No description available.

O objetivo desse estudo é analisar e sistematizar os elementos necessários à modelagem da energia primária solar para geração fotovoltaica em escala. Metodologicamente, investigam-se os assuntos inerentes à solarimetria e a caracterização da radiação solar, desde a formação das equações que definem a incidência da radiação no topo da atmosfera, o desenvolvimento tecnológico de radiômetros, até as normas e critérios de classificação desses equipamentos. Também são elementos metodológicos a caracterização do irradiância solar, incluindo algoritmos de tratamento de dados de irradiância, os processos de estimativa de irradiação para a agricultura e análises probabilísticas de índices de transmitância atmosférica. Busca-se a aplicação das etapas de caracterização e a análise do recurso, definidas neste estudo, por meio da utilização dos dados fornecidos por duas estações solarimétricas: ESUPP e ESPEL. Como resultados são definidos a média diária parcial anual de disponibilidade do recurso para uma região no interior do estado de São Paulo (localização da ESUPP) em 5,29 kWh/m² e a média diária anual de disponibilidade do recurso para a região metropolitana da cidade de São Paulo (localização da ESPEL) em 4,41 kWh/m², além disso verifica-se que a relação entre as componentes global horizontal, difusa horizontal e direta vertical varia para os dados das duas estações solarimétricas, de modo que, parte significativa dos dados da ESPEL apresenta medições de irradiância global horizontal (IGH) entre 12% e 13% superiores à respectiva componente difusa horizontal (IDH) somada a parcela vertical da respectiva componente direta normal (IDNcos?z), enquanto que, essa mesma relação para os dados da ESUPP atendem à relação IGH=IDH+IDNcos?z dentro do intervalo aceitável de mais ou menos 10%. Verifica-se também caráter trimodal das curvas de densidade de probabilidade do índice de transmitância da irradiância global para os dados da ESPEL, enquanto os dados da ESUPP refletem em curva de caráter bimodal. Assim é possível constatar a necessidade de definição de um modelo universal de previsibilidade do recurso e verifica-se que os insumos mais relevantes para o modelo podem variar de região para região dada a caracterização geográfica e de microclima. Conclui-se, portanto, a indiscutível necessidade de dados radiométricos confiáveis medidos em solo para avanços científicos, tecnológicos e comerciais do aproveitamento do recurso solar como fonte energética diante do atual contexto da busca por fontes alternativas de energia limpa e evidencia-se o grande caminho a ser percorrido para a consolidação de uma rede confiável, monitorada e amplificada de medições solarimétricas no Brasil e no mundo. / The purpose of this study is to analyze and to systematize the elements required for modeling primary solar energy for photovoltaic generation in large scale. Solarimetric subjects and subjects related to solar irradiance flux characterization, from the formation of the equations that define the incidence of radiation at the top of the atmosphere, the technologic development of radiometers and the rules and criteria for the classification of these measurement instruments, are methodologically investigated. The characterization of the irradiance flux, including irradiance data treatment algorithms, the irradiance estimate processes for agriculture, and the probability analyses of atmosphere transmittance indexes are also methodological elements. The steps of characterization and resource analysis defined in this study are applied, using data provided for two solarimetric stations: ESUPP and ESPEL. Results showed that the partial annual daily average for resource availability in the countryside of São Paulo State (ESUPP location), is 5.9 kWh/m², and the annual daily average for resource availability in the metropolitan area of São Paulo City (ESPEL location) is 4.41 kWh/m². Moreover, it was observed that the relation between the global horizontal, diffuse horizontal and direct vertical components varies between both solarimetric stations, such that a significant part of the ESPEL data shows global horizontal irradiance (GHI) between 12% and 13% above the respective diffuse horizontal irradiance (DHI) plus the vertical portion of the respective direct normal component (DNIcos?z), while the same relation for the ESUPP data attend the GHI=DHI+DNIcos?z relation within the acceptable range of 10%, give or take. ESPEL data presented trimodal characteristics for the probability density curves of the transmittance index for global irradiation, while ESUPP data reflect on the same curve, with bimodal characteristics. Therefore, it is possible to verify the need of the determination of a universal predictability model of the resource and it is possible to affirm that the more relevant inputs to the model can vary from region to region, depending on the geographic character and microclimate. In conclusion, there is an unquestionable need for reliable radiometric data, measured in ground, for scientific, technologic and commercial advances to improve the use of solar resource as energy source, considering the current scenario, which demands alternative sources for clean energy. It is also evident that there is still a long path to be tracked in order to consolidate a reliable, monitored and amplified network for solarimetric measurements in Brazil and in the world.

