DEVELOPMENT AND EVALUATION OF SOLAR THERMAL HYBRID DRYING SYSTEM

Essentially, the drying process involves reducing the moisture content of a
product to a level that prevents deterioration within a certain period of time. This
period is normally regarded as the safe storage period. The sun-drying procedure is
classified into traditional open sun drying, solar drying, and hybrid drying techniques;
the third drying type was developed to resolve the setbacks of the first and second
types. Furthermore, a biomass stove is incorporated with a solar dryer as a hybrid
drying system to reduce the dependence of the dryer on solar radiation for operation
and to improve drying quality. This system extends the period of drying high-value
products beyond the sunshine hours and into the night. On this basis, a solar thermal
hybrid drying system was designed, fabricated, and developed to dry materials
continuously in rural areas without requiring electric power supply. The developed
system comprises a solar drying chamber, solar air heater, and thermal backup unit;
this unit consists of a burner and a gas-to-gas heat exchanger.