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Da Silva, Izael

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Da Silva
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Izael
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End date: 2019 × Start date: 2010 ×

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Now showing 1 - 10 of 13
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    Inductive Voltage Transformers Calibration by the Parameters
    (WSEAS, 2010) Brandao, F.A; Da Silva, I. P.; Demetri, I.; De Silos, A. C.; Diaz, E. M; Da Silva, Izael
    The accuracy class of an IVT - Inductive Voltage Transformer - is typically assessed in laboratory installations either by comparing with another IVT presenting greater accuracy and traceable to a national laboratory or by using a capacitive divider. Calibration in the field using internal parameters is considered herein, using results obtained from typical open and short circuit tests and winding resistances, performed with common meters. A Möllinger & Gewecke graphic diagram is employed together with the results of an accuracy test previously carried out to determine the exact value of the winding turn relation and of the primary winding dispersion reactance. These values are used to calculate the phase and ratio errors, which must lie between definite limits, defined by the accuracy class of the instrument. Four commercial IVTs were tested to determine the validity of the procedure. The errors are compared with those obtained with the Schering-Alberti method (AC Bridge and comparison with standard IVT).
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    Analysis of induction generator controller techniques for Pico hydropower - a case study of a 3kW Pico hydropower scheme in Kasese, Western Uganda
    (2014) Izael Da Silva; Teddy Nalubega; Okou Richard; Mary Suzan Abbo; Da Silva, Izael
    This paper presents a comparative analysis of control techniques used on induction generators for stand-alone Pico hydropower schemes. The techniques were tested on a prototype Pico hydropower system modeled for the site developed in western Uganda by the Centre for Research in Energy and Energy Conservation. The case study scheme to date is manually operated, a process that requires constant attention due to variations in load. This demonstrated the need for an automatic load controller. The site specifications were considered when designing models using Matlab simulink employing the automatic load control techniques. These model designs are simple so that it is affordable for local practical application. The proposed designed control techniques presented in this paper are composed of logic gates, IGBT switch, uncontrolled diode rectifier, the PID controller and other semiconductor devices supplying an electrical load and a ballast load. In addition, the response of the case study site and the Matlab model to load variations is presented.
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    Analysis of induction generator controller techniques for Pico hydropower a case study of A 3kW Pico hydropower scheme in Kasese, Western Uganda
    (IEEE, 2014) Nalubega, Teddy; Da Silva, Izael Pereira; Okou, Richard; Abbo, Mary S.; Da Silva, Izael
    This paper presents a comparative analysis of control techniques used on induction generators for stand-alone Pico hydropower schemes. The techniques were tested on a prototype Pico hydropower system modeled for the site developed in western Uganda by the Centre for Research in Energy and Energy Conservation. The case study scheme to date is manually operated, a process that requires constant attention due to variations in load. This demonstrated the need for an automatic load controller. The site specifications were considered when designing models using Matlab simulink employing the automatic load control techniques. These model designs are simple so that it is affordable for local practical application. The proposed designed control techniques presented in this paper are composed of logic gates, IGBT switch, uncontrolled diode rectifier, the PID controller and other semiconductor devices supplying an electrical load and a ballast load. In addition, the response of the case study site and the Matlab model to load variations is presented.
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    Innovative Energy Access for Remote Areas “The LUAV-Light up a Village” Project
    (Springer Link, 2015-03-04) Da Silva, I. P.; Da Silva, Izael
    The Light-up a village (LUAV) program is a rural development initiative designed to improve access to modern energy solutions in remote areas of developing countries. The initiative addresses the challenge of Pico PV market penetration by empowering rural communities to actively participate in lighting up their own villages using micro-solar systems. The LUAV business model was designed by an energy company, Barefoot Power (BFP), which began the LUAV field in 2012 in Uganda. The program incorporates local SACCOs and Community Based Organizations (CBO) as well as local governmental bodies in the identification and recruitment of participants. A LUAV program is designed to involve at least 100 households per community by providing each home with its own power generation solar system to run lighting and mobile device charging services. The participating households are given the option to either pay for the micro solar power system upfront or to pay for it in 3–12 monthly installments. For this pilot program, BFP sourced for funding from private investors to operate a revolving fund which is managed the SACCOs and CBOs who have the mandate to manage debt recovery and keep the revolving fund active. Through this business model, 18 LUAV projects were implemented in Uganda during the 18 month trial period providing lighting and mobile charging services to 3,000 plus households. The program’s success has a growing interest and plans are underway to replicate it in South Sudan, Rwanda and Kenya in 2014. According to the latest count more than 7,000 households have adopted the micro-system through LUAV.
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    Reducing Carbon Emissions in a Third Level Educational Institution in Sub-Sahara Africa
    (Springer International Publishing Switzerland, 2015) Da Silva, I. P.; Ronoh, G.; Ouma, C.; Jerono, C.; Da Silva, Izael
    The effort to reduce carbon emissions as the arguably most prevalent cause of global warming has been a positive trend in most African countries. One of the most successful strategies towards reaching that goal is the shift from fossil fuel power generation to renewable sources of energy such as wind, hydro, geothermal and solar. As Kenya sits on the equator it enjoys an all year round insolation between 5 and 6 kW/m2/day which is more than double of the average insulation in Germany, a country where solar energy is widely used. Taking advantage of a green line of financial support created by the French Government, Strathmore University embarked in a project to install a 600 kW roof-top, grid connected solar PV system to cater for its electricity needs. Having as a background of the newly instituted Feed-in-Tariff regulation, the system is designed to produce more than the required self-consumption such that the extra power can be sold to the utility via a PPA (power purchase agreement) and the revenue used to pay for the electricity used by the university at night. This paper describes the whole process from the technical, regulatory, educational and financial aspect highlighting the positive and negative events along the path such that it can be useful for other private sector institutions interested in greening their sources of energy, invest in renewable energy and thus reduce their operation costs. The authors have written this work having in mind not only countries in Africa but all other countries which sit in the so called “solar belt”.
