Estudo comparativo de pás para aerogeradores de grande porte fabricadas em materiais compósitos reforçadas com fibra de carbono ou fibra de vidro

The research and development of wind turbine blades are essential to keep pace with worldwide growth in the renewable energy sector. Although currently blades are typically produced using glass fiber reinforced composite materials, the tendency for larger size blades, particularly for offshore applications, has increased the interest on carbon fiber reinforced composites because of the potential for increased stiffness and weight reduction. In this study a model of blade designed for large generators (5 MW) was studied on a small scale. A numerical simulation was performed to determine the aerodynamic loading using a Computational Fluid Dynamics (CFD) software. Two blades were then designed and manufactured using epoxy matrix composites: one reinforced with glass fibers and the other with carbon fibers. For the structural calculations, maximum stress failure criterion was adopted. The blades were manufactured by Vacuum Assisted Resin Transfer Molding (VARTM), typical for this type of component. A weight comparison of the two blades was performed and the weight of the carbon fiber blade was approximately 45% of the weight of the fiberglass reinforced blade. Static bending tests were carried out on the blades for various percentages of the design load and deflections measurements were compared with the values obtained from finite element simulations. A good agreement was observed between the measured and calculated deflections. In summary, the results of this study confirm that the low density combined with high mechanical properties of carbon fibers are particularly attractive for the production of large size wind turbine blades

Estudo comparativo de pás para aerogeradores de grande porte fabricadas em materiais compósitos reforçadas com fibra de carbono ou fibra de vidro

The research and development of wind turbine blades are essential to keep pace with worldwide growth in the renewable energy sector. Although currently blades are typically produced using glass fiber reinforced composite materials, the tendency for larger size blades, particularly for offshore applications, has increased the interest on carbon fiber reinforced composites because of the potential for increased stiffness and weight reduction. In this study a model of blade designed for large generators (5 MW) was studied on a small scale. A numerical simulation was performed to determine the aerodynamic loading using a Computational Fluid Dynamics (CFD) software. Two blades were then designed and manufactured using epoxy matrix composites: one reinforced with glass fibers and the other with carbon fibers. For the structural calculations, maximum stress failure criterion was adopted. The blades were manufactured by Vacuum Assisted Resin Transfer Molding (VARTM), typical for this type of component. A weight comparison of the two blades was performed and the weight of the carbon fiber blade was approximately 45% of the weight of the fiberglass reinforced blade. Static bending tests were carried out on the blades for various percentages of the design load and deflections measurements were compared with the values obtained from finite element simulations. A good agreement was observed between the measured and calculated deflections. In summary, the results of this study confirm that the low density combined with high mechanical properties of carbon fibers are particularly attractive for the production of large size wind turbine blades

Otimização de sistema de bombeamento com energia eólica: sistema de bombeamento de São Gabriel/BA

After the Protocol of Kyoto and of the ECHO 92 - Rio de Janeiro, the attentions of the world focus to the preservation of the environment and of the maintainable use of the natural resources. People were looking for preserving environment for the future generations. Ever since, solutions are looked for the supply of energy in its more acquaintances forms and the substitution of the use of fossil fuels for the such alternative forms as: Photovoltaics, solar heat systems for water, wind , bio-diesel, etc. and in this context the Company of Engineering of the State of Bahia - Cerb changed a diesel pumping system by an wind one, It´s the first community system of this nature in Bahia. Facing problems with the model, a Cerb involved the academic segment of the Federal Center of Technological Education of Bahia Cefetba looking for a solution. This work intends to demonstrate the possibilities of optimization of the pumping communit system that supply water to approximately 50 people in the place of Romão, municipal district of São Gabriel-Ba. Technical reports were published in AGRENERGD2004-Unicamp SP and Scientific Magazine ETC,Cefetba, 2005. A simulation of the increase of energy is presented for heights of 15 and 20m, considering the eletromecanical balance from the pumping energy to the wind turbine. From the accomplished bibliographical revision, we emphasized the mechanical aspects of the engineering once in UFRN, those studies concentrate on the Department of Mechanical Engineering while, in others eletroelectronic are more emphasized. Finally, documents that we judged important were enclosed for the perfect understanding of this work

