Browsing by Author "Yonael, Tesfaye"

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    Design, Simulation, Manufacturing and Testing of a Low-Cost Tube Type Direct Solar Oven
    (Addis Ababa University, 2022-04) Yonael, Tesfaye; Kamil, Dino (PhD)
    Ethiopia is rated as number four country in the world for solar cooking potential by the Solar Cookers International (SCI) in 2020. The country had an estimate of 24,200,000 people who live in areas that have good solar cooking power potential but with fuel scarcity. Shortage of electrical coverage in most parts of the country has led to high biomass dependency for energy demand. The household baking accounting for more than half of this energy, the country faces a great deforestation scale of around 200,000ha per year. Indoor pollution and hard labor of women and children are also results of this situation. Thus, this research focuses on designing, simulating, manufacturing and testing of a tube type direct solar oven which is low cost and easy to manufacture at the local markets of Ethiopia. The tube type direct solar oven is designed to bake 1kg of bread dough. It has a cylindrical oven inside an air tight transparent tube that acts as an insulation for the oven. For low cost and ease of fabrication the air tight transparent outer cover is a square prism made of 4 plastic (acrylic) plates. The solar oven is made of light materials which are easy to find locally. Thus, it has the advantage of being portable and affordable. Simulation of the solar ray’s trajectory using COMSOL Multiphysics showed that all the incidence rays falling on the parabolic trough will reflect back on to the receiver for a 0º incidence angle. And the bread baking simulation using COMSOL took 35min to bake 1kg of bread dough which is 5minutes longer than the analytical design. Tests conducted on the manufactured solar oven showed that the standard cooking power of the solar oven at 700W/m 3 2 is 98W. The actual bread baking time of the oven was longer than the designed and simulated results due to quality in manufacturing and quality of materials used. But the economic analysis showed that the tube type direct solar oven is al low-cost effective baking tool with a short payback period resulting in an initial investment of $100 and a maximum payback period of 4months and 24days. Thus, the tube type direct solar oven is an easy to manufacture, easy to use low-cost direct solar oven that has a potential of being widely accepted by the Ethiopian society for its economic and environmental advantages.