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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Desempenho de sistemas de condicionamento de ar com utilização de energia solar em edifícios de escritórios. / Performance of solar air conditioning systems in office buildings.

Paulo José Schiavon Ara 14 December 2010 (has links)
A preocupação energética tem impulsionado a humanidade a buscar alternativas sustentáveis de energia. Neste contexto, os edifícios de escritórios têm um papel importante, em especial, devido ao elevado consumo de energia dos sistemas de condicionamento de ar. Para esses sistemas, a possibilidade de utilização de energia solar é uma alternativa tecnicamente possível e interessante de ser considerada, principalmente porque, quando a carga térmica do edifício é mais elevada, a radiação solar também é mais elevada. Dentre os sistemas de condicionamento de ar solar, o sistema térmico - que associa coletores solares térmicos com chiller de absorção - é o mais disseminado, na atualidade. Entretanto, dependendo do caso, outras tecnologias podem ser vantajosas. Uma opção, por exemplo, no caso de edifícios de escritórios, é o sistema elétrico - que associa painéis fotovoltaicos ao chiller convencional de compressão de vapor. Neste trabalho, para um edifício de escritórios de 20 pavimentos e 1000 m2 por pavimento, na cidade de São Paulo, no Brasil, duas alternativas de ar condicionado solar tiveram seus desempenhos energéticos analisados: o sistema térmico - com coletores solares térmicos somente na cobertura e o sistema elétrico - com painéis FV somente nas superfícies opacas das fachadas. Para isso, com o software EnergyPlus do Departamento de Energia dos Estados Unidos obteve-se as carga térmica atuantes no edifício e com a aplicação do método de cálculo de consumo de energia dos sistemas de ar condicionado solar, proposto pelo Projeto SOLAIR da União Européia, adaptado para a realidade da pesquisa, obteve-se o desempenho energético dos sistemas. Os resultados mostraram que, para o edifício de 20 pavimentos, o sistema elétrico tem o melhor desempenho energético, economizando 28% e 71% da energia elétrica que consumiria um sistema de ar condicionado convencional, em um dia de verão e de inverno, respectivamente. O sistema térmico, ao contrário, apresentou um desempenho energético ruim para o edifício estudado, consumindo, por exemplo, em um dia de verão, cerca de 4 vezes mais energia elétrica do que um sistema de ar condicionado convencional. Constatouse que isso ocorreu, pois a área coletora limitada à cobertura foi insuficiente para atender a demanda do chiller de absorção, que passou a operar com frações solares baixas, da ordem de 50% e 20%, de pico, no dia de inverno e de verão, respectivamente. Assim, constatou-se que para que o sistema térmico apresente um desempenho energético satisfatório é preciso que o edifício não seja tão alto. De fato, os resultados mostraram que somente se o edifício tivesse no máximo 2 pavimentos, o sistema térmico teria um desempenho energético melhor do que um sistema convencional. No caso de ser aplicado ao edifício térreo de 1000m2 de área, por exemplo, esse sistema economizaria aproximadamente 65% da energia elétrica do sistema convencional. Por fim, constatou-se também que o desempenho energético do sistema térmico seria elevado com a otimização da área e da tecnologia de coletores solares, com o aprimoramento do sistema de aquecimento auxiliar e com a redução da carga térmica do edifício por meio de técnicas passivas de climatização. / Energy concern has driven human kind to seek sustainable energy alternatives. In this context, office buildings have an important role, especially due to the high energy consumption of air conditioning systems. For these systems, the possibility of using solar energy is technically feasible and interesting to be considered, mainly because generally when the building thermal load is higher, the solar radiation is also higher. Among solar airconditioning systems, the thermal system - which combines solar collectors with absorption chiller - is the most widespread, nowadays. However, depending on the case, other technologies may take advantage. One option, for example, in the case of office buildings, is the electrical system - which combines photovoltaic panels with conventional vapor compression chiller. In this work, an office building of 20 floors with 1,000 m2 floor area, in Sao Paulo, Brazil, two technologies of solar air conditioning had their performance analyzed: the thermal system - presenting solar thermal collectors only on the roof and the electrical system with PV panels only on the opaque surfaces of the facades. For this, the software EnergyPlus of the United States Department of Energy obtained the building thermal load and the with the solar air conditioning energy consumption calculating method proposed by SOLAIR project of the European Union and adapted to this work, energy performance of systems was obtained. The results showed that for this building, the electrical system had the best energy performance, saving 28% and 71% of electricity that would consume a conventional air conditioning system in a summer day and a winter day, respectively. The thermal system, in contrast, showed a poor energy performance, consuming, for example, on a summer day, about four times more electricity than a conventional air conditioning system. It was found that this occurred because the collectors area limited to the roof of the building was insufficient to meet the absorption chiller demand, causing low solar fractions in the operation, of around 50% and 20% peak, in a winter day and in a summer day, respectively. Thus, in order of provide a satisfactory energy performance, the thermal system requires that the building not to be so tall. In fact, the results showed that only if the building had up to two floors, the system would perform better than a conventional system. In case of be installed in a building with the ground floor only, and floor area of 1000m2, for example, this system would save about 65% of the electricity comparing to a conventional system. Finally, it was found that this energy performance would be elevated as well with the optimization of solar collectors area and technology, with auxiliary heating system improvement and with the reduction of thermal load of the building by means of passive air conditioning techniques.
82

