In this book, following objectives has been set to investigate the performance of arc shaped wire rib roughened solar air heater (SAH): (i) To perform the experiments using arc shaped wire rib roughness apex up and down stream air stream ?ow under actual outdoor conditions, (ii) To evaluate the thermal efficiency and heat transfer of arc shaped roughened SAH, (iii) To investigate the better performance of SAH using comparative study of apex upstream and apex downstream flow.