A numerical investigation was performed on triangular solar air collectors by integrating unique layouts of triangular and alternating triangular copper metal foams with graded and non-graded pore densities. A three-dimensional CFD model was established to solve the governing equations of coupled systems for porous and non-porous domains. The two-energy-equations model was implemented to simulate heat transfer in porous media. The mathematical model was validated with numerical and experimental tests, with maximum mean absolute percentage error of 5% and 7%, respectively. To compromise heat transfer improvement with pressure losses, a partial metal foam insertion was adopted, covering 10% to 25% of the air duct volume. The findings indicate a significant enhancement compared to conventional design, particularly for the third triangular metal foam sample characterized by high pore density and elevated permeability. Improved mixing, augmented heat exchange surface area, and localized turbulence intensification contributed to the noted gains in performance. The findings confirm that the spatial distribution and graded pore densities of metal foams are a promising approach for improving performance. Furthermore, the alternating configuration facilitated flow redistribution while mitigating excessive pressure penalties. Thermal and thermo-hydraulic efficiencies, as well as the performance evaluation criterion, rose from 63.22% to 85.39%, 53.69% to 71.91%, and 2.70 to 5.02, respectively, when the metal foam volume fraction was increased from 10% to 25%. Such systems can be integrated into building as part of energy transition scenario to decrease carbon dioxide emissions and improve overall energy efficiency.
