Browsing by Author "Abiyot Lakew"

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    Development of Solar Baking Oven Integrated with Linear Fresnel Parabolic Mirror Reflector (LFPMR)
    (Addis Ababa University, 2026-02-01) Abiyot Lakew; Solomon Tesfamariam
    The increasing demand for sustainable medium-temperature thermal energy applications highlights the need for cost-effective solar thermal technologies. This study presents the numerical modeling, simulation, and experimental validation of a solar baking oven integrated with a Linear Fresnel Parabolic Mirror Reflector (LFPMR). Optical performance was evaluated using Monte Carlo ray-tracing simulations in SolTrace to assess flux distribution, absorbed power, and optical efficiency under two aiming strategies: plate-based aiming (Case 1) and global aiming (Case 2). Under a direct normal irradiance of 1,000 W/m² and an aperture area of 5.13 m², Case 1 produced an absorbed power of 1.64 kW, corresponding to an optical efficiency of 36%. In contrast, Case 2 increased the absorbed power to 2.22 kW and improved the optical efficiency to 49.7%, indicating significantly enhanced solar energy capture with the global aiming approach. Thermal behavior and airflow within the baking chamber were analyzed using ANSYS Fluent, incorporating the optical heat flux as a boundary condition. The simulations predicted stable air temperatures ranging from 425 to 443 K and buoyancy-driven convection that promotes uniform heat transfer across baking trays. A prototype was fabricated and experimentally tested under no-load and load conditions. The oven achieved a stagnation temperature of 330oC, corresponding to a first figure of merit of 0.37. Bread baking tests demonstrated successful baking of 9.2 kg of dough within 70 minutes at tray temperatures between 201 and 250 oC, with an overall system efficiency of 36%. The results confirm that LFPMR-based solar thermal systems offer a technically viable and energy-efficient solution for medium-temperature applications such as solar baking, with potential for decentralized and community-scale deployment.