Experimental and Economic Performance of Two Solar Dryer Systems in Tunisia

Abstract

Solar drying is the oldest preservation technique of agricultural products using several types of solar crop dryers based mostly on solar energy, which is abundant, renewable, and sustainable. This chapter presents an experimental analysis to investigate the performance of two solar drying systems that were used to dry red pepper: solar greenhouse dryer and indirect solar dryer. The solar greenhouse dryer consisted of a flat-plate solar collector and a chapel-shaped greenhouse. Also, the indirect solar dyer consisted of a flat-plate collector and a drying chamber. The results show that the constant rate period is absent from the experimental drying curves. The experimental drying curves show only the falling rate period. Thus, the drying time was 17 hours in the solar greenhouse dryer and 52 hours in the indirect solar dryer. The drying data were fitted to eight different mathematical models. The fit quality of the proposed models was evaluated by using the coefficient determination (R2), reduced chi-square (χ2), and root means square error (RMSE). The experimental tests show that the solar greenhouse dryer was found to be satisfactory and competitive to the indirect solar dryer.