Performance evaluation of a multi-arc ribbed mixed solar dryer for quinoa drying

Resumen

The objective of this research was to develop and evaluate a forced convection mixed type 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. The solar dryer is low cost and easy to build, has a drying chamber and an air blower system that operates autonomously with photovoltaic energy. Thermal performance and drying kinetics were evaluated for quinoa. Performance tests were conducted for mass flow rates of 0.189 kg/min, 1.197 kg/min, 1.547 kg/min and 1.893 kg/min. The results reveal that, 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, for a flow rate of 1.197 kg/min. 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. The Page model is the best fit for describing the drying kinetics of quinoa under forced flow conditions, and the Wang and Singh model is the best fit for natural convection drying of the dryer and open sun drying of quinoa.