Performance evaluation of forced convection mixed-mode solar dryer: Experimental investigation

In present experimental investigation, a modest attempt is made to study the influence of load density and size of food product on drying efficiency of solar dryer. In order to achieve this objective, the laboratory model of mixed-mode solar dryer is fabricated and tested under indoor simulated conditions. Experiments have been performed on dryer with cylindrical potato samples of different thicknesses (5, 8 10 and 18 mm) and loading density (1.08, 2.16, 3.24 and 4.33 kg/m2 of food sample tray area) under forced air circulation. The air mass flow through dryer system is kept constant at 0.011 kg/s (1.3 m/s). Experimental variation of food product moisture content with drying time data have been plotted and analyzed for a wide range of product size and loading density. Results of experimental investigation reveal that the load density and food product size have significant effect on drying efficiency. It is also found that load density has an increasing influence on efficiency whereas the opposite trend is observed for food product size. Sensitivity analysis results indicate that both the variables are equally sensitive to overall efficiency of the dryer.