O objetivo do trabalho é apresentar o funcionamento de um gerador a relutância chaveado monofásico. Para isso, foi desenvolvido um modelo computacional em ambiente Matlab Simulink, fazendo-se a comunicação entre diferentes partes do sistema. O comportamento da dinâmica de geração é apresentado para diferentes pontos do sistema, e testes experimentais realizados em um pequeno protótipo confirmam as características funcionais desta máquina. Ensaios realizados comprovam sua funcionalidade e simplicidade de operação, tendo estabilidade de geração para ampla faixa de velocidade de funcionamento, caracterizando uma máquina promissora, robusta e eficiente para aplicações especiais. / This work presents a single-phase switched reluctance machine operating as a generator. For that purpose, a computational model was developed in Matlab Simulink environment, wherein all the system components, such as voltage source, drive and machine model, and load were integrated. The current and voltage behavior for several points of operations are presented. Furthermore, experimental tests were also carried out in a simple prototype to validate its functionality and simplicity of operation, providing a stable power generation over a wide range of speed. The results showed that the single-phase switched reluctance generator can be robust, efficient, and promising for especial applications.

O aumento da população, o crescimento das grandes cidades, da industrialização e do consumo, tem trazido preocupação com relação a sustentabilidade quanto à disponibilidade energética e quanto à destinação dos resíduos sólidos urbanos gerados. Dessa forma, é fundamental realizarem-se os estudos visando novas formas de reutilização dos resíduos gerados pelas atividades industriais. Os resíduos sólidos urbanos e os pneus inservíveis gerados trazem conseqüências ao meio ambiente e às populações quando destinados inadequadamente. A destinação final dos resíduos sólidos urbanos é complexa, sendo sempre um grande desafio para as administrações públicas. Com a Política Nacional de Resíduos Sólidos (instituída pela Lei n 12.305/2010), tem-se um marco da preservação ambiental, coma a gestão e gerenciamento de resíduos sólidos, com a ordem de prioridade: não geração, redução, reutilização, reciclagem, tratamento dos resíduos sólidos e disposição final ambientalmente adequada dos rejeitos e prevê, de forma inteligente, a atribuição aos fabricantes de responsabilidade pelo retorno de produtos descartados pelos consumidores. Uma alternativa para minimizar estes aspectos e impactos ambientais é o tratamento térmico com aproveitamento energético. Este processo contribui para mais uma solução de destinação dos resíduos, proporcionado uma redução das áreas a serem utilizadas nos aterros sanitários e contribuindo como uma fonte de geração de energia elétrica / The increase in population, the growth of big cities, industrialization and consumption, have brought with them a kind of awareness about sustainability towards availability of energy and toward the destination of generated municipal solid waste. This way, it is primordial to carry out studies aiming to find new ways to reutilize the waste generated by industrial activities. The municipal solid waste and unusable tires produced cause serious consequences to the environment and to the population when these issues are improperly addressed. The final destination of the municipal solid waste is complex and it is always a big challenge to public management. With our National Policy of solid waste (established by the law number 12.305/2010).It consists of the administration and management of solid waste with the following order of priority: non-generation, reduction, reuse, recycling, treatment of solid waste and final environmentally appropriate disposal. With this we can foresee, in an intelligent way, a responsible plan for the return of goods discarded by consumers to the original manufacturers. An alternative to minimize these aspects and the negative environmental impacts caused is the usage of the thermal treatment with the good use of energy. This process contributes to another solution to the problem of the aforementioned waste, providing a reduction of landfill spaces and contributing to a new source of electrical energy generation

