Browsing by Author "M. B. Maina"

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    APPLICATION OF STEARIC ACID FOR SOLAR THERMAL ENERGY STORAGE IN A DOUBLE COMPARTMENT SOLAR BOX COOKER
    (2019-06) M. B. Maina; S. Shodiya; A. T. Abdulrahim
    Energy storage in some form is the need of the hour to even out the mismatch between energy supply and demand. Thermal Energy Storage (TES) system employing a phase change material (PCM) has been widely considered as an effective way to store and retrieve energy due to its high heat storage capacity at almost constant temperature during the phase change. In this work, an energy storage system was designed to study the heat transfer characteristics of stearic acid (as a phase change material in a double compartment solar box cooker (DCSBC) fabricated using wooden materials with high thermal energy storage system. In order to analyze the various characteristics of the PCM, the Bureau of Indian Standards (BIS) was used throughout the experiment. Investigations were performed to determine the first and second figure of merits (F1 and F2) of compartments 1 and 2 (C1 and C2) simultaneously. The results for F1 were found to be (C1= 0.14 and C2= 0.15) and F2 were (C1=0.47 and C2= 0.4) while the overall thermal efficiency of the cooker after water boiling test for C1 with 2.5kg and C2 with 3kg of water were deduced to be 77% for C1 and 92% for C2 after six hours of the load test, showing considerable temperature increase and extension of heat retention making possible to cook the dinner and even breakfast the next day.
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    DESIGN AND EXPERIMENTAL TESTING OF A SOLAR BOX COOKER WITH PARAFFIN WAX AS THERMAL ENERGY STORAGE USING MAIDUGURI WEATHER CONDITION
    (2019-06) M. B. Maina; S. Shodiya; A.T. Abdulrahim
    The performance of paraffin wax as phase change material (PCM) for thermal energy storage (TES) was investigated using a Solar Box Cooker (SBC) exposed to Maiduguri weather condition. Temperature and energy generated by SBC were experimentally established. The result shows tremendous improvement in energy storage compared to SBCs without TES in existence within Maiduguri and environs. The measured temperature and energy generated by the PCM in the experiment were 118oC and 4164.5KJ respectively, an adequate temperature and energy for cooking during off-sunshine hours and beyond. First figure of merit (F1) and second figure of merit (F2) were deduced to be 0.13 and 0.44 with overall SBC efficiency (ɳ) of 63% qualifying the SBC to grade A based on the Bureau of Indian Standards (BIS)
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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.