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.

潜热热能存储系统因其高能量密度和在接近等温温度下的放电能力而受到越来越多的关注。充分了解这些系统中使用的相变材料（PCM）的热行为，因此，表征充电和放电阶段存储介质的相变行为的方法对于优化存储设计非常重要。在这项工作中，设计了一个在圆柱形容器中的实验装置，以获取不同类别的零以下PCM的热曲线。去离子水（冰）的实验测量首先用于校准和验证一维数值模型。进一步测试了三种类型的零下PCM，包括氯化钠水溶液，乙二醇水溶液和癸烷。数值结果表明，含水醇与实验具有最好的一致性。对于石蜡和氯化钠水溶液，发现数值和实验结果之间存在差异。特别地，在熔融阶段，差异是由于自然对流的影响，而在固化阶段，差异是由于过冷的影响。这突出了正确估计那些影响以进行准确预测的重要性。但是，由于其简单性，一维模型可以被视为一种有效的方法，可以近似于不同PCM的行为并比较不同材料的热曲线。发现数值和实验结果之间存在差异。特别地，在熔融阶段，差异是由于自然对流的影响，而在固化阶段，差异是由于过冷的影响。这突出了正确估计那些影响以进行准确预测的重要性。但是，由于其简单性，一维模型可以被视为一种有效的方法，可以近似于不同PCM的行为并比较不同材料的热曲线。发现数值和实验结果之间存在差异。特别地，在熔融阶段，差异是由于自然对流的影响，而在固化阶段，差异是由于过冷的影响。这突出了正确估计那些影响以进行准确预测的重要性。但是，由于其简单性，一维模型可以被视为一种有效的方法，可以近似于不同PCM的行为并比较不同材料的热曲线。