The aim of this diploma work is the study and the modeling of an Organic Rankine Cycle (ORC). Organic Rankine Cycle is used for heat recovery from low-potential heat sources. Their working fluid is a refrigerant or a hydrocarbon whose properties are adapted to the conditions in which the heat recovery is performed. The other chapters include the technical resolution of exhaust-heat exchanger of cogeneration unit for application ORC and partially economic study use in Czech Republic.

Master thesis deals with photovoltaic components and their principles. Evaluate the types of photovoltaic systems and their impact on the transmission system. The thesis deals with financial support to small and micro-photovoltaic systems, which can be used in terms of legislation of the Czech Republic. There are also described the changes in the amendment to the energy act and effect on the price of electricity in households. Compared with the domestic photovoltaic rest of the world and the view of the German energy concept. Part of the theoretical design of a hybrid photovoltaic plant, including the use of heat pump. Thesis deals with using hybrid photovoltaic plant and economic viability of the proposed system. The last part deals with the implementation of the proposed system and assesses the true value from those anticipated in the design.

The development of new communities to facilitate the growing population isan ongoing trend, with locations outside the city limits so as to have morearea and less pollution. The main need in isolated communities is to secureenergy demand, which is normally done with power supply from the maingrid, which will require new transmission lines and transformer installation,among other things. As we strive for net-zero energy buildings, the energysource should be renewable and clean. So far, the most common andefficient renewable sources available in abundance are solar and windpower. So, based on the location, we investigate how we can make thesystem of combined solar, and wind power a successful energy source sothat the load of the community can be fulfilled while at the same time thepower from the main grid is isolated. This analysis is done for off-gridsystems to analyze a combined Solar and Wind energy production andcalculate the needed storage, also presenting a comparison with Dieselbased generation and an Economical perspective,for the different locations.As an output of this analysis a program has been developed to examineother locations on bases of local load data.

The world is currently submerged in two big problems: supply energy crisis and climate change. It is clear that society has to do its best to overcome these challenges, and one effective way to mitigate their effects is by conducting an energy audit, which helps to identify the weaknesses and strengths of the buildings, enabling improvements in their thermal efficiency.  The main goal of this study was to carry out an energy audit on a century-old single- family house located in a city in the middle of Sweden. To achieve this, relevant data of the building was gathered such as the bills and some temperature and dimension measurements. Subsequently, the calculations of the energy losses and gains were done manually. From this step it was observed that almost 70 % of the thermal losses occurred due to transmission through the walls, windows and roof. To reduce these losses, potential energy-saving measures were studied, such as replacing the 2-panel windows with 3-panel windows and adding 200 mm of mineral wool to the roof. Both improvements reduced transmission losses around 700 kWh/year and diminished CO2 emissions around 20 kg/year, which implied a decrease of 1262 and 1277 SEK per year for each measure respectively. However, the profitability of these measures was difficult to attain because the required initial capitals are probably higher than the investments allowed, which are around 17371 and 17579 SEK for each measure respectively.  Moreover, a study about installing photovoltaic solar cells was conducted and it resulted in a significant positive impact in the energy usage of the house. In particular, this improvement lead to a reduction of 2471 kWh per year, which equaled to an annual decrease of 6036 SEK. These annual savings implied an investment allowed of 58620 SEK. Furthermore, a decrease of 99 kg of CO2 emissions per year was obtained. In conclusion, this measure yielded substantial profitability, making it the most recommended option for future energy-saving improvements.  Finally, changing in the occupant’s behavior by reducing the indoor temperature had a positive impact on the house without the need for an initial investment. Specifically, it decreased around 105 kWh per year.