Orientador: Osmar de Carvalho Bueno / Banca: Paulo André de Oliveira / Banca: Leonardo de Barros Pinto / Banca: Osmar Delmanto Junior / Banca: Zacarias Xavier de Barros / Resumo: A energia é fundamental para a vida humana, já a energia elétrica é um fator determinante para o desenvolvimento e facilitador das atividades diárias. Para a geração da mesma no Brasil há diversas fontes, que podem ser classificadas como renováveis ou não renováveis. Buscando uma matriz elétrica mais limpa, no país procura-se investir cada vez mais em fontes renováveis, dentre elas a energia hídrica, a partir de Pequenas Centrais Hidrelétricas (PCHs). Porém, a implantação desses projetos vem sendo afetada pela dificuldade de obtenção de licenças ambientais e pela resistência por parte da comunidade do local da implantação. O presente trabalho tem como objetivo analisar a importância da comunicação no processo de estudo, autorização e implantação de PCHs e verificar a efetividade da comunicação entre os atores envolvidos no caso do rio Pardo - SP. O material utilizado foi a realidade brasileira no que tange a legislação para implantação de PCHs realizando um estudo de caso na bacia do rio Pardo - SP. O presente estudo foi elaborado por meio de pesquisa exploratória e descritiva; tendo suas informações sido coletadas em publicações de institutos, agências, departamentos e órgãos envolvidos no processo, bem como na bibliografia especializada existente. Com base no resultado deste estudo, conclui-se que a comunicação é de grande importância para o processo. Para que essa aconteça de maneira satisfatória é necessário que a comunidade conheça o estudo realizado e contribua com dado... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Energy is fundamental for human life, but electric power is a determining factor for development and facilitator of daily activities. For its generation, Brazil has several sources, which can be classified as renewable or non-renewable. Searching for a cleaner electrical matrix, the country seeks to invest more and more in renewable sources, among them hydroelectric power from Small Hydroelectric Power Plants (SHPs). However, the implementation of these projects has been affected by the difficulty of obtaining environmental licenses and by the local community's resistance. The present work aims to analyze the importance of the communication in the process of study, authorization and implementation of SHPs and to verify the effectiveness of communication among the actors involved in the Pardo river - SP case. The material used was the Brazilian reality regarding the legislation for the implementation of SHPs conducting a case study in the Pardo river basin - SP. The present study was elaborated through exploratory and descriptive research; having its information been collected in publications of institutes, agencies, departments and institutions involved in the process, as well as in the existing specialized bibliography. Based on the result of this study, it is concluded that the communication is of great importance for the process. For this to happen in a satisfactory way, it is necessary that the community be aware of the study and contribute with consistent data and information and that the entrepreneur knows the community's afflictions and endeavors to develop a project in line with the studied area, covering economic, environmental and social spheres, so that the project contemplates the expectation of sustainability. In the case of projects planned for the Rio Pardo-SP, the local community had several actors, including the Rio Pardo Vivo Association ("Vivo" means alive), which one has great... / Doutor

