Abstract

A semi- cylindrical natural convection solar tunnel drier (STD) was used for experiments to dry maize cobs that were partially field- dried. The air temperature recorded in the collector unit was higher than ambient temperature by 15.8^oC to 20.8^oC and this was effective in reducing the moisture content of maize cobs from 30 % wet basis to safe level storage moisture content of 12.5 % wet basis. Averages of solar radiation recorded during the experiments ranged from 585.6 W/m² to 759.8 W/m². The averages of relative humidity that prevailed in the drying unit ranged from 6.8 % to 18.2 % whereas the ambient relative humidity averaged from 27.3 % to 43.7 %. Drying time was examined with moisture content ratio as exponential and polynomial correlations. Fourteen different drying mathematical models available in literature were compared using their coefficients of determination to estimate solar drying curves. Based on statistical analysis of the results, Midilli drying model had the best fit to the experimental drying data of maize with a coefficient of determination R²= 0.99912 as compared to other models. 

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