<p><span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:14px">A comparative study of various approaches to optimise and increase the performance of solar air heater is carried out in the present work. Various types of artificial roughness geometries in the absorber plate of solar air heater duct and their characteristics have been investigated for the heat transfer improvement or enhance the performance by many researchers. However, exergy data are more practical and realistic in comparison with the respective energy values that have been found in this communication.</span></span></p>