Orientador: Teófilo Miguel de Souza / Coorientador: José Luz Silveira / Banca: Paloma Maria Silva Rocha Rizol / Banca: Francisco Antonio Lotufo / Banca: José Rui Camargo / Banca: Osiris Canciglieri Junior / Resumo: A proposta dessa Tese é o projeto e desenvolvimento de um sistema de fornecimento de energia elétrica conectada à rede sem a utilização de circuitos eletrônicos complexos. O sistema eletroeletrônico convencional utiliza um inversor de frequência que transfere a potência ativa do nível de tensão e corrente CC para o nível compatível com a rede elétrica CA em frequência, tensão e sincronismo de fases. Já o desenvolvimento do projeto teve como parte experimental a utilização de indutores adequados com valores variáveis de 200 mH a 500 mH entre os painéis fotovoltaicos e a rede convencional. A tensão e a corrente máxima de CC foi de 29,6 V e a máxima possível foi de 20 amperes. Utilizou-se do princípio do casamento de impedâncias entre o painel fotovoltaico e o sistema de fornecimento de energia CA. Assim o painel fotovoltaico fornece somente potência ativa para a rede não interferindo no sincronismo. Na onda de tensão e corrente CA há uma pequena alteração no nível CA em relação a simetria do eixo dos tempos, dentro dos limites previstos para a rede convencional de energia. Logo evidencia-se o fornecimento de potência ativa para a rede CA. Os resultados obtidos permitiram inserção na rede de cerca de 10% da potência ativa dos painéis fotovoltaicos, com a otimização dos valores dos indutores, ocorrendo a transferência de potência ativa dos painéis fotovoltaicos para a rede convencional de energia CA / Abstract: The purpose of this thesis is the design and development of a delivery system of electricity connected to the network without the use of complex electronic circuits. The electronics system uses a frequency inverter that transfers the active power level voltage and DC current to the level compatible with the mains AC frequency, voltage and phase synchronization. But the project was to develop experimental part the use of suitable inductors with variable values of 200 mH to 500 mH between the PV panels and the conventional network. The maximum current was 20 amperes. We used the principle of impedance matching between the photovoltaic panel and the power supply system CA. So the photovoltaic panel supplies only active power to the grid not interfering with the timing. In the wave of AC voltage and current for a small change in CA level against the symmetry axis of time. Logo is evident in the supply of active power to the grid CA. The results allowed inclusion in the network of about 10% of the active power of photovoltaic panels by optimizing the values of the inductors for the occurrence of power transfer of conventional photovoltaic panels for energy occurs CA / Doutor

Methods of generating renewable energy such as through solar photovoltaic (PV) cells and wind turbines offer great promise in terms of a reduced carbon footprint and overall impact on the environment. However, these methods also share the attribute of being highly stochastic, meaning they are variable in such a way that is difficult to forecast with sufficient accuracy. While solar power currently constitutes a small amount of generating potential in most regions, the cost of photovoltaics continues to decline and a trend has emerged to build larger PV plants than was once feasible. This has brought the matter of increased variability to the forefront of research in the industry. Energy storage has been proposed as a means of mitigating this increased variability -- and thus reducing the need to utilize traditional spinning reserves -- as well as offering auxiliary grid services such as peak-shifting and frequency control. This thesis addresses the feasibility of using electrochemical storage methods (i.e. batteries) to decrease the ramp rates of PV power plants. By building a simulation of a grid-connected PV array and a typical Battery Energy Storage System (BESS) in the NetLogo simulation environment, I have created a parameterized tool that can be tailored to describe almost any potential PV setup. This thesis describes the design and function of this model, and makes a case for the accuracy of its measurements by comparing its simulated output to that of well-documented real world sites. Finally, a set of recommendations for the design and operational parameters of such a system are then put forth based on the results of several experiments performed using this model.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references.

The development of organic photovoltaics (OPVs) has attracted a lot of attention due to their potential to create a low cost flexible solar cell platform. In general, an OPV is comprised of a number of layers of thin films that include the electrodes, active layers and barrier films. Thus, with all of the interfaces within OPV devices, the potential for failure exists in numerous locations if adhesion at the interface between layers is inherently low or if a loss of adhesion due to device aging is encountered. To date, few studies have focused on the basic properties of adhesion in organic photovoltaics and its implications on device reliability. In this dissertation, we investigated the adhesion between interfaces for a model multilayer barrier film (SiNx/PMMA) used to encapsulate OPVs. The barrier films were manufactured using plasma enhanced chemical vapor deposition (PECVD) and the interfacial fracture toughness (Gc, J/m2) between the SiNx and PMMA were quantified. The fundamentals of the adhesion at these interfaces and methods to increase the adhesion were investigated. In addition, we investigated the adhesive/cohesive behavior of inverted OPVs with different electrode materials and interface treatments. Inverted OPVs were fabricated incorporating different interface modification techniques to understand their impact on adhesion determined through the interfacial fracture toughness (Gc, J/m2). Overall, the goal of this study is to quantify the adhesion at typical interfaces used in inverted OPVs and barrier films, to understand methods that influence the adhesion, and to determine methods to improve the adhesion for the long term mechanical reliability of OPV devices.

