Aghil Iranmanesh

In this paper, a novel methodology is proposed to improve the melting process of a vertical triple-tube heat storage unit via inserting a middle plate into the phase change material (PCM) container. The middle tube is filled with the PCM while water as the heat transfer fluid (HTF) is passed through the inner and outer tubes. Various scenarios are considered in this research to evaluate the efficacy of the PCM-based heat storage unit with a middle plate comprehensively. Firstly, the temperature and liquid fraction contours of the cases with no fin and uniform fins are compared with those of the cases with a middle plate. Secondly, the position of the middle plate is varied to evaluate the effects of the middle plate position on the charging process. Next, the impacts of fins number and position on the thermal performance of the PCM-based heat storage unit are evaluated in the presence of the middle plate. Finally, the effects of fins arrangement including the inline and staggered configurations on the charging process of the PCM are examined. The results show that the melting time of the PCMbased heat storage unit in the presence of a middle plate (case 4) can be decreased by 52.62 % compared to that of the no-fin case (case 1). Furthermore, the heat storage rate of case 4 increases by 109.90 % compared to that of case 1.