http://ir.bdu.edu.et/handle/123456789/10222 2001-01-13T05:52:17Z http://ir.bdu.edu.et/handle/123456789/16491 PRODUCTION OF BRIQUETE CHARCOAL FROM SESAME STALK CASE STUDY OF METEMA, WEAST GONDAR ZONE, ETHIOPIA ZUFAN, MULAW KASSIE Biomass is one of the most promising energy sources to mitigate greenhouse gas emission during production and utilization. However, majority of biomass are not suitable to be utilized as fuel without an appropriate process since they are bulky, uneven and have low energy density. These characteristics make them difficult in handling, storage, transport and utilization. One of the promising solutions to overcome these problems is the briquetting technology. The study was conducted to characterize sesame stalk briquette as an alternative source of energy. The data collection result indicates that more than 41,265,999.9 kg of charcoal can be produced from the available sesame stalk in Metema at a 42.8% conversion efficiency of the carbonizer. Briquettes were produced by mixing carbonized sesame stalk with okra pod (Abelmoschus esculentus) in weight percentage levels of 10%, 15%and 20%. The experimental results revealed that the mixture that the 10% okra briquette had the highest volatile matter and heating value of 68.20% and 18.04MJ/kg while maintaining the lowest ash content and moisture content of 5.56% and 10.76% respectively. Conclude that the fuel briquette produced from sesame stalk residue have high potential as an alternative source of energy, helps to solve health problems and shortage of energy and reducing the deforestation rate. Key words: Abelmoschus esculentus, sesame stalk, briquette, calorific value 2024-10-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16490 BIOETHANOL FROM WATER HYACINTH THROUGH COUPLED MICROWAVE-ALKALINE PRETREATMENT METHOD: FERMENTATION OPTIMIZATION ZELALEM, GELAW With rising fuel costs, increasing energy demands, and the need for environmentally friendly energy sources, there is a growing interest in producing alternative fuels. Biofuels like bioethanol can be made by breaking down the lignocellulosic structure of plant materials to release fermentable sugars. Lignocellulosic biomass is becoming a top choice for biofuel production due to energy and food security concerns compared to starch and sugar-based feedstocks. One such lignocellulosic biomass is water hyacinth WH, an aquatic weed with high cellulose, hemicellulose, and low lignin content that is a key source for bioethanol production as a substantial alternative to fossil fuels. Pretreatment aims to improve cellulose surface area for acid hydrolysis, enhance cellulose to fermentable sugar/glucose conversion, and yield economical and environmentally friendly ethanol. This study used the results of water hyacinth biomass hydrolysis at optimum conditions of 500-watt microwave power, 1.5% w/v NaOH concentration, and 30-minute residence time to optimize the fermentation process of biofuel production. Compositional characterization was performed using NREL and ASTM protocols, and total reducing sugar concentrations after hydrolysis were determined by the DNSA method and found to be 347.25 mg/g. This study optimized the fermentation process by controlling incubation time, pH, and temperature. Saccharomyces cerevisiae was used to ferment the sugars to ethanol, and batch distillation was employed to purify it. The most significant parameters (temperature (28-40) OC, pH (4-6), and fermentation time (24-80) hours) were optimized using Design Expert Software version 13 and response surface methodology. The optimum fermentation conditions were a temperature of 33.5 OC, pH of 5.3, and incubation time of 62 hours, yielding 14.16 g/l of bioethanol. Finally, the properties of the bioethanol, including functional groups, were analyzed using FTIR, it was observed that the ethanol produced from water hyacinth contains the O-H functional group and C-O groups. This study demonstrates the potential of water hyacinth as a potential feedstock for bioethanol production, with optimized conditions yielding a significant amount of biofuel. The results contribute to the development of sustainable and environmentally friendly energy sources. Keywords: bioethanol, characterization, fermentation, optimization, water hyacinth 2024-10-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16489 DESIGN, DEVELOPMENT, AND PERFORMANCE EVALUATION OF VACUUM TUBE-ASSISTED SOLAR THERMAL TECHNOLOGY FOR INJERA BAKING APPLICATIONS SHEWALEM, ASFAW TEMESGEN Like most developing countries, Ethiopia's residential energy sector relies heavily on burning biomass, and cooking accounts for over 90% of the total energy used, with baking injera consuming 37% of this energy. Injera, a pan-cake-like bread consumed