Recent developments and cost analysis of different configurations of the solar air heaters

In this work, the recent advances in practical and theoretical studies on solar air heaters are reviewed in detail. Solar air heaters have proven in previous years to be a good option for obtaining hot air that can be used in daily life purposes and several industries. The low thermal efficiency is considered the main drawback of the solar air hear. Numerous studies have been conducted to improve the thermal efficiency of the solar air heater. Where two techniques are commonly investigated: first, increasing the heat transfer between the flowing air and the absorber plate, and using thermal storage material. The first technique can be achieved by increasing the heat transfer area by using finned or corrugated absorber plate, and by employing baffles with various configurations to transition the airflow from laminar to turbulent. Two categories of thermal energy storage material are commonly used: sensible heat storage, and latent heat storage. The main part of this work presents the recent studies used one of these techniques to improve the thermal performance of the solar air. Finally, the cost analysis of some selected solar air heaters is presented. Based on the reviewed results presented in this work, it is found that the corrugated air jet impinging absorber plate solar air heater is the best among the reviewed heaters as it achieves 0.00133 $/kWh, whereas the zigzag finned plate solar air heater has the highest cost of 0.0834 $/kWh.