1. Problem Statement The traditional sun-drying method—spreading grain on mats or pavements—is highly dependent on clear, sunny weather. In tropical climates, sudden rain and high humidity frequently halt this process, leading to: -Quality Deterioration: Delayed drying causes moisture-related issues such as fungi growth and grain germination. -High Losses: Inappropriate drying can result in a 3-5% loss in rice quality and physical traits. -Labor Intensive: Farmers must manually rake and monitor grain for days to achieve uniform drying.
2. Design & Engineering Objectives -The primary goal was to fabricate a machine capable of drying 25 kg of palay to the International Rice Research Institute (IRRI) standard moisture content of 14% or less. Key specific objectives included: Reducing drying time compared to conventional sun drying. -Evaluating the efficiency of a dehumidifying system using organic materials. -Maintaining a targeted drying temperature between 40°C and 55°C to prevent grain damage.
3. Technical System Architecture The machine utilizes a convective drying method consisting of four major subsystems: -Electric Heating Element: A 1800W heater warms the air to the required drying temperature. -Blower System: A 479.55W blower circulates the heated air through the drying chamber at a calculated flow rate. -Organic Dehumidifier: The system uses Coconut Coir (husk) as a natural desiccant. Coconut coir was chosen for its high surface area, hydrophilic properties, and its safety—offering lower formaldehyde emissions than chemical desiccants like silica gel. -Drying Chamber: A casing housing three trays, each capable of holding 9 kg of palay (27 kg total capacity).
4. Methodology CAD & Simulation: The system was conceptualized and simulated using SolidWorks and AutoCAD to determine optimal airflow and structural integrity. -Experimental Design: A comparative analysis was conducted across three test groups: -Drying with integrated heating and dehumidification (coconut coir). -Drying with heating but without dehumidification. -Traditional sun-drying.
Data Collection: Moisture levels were monitored using a digital grain moisture meter, while temperatures were tracked via thermostats and scanners.
5. Key Results & Performance -Drying Efficiency: The machine successfully achieved a final moisture content of 14.6%, resulting in a 95.90% efficiency relative to the 14% target. -Material Effectiveness: Coconut coir proved to be a viable, eco-friendly alternative to chemical desiccants, effectively reducing relative humidity within the system without the risk of ignition at standard operating temperatures.
Operational Benefit: The prototype demonstrates that mechanized drying can significantly reduce manual labor and mitigate the risks of crop loss during the rainy season.