Performance enhancement of evacuated U-tube solar collector integrated with phase change material

In this research, a numerical simulation was undertaken to assess the effectiveness of an Evacuated tube solar collector (ETSC). The study explored the efficacy of merging a parabolic trough solar collector (PTSC) and copper fins into the U-tube ETSC design. Two types of fins, namely annular fins and disk-shaped fins, were evaluated. Additionally, the study aimed to analyze the influence of operational and geometric parameters, such as the heat transfer fluid (HTF) mass flow rate and the U-tube bend radius, on the performance of the U-tube ETSC. Furthermore, a comparative examination was carried out to identify the most suitable type of phase change material (PCM) for the U-tube ETSC. Finally, a comparative analysis was conducted to assess the performance of the U-tube ETSC in comparison to that of the coaxial tubes ETSC. The results clearly demonstrated that the integration of an PTSC, PCM, and disk-shaped fins substantially improved the overall performance of the ETSC in comparison to the conventional solar collector. This improvement led to a remarkable increase in energy efficiency, with an impressive gain of 42.94%. The ETSC displayed remarkable performance, particularly at lower HTF mass flow rates and a reduced U-tube bend radius, achieving an average HTF temperature of 430 K. Additionally, among the tested PCMs, RT 82 emerged as the most suitable choice, providing an energy gain of 9.27% in comparison with the case without PCM.