No setor de energia elétrica, a área que se dedica ao estudo da inserção de novos parques geradores de energia no sistema é denominada planejamento da expansão da geração. Nesta área, as decisões de localização e instalação de novas usinas devem ser amplamente analisadas, a fim de se obter os diversos cenários proporcionados pelas alternativas geradas. Por uma série de fatores, o sistema de geração elétrico brasileiro, com predominância hidroelétrica, tende a ser gradualmente alterada pela inserção de usinas termoelétricas (UTEs). O problema de localização de UTEs envolve um grande número de variáveis através do qual deve ser possível analisar a importância e contribuição de cada uma. O objetivo geral deste trabalho é o desenvolvimento de um modelo de localização de usinas termoelétricas, aqui denominado SIGTE (Sistema de Informação Geográfica para Geração Termoelétrica), o qual integra as funcionalidades das ferramentas SIGs (Sistemas de Informação Geográfica) e dos métodos de decisão multicritério. A partir de uma visão global da área estudada, as componentes espaciais do problema (localização dos municípios, tipos de transporte, linhas de transmissão de diferentes tensões, áreas de preservação ambiental, etc.) podem ter uma representação mais próxima da realidade e critérios ambientais podem ser incluídos na análise. Além disso, o SIGTE permite a inserção de novas variáveis de decisão sem prejuízo da abordagem. O modelo desenvolvido foi aplicado para a realidade do Estado de São Paulo, mas deixando claro a viabilidade de uso do modelo para outro sistema ou região, com a devida atualização dos bancos de dados correspondentes. Este modelo é designado para auxiliar empreendedores que venham a ter interesse em construir uma usina ou órgãos governamentais que possuem a função de avaliar e deferir ou não a licença de instalação e operação de usinas. / In the electric power industry, there is an area devoted to study alternatives for the expansion of the energy generation system. The decisions regarding the location and installation of new plants ought to be thoroughly analyzed in that planning activity, in order to foresee the likely scenarios resulting from the combination of distinct alternatives. For a number of reasons, the predominantly hydroelectric generation system historically set in Brazil tends to be gradually altered by the introduction of thermoelectric power plants (TPPs). The site selection problem involves, in the case of TPPs, a large number of variables, which contribute to the analysis process in various ways and with different levels of importance. The general goal of this work is the development of a location model of thermoelectric plants, here named SIGTE (an acronym for Geographic Information System for Thermoelectric Generation), which integrates the functionalities of the GIS tools (Geographic Information Systems) and multicriteria decision methods. Starting from an overall view of the studied area, this combination of techniques ensures a more realistic representation of the spatial components of the problem (e.g., the location of the municipalities, the transportation alternatives, the different voltages of transmission lines, areas of environmental preservation, etc.) It thus allows a straightforward inclusion of environmental criteria in the analysis. In addition, the SIGTE framework is also flexible enough to incorporate new decisions variables. The model was applied in a case study carried out in the state of Sao Paulo, although it can be easily adapted for use in other systems or geographical areas given that the corresponding databases are available. SIGTE was envisaged to be a supporting tool to public and private stakeholders interested in building new power plants or to governmental agencies in charge of the regulation mechanisms required for the installation nd operation of plants.

Submitted by Priscilla Araujo (priscilla@ibict.br) on 2017-06-20T18:00:06Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Marcia Pires 2017.pdf: 3509214 bytes, checksum: 7e43a46cb74a8d2490119d122489b2bc (MD5) / Made available in DSpace on 2017-06-20T18:00:07Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Marcia Pires 2017.pdf: 3509214 bytes, checksum: 7e43a46cb74a8d2490119d122489b2bc (MD5) Previous issue date: 2017-03-14 / As escolhas sobre as fontes de energia ganham relevância diante da crise ecológica que deriva de um sistema que transforma tudo em mercadoria e traz como questionamento central as formas de produção e consumo. A matriz elétrica brasileira, cuja fonte hidráulica possui destaque com maior oferta de eletricidade no país, possui de um lado o discurso das vantagens de grande parte de sua composição ser de energia limpa, e, do outro lado, comprova-se um alto custo socioambiental, principalmente para comunidades que vivem próximas aos locais escolhidos para construção de empreendimentos do setor elétrico. Esta pesquisa buscou identificar e analisar as formas de participação da sociedade no processo de escolha de fontes energéticas para produção de energia elétrica em âmbito federal no Brasil, visando discutir os nexos principais entre a crise ecológica e a produção de energia elétrica; como funcionam os mecanismos institucionais para participação social nas questões relacionadas à produção de energia elétrica no Brasil; e, de que forma a sociedade civil participa dos assuntos referentes ao licenciamento ambiental no Conselho Nacional do Meio Ambiente (CONAMA). Um conjunto de abordagens relacionadas à natureza da crise ecológica e das formas de participação social foi adotado no referencial teórico e uma análise do panorama do setor elétrico no Brasil foi elaborada. Para investigar as