The present paper investigates the turbulent forced convection of TiO2/water nanofluid through a ribbed flat-plate solar collector numerically. A three-dimensional simulation of solid flat-plate with flow through the plain and ribbed duct has been performed. The scale-adaptive-simulation approach has been employed to simulate the flow turbulence. The velocity and temperature profiles, Nusselt number and the efficiency of solar flat-plate solar collector have been studied by using plain and ribbed ducts at different Reynolds number and nanoparticles volume fraction. Results indicate that wake circulation region in the back of the rib is intensified at higher Reynolds number leading to an enhancement in the convective heat transfer. Moreover, the efficiency of flat-plate solar collector increases with the nano particles volume fraction whilst an enhancement in the efficiency of the ribbed duct is approximately 10% higher than that of the plain duct. This enhancement varies for different nanofluids such that the CuO/water nanofluid provides a higher thermal efficiency than that of TiO2/water. (C) 2018 Elsevier Ltd. All rights reserved.