Automation and Performance Evaluation of a Solar Tunnel Dryer Using Arduino UNO

Abstract

The study on automation of an existing solar tunnel dryer was done using the Arduino UNO and DHT11 sensor during 2020–2021 at the Research Farm, Department of Farm Machinery and Power Engineering, Sam Higginbottom University of Agriculture, Science, and Technology, Allahabad, Uttar Pradesh, India. To ensure optimal drying conditions, the Arduino UNO was employed to regulate the operation of an exhaust fan. This control system was activated whenever the humidity level inside the dryer reached a specific threshold. The system was configured to operate at three different humidity levels- 35%, 30% and 25% for three weeks of five working days each. Potatoes weighing 5000 g were sliced and spread inside the dryer daily between 9:30 am to 5:30 pm, ensuring consistent and regular activity within the specified timeframe. It was found that the moisture removal rate and the successive drying time were fastest when the exhaust fan was operated to remove 25% humidity, followed by 30% and 35%. During the third week, the drying time was two hours less than the first week and one hour less than the second. These results demonstrate that removing humidity at lower levels significantly contributed to faster drying. Therefore, it can be inferred that automating the solar tunnel dryer and maintaining a lower humidity threshold can significantly enhance the efficiency of the drying process.