Exergy and sustainability analysis of a solar heat collector with wavy delta winglets as turbulent promoters: A numerical analysis

This numerical study aims to determine the exergy analysis for a modified solar heat collector (SHC) having wavy delta winglets as turbulent promoters. These winglets disrupt the viscous layer to improve the heat transfer rate from the heat-absorbing surface to the fluid medium in the rectangular channel. The analysis considers following parameters: the relative longitudinal pitch (P/H), number of waves (φ), and flow angle of attack (α⁰) and flow Reynolds number range of 4000–18000. The maximum exergy efficiency of 29.18% is achieved with a longitudinal pitch of 5, an angle of attack of 60°, and a relative number of waves of 5. To evaluate the system's feasibility and sustainability, the study uses a Sustainability Index (SI), which reflects the system's Waste Energy Ratio (WER) and Improvement Potential (IP). This assessment helps identify opportunities for improvement in the thermal system.