Prospecção tecnológica para geração de energia eólica

The acceleration of technological change and the process of globalization has intensified competition and the need for new products (goods and services), resulting in growing concern for organizations in the development of technological, economic and social advances. This work presents an overview of the development of wind energy-related technologies and design trends. To conduct this research, it is (i) a literature review on technological innovation, technological forecasting methods and fundamentals of wind power; (ii) the analysis of patents, with the current technology landscape studied by means of finding information in patent databases; and (iii) the preparation of the map of technological development and construction of wind turbines of the future trend information from the literature and news from the sector studied. Step (ii) allowed the study of 25 644 patents between the years 2003-2012, in which the US and China lead the ranking of depositors and the American company General Electric and the Japanese Mitsubishi stand as the largest holder of wind technology. Step (iii) analyzed and identified that most of the innovations presented in the technological evolution of wind power are incremental product innovations to market. The proposed future trends shows that the future wind turbines tend to have a horizontal synchronous shaft, which with the highest diameter of 194m and 164m rotor nacelle top, the top having 7,5MW generation. The materials used for the blades are new materials with characteristics of low density and high strength. The towers are trend with hybrid materials, uniting the steel to the concrete. This work tries to cover the existing gap in the gym on the use of technological forecasting techniques for the wind energy industry, through the recognition that utilize the patent analysis, analysis of scientific articles and stories of the area, provide knowledge about the industry and influencing the quality of investment decisions in R & D and hence improves the efficiency and effectiveness of wind power generation

Relação entre stakeholders, recursos estratégicos e sustentabilidade em uma organização atuante na cadeia de valor da indústria brasileira de energia eólica

This paper approaches the strategy in business management and aimed at identifying and outlining the interests and commitment of stakeholders in strategic resources management concerning production and implementation of wind turbine equipment of a Brazilian wind power company and also verifying if internal and external results deriving from such activities were sustainable, taking as main reference seminal publications and periodicals relevant to the research point that discuss the Resource Theory, Stakeholders and Sustainability. An analysis was carried out to assess how stakeholders, beyond the temporal context, intermediated the composition, development and management of the organization´s resources, as well as the social, environmental and economic results obtained from resources management in the production and supply of wind turbines to a Wind Power Plant located in the State of Ceara, in order to portray that Brazil sustainability can be an important competitive advantage source that creates value for shareholders and the community (Hart & Milstein, 2003). The strategy herein applied was the qualitative investigation using a single study case, which allowed for the thorough examination of an active organization operating in the Brazilian industry of wind power and also the resources used in the production and implementation of wind turbines supplied to the a Wind Power Plant in Ceara. Considering the content analysis and the triangulation principle, three qualitative data collection methods were applied to identify and characterize stakeholders’ interest and commitment in resource management of the organization operating in the Brazilian wind power industry, as follows, semistructured deep interview with managers of tactic-strategic level and analysts of organization´s value chain nine activities, analysis of public internal and external documents; and analysis of audio-visual material. Nonetheless, to identify the internal and external economic, social and environmental results of implementation and supply of wind turbines to the Wind Power Plant in Ceara, semistructured interviews were also carried out with the residents of the region. Results showed the BNDES (Brazilian Development Bank) and the organization head office were the stakeholders who exerted the strongest influence on resources related to production and implementation of the aerogenerator product at Trairi Wind Plant in Ceara. Concerning the organization resources, at the current stage of the Brazilian Wind Industry ,although the brand, reliability and reputation of the organization under study were valuable esources, rare, hard to imitate and exploited by the organization, it was noticed that opposed to RBV, they did not actually represent a source of competitive advantage . For the local community the social, economic and environmental results related to the wind turbines implementation were more positive than negative, despite the fact that the productive process caused negative environmental impacts such as the high emission of CO2 to transport wind turbines components to Trairi Wind Power Plant.

