Performance Improvement Of A Forced Convection Solar Dryer For Agri-food Products

Résumé: This work presents the results of an experimental study on the spinach leaves drying in a solar-assisted forced convection dryer, developed and improved at the food science laboratory. The solar dryer was equipped with a flat air solar collector with an absorbent plate painted in matt black with a surface area of 2 m2 exposed to solar radiation and a drying chamber with a volume of 0.5 m3. It was developed to study the effect of the temperature of the drying air and the fraction of the exhaust air recycled (0, 50 up to 90%) on the total energy requirement of spinach drying as a function of time. In this dryer, the spinach leaves are dried from an initial moisture content of 93.23% (wet base) to a final moisture content of about 2% (wet base), with drying air velocity equal to 1 m/s. The spinach dries and reaches the final water content after 6 hours of drying, for air-recycled rate of 0%, and a low drying temperature of about 40°C. The drying rate has slightly increased in relation to the fraction of air-recycled, the drying time has been reduced from 3 to 4 hours for the fraction of air-recycled from 50 to 90% respectively with a significant gain in thermal energy; hence, the drying temperature is higher and stable in the drying chamber in the range of 55 to 65 °C (90% air is recycled).

Publié dans la revue: Journal Algérien des Régions Arides