Optimizing Performance of a Solar Flat Plate Collector for Sustainable Operation Using Box–Behnken Design (BBD)

This study investigated the performance optimization of nickel-cobalt (Ni-Co)-coated absorber panels in solar flat plate collectors (SFPCs) using response surface methodology for sustainable operation and optimized performance. Ni-Co coatings, applied through an electroplating process, represent a novel approach by offering superior thermal conductivity, durability, and environmental benefits compared to conventional black chrome coatings, addressing critical concerns related to ecological impact and long-term reliability. Experiments were conducted to evaluate the thermal efficiency of Ni-Co-coated panels with and without reflectors under varying flow rates, collector angles, and reflector angles. The thermal efficiency was calculated based on the inlet and outlet water temperatures, solar radiation intensity, and panel area. The results showed that the SFPC achieved average efficiencies of 50.9% without reflectors and 59.0% with reflectors, demonstrating the effectiveness of the coatings in enhancing solar energy absorption and heat transfer. A validated quadratic regression model (R 2 = 0.9941) predicted efficiency based on the process variables, revealing significant individual and interaction effects. Optimization using the Box–Behnken design identified the optimal parameter settings for maximum efficiency: a flow rate of 1.32 L/min, collector angle of 46.91°, and reflector angle of 42.34°, yielding a predicted efficiency of 79.2%. These findings highlight the potential of Ni-Co coatings and reflectors for enhancing SFPC performance and provide valuable insights into the sustainable operation of solar thermal systems. Furthermore, the introduction of Ni-Co coatings offers a sustainable alternative to black chrome, reducing environmental risks while enhancing efficiency, thereby contributing to the advancement of renewable energy technologies.