Dimensionamento e gestão de energia solar fotovoltaica para aplicação em sistemas automatizados isolados da rede elétrica

Borges, Leandro da Motta 27 September 2013 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-03-04T10:45:15Z No. of bitstreams: 1 leandrodamottaborges.pdf: 2242416 bytes, checksum: 10ac80b836250ec857dfe2dc8f819119 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T01:49:45Z (GMT) No. of bitstreams: 1 leandrodamottaborges.pdf: 2242416 bytes, checksum: 10ac80b836250ec857dfe2dc8f819119 (MD5) / Made available in DSpace on 2016-04-24T01:49:45Z (GMT). No. of bitstreams: 1 leandrodamottaborges.pdf: 2242416 bytes, checksum: 10ac80b836250ec857dfe2dc8f819119 (MD5) Previous issue date: 2013-09-27 / Este trabalho apresenta o estudo, dimensionamento e gestão de um sistema solar fotovoltaico isolado da rede elétrica para alimentar cargas de equipamentos de automação industrial. Um exemplo de aplicação são unidades de comando e sinalização ferroviária que, em alguns casos, são comandadas por relés e, mais atualmente, sendo substituídas por Controladores Lógico Programáveis. No sistema solar fotovoltaico isolado, o excedente de energia elétrica produzida nos painéis solares fotovoltaicos é armazenado em baterias eletroquímicas estacionárias de chumbo-ácido para posterior aproveitamento durante o período noturno e de baixa produção de eletricidade. Esse tipo de bateria apresenta efeito de memória, não pode sofrer descarga profunda ou ser submetida a tensões elevadas. Assim, este trabalho visa especificar e dimensionar um sistema solar fotovoltaico para aplicações em cargas de automação industrial isolados da rede elétrica, bem como assegurar elevada vida útil da bateria eletroquímica de chumbo-ácido sem prejudicar o rastreamento de máxima potência dos painéis solares fotovoltaicos. Para isso, uma estratégia de gestão de energia possibilita alterar o controle do conversor CC-CC que realiza a interconexão entre os painéis solares fotovoltaicos e a bateria eletroquímica. Resultados de simulação computacional apontam para o bom desempenho conceitual do sistema e seu potencial para a aplicação pretendida. / This work presents the study, design and management of a stand-alone photovoltaic system to feed industrial automation load. E examples of application are railway signaling unit controls, which in some cases are controlled by electromechanical relays and more currently being replaced by programmable logical controllers. In a stand-alone photovoltaic system, the excess of electricity produced in the photovoltaic panels is stored in lead-acid stationary electrochemical batteries for later use during the night and low electricity production periods. This kind of battery presents memory effect, cannot have deep discharge or be subjected to high voltages. Thus, this work aims to specify and size a solar photovoltaic system for applications in industrial automation loads isolated from the grid, as well as ensuring longer lifetime to electrochemical battery of lead-acid without harming the maximum power tracker of photovoltaic panels. For this, a strategy for changing power management enables the control of DC-DC converter that performs the interconnection of photovoltaic panels and electrochemical battery. Results of computer simulation indicate the good conceptual performance of the system and its potential for the intended application.
83

