M.Sc. (Physics) / Amorhous silicon is one of the most promising materials for large area solar cells for terestrial photovoltaic applications. Unfortunately these cells suffer from two serious problems: the efficiencies drop when laboratory processes are scaled up and the cells degrade after some exposure to sunlight. The exact causes of these two problems are still unknown. In this project some aspects of the above two problems where investigated. The drop in efficiency due to scaling up of laboratory processes can be ascribed to macroscopic inhomogeneities in the film. An investigation was done by changing the chamber geometry and gas flow pattern to establish empirical conditions to obtain films with maximum macroscopic homogeneity. It was found that a uniform electric field above the substrate was the most important factor determining the macroscopic homogeneity of the film. The hydronamic gas flow pattern was of secondary importance. Some techniques to obtain a uniform electric field has been devised. The photo-degradation was investigated by illuminating films of o-Si.H with simulated sunlight for different lenghts of time. The change in the electrical and optical properties of the intrinsic films were determined as function of total photon flux. No change in the optical properties could be detected. The effect of the photo-degradation manifests itself in a drop in the the dark conductivity and photoconductivity. The observed phenomena is explained in terms of photo-induced deep levels in the gap. The Fermi level shifts to the middle of the gap due to these defect states, causing a drop in the free carrier concentration and conductivity. These defect levels increase the absorptiom coefficient in the long wavelength region, but they also decrease the lifetime of the photo-generated carriers. The photo-induced defects were investigated with the CPM-technique. A large part of this project involved the construction and commissioning of the CPM-apparatus. It was found that the light introduced two types of defects at energies 0.5 eV and 0.75 eV below the conduction band edge. The concentration of the defects increases with illumination, but saturates after about 24 hours of illumination. The defects could almost completely be annealed at ISOaC. The photo-degradation of o-Si.H solar cells is ascribed to the reduction in the carrier lifetimes of photo-generated carriers due to recombination at these defect centers.

Orientador: Ennio Peres da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T02:08:03Z (GMT). No. of bitstreams: 1 Castro_RodolfoDamasiode_M.pdf: 3152478 bytes, checksum: a4e0e80e4ac1f8804a7b3aa8589139b4 (MD5) Previous issue date: 2015 / Resumo: A busca por meios de geração de energia para atender às necessidades humanas com menores impactos sociais e ambientais é constante. A geração de energia elétrica por meio de fontes renováveis na forma distribuída, ou não centralizada, é um meio ou método de minimizar tais impactos. O objetivo da pesquisa foi analisar a viabilidade econômica, frente a tarifa de energia elétrica das concessionárias locais, da utilização de sistemas de geração solar em residências brasileiras situadas nas capitais dos estados, na capital federal, Brasília e na cidade de Campinas (SP). Diferentes situações de dimensionamento foram utilizadas para dois tipos de sistemas: um sistema fotovoltaico puro, para atender toda a necessidade energética da residência, incluindo o chuveiro elétrico, e um sistema solar híbrido, composto por aquecimento solar para atender a demanda por água quente no banho em conjunto com geração fotovoltaica para atender as necessidades em equipamentos elétricos. As situações de dimensionamento utilizadas foram três, onde em cada uma o sistema fotovoltaico foi projetado para uma determinada produção de energia. Os sistemas fotovoltaico e de aquecimento solar foram dimensionados com o auxílio dos softwares PVSyst e Dimensol, respectivamente. O custo total dos sistemas foi estimado a partir de pesquisa em lojas com endereço eletrônico na rede de computadores e de orçamentos fornecidos por empresas do ramo. Determinou-se o preço final da energia elétrica convencional para todas as cidades a partir da tarifa definida pela ANEEL, do valor médio do PIS efetivo cobrado pelas concessionárias e da alíquota de ICMS que os governos estaduais recolhem. Após realizados os cálculos, chegou-se ao resultado de que somente nas cidades de Macapá (AP) e Boa Vista (RR), devido principalmente ao baixo custo das tarifas de energia elétrica, o usuário não economizaria com a instalação dos sistemas. Porém, em cidades de elevada tarifa, como Belém (PA) e Belo Horizonte (MG), o usuário pagaria cerca de R$ 0,30 por quilowatt hora consumido a menos / Abstract: The search for power generation means to meet human needs with lower social and environmental impacts is constant. The distributed generation of electricity by renewable energies is a method to minimize those impacts. The research aimed to analyze the economic viability against local electricity tariff of the use of solar power generation systems in Brazilian households located in the capitals of the states, in the federal capital, Brasilia, and in the city of Campinas (SP) Different sizing situations were used for two types of systems: a pure PV system to meet all the energy needs of the residence, including electric shower, and a hybrid solar system, consisting of solar heating to meet the demand for hot water in the bath together with photovoltaic generation to meet the needs in electrical equipment. Sizing situations used were three, where in each one the PV system is designed for a certain production of energy. The photovoltaic systems and solar heating were sized with the help of the softwares PVSyst and Dimensol, respectively. The total cost of the systems was estimated by a research in webstores and budgets provided by companies in the field. Was determined the final price of conventional electricity to all cities from the tariff set by ANEEL, the average value of the effective PIS charged by concessionaires and ICMS aliquot that state governments collect. After performing the calculations, came to the result that only the cities of Macapa (AP) and Boa Vista (RR), mainly due to the low cost of electricity tariffs, the user does not save due to the installation of the systems. However, in cities of high tariff, as Belém (PA) and Belo Horizonte (MG), the user would save about R$ 0.30 per quilowatt-hour / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Planejamento de Sistemas Energéticos

