Numerical modeling of an innovative arc shape rib based solar air heater

Solar air heating is a solar thermal technology wherein the sun energy is absorbed by an intermediate medium and utilized to heat air. In the present paper, a solar air heater equipped with innovative arc shaped ribs is considered. The heat transfer process in the proposed solar air heater is evaluated numerically for Reynolds numbers between 6000 and 12000. The influences of the rib cross section type, the inter-rib distance, the aspect ratio and the pitch of the ribs on the thermal efficiency of solar air heater are analyzed. Results indicate that firstly, ribs with quadrangular type of cross section exhibit the best coefficient of performance. Moreover, ribs with low pitch (40 mm) and aspect ratio equal to 0.5 show the highest thermal performance. Also, the effect of the distance between the ribs on the thermal efficiency of the considered solar air heater is insignificant. Finally, two correlations are obtained for the average Nusselt number and friction factor based on three dimensionless geometric factors.

Automated summary

This study investigates the heat transfer process in a solar air heater with innovative arc shaped ribs and analyzes the influences of rib cross section, inter-rib distance, aspect ratio, and pitch on thermal efficiency. Results show that ribs with quadrangular cross section exhibit the best performance.