[pt] O aumento da participação de fontes de energias renováveis variáveis (ERVs) na matriz elétrica do Brasil traz diversos desafios ao planejamento e à operação do Sistema Elétrico Brasileiro (SEB), devido à estocasticidade das ERVs. Tais desafios envolvem a modelagem e simulação dos processos intermitentes de geração e, dessa forma, um volume considerável de pesquisas tem sido direcionado ao tema. Nesse contexto, um tópico de crescente importância na literatura relaciona-se ao desenvolvimento de metodologias para simulação estocástica conjunta de recursos intermitentes com características complementares, como, por exemplo, as fontes eólica e solar. Visando contribuir com essa temática, este trabalho propõe melhorias a um modelo de simulação já estabelecido na literatura, avaliando sua aplicabilidade a partir de dados do Nordeste brasileiro. A metodologia proposta baseia-se em discretização das séries temporais de energia aplicando a técnica de machine learning k-means, construção de matrizes de transição de estados com base nos clusters identificados e simulação de Monte Carlo para obtenção dos cenários. As séries sintéticas obtidas são comparadas aos resultados gerados pelo modelo já estabelecido na literatura a partir de técnicas estatísticas. Quanto ao alcance dos objetivos da pesquisa, a modelagem proposta se mostrou mais eficiente, gerando cenários que reproduziram satisfatoriamente todas as características dos dados históricos avaliadas. / [en] The increased participation of variable renewable energy sources (VRES) in Brazil s electricity matrix brings several challenges to the planning and operation of the Brazilian Power System (BPS), due to the VRES stochasticity. Such challenges involve the modeling and simulation of intermittent generation processes and, in this context, a considerable amount of research has been directed to the theme. In this context, a topic of increasing importance in the literature is related to the development of methodologies for joint stochastic simulation of intermittent resources with complementary characteristics, such as wind and solar sources. Aiming to contribute to this theme, this work proposes improvements in a simulation model already established in the literature, evaluating its applicability based on Brazilian Northeast data. The proposed methodology is based on the discretization of energy time series applying the kmeans machine learning technique, construction of state transition matrices based on the identified clusters, and Monte Carlo simulation to obtain the scenarios. The synthetic series obtained are compared to the results generated by the model already established in the literature from statistical techniques. Regarding the scope of the research objectives, the proposed modeling demonstrated more promising results, generating scenarios that satisfactorily reproduced all the evaluated characteristics of the historical data.

[pt] Fontes renováveis são importantes recursos a serem agregados aos sistemas de energia elétrica em prol da descentralização da geração. Discussões acerca dos efeitos ambientais direcionam os estudos em busca de alternativas que possibilitem minimizar a emissão de gases poluentes e diversifiquem a matriz elétrica. Nesse contexto, a geração distribuída (GD) de natureza renovável vem se mostrando cada vez mais presente, alterando a estrutura clássica do sistema e conferindo um maior protagonismo do consumidor. Assim, torna-se essencial avaliar o desempenho dessas novas redes de distribuição no atendimento à demanda, de modo a estabelecer padrões adequados e monitorá-los através das agências reguladoras. Há uma diversidade de métodos de avaliação do desempenho dessas redes, principalmente através dos conceitos de confiabilidade, para lidar com as falhas de equipamentos e os efeitos decorrentes. A presente tese tem como objetivo avaliar índices de confiabilidade de sistemas de distribuição na presença de GD. Para isso, são apresentadas três técnicas baseadas em simulação Monte Carlo (SMC). Uma clássica, denominada SMC sequencial, tem como objetivo modelar a natureza cronológica do problema bem como as incertezas provenientes da intermitência de fontes de GD. A segunda, baseada na SMC quase sequencial, caracteriza-se por sua simplicidade e capacidade em manter a flexibilidade da SMC sequencial, porém, com melhor desempenho em termos de precisão e tempo de processamento. Por último, uma SMC baseada nos conceitos de transição de estado do sistema de forma cronológica assegura também precisão e flexibilidade à técnica. Novas funções teste são propostas para alcançar tal objetivo. Dois sistemas com inserção de GD são utilizados para avaliar o desempenho dos conceitos e técnicas propostas: IEEE RBTS, rede acadêmica padrão amplamente utilizada na área de confiabilidade; e uma rede real. A discussão exaustiva dos resultados confirma que as propostas cumprem os objetivos estabelecidos. / [en] Renewable sources are important resources to be added to electrical energy systems in favor of decentralized generation. Discussions about environmental effects drive the studies in search of alternatives that make it possible to minimize the emission of polluting gases and diversify the electrical matrix. In this context, distributed generation (DG) of a renewable nature has been increasingly present, changing the classic structure of the system and giving greater engagement to the consumer. Therefore, it is essential to evaluate the performance of these new distribution grids in meeting the power demand, in order to establish appropriate standards and monitor them through the regulatory agencies. There is a diversity of methods for evaluating the performance of these networks, mainly through reliability concepts, to deal with equipment failures and the resulting effects. This thesis aims to evaluate reliability indices of distribution systems in the presence of DG. To this end, three techniques based on Monte Carlo simulation (MCS) are presented. A classic one, called sequential MCS, aims at modeling the chronological nature of the problem as well as the uncertainties arising from the intermittency of the DG sources. The second one, based on a quasi-sequential MCS, is characterized by its simplicity and ability to maintain the flexibility of sequential MCS, but with better performance in terms of precision and processing time. Finally, an MCS based on the concepts of chronological system state transition, also provides precision and flexibility to the reliability assessment. New test functions are proposed to achieve this goal. Two systems with DG insertion are used to evaluate the performance of the proposed concepts and techniques: IEEE RBTS, a standard academic network widely used in the reliability area; and another real network. The exhaustive discussion of the results confirms that both proposals meet the established objectives.

