An experimental investigation has been carried out for a range of system an operating parameters in order to analyze effect of artificial roughness on Collector heat removal factor and Collector efficiency factor in flat plate solar air heater having rhombus shape (sheet metal) as roughness geometry. Duct has an aspect ratio W/H of 7, relative roughness pitch (p/e) range of 40 to 60 relative roughness height (e/D) range of 0.071 to 0.119 and Reynolds Number (Re) range from to 5100 to 28000. A considerable increase in Collector heat removal factor and Collector efficiency factor has been observed.