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

Quiñonez-Choquecota J.; Holguino-Huarza A.; Pedro Quispe-Aymachoque J.; Quea-Gutierrez L.; Luis Apaza-Cruz J.; Fredy Chura-Acero J. · Proceedings of the LACCEI international Multi-conference for Engineering, Education and Technology (2025) · DOI: 10.18687/laccei2025.1.1.315

Resumen

Thermal solar energy is a clean and sustainable energy source that can meet energy demands in various areas of life, such as drying agricultural products. The objective of this research was to design and construct a single-flow mixed-mode solar dryer with enhanced artificial roughness, consisting of multiple-arched ribs attached to the upper surface of the flat absorber plate, and to evaluate its thermal performance for the drying of quinoa (Chenopodium quinoa Willd) under mass flow rates ranging from 0.189 kg/min to 1.893 kg/min, comparing the results with those of open sun drying. The solar dryer is low-cost (approximately 100 USD), includes a drying chamber, and features a rib geometry optimized to improve thermal efficiency. It also incorporates an autonomous air blower system powered by photovoltaic energy. The study evaluated the thermal performance of the solar air heater, the overall drying efficiency, and the moisture ratio. The tests were conducted under both forced convection (1.197 kg/min, 1.547 kg/min, and 1.893 kg/min) and natural convection (0.189 kg/min) conditions. The results showed that the maximum average thermal efficiency of the solar collector was 77% at an average solar irradiance of 1055 W/m2 and a mass flow rate of 1.197 kg/min, with an average drying temperature of 56 °C. The highest average overall drying efficiency reached 23.28%, and the shortest drying time was 2.1 hours at the same flow rate. The mixed-mode solar dryer achieved optimal efficiency at a forced flow of 1.02 kg/min, reducing drying time by 68% compared to open sun drying. The moisture ratio (MR) analysis revealed that efficiency decreased at the extreme flow rates (0.189–1.893 kg/min), highlighting the importance of selecting an appropriate airflow rate.

Instituciones: Universidad Nacional del Altiplano