A engenharia Civil e a produção industrial de energia eólica

Dissertação para obtenção do grau de Engenharia Civil na Área de Especialização de Edificações

Materiais compósitos biocidas baseados em resinas reticuladas contendo nanopartículas de prata

Nesta dissertação, duas resinas reticuladas comerciais (denominadas, AmberliteGT73 e AmberliteIRC748) foram empregadas para suportar partículas de prata. Os grupos tiol da GT73 e ácido iminodiacético da IRC748 presentes nessas resinas foram empregados para a fixação de íons Ag+ a partir de solução aquosa. Posteriormente, os íons Ag+ foram reduzidos pelo emprego de três redutores diferentes em pH alcalino, denominados hidrazina, hidroxilamina e formaldeído (pH  12). A morfologia e a impregnação de prata dos materiais binários assim obtidos foram avaliadas por meio de microscópio eletrônico de varredura equipado com detector de elétrons retro-espalhados (SEM-BSE). O detector de espectrometria de energia dispersiva de raios-X (EDAX) acoplado ao SEM permitiu a observação de partículas de prata. Os espectros de raios-X revelaram a presença do metal nas superfícies interna e externa das microesferas dos compósitos. A quantidade de prata incorporada foi determinada pelo método titulométrico, empregando solução padrão de tiocianato de potássio. As características antibactericidas dos compósitos foram avaliadas em colunas contendo pérolas de resina por onde foram percoladas suspensões da bactéria Escherichia coli auxotrópica AB1157 (tipo selvagem) nas concentrações de 103 a 107 células/mL. A avaliação biocida mostrou que estes materiais foram completamente bactericidas, sendo efetivos na eliminação da bactéria em poucos minutos. Esta ação biocida foi atribuída à combinação da atuação da prata e dos grupos funcionais das resinas

Estudo do comportamento de materiais compósitos fibrosos para aplicação como reforço de base de fundações superficiais

Neste trabalho foram avaliadas as propriedades de resistência e deformabilidade de misturas solo-cimento-fibra. O estudo experimental consistiu de duas etapas, denominadas de etapa de laboratório e etapa de campo. Na etapa de laboratório foi verificada a influência da adição de fibras de polipropileno no comportamento tensão x deformação de um solo arenoso cimentado e não cimentado. Ensaios de resistência à compressão triaxial foram realizados para avaliar os efeitos da porcentagem de fibras, do comprimento das fibras, do diâmetro das fibras, da porcentagem de cimento, da densidade relativa, da tensão de confinamento e da distribuição granulométrica no comportamento do compósito. Na etapa de campo, o comportamento carga x recalque do solo arenoso cimentado reforçado com fibras foi avaliado, juntamente com os mecanismos de ruptura de cada compósito, através da execução de ensaios de placa de 0,30 m e 0,60 m de diâmetro sobre camadas tratadas de 0,30 m de espessura. Os métodos propostos por Vesic (1975), Meyerhof & Hanna (1978) e Thomé (1999) foram utilizados para a previsão da capacidade de suporte das camadas tratadas em campo A partir dos resultados obtidos chegou-se às seguintes conclusões: (1) a influência da inclusão de fibras sobre as propriedades mecânicas do compósito depende fundamentalmente das propriedades da matriz; (2) a porcentagem de cimento e a tensão de confinamento exercem forte influência no comportamento mecânico do material compósito; (3) o efeito da inclusão de fibras é mais evidente para maiores comprimentos e maiores teores de fibras, sendo seu efeito mais pronunciado para materiais compósitos com maiores densidades; (4) a influência das fibras na resistência de pico e última do material depende também do diâmetro das fibras e da distribuição granulométrica do solo; (5) O comportamento carga x recalque do solo cimentado é influenciado pela adição das fibras, alterando principalmente o comportamento pós-pico e o mecanismo de ruptura; (6) os valores de previsão da capacidade de suporte das camadas cimentadas, com e sem reforço de fibras, apresentam boa aproximação com os valores experimentais.

Avaliação do comportamento de materiais compósitos de matrizes cimentícias reforçadas com fibra de aramida kevlar

Esse trabalho aborda a questão de materiais compósitos reforçados com fibras (fiber reinforced concrete) com enfoque em matrizes cimentícias reforçadas com fibra de aramida Kevlar. O objetivo é caracterizar o potencial da fibra de aramida Kevlar como elemento de reforço a ser adicionado ao concreto. O trabalho busca caracterizar o desempenho dos compósitos formados, identificando as alterações decorrentes da incorporação em função do comportamento mecânico e da resistência ao impacto. Os objetivos são verificar a potencialidade de utilização dessa fibra em termos de trabalhabilidade e resistência mecânica; definir como deve ser a forma de incorporação, verificar a aderência da fibra à matriz através de microscopia eletrônica de varredura por elétrons secundários e determinar a resistência ao impacto, comparando matrizes sem adição de fibra com corpos-de-prova moldados com vários tipos e teores de fibra (aço, sisal, vidro, polipropileno e aramida). Como vantagens da incorporação das fibras de aramida Kevlar, constata-se um incremento na resistência à compressão dos compósitos aos 28 dias em relação aos espécimes sem adição de fibra. Observam-se, também, reduções na massa específica e na trabalhabilidade dos espécimes com adição de fibra de aramida Kevlar em comparação aos sem adição. Em relação à resistência ao impacto, conclui-se que os compósitos com adição de fibra de aço e fibra de aramida são os que apresentaram melhor comportamento dinâmico em relação a energia de ruptura acumulada e à energia para aparecimento da primeira fissura, respectivamente.