An efficient application and development of renewable energy sources is one of the most important contribution to the energetic balance of the human society. Anyhow, statistical model of the renewable energy market, which would fundamentally explain relevant economical rules related to these perspective energetic resources, is not clearly known up to now. Nevertheless, the relevant statistical data concerning application of solar energy (photovoltaic and thermo-solar heating) are available for the last twenty years. Based on the economic models, statistical data concerning sales of photovoltaic models and thermo-solar collectors sales have been analysed in this work. It has been shown that the model of constant elasticity predicts an exponential increase which will slow down when a certain level of annual cumulative sales was reached. The model of constant elasticity was found to be successful to interpret past sales data. In the approach of variable elasticity model the parameter of the elasticity has been modified as a function of variables such as market volume, price and time through the statistical evaluation. It enabled to calculate initial, saturation and competitive market conditions, as well. Whereas the constant elasticity demand model describes exponential growth of sales and installations, which was characteristic for the beginning of the application of these renewable resources of energy, the variable elasticity demand model describes a more realistic situation, where cumulative sales either increase or decrease and prices vary subsequently. Simple growth model of unlimited demand based on the growing sales is not realistic and could not be feasible in the long term. The market elasticity could be understood as a real economical parameter representing percentual market increase or decrease at a given time; in the variable demand elasticity model, the constant elasticity is replaced by a function of a market volume, price and time. In this case, we can estimate model parameters for the different market conditions: growth, saturation and decrease. The function representing the capital adequacy in the generalized market model has also been deliberated. Statistical models have been used to determine cumulative sales and market prices of photovoltaic modules and thermo-solar collectors. Moreover, model parameters have been used for the calculation of the realized photovoltaic and thermo solar projects' capital adequacy on the renewable energy market. By using model parameters, renewable energy market forecast up to 2020 has been estimated. We have used generalized market model to credibly estimate future renewable energy market until 2020; as well as extend model parameterization on other resources of renewable energy (water and wind, geothermal sources, biomass) and set prices of energy produced from these renewable sources. Potential energetic savings have been estimated for households (apartments and private houses), who can be relevant consumers of energy from renewable sources. We have performed statistical findings on randomly selected files, where we have reached a real energy consumption, to prove this. This research allowed us to perform a real estimate of a renewable energy contribution to the total energy balance. We have successfully proved that linearly growing capital adequacy function, with an annual growth between 2.5% and 3.0%, is reflecting the renewable energy market sufficiently and is fully in line with an average growth of the total energy consumption. Renewable energy share on the total energy balance will grow substantially to reach a level of 15% in 2015 on the world market and a level of 8% in the Czech Republic for the same period with a perspective to reach a level of 11% in 2020 respectively. Assuming this level of renewable energy on the total production will lead to a decrease of CO2 emissions by three million of tones in 2015 and by four million of tones in 2020. Final reach of this status quo is fully predicted by our statistical model for renewable energy market.

