Thermal performance and drying kinetics of quinoa in a mixed-mode solar dryer with natural and forced convection

Quiñonez-Choquecota J.; Holguino-Huarza A.; Fredy Chura-Acero J.; Pedro Quispe-Aymachoque J.; Quea-Gutierrez L.; Manuel Yanarico-Coaquira V. · Proceedings of the LACCEI international Multi-conference for Engineering, Education and Technology (2025) · DOI: 10.18687/laccei2025.1.1.1653

Resumen

The objective of this research was to analyze the thermal performance of a mixed-mode solar dryer with both natural and forced convection, featuring multiple-arched fins attached to the upper part of the absorber plate, and to determine the drying kinetics of quinoa (Chenopodium quinoa Willd). The mixed-mode solar dryer is low-cost and easy to construct, and it includes an air blower system powered autonomously by a photovoltaic panel. The thermal efficiency and mathematical models describing the drying kinetics of quinoa were evaluated. Experimental tests were conducted at mass flow rates of 0.189 kg/min, 1.197 kg/min, 1.547 kg/min, and 1.893 kg/min. The results showed that the maximum average thermal efficiency of the solar air heater reached 77% at an average solar irradiance of 1055 W/m2 and a flow rate of 1.197 kg/min, with an average drying temperature of 56 °C. The maximum average overall efficiency was 23.28%, and the minimum drying time was 2.1 hours at the same flow rate. The mixed-mode solar dryer demonstrated maximum efficiency at a forced flow rate of 1.02 kg/min, reducing the drying time by 68% compared to open sun drying. The Page model best described the drying kinetics of quinoa under forced convection, while the Wang and Singh model better represented quinoa drying by natural convection in the solar dryer and in open sun conditions.

Instituciones: Universidad Nacional del Altiplano