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    Book review : Renewable Energy for Residential Heating and Cooling Policy Handbook
    (ICE Publishing, 2012-08) Da Silva, I. P.; Da Silva, Izael
    The scope of this book, as far as REHC projects are concerned, covers programme phases: portfolio planning, programme design, implementation and evaluation. It also covers market maturity stages from initial deployment to full market. It considers instruments such as: economic incentives, regulations, information and market activities. As the title mentions, the content is applicable to the residential sector only: new and existing buildings, including single and multi-family dwellings. As far as technology is concerned, it covers active solar thermal systems for air and water heating; biomass (pellets, wood and wood waste); geothermal (ground source and heat-pump) and finally heat-pump technologies based on ambient air heat (air-to-air and air-to-liquid)
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    Curriculum Vitae
    (Izael Pereira Da Silva, 2015) Da Silva, Izael Pereira; Da Silva, Izael
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    Electricity from wood-fired gasification in Uganda - a 250 and 10kW case study
    (IEEE, 2016-06) Buchholz, T.; Da Silva, I. P.; Furtado, J.; Da Silva, Izael
    Wood gasification systems have the potential to contribute to the rural electrification in Sub-Saharan Africa. This paper presents an operational and economic analysis of two wood-based gasification systems (250 and 10 kW) installed in Uganda in 2007. Both systems proved their potential to compete economically with diesel generated electricity when operating close to the rated capacity. At an output of 150 kW running for ~12 h/day and 8 kW running for ~8h/day, the systems produced electricity at US$ 0.18 and 0.34/kWh, respectively. A stable electricity demand close to the rated capacity proved to be a challenge for both systems. Fuelwood costs accounted for ~US$0.03/kWh for both systems. Recovery of even a small fraction of the excess heat (22%) already resulted in substantial profitability gains for the 250 kW system. Results indicate that replicating successful wood gasification systems stipulates integration of sustainable fuelwood supply and viable business models.
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    Modeling the profitability of power production from short-rotation woody crops in Sub-Saharan Africa
    (2012) Da Silva, I. P; Da Silva, Izael
    Increasing electricity supply in Sub-Saharan Africa is a prerequisite to enable economic development and reduce poverty. Renewable sources such as wood-fueled power plants are being promoted for social, environmental and economic reasons. We analyzed an economic model of a vertically integrated system of short-rotation woody crops (SRWC) plantations coupled with a combined heat and power (CHP) plant under Sub-Saharan African conditions. We analyzed a 5 MW (electric) base-case scenario under Ugandan conditions with a 2870 ha Eucalyptus grandis plantation and a productivity of 12 t ha 1 y 1 (oven dry basis) under a 5-year rotation. Plant construction and maintenance constituted 27% and 41% of total costs, respectively. Plantation productivity, carbon credit sales as well as land, fuel, labor & transport costs played an economic minor role. Highly influential variables included plant efficiency & construction costs, plantation design (spacing and rotation length) and harvest technologies. We conclude that growing 12e24 t ha 1 y 1 at a five-year rotation can produce IRR’s of 16 and 19% over 30-years, respectively. Reducing rotation length significantly reduced short-term financial risk related to frontloaded costs and relatively late revenues from electricity sales. Long-term feed-in tariffs and availability of a heat market played a significant economic role. The base-case scenario’s 30-year IRR dropped from 16% to 9% when a heat market was absent. Results suggest a leveling-off of economies-of-scale effects above 20MW(electric) installations. Implementation-related research needs for pilot activities should focus on SRWC productivity and energy life cycle analysis
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    Sustainability of Sugarcane, Bagasse, Briquettes and Charcoal Value Chains in Kenya: Results and Recommendations from Implementation of the Global Bioenergy Partnership Indicators
    (United Nations Environment Programme, 2019) Williamson, L.; N’Goran, K.; Labriet, M.; Diaz-Chavez, R.; Wanjiru, H.; Ogeya, M.; López, N. G.; Oduor, N.; Ogutu, P. C.; Da Silva, I. P.; Wambugu, A. C.; Ndufa, J.; Ochieng, P. A.; Gitau, J. K.; Muchiri, M.; Nyambati, R.; United Nations Environment Programme; Da Silva, Izael
    The following report, Sustainability of Sugarcane Bagasse Briquettes and Charcoal Value Chains in Kenya: Results and Recommendations from Implementation of the Global Bioenergy Partnership (GBEP) Indicators, assesses the current and future potential of Kenya’s bioenergy sector. It outlines the consequences of the widening gap between supply and demand for wood fuel, with the current supply not matching demand in various parts of the country.The report also illustrates key factors that can shape the long-term and periodic monitoring of the sector. Kenya Vision 2030 has identified energy as one of the enablers of the three pillars of its vision. The level and intensity of commercial energy use will be the key indicator of economic growth and development. Bioenergy, like other energy sources, will continue to play a role in both the traditional and commercial energy mix. Kenya’s Nationally Determined Contribution (NDC) includes four key climate change mitigation targets related to forestry and bioenergy: working towards 10 per cent tree cover of the land area of Kenya; promoting clean energy technologies to reduce overreliance on wood fuel; employing low-carbon and efficient transport systems; and using climate-smart agriculture (CSA) in line with the National CSA Framework.