Design and Development of Smart Dryer for Agriculture

After harvest, a large part of the food that farmers grow is lost because it stays wet, grows mould, or is spoiled by rain and insects. Open-sun drying is cheap but slow and weather-dependent; fuel- or grid-powered dryers are fast but too costly for small farmers in remote areas. This paper combines the findings of fourteen recent research papers and proposes a simple design for a smart solar dryer: a solar air collector, a solar panel with battery, an optional heat-storage box (phase change material, PCM), sensors for temperature, humidity, airflow and weight, a low-cost controller (ESP32, NodeMCU or Arduino), wireless links (Wi-Fi, GSM or LoRa) and a phone/cloud dashboard. The reviewed papers show that solar dryers cut drying time by 40–70 % compared with open sun drying, hybrid and PCM dryers reach about 25–45 % efficiency, smart IoT control can save 20–30 % of energy and reduce post-harvest loss by 15–25 %, and the investment is usually recovered in 1.1–2.7 years. PID and fuzzy control keep temperature within ±1–2 °C, against ±5–10 °C for simple on–off control. The paper also explains each main component in plain words with photos and shows how a temperature-controlled dryer can protect the germination of soybean and sunflower seed. It is a review-based design study: it contains no new experiments, and its calculations are estimates that must be tested.