Development of a Solar Grain Dryer for Paddy Rice in Humid Regions

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Drying paddy rice in humid regions is challenging, leading to quality losses. This project developed a solar grain dryer for humid conditions. The dryer comprised a solar collector (4 m2), drying chamber (500 kg capacity), and supplementary electric heater for cloudy periods. The design included a fan for forced convection and temperature control system. Performance testing during wet season showed drying time reduction from 5 days (sun drying) to 8 hours. Moisture content was reduced from 24% to 14% uniformly. Drying efficiency was 28% in solar-only mode and 45% with supplementary heating. Grain quality analysis showed lower broken rice percentage (12% versus 22% for sun drying) and better milling recovery. System cost was N320,000 with significant quality premium recovery.