Precificação de energia eólica offshore no Brasil

Offshore wind power emits low amounts of gases, is renewable and has better performance than onshore due to its greater stability and higher wind power density, less visual and noise impact, among others. Brazil has a high capacity of generation, but has not yet developed any offshore projects. High costs are a strong impediment. This study is an effort towards pricing offshore resources through Livelized Cost of Energy - LCOE, which represents the minimum return to cover the costs of development, production and maintenance of a wind project. Initially LCOE was calculated for all Brazilian onshore wind farms listed at Bloomberg New Energy Finance R○, accounting for 71 farms. Then hypothetical offshore wind farms were created from the onshore farms, tripling the cost of generation, which is consistent with the literature, and estimating the offshore energy for two locations off the Brazilian coast using satellite data extracted from National Oceanic and Atmospheric Administration. The results demonstrate that offshore resources have the potential to significantly reduce the energy price due to the better performance of the wind at sea

Desenvolvimento energético e energia eólica na ordem jurídica do Brasil: aspectos Institucionais e Socioambientais

A conformação do desenvolvimento propugnado pela Constituição Federal de 1988 como objetivo fundamental da república, certamente perpassa pela racionalização das questões energéticas e pela diversificação da matriz nacional enquanto estratégia de aprovisionamento. O desenvolvimento energético em toda a sua complexidade deve ser alicerçado não em uma relação de contraposição à sustentabilidade, mas cooperativismo normativo e de projetos sociais que objetivam a melhorias para a população nestes dois seguimentos. O advento das energias renováveis nesse contexto se consolida como uma alternativa viável, apesar do tratamento dado pela Lei Maior ao tema ter sido apenas com relação à geração em pequena escala. A interpretação sistemática dos postulados da ordem econômica e as exigências da sociedade estimulam o aproveitamento dos potenciais renováveis em escala comercial e regional, além do fortalecimento nos segmentos de autoprodução e produção independente. Dentre as energias tratadas como prioritárias neste contexto, a eólica revela-se como carecedora de aprofundamento das estruturas dogmáticas de sua positivação, que envolve um vasto manancial de regras pulverizadas na regulação econômica do setor elétrico e no controle ambiental. Esta textura submete os empreendimentos elioelétricos aos instrumentos da política nacional do meio ambiente e às determinações do poder concedente dos serviços de energia elétrica, responsável pela pormenorização da geração, transmissão, distribuição e comercialização de energia, independentemente da fonte primária utilizada no processo de transformação. Tratar destas questões com o compromisso na formulação de raciocínios críticos e propositivos, especialmente acerca de temas como a liberdade energética e controle de mercado, é imperioso para superar juridicamente as limitações presentes inclusive no discurso da delimitação de marcos normativos adequados. Havendo vantagens ambientais, tecnológicas e comerciais na exploração da energia cinética do vento como propulsora do desenvolvimento no modelo civilizatório estabelecido, cumpre também ao Estado dar a sua contribuição setorial na forma de incentivos, desburocratização e aprimoramento do modelo concorrencial. O estudo adota os métodos histórico-evolutivo, dialético e sistêmico de abordagem, encarando as hipóteses formuladas no aspecto das consequências multilaterais que as soluções encontradas apontam, exigindo que a estabilização de expectativas sociais por parte do ordenamento jurídico não ignorem o sentido material cognitivamente aberto do desenvolvimento. Hodiernamente, a perspectiva de desenvolvimento energético alia tendências econômicas e tecnológicas em favor das fontes alternativas mais eficientes, revelando a energia eólica como uma representante adequada em termos pragmáticos de normatização e preservação ambiental

