3rd TAGRA

In this study, the effects of the number of turbulators (1, 5, 9), fluid type (water, ethylene glycol, ammonia), absorber surface coating (standard, Black 2.0, Black 3.0), and fluid mass flow rate (50, 100, 150 kg/h) on the thermal performance of a flat-plate solar collector (FPSC) were investigated using both numerical (ANSYS-Fluent, CFD) and experimental methods. The Response Surface Method (RSM) was employed for experimental design and the determination of optimum parameters, while Analysis of Variance (ANOVA) was performed separately for the numerical and experimental datasets to compare the results. In the experimental study, halogen floodlights were used to simulate solar radiation, and a pyranometer, T-type thermocouples, and a flow meter were used for measurements; an uncertainty of ±1.06% in efficiency was determined using the Kline-McClintock method. In both models, fluid type was identified as the most influential parameter regarding the outcome variable (contributing 56.48% and 53.83%, respectively); however, while the effects of flow rate and the number of turbulators were found to be statistically insignificant (P>0.05) in the numerical model, they were significant (P<0.05) in the experimental model. The maximum thermal energy was calculated as 96.91 W (at 100 kg/h) in the numerical model, whereas it was measured as 132.51 W (at 150 kg/h) in the experimental study, and a systematic deviation ranging from 4% to 37% was observed between the two methods. Consequently, a configuration comprising a mass flow rate of 150 kg/h, 9 turbulators, ammonia as the working fluid, and a Black 3.0-coated collector has been identified as the experimentally validated point of maximum performance. The findings demonstrate that designs based solely on numerical optimization can yield misleading results in the absence of experimental validation.