by most of the population, demands a temperature of 180–220 °C to be well baked. The widely spread injera baking stoves, an open-fire three-stone and electric injera baking stove, are energy inefficient; besides, for the biomass stove, the kitchen environment is highly polluted with soot and smoke that affect the health of household inhabitants. This thesis presents a new technology designed to address these challenges by utilizing an indirect solar stove for injera baking. The system incorporates an evacuated tube solar collector with a 0.52 m² absorbing area, two well-insulated heat transfer fluid (HTF) storage units, a rectangular stainless steel heat absorber tube, and three shut-off valves. Temperature is monitored using K-type thermocouples, and heat transfer is facilitated through natural circulation, driven by density variations between the receiver and stove. To optimize solar collection, V-shaped reflectors having a size (length × aperture width) of 190 cm by 18.74 cm are used to address the issue of areas of the tube that do not face the sun. The system also includes a shut-off valve to control the flow of sunflower oil (HTF), heated to 300 °C, which reaches to the bottom surface of the baking pan. The technology was developed and tested at the Bahir Dar Institute of Technology, achieving a header tank temperature of up to 325 °C, an oil temperature of 282 °C in the baking compartment, and a baking pan top surface temperature of 184 °C under clear sky conditions. For the baking performance test, two rounds of injera were successfully baked. Additionally, the economic and environmental impact analyses yielded encouraging results. Overall, the solar thermal baking system demonstrated an efficiency of 38.3%. However, challenges such as HTF smokes and direct thermal-based baking models suggest that there is room for performance improvement. The adoption of the technology could be significantly enhanced by integrating refined mineral oils as HTFs and incorporating a heat storage mechanism. In conclusion, the analytical and experimental results confirm the feasibility of indirect baking of injera, a process that has not been successfully demonstrated in previous efforts. Keywords: solar collector; evacuated tube; reflector; GHGs; injera baking stove. 2024-08-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16488 DESIGN AND MODELING OF SOLAR PV SMART GRID WITH ENERGY MANAGEMENT SYSTEM FOR REMOTE AREA ELECTRIFICATION Case Study: Dek Island Community in Lake Tana Tamiru, Ayana Ejigu This study presents the design and modeling of a solar PV smart grid with EMS for remote area electrification. The case study focuses on the Dek island community located in lake Tana. The community consists of 1,152 households, and the total demand load is 206 kW. Additionally, the smart grid incorporates smart meters and central control, and the modeling and simulation using MATLAB Simulink. This study will involve the development of mathematical models for the various components of the system, including solar PV arrays, battery storage, inverters. The study discuss in detail for AC smart off grid system of design, simulation performance evaluation with economic feasibility analysis of the system in remote area electrification. The solar resources and weather data collected from primary and secondary resources to test and analyze the performance of the system. The battery use to balance the demand and renewable power generation. MATLAB Simulink toolbox use to model the solar PV, battery bank and conversion systems like DC-DC converters, and inverter with controller of each component. The system model individual components and analyze the system voltage stability for proper function of the off grid. Furthermore, the proposed system empowers the community by providing access to electricity, which enhances education, communication, and access to information. It opens up opportunities for various community development initiatives, such as healthcare centers, schools, and other essential services, further improving the standard of living and overall well-being of the residents. In conclusion, the implementation of a solar PV smart grid with an EMS, featuring solar PV array capacity of 283 kW, inverter 260 kW, and battery capacity of 600,000Ah, with the system integrates 1,155 smart meters with RF for centralized control. In this study, the economic evaluations are performed using HOMER Software and assess the affordability of a community electricity energy cost is $0.082/kWh,which is feasible through design period. Keywords: Solar PV-battery smart grid, EMS, Remote area electrification, Smart meters, Central concentrator, Load demand, Solar PV array, Inverter, Battery bank. 2024-10-16T00:00:00Z