Development of a Solar Aided Crib for Drying and Storage of Maize Cobs

Abstract

The aim of this study was to design, construct and evaluate the performance of solar aided crib for storage of freshly harvested maize (Zea mays) in a humid tropical climate. A crib with two drying chambers of size 600 mm x 685 mm x 1500 mm with moisture emission chamber of 600 mm x 115 mm x 1500 mm was designed, constructed and evaluated using appropriate design procedures at the department of Agricultural and Environmental Engineering, Federal University of Technology, Akure, Ondo State, Nigeria. The roof of the crib is made of perspex which transmits the sun's energy into stored maize in the crib for effective drying purpose. The crib was raised at 50 mm above the ground surface and wire netted against rodents. It has two doors for easy loading and off-loading. Freshly harvested Maize weighing 500 kg of 30.5% moisture content (wet basis) was stored for three months. Moisture content of the maize was taken on weekly basis while relative humidity and temperature were measured on daily basis. Readings were taken at three positions (top, middle and bottom) in apertures that were made in those positions but were immediately covered up at the end of every reading. The ambient temperatures varied from 20.90C to 380C and also relative humidity varied from 41% to 91% throughout the period of the experiment. The moisture content at the point of storage was 30.5 % but was reduced to 4 % after three months. The final weight of maize in cobs was 362 kg which implied that the Perspex roof significantly aided in the drying process. The structure is structurally balanced and there was no grain deterioration either by fungal invasion or insects attack during the storage period. Keywords: Crib, Drying, Moisture content, Storage, Temperature