Development and assessment of generalized drying kinetics in multi-tray solar cabinet dryer

Abstract This work evaluates the feasibility and determines a generalized drying characteristic curve in an indirect mode multi-tray solar cabinet dryer. The study considers a combination of tray reordering pattern and dryer performance index (DPI) method to map the influence of four primary factors, which influence the drying kinetics into a generalized curve. Three levels of each of the four factors, such as the mass flow rate (0.03–0.05 kg/s), heat input (500–1000 W/m2), loading density (1.0–2.5 kg/m2), and flake thickness (2–8 mm), represent twelve different drying kinetic curves. Therefore, the DPI value corresponding to the generalized curve would directly indicate the dryer performance and reduce the complexity in assessing the agro-product samples' drying behaviour in multiple trays. This study was initially validated, and it highlighted the merits of a tray reordering pattern in achieving drying uniformity per batch. Dimensionless drying process time ( τ ), a function of drying constant ( k ) and drying time ( t ), resulted in a maximum percentage deviation of 27.93% among the twelve drying kinetic curves. In contrast, expressing the moisture ratio as a function of DPI and drying process time ( τ ) reduced the maximum percentage deviation to 2.33%, with the value of correlation coefficient ( r ) above 0.972 for all the twelve drying kinetic curves. These consolidated findings pointed out that the adopted tray reordering pattern greatly influences the DPI method’s success in establishing a generalized curve in a multi-tray dryer.