Tools and algorithms are proposed that are useful for planning, designing, and operating a distribution network with a significant penetration of distributed generation (DG). In Task 1, a PV system simulation program is developed, which incorporates the most rigorous models for the calculation of insolation, module temperature, and DC and AC power output of a PV system. The effect of random inverter failures is incorporated in the model of a PV system, and a novel performance-derating coefficient is introduced. Furthermore, a novel inverter control algorithm is presented for systems with multiple inverters. The algorithm is designed to increase overall DC/AC conversion efficiency by selectively shutting down some of the inverters during periods of low insolation, thus forcing the remaining inverters to operate at higher efficiency. In Task 2, a procedure is developed to incorporate the uncertainties imposed by stochastic, renewable DG into the conventional tools for analysis of distribution systems. A clustering algorithm is proposed to reduce large input data sets that result from the interaction of stochastic processes that drive DG output with field measurements of feeder load profiles. In addition, a procedure is proposed to determine the boundary points of the original data set, which yield feeder extreme operating conditions. Finally, a Monte Carlo analysis using a reduced data set is presented, to determine the effects of deploying a large number of renewable DG systems on a distribution feeder. In Task 3, the reliability model of an asymmetric, three--phase, non-radial distribution feeder equipped with capacity-constrained DGs is developed and used to quantify the potential reliability improvements due to the intentional islanded operation of parts of the feeder. A procedure for finding optimal positions for DG and protection devices is presented using a custom-tailored adaptive genetic algorithm.

Photovoltaics (PV) offers a unique opportunity to solve energy and environmental problems simultaneously since the solar energy is essentially free, unlimited, and not localized any part of the world. Currently, more than 90% of PV modules are produced from crystalline Si. However, wafer preparation of cast multicrystalline Si materials account for more than 40% of the PV module manufacturing cost, which can be significantly reduced by introducing the ribbon-type Si materials. Edge-defined film-fed grown (EFG) and String Ribbon Si materials are among the promising candidates for the cost-effective PV because they are grown directly from the Si melt, which eliminates the need for ingot slicing and chemical etch for surface preparation. However, the growth of these ribbon Si materials leads to relatively high concentration of metallic impurities and structural defects, resulting in very low as-grown carrier lifetime of less than 5 µs. Therefore, the challenge is to produce high-efficiency cells on EFG and String Ribbon Si by enhancing the carrier lifetime during the cell processing and to understand the effect of electrically active defects on cell performance through in-depth device characterization and modeling. The research tasks of this thesis focus on the understanding, development, and implementation of defect passivation to enhance the bulk carrier lifetime in ribbon Si materials for achieving high-efficiency cells. It is shown in this thesis that the release of hydrogen from SiNx layer is initially rapid and then slows down with time. However, the dissociation of hydrogen from defects continues at the same pace. Therefore, a short firing provides an effective defect passivation. An optimized hydrogenation process produces a record high-efficiency ribbon Si cells (4.0 cm2) with photolithography (18.3%) and screen-printed (16.8%) contacts. However, active defects are still present even after the optimized hydrogenation process. An analytical model is developed to assess the impact of inhomogeneously distributed active defects on cell performance, and the model is applied to establish the roadmap for achieving high-efficiency ribbon Si cells in the presence of defects. Finally, PC1D simulations reveal that the successful implementation of the surface texturing can raise the cell efficiency to 18%.

Though relatively young, the field of organic electronics is a rapidly growing market and considerable research is being done in creating a whole range of devices from organic molecules from organic field effect transistors to LEDs to photovoltaic devices. The field of organic photovoltaic in particular has become important in recent years with the push for newer, renewable sources of energy to end the dependence on fossil fuels. While the efficiencies of organic photovoltaic devices continue to rise, one barrier to their commercial adoption has been the limited lifetimes of these devices. While certain degradation methods of organic photovoltaics, such as photo-oxidation, have been extensively studied and solutions to these problems, such as encapsulation, are being researched, certain other degradation mechanisms are less understood and studied. The focus of this thesis is on one such degradation mechanism, UV degradation, specific to the ITO-pentacene interface in pentacene/C60 organic photovoltaic devices. Attempts were made to increase the lifetime of the devices by using phosphonic acids or oxygen plasma to modify the surface of the ITO. While conducting these experiments, the lack of a system to test the lifetime of multiple devices for long periods of time became apparent. As such as system was a requirement for future research into the lifetimes of organic photovoltaic devices a system was designed and built. The system would operate the photovoltaic device in a way comparable to its end-use and would allow over 100 devices to be tested simultaneously for durations exceeding 10,000 hours if necessary. This system would allow for statistically significant lifetime testing to be carried out in the future.