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In Egypt, the climate has a direct impact on the dried date fruit production. The traditional drying method or open sun drying (OSD) leads to pollution of the final product caused by sand-laden winds, rain, or animals and harmful insects, etc. This study is aimed at designing, implementing, and experimentally validating a solar dryer based on IoT technology and integrated with a PV system in Aswan, Egypt. The purpose of the dryer is to monitor and control the quality of the three most popular date fruit varieties and determine the most effective drying method, with an algorithm that operates the system automatically for optimal performance and high-quality products. The automatic solar dryer (ASD) significantly affects the final moisture content and color characteristics and reaches the equilibrium moisture content (EMC) at a faster rate for dried date samples compared to the OSD. The drying rate of ASD was 29.03% (Sakkoti), 31.04% (Malkabi), and 25.49% (Gondaila) higher than OSD. Also, the dried date fruit samples reached EMC on the ASD after 8 days for both Malkabi and Gondaila and 9 days for Sakkoti, while it took 14 to 15 days on OSD. The maximum open circuit voltage V oc , short circuit current I sc , and output power P output were 41.70 V, 8.84 A, and 365.09 W, respectively. All values of total color change ( Δ E ∗ ) after open-air drying of dry date varieties were higher than solar drying for both drying systems. This study can be then more helpful for producers of dried foods.
Elwakeel et al. (Tue,) studied this question.