formas de participação da sociedade nas questões relacionadas à composição da matriz elétrica brasileira foi efetuada uma análise documental, além de um estudo de caso que contemplou três categorias de atores: conselheiros do CONAMA, especialistas da área e dirigentes de órgãos do Estado, envolvidos no planejamento e gestão do setor elétrico. A pesquisa permitiu identificar inconsistências, ambiguidades e outros aspectos relevantes sobre a participação da sociedade na produção de energia elétrica. Tais questões estão associadas a: deficiências nos mecanismos de acesso à informação; falta de transparência e de padronização de documentos; falta de participação social na elaboração dos compromissos internacionais; ausência de participação da sociedade em espaços institucionalizados; ausência da representação da sociedade e de especialistas no Conselho Nacional de Política Energética (CNPE); invisibilidade da discussão sobre possíveis impactos e conflitos sociais; falta de representação da diversidade; deficiência na participação das minorias; falta de iniciativas para a educação para cidadania focadas na questão energética; ausência de debate sobre produção de energia versus consumo; os problemas decorrentes da opção desenvolvimentista das decisões governamentais (mesmo que implícita). Ao final, apresenta sugestões para o aperfeiçoamento deste processo, a partir das três questões chave identificadas nesta tese: crise ecológica; produção de energia elétrica; e participação social. O estudo conclui apontando para a necessidade de mudanças nas formas de participação da sociedade no processo de escolha de fontes energéticas para produção de energia elétrica em âmbito federal no Brasil. Além disso, propõe uma reflexão sobre o modelo de geração e consumo de energia elétrica e a avaliação sistemática do consumo humano sobre os recursos naturais. / The choices of energy sources gain relevance in the face of the ecological crisis which has a central questioning on the modes of production and consumption and that stems from a system which changes everything into merchandise. On one hand, brazilian electricity generation has the advantage of using clean energy in great part of its composition, at least in discourse. On the other hand, though, there are high social and environmental costs, especially for communities living near the regions where projects for the electricity sector are built. This research aimed to identify and analyse different modes society takes part in the process of choosing energy sources for electricity generation in Brazil. It discusses the links between the ecological crisis and the production of electrical energy; how the institutional mechanisms for social participation on issues related to the production of electric power in Brazil work; and, how civil society participates in environmental licensing in the National Environment Council (CONAMA). A set of related approaches to the nature of the ecological crisis and the forms of social participation was adopted in the theoretical framework and an analysis of the electric sector panorama in Brazil has been drawn up. In order to investigate the forms society participates in issues related to the composition of the brazilian electricity matrix, the methodology comprised a documentary analysis and a case study. They included three categories of actors: (i) CONAMA's councilors, (ii) experts from the Field; and (iii) actors involved in the diagnosis study, planning and management of the electricity sector. The research identified inconsistencies, ambiguities and other relevant issues about the participation of society in the production of electrical energy. Such issues are related to: deficiencies in the mechanisms for information access; lack of transparency and patterns in internal documents; lack of social participation in the elaboration of international commitments; absence of participation of the society in institutionalized spaces; absence of representation of the society and specialists in the National Energy Policy Council (CNPE); invisibility of the discussion on possible impacts and social conflicts; lack of diversity's representation; deficiency in minority participation; lack of citizenship education initiatives focused on energy issue; absence of debates on energy production versus consumption; problems arising from developmental choice of Government decisions (even if implied). At the end, the present research offer suggestions for the improvement of this process, from the perspective of three key issues identified in this thesis: ecological crisis; electric power production; and social participation. The study concludes by pointing to the need of changes in the modes society’ participate in the process of choosing energy sources for the electrical energy production at the federal level in Brazil. In addition, it proposes a reflection on the model of generation and consumption of electricity and a systematic evaluation of human consumption on natural resources.