Planejamento de microrredes em sistemas de distribuição de energia elétrica

Rocha, Kamila Peres 29 August 2018 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-11-12T14:43:57Z No. of bitstreams: 1 kamilaperesrocha.pdf: 4837972 bytes, checksum: 8ccb175cc20788fe527b134046b240f4 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-11-23T13:11:27Z (GMT) No. of bitstreams: 1 kamilaperesrocha.pdf: 4837972 bytes, checksum: 8ccb175cc20788fe527b134046b240f4 (MD5) / Made available in DSpace on 2018-11-23T13:11:27Z (GMT). No. of bitstreams: 1 kamilaperesrocha.pdf: 4837972 bytes, checksum: 8ccb175cc20788fe527b134046b240f4 (MD5) Previous issue date: 2018-08-29 / O presente trabalho apresenta uma metodologia para o planejamento ótimo de microrredes em redes de distribuição de energia elétrica. Para tanto, é apresentada a formulação dos elementos propostos incluindo sua modelagem técnico-econômica. O objetivo principal é a abordagem das vantagens do sistema de compensação de energia elétrica estipulado pela resolução normativa n◦ 482/2012 da ANEEL, na busca por redução dos custos de energia em um horizonte de planejamento de longo prazo. Para isso, faz-se a utilização da meta-heurística denominada SIA com propósito de obter o dimensionamento otimizado dos elementos da microrrede. A determinação dessa técnica se deve a quantidade de combinações possíveis devido a complexidade do problema apresentado. É traçado, ainda, um comparativo com o método de busca exaustiva para análise das soluções geradas e do tempo computacional requerido para as duas metodologias propostas. O projeto aborda a implantação de fontes de energia renovável eólica e solar e gerador a diesel para análise de estudos de caso para consumidores comercial e residencial. Por último, é realizado um comparativo com resultados provenientes de um software de dimensionamento de microrredes, denominado HOMER Pro R . / The present work presents a methodology for the optimal planning of microgrids in electricitydistributionnetworks. Forthatreason, theformulationoftheproposedelements includingtheirtechnical-economicmodelingispresented. Themainobjectiveistoapproach the advantages of the net metering stipulated by ANEEL normative resolution 482/2012, in the search for reduction of energy costs in a long-term planning horizon. Therefore, the meta-heuristic called SIA is implemented with the purpose of obtaining the optimized sizing of the elements of the microgrid. The determination of this technique come from the amount of possible combinations due to the complexity of the presented problem. A comparison with the exhaustive search method for the analysis of the generated solutions and the computational time required for the two proposed methodologies is also drawn. The project addresses the deployment of wind and solar renewable energy sources and diesel generator for analysis of case studies for commercial and residential consumers. Finally, a comparison is made with results from HOMER Pro R, a microgrid software.
84

Integrability Evaluation Methodology for Building Integrated Photovoltaic's (BIPV) : A Study in Indian Climatic Conditions

