Comparative study based on thermal efficiency of solar air heaters

This article investigates various aspects of solar air heaters applied to drying process. Also, the paper presents a comparison between different types of solar collectors in terms of thermal efficiency and outlet temperature based on experimental results achieved by different authors. New improved technologies that increase the efficiency of these devices are discussed. Analysis and tables obtained in this document can be a helpful tool for a designing engineer to construct economical and efficient solar air heaters.