Orientador: Paulo Sergio Franco Barbosa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-26T04:51:16Z (GMT). No. of bitstreams: 1 FreitasFilho_ItaloTadeudeCarvalho_M.pdf: 5022061 bytes, checksum: 47deab221cec3de1cda8326f13e3e7ef (MD5) Previous issue date: 2014 / Resumo: Os agentes reguladores do setor elétrico brasileiro têm como requisito básico garan-tir o adequado balanço entre oferta e demanda com o melhor preço da energia por meio de negócios sustentáveis. Por outro lado, o mercado, cada vez mais exigente e competitivo, em que a busca pela disponibilidade e preço da energia são fatores decisórios tanto para grandes quanto para pequenos consumidores, faz que os investidores busquem a gestão ótima dos riscos operacionais visando garantir os retornos do capital investido. Para tanto, uma metodologia de gestão de ativos físicos é essencial ao bom desempenho financeiro das empresas de geração de energia no Brasil, pois uma má estratégia de gestão de ativos pode acarretar prejuízos consideráveis, tanto para o empreendedor quanto para o sistema elétrico nacional. Esta pesquisa propõe a identificação de requisitos básicos para gestão ótima dos ativos, por meio da avaliação dos riscos operacionais considerando as várias dimensões que afetam uma empresa de geração de grande porte, atualmente com projetos em diferentes estágios do ciclo de vida. Foi feita uma análise de indicadores de desempenho e a identificação dos modos de falhas, e respectivas causas mais comuns que afetam as características de seus ativos em determinadas etapas dos ciclos de vida. A proposta foi criar subsídios à elaboração de uma metodologia para otimização dos conflitos de prioridades entre a utilização e cuidado com os ativos, desempenho de curto e longo prazo, entre investimento de capital, custos de operação e riscos, como forma de melhorar o desempenho da empresa / Abstract: To ensure the proper balance between supply and demand with best energy price through sustainable business, are considered as basic requirements for the electricity sector regulators, on the other hand, a market increasingly demanding and competitive, where the search for availability and price of energy are decisive factors for both large and small consumers, drive the investors to seek an optimal management of operational risks to ensure the returns on invested capital, to this end, a methodology for managing physical assets is essential for the power generation companies in Brazil to guarantee a good financial performance, an inadequate asset management strategy can cause some negative effect to the national electricity grid as well. This research aims to identify, through an operational risk assessment a basics requirements for an optimum asset management, considering various dimensions, that affect a generation company with large scale projects, currently in various stages of the their life cycle, through the analyses of their performance indicators and identifying causes and most common failures modes that affect the characteristics of its assets in certain stages of life cycles, to support the development of a methodology to optimize the prioritizations conflicts between the use and care of assets, short-term and long term performance, capital investment, operating costs and risks, with the objective to increase the company performance / Mestrado / Recursos Hidricos, Energeticos e Ambientais / Mestre em Engenharia Civil

<p>In recent years lithium-ion battery electric vehicles and stored hydrogen electric vehicles have been developed to address the ever-present threat of climate change and global warming. These technologies have failed to achieve profitability at costs consumers are willing to bear when purchasing a vehicle. IFBattery, Inc. has developed a unique primary battery chemistry which simultaneously produces both electricity and hydrogen-on-demand while being both low cost and without carbon emissions. In order to determine the feasibility of the IFBattery chemistry for mobile applications, a prototype golf cart was constructed as the first public application of IFBattery technology. The legacy lead acid batteries of the prototype golf cart were replaced with an IFBattery chemistry tuned to primarily produce hydrogen-on-demand with supplemental electricity. Hydrogen produced by the IFBattery was purified and then fed into a hydrogen fuel cell where electricity was produced to power the vehicle. Electricity from the IFBattery was converted to the common voltage of the golf cart and also used to power the vehicle. Validation testing of the IFBattery powered golf cart demonstrated favorable results as an alternative to both lithium-ion battery and stored hydrogen technologies, and displayed potential for future applications.</p>

