of supercooling. This highlights the importance of correct estimation of those effects for an accurate prediction. However, due to its simplicity, the 1-D model can be considered a valid method to approximate behavior of the different PCM and to compare the thermal profiles of different materials.