Collaborative optimization of intersectional angle and installation height of branched fin for ameliorating melting characteristics of lowly thermal conductive phase change materials (PCMs)

Energy storage systems based on phase change materials (PCMs) have become reliable methods to alleviate energy shortages and adjust energy structure. Optimizing fin structure parameters has a vital impact on improving the equivalent thermal conductivity of PCMs and enhancing thermal charging performance. In this numerical investigation, collaborative optimization of intersectional angle and installation height of branched fin on melting of organic PCMs have been systematically studied to coordinate transient thermal conduction and natural convective heat transfer thus ameliorating melting characteristics. Results clarify that optimizing intersectional angle between adjustable fin and horizontal direction can shorten total melting time by 9.39% and ameliorate the average heat transfer rate during melting by 11.07% compared to the case of 0o intersectional angle. These improvements are dependent of installation height of adjustable fin. Meanwhile, average heat transfer rate during melting induced by optimizing intersectional angle is enhanced by 2.77% compared with that caused by optimal orthogonal fins. Moreover, optimum intersectional angle is significantly depended on installation height. A linear correlation between optimum intersectional angle and installation height is obtained. The reliability and rationality of the correlation is confirmed. Effective guidelines for designing optimum branched fin to improve melting performance of organic PCMs are consequently acquired.