Medição de desempenho na cadeia de suprimentos da energia eólica: proposta de um conjunto de indicadores de desempenho

Performance measurement in highly competitive markets is a necessary measure for those who aim the top positions. The business performance measurement approach have reached relevant results in the literature, however, a different approach has recently appeared that broadened the perception of competition, where companies do not seek the competition among companies only, but also among supply chains. Brazilian Wind energy supply chain is living a structuring and expanding moment, with the major global players in the industry making investments in the country. This research aims to answer which are the key performance indicators that must be considered by the Brazilian wind energy sector companies, which are part in a broad perspective of supply chain competition. The research was executed in two steps: exploratory (literature review and a field research in the companies) and later a survey was conducted with the Brazilian Wind energy companies workers with the purpose to validate the performance indicators found in the exploratory step. The survey evaluated 40 performance indicators distributed among five major activities: Project prospection, building/execution, operation and maintenance, logistics and transverse processes, which summarize the performance of the entire supply chain, pointing the sinergy and the competitive level of the supply chain. The selected performance indicators reflect the high relevance of the costs dimension in the Brazilian energy companies performance, acting as a key performance indicator, is also indicates the limited performance management integration throughout the Brazilian wind energy supply chain

Utilização de RNA´s na construção do diagrama de vida constante de probabilidade de materiais compósitos

The static and cyclic assays are common to test materials in structures.. For cycling assays to assess the fatigue behavior of the material and thereby obtain the S-N curves and these are used to construct the diagrams of living constant. However, these diagrams, when constructed with small amounts of S-N curves underestimate or overestimate the actual behavior of the composite, there is increasing need for more testing to obtain more accurate results. Therewith, , a way of reducing costs is the statistical analysis of the fatigue behavior. The aim of this research was evaluate the probabilistic fatigue behavior of composite materials. The research was conducted in three parts. The first part consists of associating the equation of probability Weilbull equations commonly used in modeling of composite materials S-N curve, namely the exponential equation and power law and their generalizations. The second part was used the results obtained by the equation which best represents the S-N curves of probability and trained a network to the modular 5% failure. In the third part, we carried out a comparative study of the results obtained using the nonlinear model by parts (PNL) with the results of a modular network architecture (MN) in the analysis of fatigue behavior. For this we used a database of ten materials obtained from the literature to assess the ability of generalization of the modular network as well as its robustness. From the results it was found that the power law of probability generalized probabilistic behavior better represents the fatigue and composites that although the generalization ability of the MN that was not robust training with 5% failure rate, but for values mean the MN showed more accurate results than the PNL model

Conhecimento sobre energia eólica: um estudo exploratório a partir das redes semânticas naturais de estudantes da cidade de Natal

The human being has a fundamental role in issues concerning scarcity of energy resources as well as in the success of technologies which favor the use of renewable sources, such as wind energy. But what does wind energy mean for people? What are the psychological meanings concerning this term? Aiming to answer these questions, the general objective of this dissertation was to identify and to analyze the knowledge about wind energy taking into account a network of psychological meanings. One hundred and ninety one (191) university students from Natal-RN participated in the study, being male the majority (53%); aged between 17 and 51 years old (M=23.3 years; SD=5.7). Participants responded to self reports using the Natural Semantic Networks (NSW) technique, as well as to several sociodemographic questions. The results showed a consistent, positive and useful general semantic network. In this semantic network, knowledge about wind energy was represented by words that correspond to the appeal of (pro) environmental stance (e.g., clean and nature), that evinced both the technological aspect (e.g., force) and the economic aspect (e.g., economy). Results from different groups were also analyzed. The first set of groups (non-environemental and environmental) was divided considering the course (e.g., ecology and economy). The second set of groups(non-caretaker and caretaker) was divided based on the practice of environmental care expressed. Subtle differences were observed in the semantic networks of caretakers, who emphasized environment, an attribute not mentioned by non-caretakes. This indicates a construction of knowledge that is influenced by the presence or absence of the environmental commitment. Such findings may be useful in the construction of instruments for surveys and in the development of public and educational policies. Additionally, they may assist the media towards a more objective performance concerning wind energy

Materiais compósitos orgânicos-inorgânicos a base de celulose bacteriana com peptídeos regulatórios de fatores de crescimento, OGP e OGP [10-14], para regeneração óssea

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)