Browsing by Author "Silva, Izael Da"

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    Technical, Economic And Sustainability Considerations Of A Solar Pv Mini Grid As A Tool For Rural Electrification In Uganda
    (Bakkabulindi, G., Sendegeya, A., Da Silva, I., & Lugujjo, E. (2010, July), 2010) Bakkabulindi, Geofrey; Sendegeya, Al-Mas; Silva, Izael Da; Lugujjo, Eriabu
    The challenges facing rural electrification in Uganda are diverse with less than 3% of the rural population having access to electricity. The establishment of mini-grids powered by renewable energy sources makes it possible to electrify remote areas at affordable rates. In this study, an assessment of a solar PV mini-grid system to provide electricity to forty households in rural Uganda was carried out. The considered system comprised six solar modules each rated 175 Wp, a controller, off-grid inverter and batteries with a capacity of 600 Ah. Manufactured by SMA, the Sunny Island inverter proposed for the mini-grid would ensure provision of grid-quality electricity. The study aimed to investigate the mini-grid’s technical design with focus on optimal distribution against constraints of voltage drops, electrical losses and increasing load. Customised load limiters shared between households using thermistors were included to reduce costs and limit consumption. The incomes of rural households are often seasonal and thus issues pertaining to affordability and sustainability were also considered. Results of the economic analysis showed a payback period of less than 5 years given an affordable fixed monthly tariff for the case study area.
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    Thermodynamic Modeling of Allothermal Steam Gasification in a Downdraft Fixed-bed Gasifier
    (Trans Tech Publications Ltd., 2014) Musinguzi, Wilson B.; Okure, Mackay A.E.; Sebbit, Adam; Løvås, Terese; Silva, Izael Da
    A process of converting a solid carbonaceous fuel into a gaseous energy carrier in presence of a gasifying medium at high temperature is called gasification. The resulting gaseous energy carrier, known as producer gas, is more versatile in its use than the original solid fuel. Gasification is widely considered as a more efficient and less polluting initial thermochemical upstream process of converting biomass to electricity. The objective of this study was to investigate the process of allothermal steam gasification in a fixed-bed downdraft gasifier for improved quality (HHV, high hydrogen content) of the producer gas generated. The study involved thermodynamic equilibrium modeling based on equilibrium approach in which the concentrations of the gaseous components in the producer gas at equilibrium temperature are determined based on balancing the moles in the overall gasification equation. The results obtained suggest that the maximum equilibrium yield of producer gas with high energy density is attained at a gasification temperature of around 820oC and a steam/biomass ratio of 0.825 mol/mol. The equilibrium yield was richer in hydrogen at 52.23%vol, and with a higher heating value of 11.6 MJ/Nm3. Preliminary validation of the model results using experimental data from literature shows a close relationship. The study has further shown the advantage of using steam as a gasifying medium towards the improved quality of the producer gas generated.