Eranki, Gayathri Aaditya January 2016 (has links) (PDF)
India’s geographical location renders it with ample solar-energy potential ranging from 4-7 kWh/m2 daily and 2,300–3,200 sunshine hours annually. The diverse nature of human settlements (scattered low-rise to dense high-rise) in India is one of the unexplored avenues of harnessing solar energy through electricity generation using photovoltaic (PV) technology. Solar energy is a promising alternative that carries adequate potential to support the growing energy demands of India’s burgeoning population. A previous study estimates, by the year 2070, with 425 million households (of which utilizing only 20 %), about 90 TWh of electrical energy can be generated utilizing solar energy. PV is viable for onsite distributed (decentralized) power generation offering advantages of size and scale variability, modularity, relatively low maintenance and integration into buildings (no additional demand land). The application of solar PV technology as the building envelope viz., walls, façade, fenestration, roof and skylights is termed Building Integrated Photovoltaic (BIPV). Apart from generating electricity, PV has to also function as a building envelope, which makes BIPV systems unique. Even with a gradual rise in the number of BIPV installations across the world over the years, a common consensus on their evaluation has not yet been developed. Unlike PV in a ground mounted system, its application in buildings as an envelope has huge implications on both PV and building performance. The functions of PV as a building material translates well beyond electricity generation alone and would also have to look into various aspects like the thermal comfort, weather proofing, structural rigidity, natural lighting, thermal insulation, shading, noise protection safety and aesthetics. To integrate PV into a residential building successfully serving the purpose (given the low energy densities of PV and initial cost), would also mean considering factors like the buildings electricity requirement and economic viability. As many studies have revealed, 40% of electricity consumed in a building is utilized for maintaining indoor thermal comfort. Tropical regions, such as India, are generally characterized by high temperatures and humidity attributed to good sunlight, therefore, the externality considered for this study has been the impact of BIPV on the thermal comfort. Passive designs need to regulate the buildings solar exposure by integrating a combination of appropriate thermal massing, material selection, space orientation and natural ventilation. On the other hand, PV design primarily aims to maximize solar to generate maximum energy. The design requirements for climate-responsive building design may thus infringe upon those required for optimal PV performance. Regulating indoor thermal comfort in tropical regions poses a particular challenge under such conditions, as the indoor temperature is likely to be sensitive to external temperature variations. In addition, given current performance efficiencies for various PVs, high initial cost and space requirement, it is also crucial to ascertain PV’s ability to efficiently support buildings energy requirement. Thus, BIPV would require addressing, concurrently, design requirements for energy-efficient building performance, effective PV integration, and societal feasibility. A real time roof integrated BIPV system (5.25 kW) installed at the Center for Sustainable Technologies at the Indian Institute of Science, Bangalore has been studied for its PV and building thermal performance. The study aims at understanding a BIPV system (based on crystalline silicon) from the technical (climate-responsiveness and PV performance), social (energy requirement and energy efficiency) and economical (costs and benefits) grounds and identifies relevant factors to quantify performance of any BIPV system. A methodology for BIPV evaluation has been proposed (Integrability Methodology), especially for urban localities, which can also be adopted for various PV configurations, building typologies and climatic zones. In the process, a novel parameter (thermal comfort energy) to evaluate the thermal performance of naturally ventilated buildings combining climate-responsiveness and thermal comfort aspects has also been developed. An Integrability Index has also been devised, integrating various building performance factors, to evaluate and compare the performance of BIPV structures. The methodology has been applied to the 5.25 kW BIPV system and the index has been computed to be 0.17 (on a scale of 0 – 1). An insulated BIPV system (building applied photovoltaic system) has been found to be favorable for the climate of Bangalore than BIPV. BIPV systems have also been compared across three different climates (Bangalore, Shillong and Delhi) and given the consideration of the same system for comparison, the system in Delhi is predicted to have a higher Integrability than the other two systems. The current research work is a maiden effort, that aims at developing and testing a framework to evaluate BIPV systems comprising technical, social and economic factors.
85

