Thermal performance enhancement of solar flat plate collectors under transient irradiation using novel longitudinal and wavy finned absorber plates: A validated CFD study

Even though solar flat plate collectors (SFPCs) are widely used in thermal energy systems, intermittent and uneven solar radiation still limits their efficacy. Therefore, to optimize the effective use of renewable energy, solar flat plate collector must improve their thermal performance (TP). By putting forth two innovative finned absorber topologies and comparing them to a traditional flat plate collector, the current study seeks to improve the thermal efficiency (TE) of solar flat plat collectors. The method involves incorporating wavy fins or longitudinal fins into the absorber plate. The introduction of wavy fins (Model II) offers an additional enhancement pathway by expanding the heat-transfer surface and encouraging stronger fluid mixing, even though finned collectors have been studied in earlier studies. ANSYS Fluent was used to perform a numerical analysis of two updated solar flat plat collector configurations: Four longitudinal fins are included in Model I, and four wavy fins are included in Model II. Simulations were run under naturally fluctuating transient solar radiation circumstances, and the numerical model was verified against existing experimental data to guarantee accuracy. The output working-fluid temperature, the water temperature in the storage tank, and the total TE were used to evaluate performance. In terms of thermal response, both suggested solutions fared better than the baseline solar flat plat collector. When compared to the conventional design, Model II (SFPC with wavy fins) produced the greatest improvement, raising the outlet working fluid temperature by 12.11% and the tank water temperature by 12.9%. Additionally, Model II demonstrated the benefit of wavy-fin integration for improving SFPC performance under actual irradiation fluctuations by increasing the overall TE by 13.21%.