Thermal performance enhancement of flat plate solar collectors formed by using rectangular reserve chamber Available to Purchase

This study investigates the thermal performance of flat plate collectors (FPCs) based on the impact of different contact materials between riser and absorber stored in a rectangular box at the bottom of riser tube on heat transfer efficiency. The study introduces a unique approach by incorporating a stationary chamber beneath the absorber plate to increase the contact area between riser and absorber. Inside this chamber different materials such as air and water are inserted to facilitate the heat transfer improvement to the heat transfer fluid (HTF). Considering constant inlet temperature of 300 °C, numerical simulations were conducted, and inserted material volume (1.3 cm³, 2.1 cm³, 3.2 cm³). The results indicate that water, as a contact material, leads to the highest outlet temperatures than traditional FPC. In contrast, air consistently performs lower. The peak outlet temperature for water at a Reynolds number of 615 was 312.78 K, while for air, it was 309.35 K. When examining the impact of contact material volume, an increase in air volume resulted in a decline in the average heat transfer rate by about 20%. However, for water, the increase in volume had a marginal effect, while engine oil’s heat transfer rate remained relatively constant. Additionally, the efficiency analysis showed that water achieved about 65%, at 3.2 cm³ volume of rectangular reserve chambers. This study contributes to understanding the effects of contact material selection and volume in FPC systems, providing insights into optimizing solar thermal energy applications for improved efficiency and.