Performance Evaluation of a Multi-Arc Ribbed Mixed Solar Dryer for Quinoa Drying

Objective: The objective of this research was to evaluate a forced convection mixed solar dryer incorporating an artificial multi-arc ribbed roughness coupled to the top of the absorber plate for the drying process of quinoa (Chenopodium quinoa Willd) and compare it with open sun drying. Theoretical Framework: The study is based on the thermal efficiency of the solar air heating collector and the overall thermal efficiency of the mixed dryer. Method: The solar dryer is low cost and easy to construct, consisting of a solar air heating collector, a drying chamber and an air blower system powered by photovoltaic energy. The thermal efficiency for quinoa was evaluated for mass flow rates of 0.189 kg/min, 1.197 kg/min, 1.547 kg/min and 1.893 kg/min. Results and Discussion: The maximum average thermal efficiency of the solar collector is 77 % for an average solar irradiance of 1055 W/m2 and for a mass flow rate of 1.197 kg/min where the average drying temperature was 56 °C. The maximum average overall efficiency achieved was 23.28% and the minimum drying time was 2.1 hours. Research Implications: The mixed solar dryer has a maximum efficiency for a forced flow of 1.02 kg/min and the drying time is reduced to 68% compared to open sun drying. Originality/Value: This research reveals the drying process of quinoa and a way to increase the efficiency of the arc-ribbed solar dryer that reduces drying time by more than half compared to open sun drying.