CFD simulation of double-pass solar dryer with air return

Abstract

An indirect solar dryer was designed and manufactured in Yamoussoukro, Côte d’Ivoire. It is equipped with three parameters including two air intake ports, a fan and a removable hot air recovery system. Vacuum CFD simulations were performed in order to observe the influence of these parameters on the effectiveness of the device. The fan switched off speeds of 9 m/s and made the air distribution uniform in the drying cabin. The natural convection operation made it possible to reach 62°C in the drying chamber compared to 55°C for the forced convection operation. The unique opening of the low air intake port in operation accentuates the temperature variations in the cabin compartments with differences of + 5°C from one level to another. The hot air return system has a positive impact on temperature trends because it allows values of 65°C to be reached inside the chamber, ideal for drying agri-food products. However, this recovery reduces the air velocity in the cabin, which is a disadvantage for the performance during products. This problem could be solved by increasing the fan power.