SunSync Innovation: Empowering Traditional Solar Flat Plate Collectors with Autonomous Sun-Tracking for Tea Leaf Drying

Abstract

Aim: This research focused on post-harvest technology for preserving tea leaves. The research introduces an innovative approach by incorporating an autonomous solar tracker into a flat plate solar collector, strategically optimizing its orientation towards the sun. The solar tracker, a low-cost and fully automatic prototype, plays a pivotal role in maximizing incident solar rays, thereby enhancing the overall energy absorption efficiency of the system at the same time increasing the quality of dried tea leaves.
 Methodology: The investigation delves into the realm of indirect solar drying methodologies, with a specific focus on the Sun-Tracking Solar Dryer (STSD). This sophisticated apparatus, engineered through the integration of light-dependent resistors, a wiper DC motor with gearbox, and a microcontroller, was developed within the confines of the Agricultural and Food Engineering department at IIT Kharagpur. Subsequent to its development, the study entails a comparative analysis wherein the position of the absorber in the dryer, as ascertained by the developed prototype, is juxtaposed with the ideal position requisite for optimal solar light incidence. Moreover, an examination of the dried tea leaves produced by the prototype is conducted, involving a comprehensive comparison with those dried using the conventional open sun drying method.
 Results: The instantiated prototype demonstrated commendable efficacy in aligning with the ideal position, exhibiting an average deviation of 3.25 degrees. Facilitated by this prototype, the attainment of the targeted moisture content in tea leaves was expedited, culminating 2 hours earlier than the conventional open sun drying method. The resultant dried product manifested a water activity of 0.531 and a DPPH radical scavenging activity of 73.53%, both registering a reduction in comparison to the open sun drying counterpart. Concurrently, the total phenolic content exhibited an increment of 11.48% when contrasted with the open sun drying process.
 Conclusion: The affordably developed prototype demonstrated exceptional capabilities in sun tracking, showcasing the promising potential for augmenting the efficiency of conventional flat plate solar collectors. Additionally, its performance in preserving the quality attributes of dried tea leaves was commendable.