In this work, an experimental investigation on heat and fluid flow characteristics of artificially roughened solar air heater duct has been carried out. The roughness and operating parameters covered a range of Reynolds number (Re) from 2000 to 20000, relative roughness pitch (P/e) from 15 to 30, relative rib length (r/g) from 0.4 to 1.0, and relative rib pitch (P-r/P) from 0.2 to 0.8. Other parameters, i.e., relative roughness height (e/D), angle of attack (alpha), and relative roughness gap are kept constant. Results show that the considerable enhancement in Nusselt number and Thermo-hydraulic performance has been obtained with an increase in friction factor using roughened surface.