Submitted by ALESSANDRO LUCINDO DA LUZ null (aledaluz@hotmail.com) on 2018-01-10T01:24:32Z No. of bitstreams: 1 Operacao flexivel conversores_ALuz.pdf: 10997918 bytes, checksum: 18fe1f6d3eba73d11bf63fab8cf0a0be (MD5) / Approved for entry into archive by Maria Marlene Zaniboni null (zaniboni@bauru.unesp.br) on 2018-01-10T11:41:48Z (GMT) No. of bitstreams: 1 luz_al_me_bauru.pdf: 10997918 bytes, checksum: 18fe1f6d3eba73d11bf63fab8cf0a0be (MD5) / Made available in DSpace on 2018-01-10T11:41:48Z (GMT). No. of bitstreams: 1 luz_al_me_bauru.pdf: 10997918 bytes, checksum: 18fe1f6d3eba73d11bf63fab8cf0a0be (MD5) Previous issue date: 2017-11-13 / Este trabalho de mestrado descreve uma estratégia de operação multifuncional e flexível aplicado a conversores trifásicos CC-CA (inversores) conectados à rede de distribuição de energia elétrica. A estratégia proposta é capaz de injetar potência ativa na rede e compensar correntes de distúrbios (reativos, desbalanço e harmônicos) simultaneamente. O maior objetivo desta operação flexível é de melhorar a Qualidade de Energia Elétrica em um ponto de acoplamento comum (PAC) permitindo a compensação total ou parcial destes distúrbios ou fatores que degradam a Qualidade de Energia Elétrica. O fator de potência é o principal fator de qualidade a ser observado e ele é calculado através da Teoria da Potência Conservativa – CPT. Entretanto, com base no fator de potência medido pelo lado da rede de distribuição e o fator de potência desejado, um coeficiente de compensação – k é calculado para o ajuste das correntes de compensação dos distúrbios que geram a potência não ativa. / This paper depicts a multifunctional and flexible control strategy applied in three-phase inverters, which are connected to the distribution network. The proposed strategy is able to inject active power into the electrical grid and compensate current disturbances (reactive, harmonics and unbalance) simultaneously. The main goal of this flexible strategy is to improve the Power Quality at the point of common coupling (PCC) allowing full or partial compensation of disturbances. Power factor is the main quality index observed and it is calculated according to Conservative Power Theory - CPT. Therefore, based on the power factor measured in the grid side and the desired value for the power factor, a compensation coefficient - k is calculated continuously adjusting the amplitude of the compensation current.