A series of 28 square-planar dithiol(diimine)platinum(II) chromophoric complexes have been synthesized, characterized, and evaluated for potential efficacy in sensitization of solid state photovoltaic devices to the near-infrared regions of the electromagnetic spectrum. The effect of molecular stacking in the solid state and self-association in solution are shown to influence spectral, electronic, and magnetic properties of the chromophores. Such properties are investigated in the pure form and as partners in donor-acceptor charge transfer adducts. Finally, selected chromophores have been incorporated into single layer schottky diodes as neat films and as dopants in multi-layer organic photovoltaic devices. Evaluation of the devices internal quantum efficiency and voltage-current was measured as proof of concept.

abstract: The availability of data for monitoring and controlling the electrical grid has increased exponentially over the years in both resolution and quantity leaving a large data footprint. This dissertation is motivated by the need for equivalent representations of grid data in lower-dimensional feature spaces so that machine learning algorithms can be employed for a variety of purposes. To achieve that, without sacrificing the interpretation of the results, the dissertation leverages the physics behind power systems, well-known laws that underlie this man-made infrastructure, and the nature of the underlying stochastic phenomena that define the system operating conditions as the backbone for modeling data from the grid. The first part of the dissertation introduces a new framework of graph signal processing (GSP) for the power grid, Grid-GSP, and applies it to voltage phasor measurements that characterize the overall system state of the power grid. Concepts from GSP are used in conjunction with known power system models in order to highlight the low-dimensional structure in data and present generative models for voltage phasors measurements. Applications such as identification of graphical communities, network inference, interpolation of missing data, detection of false data injection attacks and data compression are explored wherein Grid-GSP based generative models are used. The second part of the dissertation develops a model for a joint statistical description of solar photo-voltaic (PV) power and the outdoor temperature which can lead to better management of power generation resources so that electricity demand such as air conditioning and supply from solar power are always matched in the face of stochasticity. The low-rank structure inherent in solar PV power data is used for forecasting and to detect partial-shading type of faults in solar panels. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2020

The theme of this master thesis is „Energy supply to the site Technická 2“. This thesis is divided into several parts. First we will get in touch with concept of combined heat and power and also with principle of photovoltaic electricity production. We will continue with description of site before and after reconstruction. Then we will follow with analyze the effect of reconstruction on energy consumption. In the end we will make some suggestions for using the local source of heat and electricity in Faculty of mechanical engineering, Brno university of technology. All suggestions will be analyzed from energy and economic point of view.

The diploma thesis is focused on the evaluation of a photovoltaic power plant in the company premises. The first chapters briefly discuss the theory of electricity generation using photovoltaic panels. It describes the principle of operation of photovoltaic panels, history, production, etc. In the practical part of the thesis we focus on the evaluation of the company's photovoltaic power plant when comparing real data with simulations.

This diploma thesis is focused on the assessment of the possibilities of disposal of photovoltaic panels installed in the Czech Republic. In addition to the basic theory of photovoltaic cells and panels, the theoretical parts describe legislation, subsidies in the field of photovoltaics and the development of photovoltaics in the Czech Republic. As part of recycling, their methods, work with the collective system, as well as the impact on the environment are analyzed. In the experimental part, using the data of the installed capacity and the average weights of the panels, various projections of the disposal of the panels over time are made, which take into account factors such as the life of the power plant or the capacity of the recycling line. Furthermore, according to the available literature, an analysis of the revenue from the sale of recycled materials contained in panels installed in our territory is performed. Subsequently, the needs of future implementers of proven estimates of labor and logical demands were assessed. Finally, an economic evaluation of the fundamental aspects of the FRELP recycling process was performed and the net prices of different recycling directions were determined.

The master’s thesis deals with study the effectiveness of operation of photovoltaic power station. The theoretical part describes the legislative steps that led to the development of photovoltaic power stations, not only in Czech Republic but throughout Europe. The following is a review of the issue of photovoltaics, which includes the development of photovoltaics in the world, research of photovoltaic power stations in the Czech Republic and technology of photovoltaic power stations. At the end of the theoretical part is a list of methods to evaluate efficiency investments. The practical part includes a description of the selected photovoltaic station Zakřany 5.4 MWp, financial projection and economic evaluation of the real operation and there is also explicit evaluation of the economic efficiency of the project.. The comparison of the projection and the real operation and the possible negative influences affecting the power station are in conclusion.

The output of our work is complete proposal of the building wiring, the photovoltaic power plant proposal and technical report. In the first part we find the theoretical information concerning the proposal of the house wiring, explanations of basic terms and principles of technical documentation. We can find also an overview of known intelligent systems and a brief description. In the second part we describe itself proposal of concrete building, step by step. We can find a description of a created program to control building. The third part is focused on theoretical information about photovoltaics. Here we explain the basic principle, the limits of technology, materials and the panel structure. In the fourth part we proceeded to the actual plant proposal. Here we find the principle and a block diagram of system and description of the components of the plant, evaluation of production and energy consumption. Drawings of the technical documentation wiring as a photovoltaic power plant, distributor scheme and its layout can be found in the technical report, in Attachment.

Nowadays, electricity production from photovoltaics power plants is becoming important increasingly. In order to set production to other power plants, it is necessary to predict the generation of electricity from these sources. The thesis is mainly devoted to models for short-term prediction, which is based on weather forecast. The models were designated by beta regression and linear regression with transformed explanatory variable. One part of thesis is devoted to Clear sky model, which is used to estimated the maximum possible production at given hour. 1