Thermal radiation is a fundamental heat transfer process, with certain basic aspects still not fully understood. Furthermore, tailoring its properties has potential to affect a wide range of applications, particularly thermophotovoltaics (TPV) and radiative cooling. TPV converts heat into electricity using thermal radiation to illuminate a photovoltaic diode, with no moving parts. With its realistic efficiency limit up to 50% (heat source at 1200 ^oC), TPV has garnered substantial interest. However, state-of-the-art TPV demonstrations are still well below theoretical limits, because of losses from generating and efficiently converting or recycling thermal radiation. In this thesis, tailored integrated photonic crystal structures are numerically simulated to enhance the efficiency of solar TPV. Next, a high-temperature thin-film Si-based selective absorber and emitter is designed, fabricated and experimentally characterized. It exhibits great potential to open up new applications, as it lends itself to large-scale production with substantial mechanical flexibility and excellent spectral selectivity for extended time periods, even when operating under high operating temperatures (600 ^oC) for up to 6 hours, with partial degradation after 24 hours. To perform this high-temperature characterization, an emittance measurement setup has been built; its performance agrees well with numerical simulations. Second, a unique passive cooling mechanism known as radiative cooling is developed to reduce the operating temperature of the photovoltaic diode. The significant effect of radiative cooling as a complement for an all-passive-cooling TPV system is proposed and numerically analyzed under a range of conditions. Furthermore, an outdoor experiment has been performed to demonstrate the effect of radiative cooling on a concentrating photovoltaic system, which can potentially be applied to the thermal management of a TPV system. In summary, this work paves the way towards the development of reliable, quiet, lightweight, and sustainable TPV and radiatively cooled power sources for outdoor applications.

<p>Managing the highly dynamic and interdependent systems within a district energy system is an intricately complex undertaking. A district energy manager is expected to make decisions that will result in the achievement of the district’s goals, often with limited capital and personnel resources. What has been lacking in the tools available to a district energy manager is an established decision-making framework with which to process the complex internal and external variables involved to effectively develop and evaluate options to make successful decisions.<br><a></a></p> <p> </p> <p>While capitalizing on the experience of seasoned district energy managers and a literature review of current methodologies, this dissertation assesses the strengths and weaknesses of the methodologies currently available to managers of district energy systems and presents a new and more comprehensive decision-making framework. A system of systems engineering approach is applied, and multiple relevant case studies are analyzed. Procedures for significantly mitigating many of the external risks to a district energy system are developed and documented. </p> <p> </p> <p>The main contribution of this dissertation is a unique decision-making framework with a holistic approach encompassing the complexity, emergence, and interdependency of district energy subsystems. This framework will aid a district energy manager in making successful decisions which meet the goals of the district.</p>

<p>  </p> <p>Room-temperature sodium-sulfur (RT Na-S) batteries are an emergent new technology that are highly attractive due to their low raw materials cost and large theoretical specific energy. However, many fundamental problems still plague RT Na-S batteries that prevent their progression from the research and development phase to the commercial phase. Sulfur and its final discharge product are insulators, and intermediate polysulfide discharge products are soluble in commonly used liquid electrolytes. As a result, RT Na-S cells exhibit large capacity defects, low coulombic efficiencies, and rapid capacity fading. Additionally, the reactive sodium metal anode can form dendrites during cycling, which reduces capacity and shortens cell life. One way to combat these issues is the judicious selection of electrolyte components. In this study, the effects of monoglyme (G1), diglyme (G2), and tetraglyme (G4) glyme ether electrolyte solvents on RT Na-S cell performance are investigated. Galvanostatic cycling of Na/Na symmetric coin cells reveals that the G2 solvent enable stable cycling at low overpotentials over a wide range of current densities. In contrast, the G1-based cells show evidence of dendritic plating, and G4-based cells are not suitable for use at high current densities. Electrochemical impedance spectroscopy during cycling confirms that the G2 solvent facilitates the formation of a strong, stable SEI on the Na electrode surface. Results from galvanostatic cycling of RT Na-S full coin cells demonstrates that G1-based cells deliver the highest initial specific discharge capacities among the three cell types, but G4-based cells are the most reversible. Infinite charging, the indefinite accrual of charge capacity at the high charge voltage plateau, affects all cell types at different cycle numbers and to different extents. This behavior is linked to the strength of the polysulfide shuttle during charge. Optical microscopy experiments show that G2 and G4 facilitate the formation of the S3•- sulfur radical, which reduces capacity. G1 minimizes the radical formation and thus delivers higher initial specific discharge capacity. In order to fully optimize the electrolyte for RT Na-S cells, future work should study glyme solvent blends, additives, and concentrated salts.</p>

