Design and Development of a Forced-Convection Solar Dryer: Application to Beetroot Cultivated in Béchar, Algeria

What is it about?

The aim of this study is to design, build, and evaluate an indirect forced convection solar dryer adapted to semi-arid climate, such as that of Béchar situated in the west south region of Algeria.

Featured Image

Why is it important?

The tested drying system consists of a flat-plate solar collector, an insulated two-chamber drying unit, and an Arduino-controlled device that ensures uniform temperature distribution and real-time monitoring using DHT22 sensors. Drying tests were conducted on locally grown beet slices at air temperatures of 45°C, 60°C, and 80°C, with a constant air velocity of 1.2 m/s and a mass flow rate of 0.0027 kg/s. The collector reached a maximum temperature of 65°C, with thermal efficiencies ranging from 20% to 35%. In these conditions, the drying times were cut down to 200–300 min, and the beet’s moisture content dropped to 0.47, 0.27, and 0.24 g/g dry matter, respectively. The experimental data were fitted to several empirical models, including the logarithmic model. The modelled results showed strong agreement with the experimental ones (correlation coefficients r = 0.9919–0.9989; standard errors SE = 0.017–0.043; root-mean-square errors RMSE = 0.016–0.027). The results demonstrate that the system operates efficiently and consistently, making it suitable for the sustainable drying of agricultural and medicinal products in arid climates.},