Darici, SelcukOzer, Ahmet Emre2026-02-102026-02-1020260735-19331879-0178https://doi.org/10.1016/j.icheatmasstransfer.2026.110505https://hdl.handle.net/20.500.13091/12974Hot air generation for applications like crop drying and space heating is commonly achieved using solar air collectors. However, the formation of a viscous sublayer at the absorber-air interface reduces the convective heat transfer coefficient and overall thermal efficiency. To overcome this limitation, this study analytically investigates the thermo-hydraulic performance of a two-glass, double-pass solar air collector equipped with continuous transverse wire roughness beneath the absorber plate. An iterative MATLAB-based computational program was developed using the Nusselt number (Nu) and friction factor (f) correlations available in the literature for similar roughened surfaces to solve the governing energy equations. An analytical model was developed to evaluate the thermal and flow resistance characteristics while varying relative roughness pitch (p/e = 10-40), relative roughness height (e/Dh = 0.011-0.030), and Reynolds number (Re = 5000-20,000). The proposed analytical formulation enables direct prediction of thermo-hydraulic performance without reliance on empirical correlations. Results indicate that the use of transverse ribs significantly enhances heat transfer with a moderate increase in friction losses. The configuration at p/e = 10, e/Dh = 0.030, and Re = 5000 demonstrates the highest thermal hydraulic performance, achieving a THPP value of 1.25. This study provides analytical insight into the optimal roughness configuration for improving the performance of double-pass solar air collectors.eninfo:eu-repo/semantics/closedAccessSolar Air CollectorDouble PassTransverse RibsHeat TransferFriction FactorArticle10.1016/j.icheatmasstransfer.2026.1105052-s2.0-105027114053