[pt] O planejamento da expansão da transmissão (PET) visa identificar os novos reforços a serem implementados na rede do sistema elétrico de potência, necessá-rios para assegurar uma adequada interligação entre a demanda e a geração do sistema, ambas previstas para o horizonte de planejamento. Um bom plano de expansão deve garantir o equilíbrio entre os custos de investimento e operação, mantendo um nível satisfatório de continuidade no fornecimento de energia. En-tretanto, a identificação de boas soluções para o PET tem se tornado uma tarefa cada vez mais difícil. Isso se deve, principalmente, às características e dimensões dos sistemas atuais, incluindo o aumento na dependência de fontes renováveis, e à não linearidade e natureza combinatória do problema de otimização. Nesta dissertação é proposta uma nova metodologia para resolver o proble-ma PET com alta penetração de energia renovável, em particular a eólica. A me-todologia é baseada na aplicação de uma nova ferramenta de otimização para so-lução do PET estático, a qual é classificada como metaheurística construtiva, onde soluções viáveis de boa qualidade são paralelamente construídas a partir da topo-logia inicial, por meio de adições graduais de reforços mais atrativos para a rede. Outras heurísticas são também utilizadas. Ênfase é dada à modelagem de cenários de geração eólica, que representam a energia renovável da rede a ser planejada, a qual deverá permitir uma operação flexível e adaptada à intermitência destas fon-tes. São utilizados o critério de segurança N-1 e o modelo linear DC de rede, com a consideração de perdas ôhmicas. Uma variante do sistema IEEE RTS, com inserção de fontes eólicas, é utilizada para testar a metodologia proposta. / [en] Transmission expansion planning (TEP) aims to identify the new reinforce-ments to be installed in the electric power system, necessary to ensure an adequate interconnection between demand and generation of the system, both foreseen for the planning horizon. A good expansion plan should ensure a balance between investment and operating costs, while maintaining a satisfactory level of continui-ty in the energy supply. However, identifying good expansion solutions for TEP has become an increasingly difficult task. This is mainly due to the characteristics and dimensions of the current systems, including the increase in the dependence of renewable sources, and the nonlinearity and combinatorial nature of the optimi-zation problem. In this dissertation, a new methodology is proposed to solve the TEP prob-lem with high penetration of renewable energy, in particular wind power. The methodology is based on the application of a new optimization tool for static TEP solution, which is classified as a constructive metaheuristic, where feasible solu-tions of good quality are simultaneously constructed from the initial topology of the network, through incremental additions of reinforcements more attractive to the grid. Other heuristics are also used. Emphasis is given to the modeling of wind power scenarios, which represent the renewable energy of the network to be planned, which should allow a flexible operation and adapted to the intermittency of these sources. The security criterion N-1 and the linear DC network model are used, with the consideration of ohmic losses. A variant of the IEEE RTS sys-tem, with insertion of wind sources, is used to test the proposed methodology.

Cette thèse est une contribution à l'étude des systèmes hybrides éoliens-photovoltaïques avec batteries sur plusieurs aspects : évaluation des sources, modélisation, simulation, optimisation du dimensionnement et enfin commande et supervision. Ainsi, dans un premier temps, une étude d'impact sur l'évaluation du potentiel en énergies renouvelables sur un site donné en prenant en compte la consommation dans un habitat résidentiel (période et méthode d'acquisition des données, techniques d'évaluation, ...) est présentée. Puis, les modèles énergétiques des différents composants du système ainsi que les aspects économiques et écologiques sont définis. L'ensemble est représenté à l'aide du logiciel Matlab/Simulink. Ensuite, une méthodologie d'optimisation du dimensionnement du système multi-sources est développée et comparée à plusieurs approches, allant d'une optimisation mono-objective à une multi-objective et évaluant le coût économique et écologique de chacune de ces solutions. Une solution « pratique » est retenue pour les composants PV, éolien et batteries du système final afin d'en évaluer la viabilité énergétique, économique et écologique. Les résultats montrent un impact environnemental faible et un coût raisonnable du point de vue économique ainsi qu'une satisfaction de la charge dans les limites tolérées par l'usager. La méthode développée de dimensionnement est comparée à un outil commercial existant. Enfin, un banc expérimental PV-éolien avec batteries est mis en oeuvre avec une nouvelle technique de supervision basée sur le contrôle des courants et l'estimation de l'état de charge des batteries. / This thesis is a contribution to the study of photovoltaic-wind-battery hybrid systems for several aspects: source evaluation, modeling and simulation, design optimization and finally control and supervision. Thus, an impact study on the evaluation of renewable energy potential at a given site taking into account consumption in residential housing (period and method of data acquisition, evaluation techniques...) is presented. In addition, all the components of the system are modeled and economic and ecological aspects are defined in order to make an overall assessment of various system configurations. All models are represented using Matlab/Simulink tool. Then, a methodology for single and multi-objective design optimization of a multi-source system is developed to minimize system Life Cycle Cost (LCC), Embodied Energy (EE) and Loss of Power Supply Probability (LPSP). A "practice solution" is thus retained and evaluated. Results show a low environmental impact and a reasonable economic cost as well as a satisfaction of the load within the limits tolerated by the user. Besides, a very convincing comparison of the developed sizing method to an existing commercial tool is presented. At the end, an experimental PV-wind-battery tested is developed in laboratory to ensure a quasi-realistic emulation of hybrid system behavior for different configurations. Accordingly, a new supervision strategy based on currents control and battery state of charge estimation is successfully validated.