In this paper, numerical and experimental investigations of thermal performance enhancement of horizontal longitudinal shell and tube latent heat thermal energy storage unit (LHTESU) via eccentricity (e), fin design optimization, and nanoparticles in the phase change material (PCM) of stearic acid are presented. An enthalpy-porosity-based two-dimensional, transient numerical methodology is used after validating against the experimental results and the literature. Five different eccentric positions, e = 0.14, 0.28, 0.42, 0.56, and 0.63 are investigated by modifying the design of Y-finned tube. The eccentricity and fin design modifications improved natural convection effects as compared to concentric Y-finned tube. Thermal performances of LHTESU are analyzed on the basis of melting time, heat storage capacity, heat storage rate, and performance enhancement ratio. Based on the performance analysis, an optimum eccentric configuration of LHTESU is proposed. For optimized eccentric unit (e=0.42), a reduction of 34.14% in melting time along with 30.7% improvement in thermal energy storage rate is achieved as compared to concentric (e=0) LHTESU. The effect of temperature of the tube on PCM's melting time and heat transfer is also analyzed and two important correlations are proposed. The thermal performance of the optimized eccentric unit is further enhanced by adding nanoparticles of $A{l}_2{O}_3$ and $CuO$ ranging from 0.5% to 10% by volume in the pure PCM. The nano-enhanced PCM with 1% of $A{l}_2{O}_3$ further improves melting and energy storage rates of optimum LHTESU by 10%.

在本文中，通过偏心距 (e)、翅片设计优化和硬脂酸相变材料 (PCM) 中的纳米颗粒对水平纵向壳管潜热蓄热单元 (LHTESU) 的热性能增强进行了数值和实验研究被提出。在对实验结果和文献进行验证后，使用基于焓孔隙度的二维瞬态数值方法。通过修改 Y 翅片管的设计，研究了五种不同的偏心位置，e = 0.14、0.28、0.42、0.56 和 0.63。与同心 Y 型翅片管相比，偏心距和翅片设计修改改善了自然对流效果。LHTESU 的热性能从熔化时间、蓄热容量、蓄热率、和性能提升率。基于性能分析，提出了LHTESU的最佳偏心配置。对于优化的偏心单元 (e=0.42)，与同心 (e=0) LHTESU 相比，熔化时间减少了 34.14%，热能储存率提高了 30.7%。还分析了管子温度对 PCM 熔化时间和传热的影响，并提出了两个重要的相关性。通过添加纳米颗粒，优化偏心单元的热性能进一步增强 还分析了管子温度对 PCM 熔化时间和传热的影响，并提出了两个重要的相关性。通过添加纳米颗粒，优化偏心单元的热性能进一步增强 还分析了管子温度对 PCM 熔化时间和传热的影响，并提出了两个重要的相关性。通过添加纳米颗粒，优化偏心单元的热性能进一步增强$\mathrm{一种}{升}_2{哦}_3$ 和 $C你哦$在纯 PCM 中按体积计从 0.5% 到 10% 不等。含 1% 的纳米增强型 PCM$\mathrm{一种}{升}_2{哦}_3$ 进一步将最佳 LHTESU 的熔化率和储能率提高 10%。