INNOVATION OF A PROTOTYPE POST-HARVEST RICE GRAIN DRYER MACHINE THROUGH THE APPLICATION OF JOULE HEATING

Abstract

In the Philippines, the traditional method of sun-drying rice grains often exposes them to various vulnerabilities, resulting in significant damage. Despite existing innovations in grain dryer machines, the use of unfavorable combustible heat sources remains a concern. Thus, this study aimed to develop a prototype post-harvest rice grain dryer machine utilizing Joule heating through the use of nichrome wire to enhance drying efficiency and effectiveness. A true experimental research design was employed to assess the drying capability of the developed machine compared to the traditional sun-drying method. The prototype integrated a Proportional–Integral–Derivative (PID) control system, combined with a nichrome wire heating element and an air blower, to maintain a uniform drying environment. The system operated within a temperature range of 50–60 °C to achieve the desired moisture content of 14% and below. The results of rigorous testing confirmed that the prototype consistently reached and maintained the optimal drying temperature of 60 °C, with an average energy consumption of Php 1.146 per session lasting 1 hour and 40 minutes. The computed p-value from the Analysis of Variance (single factor) exceeded 0.05, indicating uniform air distribution within the drying chamber. The machine successfully dried rice grains to the target moisture content of 14% and below across batch loads of 5 kg, 10 kg, and 15 kg. Furthermore, machine-dried rice grains demonstrated clear advantages over sun-dried grains in terms of reduced moisture content, shorter drying time, and lower production cost. The findings indicate that the developed rice grain dryer machine shows strong potential in addressing post-harvest drying challenges in the agricultural sector. Its efficient performance, reduced drying time, and lower production cost make it a viable alternative to traditional sun-drying methods, offering significant benefits for rice grain preservation and overall post-harvest processing.