Optimization of drying parameters for hybrid indirect solar dryer for banana slices using response surface methodology

Present research work focuses on applying response surface methodology (RSM) in optimization and modeling dried banana slices in a hybrid indirect solar dryer. The relationship of independent variables in terms of mass of banana slices (kg), drying chamber temperature (°C), water flow rate (L/hr), and geometry (cm2). Therefore, responses of interest or dependent variable consisting of moisture content (% db), energy consumption (kW/h), and shrinkage (%) utilization are concluded. A short drying period and energy consumption are seen as the optimizing drying parameters of banana slices. Response surface methodology with central composite design (CCD) was applied to optimize the dependent variable. Experimentally observed data are adjusted by applying a second-order polynomial regression model. The predicted R2 in the range of 0.9828–0.9530, adjusted R2 value (0.9571–0.9974), and model F value (08.18) for banana slices were calculated. Optimal operational parameters are observed 89.99 ℃ (drying cabin temperature), 14.0 L/hr (water flow rate), 0.9998 (circular geometry), and 0.24004 kg (product mass). Optimum responses were 7.55% db (moisture content, MC), 5.54 kW/h (energy consumption), and 69.54% (shrinkage). Further, experiment was conducted at optimal operating conditions, and the results indicate good consistency between predicted and experimental data with a deviation of 3.14%, 2.16% and, 1.41% for the minimum moisture content (wb), energy consumption and, shrinkage, respectively.