Posouzení možnosti využití alternativních zdrojů v energetickém hospodářství výrobního areálu / Possibility of using alternative sources of energy in manufacturing facility

Malchar, Jakub January 2017 (has links)
The Master’s Thesis prospects the suitability of installing a photovoltaic system and a cogeneration unit in the LIPOELASTIC manufacturing facility and proposes their actual realization. Theoretical part describes said facility, its current energy supply situation and presents the proposed realizations' principle of operation. Practical part contains concrete calculations needed for realizations' proposal and their economic evaluation both independently and jointly.
86

Energetický audit / Energy Audit

Hrazdira, David January 2018 (has links)
The theme of this master's thesis is the elaborating of an energy audit according to the valid legislation in the Czech Republic a five-storey apartment building. The master's thesis consists of three main parts. Theoretical, Computional and Energy Audit. The theoretical part focuses on the theme of solar thermal collectors. In the calculation part, the energy consumption of the assessed object is analyzed in both the initial and the new state. The energy audit is drawn up in accordance the Decree number 480/2012 Sb. in the current version.
87

Rekonstrukce vytápění v rodinném domě / Retrofit of heating system in a family house

Doležel, Pavel January 2020 (has links)
The master’s thesis deals with the solid-fuel fired furnaces, complying with the new emission legislation, and their application in central heating. The introductory part of the thesis focuses on the theory of solid fuels combustion, pertinent legislation, and various designs of solid-fuel fired furnaces. The main part of the thesis deals with the design of a central heating system for a townhouse with a solid-fuel fired furnace as the primary heat source for central heating. A roof-mounted PV system was considered for solar-assisted domestic hot water heating. The energy performance of the house was evaluated with the use of the degree-day method and also with a detailed computer simulation in TRNSYS. As an appendix, the thesis includes the detailed engineering calculations and the engineering drawings and diagrams of the central heating system.
88

Zpracování projektu fotovoltaického systému / Project of the photovoltaic system

Ševčíková, Kateřina January 2011 (has links)
The diploma thesis deals with elaboration of project solar thermal and photovoltaic solar systems for all-season service. The theoretical part focuses on the general description of the solar thermal and photovoltaic systems, legislation of renewable sources in the Czech Republic and the status of photovoltaics in the Czech Republic. The experimental part deals with the design of measures for energy saving by using solar energy systems. These measures are proposed for construction of houses in Podolí u Brna, especially on extra-family house. The aim of the work is to make a proportioning, choosing the right parts and calculating the economic and ecologic balance. Finally, thesis gives recommendations for further action in saving energy in houses in Podolí u Brna.
89

Návrh optimalizace spotřeby elektrické energie z fotovoltaické elektrárny / Proposal for power consumption optimization of photovoltaic power plant

Mareček, Jan January 2015 (has links)
This master’s thesis is focused on opportunities of optimization of electric power consumption from photovoltaic power plant. In theoretical part are presented basic principles and possibilities of photovoltaic system connection. It continues with an overview of backup systems and types of batteries. Practical part is about prediction of production and consumption of electric power, possibilities of power management and optimization. Next chapter deals with battery life cycle and their suitability for photovoltaic system. The last part of this thesis is the quantification of the stored electric energy economic value.
90

Fotovoltaický systém pro dobíjení elektromobilu / Photovoltaic System for Recharging Electric Vehicle

Krúpa, Lukáš January 2016 (has links)
This master thesis deals with use grid-off photovoltaic system for recharging electric vehicle. First is explained the principle of converting solar energy into electric energy and theoretically describes the components of the system. Furthermore, is presented a real application of the photovoltaic power plants in the world for recharging electric vehicles but also for other uses. The next section theoretically describes the grid-off system how it shout look like in real and there are presented the possibilities of choice of components. The main part is the actual construction of the grid-off system for recharging electric vehicle and measurement. The conclusion of this thesis is made up for the expected economic recovery of the entire system.

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