Browsing by Author "M. B. Maina"

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    Design, Fabrication and Performance Evaluation of Solar Brick Oven
    (2016-01-01) M. B. Maina; G. M. Ngala; A. T. Abdulrahim
    -Bread baking in Maiduguri and environs (north eastern Nigeria) is mainly done in ovens that are fuelled by charcoal sourced from fuel-wood; this process releases harmful greenhouse gasses to the atmosphere with known negative effects on the environment. The demand for fuelwood as energy source by bakeries and household users is increasing while the resource is becoming scarce and costly when available. These require immediate attention by providing alternative sources that are environmentally safe, less costly and accessible locally, so that overdependence on fuel-wood is greatly reduced. A potentially cost effective alternative energy source that is locally available is the solar energy. Three materials (glass, Perspex and aluminum) were used as window/screen materials for the oven, onto which a parabolic solar collector was focused. All the three materials achieved baking bread at different temperatures and time, Glass oven baked at 90oC screen temperature and 120OC oven temperature in 3hours, Perspex oven baked at 150oC screen temperature and 130OC oven temperature in 3 ½ hours and aluminum oven baked at 130oC screen temperature and 150OC oven temperature in 2hours thirty minutes with solar insolation of 850 w/m2 on the test day. Glass and Perspex sustained defect at different temperatures and exposure time. It was observed that aluminum screened solar oven produced bread with oven performance efficiency of 16% while glass screened oven produced bread at 63% efficiency and Perspex screened oven produced bread at 51% efficiency. Temperature profiles within and outside the oven were analyzed (with and without load). Analysis of the experimental results showed that solar radiation, ambient temperature and wind velocity with respect to the screening materials were the most influential factors.