Abstract Inclusion of fins in phase change energy storage systems has been widely investigated for improving the rate of energy storage. Despite significant past experimental research in this direction, there is a lack of comprehensive theoretical models for fin-based enhancement in energy storage, particularly for cylindrical geometries. This is a considerably challenging, non-linear problem. This paper presents a semi-analytical model for temperature distribution and energy storage in an annular phase change material (PCM) material around a hot cylinder in the presence of transverse and longitudinal fins extending into the PCM. Two distinct pathways for heat transfer into the PCM are analyzed separately and expressions for total heat flux into the PCM are determined for both fin types. The perturbation method is used for analyzing the non-linear phase change problem and determining the heat flux into the PCM through the fin. The dependence of total energy stored on fin thermal properties and geometrical parameters is determined. Results indicate key similarities and differences between cylindrical fins and recently-reported Cartesian fins. It is shown that even a thin fin results in considerable heat transfer enhancement. Results also indicate diminishing results when the fin size is further increased. Theoretical modeling presented in this paper improves the fundamental understanding of an important heat transfer enhancement strategy for phase change based energy storage systems. Results discussed here may help improve the practical design of finned, cylindrical phase change energy storage systems that are commonly used for harnessing renewable energy.

中文翻译：

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圆柱形相变储能系统中横向和纵向翅片的半解析热建模

摘要 在相变储能系统中加入鳍片已被广泛研究以提高储能率。尽管过去在这个方向上进行了大量的实验研究，但缺乏基于鳍的能量存储增强的综合理论模型，特别是对于圆柱形几何形状。这是一个相当具有挑战性的非线性问题。本文提出了一种半解析模型，用于在存在延伸到 PCM 中的横向和纵向翅片的情况下，围绕热圆柱体的环形相变材料 (PCM) 材料中的温度分布和能量存储。分别分析了两种不同的传热到 PCM 的途径，并确定了两种翅片类型的进入 PCM 的总热通量的表达式。微扰法用于分析非线性相变问题并确定通过翅片进入 PCM 的热通量。确定存储的总能量对翅片热特性和几何参数的依赖性。结果表明圆柱形鳍和最近报道的笛卡尔鳍之间的关键异同。结果表明，即使是薄翅片也会导致相当大的传热增强。结果还表明，当翅片尺寸进一步增加时，结果会逐渐减少。本文提出的理论模型提高了对基于相变的储能系统的重要传热增强策略的基本理解。此处讨论的结果可能有助于改进翅片的实际设计，