<p>Recently, energy storage systems have become more focused towards sustainable energy sources like LIBs due to attractive attributes like high energy density and volumetric density which make them extremely competitive compared to other energy sources for many portable and non-portable applications (smartphones, eVTOLs, stationary storage systems, electric vehicle and so on). Longer cycling stability, capacitance retentive power, lower self-discharge rate and high voltage window are qualitative features in LIB. Even though LIBs are rechargeable energy storage systems, all cells decay and degrade over time causing capacity and power fade due to a number of factors such as manufacturing defects, usage outside the normal operating conditions, and other abuse conditions like overcharge, over-discharge and indentation. This work presents a systematic investigation of several off-nominal conditions which are typically observed in LIBs such as overcharge, over-discharge, nail indentation, periodic overcharge, and over-discharge in order to form a comparative analysis on the effect of each of these conditions on cycle life aging, morphological changes on the cell components and also to evaluate potential internal short circuit (ISC) mechanisms. The cell failure mechanism induced by each condition and its negative impact on the electrochemical performance has been rigorously analyzed in this work based on the proper protocols. The correlation of the galvanostatic performance with the morphological change of the individual electrodes was also scrutinized under SEM and EDS to demarcate the severity of the defect into Li-ion cells. The practical off-nominal condition analysis of LIB will pave the way for more reliable cell functioning and recommendations to be considered to effectively analyze these off-nominal conditions. The analysis was divided into two parts; 1) curve-based analysis which included capacity fade, internal resistance, Incremental & Differential capacity analysis and EIS analysis 2) disassembly-based analysis which consisted of post-mortem visual inspection, morphology-based analysis using electron microscopy and composition analysis. From the capacity fade and IR evolution study, it was observed that periodic off-nominal conditions exhibited the highest rate of capacity fade and the greatest increase in DC internal resistance consistently. The least rate of capacity loss was shown by overcharged and no defect cells and a similar trend for DCIR values as well indicating that there was a positive correlation between capacity fade and internal resistance evolution. From the EIS study a slightly different trend was observed with the overcharged cell exhibiting the highest ohmic resistance and the no defect cell XV </p> <p>the least indicating ORI as an aging mechanism in overcharged and periodic overcharge/over-discharged cells. Another interesting observation was that the highest change in change transfer resistance was shown by over-discharged cell followed by nail-indented and overcharged cells and the least for cells subjected to periodic off-nominal conditions. This was attributed to a large amount of delamination caused by particle cracking in no defect cells causing LAM in these cells, lithium plating in Overcharged, copper current collector dissolution in over-discharged cells which resulted in LLI as the primary aging mechanism in these cells. This was further confirmed by ICA-DVA curve analysis at various capacity fades, postmortem inspection and SEM-EDS analysis. The periodic overcharged cells underwent a combination of degradation mechanisms including LAM from delamination, LLI through lithium deposition on the separators and Contact loss due to electrolyte vaporization causing active material adhesion on the separator and vice versa. The last degradation mechanism exacerbated the rate of increase of internal resistance by blocking pathways for Li+ ion diffusion. To summarize, while no defect and nail-indented cells exhibited primarily one aging mechanism (ORI) other cells exhibited a combination of degradation modes and the decoupling of these modes became increasingly indistinguishable for the cells subjected to periodic off-nominal conditions. Interestingly, no manifestation of soft or hard Internal short circuits was observed in the tested cells. However, it should be noted that for the periodic overcharged cells which underwent excessive lithium plating on the separators and charring of electrodes, dendrite formation could potentially have caused ISC upon further cycling. This cements the fact that periodic off-nominal conditions exacerbate the possibility of sudden failures and accelerate degradation in Li-ion cells. </p>