Computational fluid dynamics analysis of cabinet‐type solar dryer

Abstract

AbstractOne of the major constraints in the acceptability of solar dryer in industrial and commercial applications is lack of control on the drying process due to variable, periodic, and dilute availability of solar heat. For reliable operation, process control with auxiliaries become essential in industrial solar dryers. Integration of solar dryers with auxiliaries is also not studied substantially. This research document focuses on CFD simulation of cabinet‐type solar dryer integrated with auxiliaries, which can be operated under different operating conditions. The dryer is equipped with auxiliary heaters and blowers to have precise control over the temperature inside the chamber. The simulations are carried out for drying temperature of 318 K. The results showed that as the day progresses (radiation intensity increases), the region of average temperature increases. The extent of temperature distribution also helps to locate the region of temperature around the drying temperature. Also to facilitate the control of input energy by the auxiliary heaters, a region is located where the average temperature of air inside the drying chamber can be obtained for varying operating conditions. The region lies about 1.2–1.6 m on X‐ordinate, 0.8–1.0 m on Y‐ordinate, and 0.7–1.2 and 3.7–4.3 m on Z‐ordinate. Thus, a feedback loop developed can modulate the input and make it possible to operate the dryer with maximum effectiveness.Practical ApplicationsThe potential for utilization of solar thermal energy in commercial and industrial drying applications up to air temperature of 80°C is remarkable. Solar dryers integrated with an auxiliary heating arrangement assure to save a lot of fossil fuel energy. Reliability and uninterrupted operation are the major requirements from a solar dryer. The manuscript presents computational fluid dynamics analysis of the solar dryer equipped with auxiliary heating. The extent of temperature distribution is determined for dryer with and without auxiliary heating and it clearly reveals that proper auxiliary heating control, helps to maintain temperature inside the dryer. Also the effect of variation of geometry and variation of solar radiation is studied and common region is found which can help to modulate the auxiliary heating. It provided sound background for feedback control mechanism design that will keep temperature near the drying temperature of product and improve drying product quality.