Performance Evaluation and Comparison Studies on Drying Characteristics of Sliced Plantain and Maize

Solar dryer was developed and comparison between using solar energy and air-sun drying methods with sliced plantain and maize (shelled corn) were assessed. The dryer consist of a solar collector panel (concentrator type), a thermal storage unit and a drying chamber. The solar chamber was tilted at 7° to the horizontal with the aid of four supports at two differ heights and was covered with the transparent Polyvinylchloride (PVC) film, of 0.15 mm, thickness. The absorber material used was aluminium pipe 145 cm long of external diameter 5 cm, painted black and fixed at the focal point of the parabolic mirror. The thermal storage unit and the drying chamber were built of wood because of its good insulation properties. Results showed the collector outlet, storage unit and drying chamber temperatures ranged from 37°C–47°C, 36°C–46°C, and 33°C–45°C, respectively. About 70.1% of moisture evaporated using solar dryer for plantain as compared to 45% using open air drying. Also more moisture evaporated from the maize (100%) using solar dyer than using open air drying (65%). The degree of variation between using solar dryer and open air drying was found to be statistically significant (P = 0.05) for both treatments. Results showed that using solar collector/dryer evaporated more moisture from the products than using the open –air sun drying.