Artificially roughened solar air heater has been the topic of research for last thirty years. Several designs for artificially roughened solar air heaters have been proposed and discussed in the literature [3–30]. Several investigators have attempted to optimize a roughness element, which can enhance convective heat transfer with minimum pumping power requirement by adopting experimental and numerical approaches. Most of the experiments are also conducted to specifically understand the influence of pitchto- rib height ratio (P/e) and/or rib height-to-hydraulic diameter ratio (e/D) on average heat transfer and flow friction characteristics, and distributions of the mean velocities, pressure and turbulent statistics in the flows through the duct of an artificially roughened solar air heater. Literature search in this areas revealed that the heat transfer enhancement is strongly dependent on the relative roughness pitch (P/e) and relative roughness height (e/D) of roughness elements together with the flow Reynolds number (Re). There are lot of experiments have been done and so many experiments are going on right now to optimize roughness parameters for heat transfer enhancement in roughened duct of solar air heaters [3–30]. Table 1 lists the major experimental works for different roughness geometries and configurations applied on the absorber plate of a solar air heater.