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Abstract(s)
Este trabalho foi desenvolvido no âmbito da Unidade Curricular de Tese/Dissertação do Mestrado em Engenharia Eletrotécnica e de Computadores do ISEP e tem como foco de estudo a avaliação energética de portagens em autoestradas, a identificação de oportunidades de melhoria economicamente viáveis e a implementação de um caso prático em portagens da empresa Ascendi. Com o crescente aumento do consumo energético a nível mundial e a elevada exploração dos recursos fósseis existentes, é cada vez mais premente a necessidade de procurar soluções criativas de eficiência e até a possibilidade de produção de energia para autoconsumo. O consumo de energia elétrica nas portagens da Ascendi representa um custo anual na ordem de 300 mil €, parte relevante da estrutura de custos de operação, facto que justifica o interesse na identificação de oportunidades de otimização. Numa primeira etapa do estudo foi elaborada a caracterização das infraestruturas consumidoras de energia nas portagens, a análise das faturas de eletricidade, a desagregação das mesmas pelos grupos de consumo, nomeadamente, sistema de cobrança de portagens, iluminação e climatização. Esta fase permitiu identificar as necessidades energéticas e eventuais desperdícios no consumo em cada grupo de consumo; resumidamente, 20% do consumo total é atribuído ao sistema de cobrança; 20% à climatização e 60% à iluminação. Concluída a primeira etapa, foi realizado um estudo ao estado atual da arte sobre diferentes soluções para permitir posteriormente apresentar propostas de eficiência energética. A pesquisa incidiu na tecnologia de iluminação LED, por ser comparativamente mais eficiente, ter uma vida útil superior, reduzindo assim os custos com manutenção, evidenciando-se como uma alternativa economicamente viável para a iluminação pública existente na zona da portagem e respetivos nós de ligação. O estudo recaiu também na tecnologia de iluminação com tubos solares, por se apresentar como totalmente “limpa”, uma vez que a sua fonte é a irradiação solar. Todavia, não se considerou aplicável, visto que a sua instalação nas infraestruturas existentes implicaria complexa construção civil. Por último, a pesquisa recaiu nas unidades de produção para autoconsumo (UPAC) com recurso a painéis fotovoltaicos. Esta tecnologia apresenta-se em Portugal como a terceira fonte de captação de energia renovável, sendo a que mais cresce nos últimos anos. Por um lado, o fotovoltaico tem evoluído significativamente com soluções de células monocristalinas mais eficientes, por outro lado, as últimas alterações à legislação em Portugal viabilizam a utilização destes sistemas numa produção para autoconsumo e venda do excedente à rede elétrica nacional. Por fim, foram identificadas medidas de melhoria de eficiência energética, umas implementadas no decorrer desta dissertação, outras a implementar futuramente. A identificação de melhorias estende-se a todos os grupos de consumo acima referidos, sendo as mais relevantes, a otimização obtida a nível dos equipamentos de cobrança, a identificação de ações de manutenção que melhorem a eficiência nos sistemas de climatização, a substituição da iluminação pública de vapor de sódio por LED e ainda o projeto de uma UPAC. Para suporte à análise das medidas ainda a implementar, foram realizados testes locais, em condições de operação real, quer ao nível da iluminação pública, quer na avaliação das condições para implementação da UPAC. O projeto de dimensionamento da UPAC foi realizado com suporte a softwares profissionais de simulação, respeitando uma metodologia em linha com o estado da arte estudado. Essa metodologia compreende as etapas seguintes: determinação do local de instalação da central fotovoltaica, análise do mesmo e definição das características do local e do projeto; seleção dos módulos fotovoltaicos; seleção do inversor; configuração da disposição do sistema e definição da potência de ligação à rede. Para completar a análise da viabilidade das soluções propostas foi efetuado um estudo económico onde se apresenta os períodos necessários retorno dos respetivos investimentos, as taxas de internas de retorno e os valores atuais líquidos para a substituição da iluminação pública e a UPAC.
This project was developed for the Master’s thesis module in ISEP’s Electrotechnical and Computer Engineering course and aims at studying the energetic evaluation of motorway tolls, the identification of economically viable opportunities for improvement and the implementation of a practical case in one of Ascendi’s motorway tolls. The increased growth of global energy consumption and the extreme exploitation of fossil resources arise the need for creative efficiency solutions and even the possibility to produce self-consumption energy. Ascendi’s tolls energy consumption represents an annual budgetary cost of 300 thousand euros, a significant share of the overall operational costs, which justifies the interest in identifying optimization opportunities. In the first stage of this study, energy consuming infrastructures in tolls were described and electricity bills were analysed and sorted by consumption groups, namely toll systems, lighting and acclimatization. This analysis made it possible to determine energy requirements and potential consumption waste in each of the groups, the shares of total consumption being 20% for toll systems, 20% for acclimatization and 60% for lighting. Having completed the first stage, it became necessary to study the current situation in order to further present energy efficiency proposals. The research focused on LED lighting technology as it is cheaper by comparison and it has a longer useful life, therefore reducing the costs of maintenance, establishing itself as an economically viable alternative for the public lighting of the toll area and connections roads. Focus was also on solar tubes lighting technology, a form of completely clean energy as it uses solar irradiation as its source. However, this alternative was not viable, because of the complex civil engineering works required for its installation in the existing structures. Finally, focus was on self-consumption energy production using photovoltaic panels. In Portugal, this is the third source of renewable energy and the one with the largest growing rates in recent years. The photovoltaic system has significantly evolved, presenting now more efficient with the monocrystalline cells. Furthermore, recent amendments to the Portuguese legislation have enabled the use of these systems for the production of self-consumption energy and the selling of the electric energy surplus to the national electrical network. Finally, improvement measures were identified, some of which have already been implemented as others are still to implement. The identification of improvements extends to all consumption groups mentioned above, being the most relevant the optimization of tolling equipment, the identification of maintenance procedures that improve the efficiency of acclimatization systems, the replacement of sodium vapour lamps used in public lighting with LED and a self-consumption energy production project. In order to ensure the implementation of the proposed measures, local tests were conducted, in the context of real working conditions as far as public lighting and evaluation of the conditions required to implement self-consumption energy production projects are concerned. The scaling of the self-consumption energy production project was conducted based on professional simulation software, according to a methodology in line with the current state of the art of the subject studied. The above-mentioned methodology consists of the following stages: determination of the location for the photovoltaic plant installation, its analysis and description; selection of the photovoltaic modules; selection of the inverter; configuration of the system’s layout and definition of the total capacity for the network connection. To conclude the analysis of the viability of the solutions proposed, an economical study was conducted, in which the payback time for a return on investments, the internal rate of return and the net present values for the replacement of public lighting and selfconsumption energy are presented.
This project was developed for the Master’s thesis module in ISEP’s Electrotechnical and Computer Engineering course and aims at studying the energetic evaluation of motorway tolls, the identification of economically viable opportunities for improvement and the implementation of a practical case in one of Ascendi’s motorway tolls. The increased growth of global energy consumption and the extreme exploitation of fossil resources arise the need for creative efficiency solutions and even the possibility to produce self-consumption energy. Ascendi’s tolls energy consumption represents an annual budgetary cost of 300 thousand euros, a significant share of the overall operational costs, which justifies the interest in identifying optimization opportunities. In the first stage of this study, energy consuming infrastructures in tolls were described and electricity bills were analysed and sorted by consumption groups, namely toll systems, lighting and acclimatization. This analysis made it possible to determine energy requirements and potential consumption waste in each of the groups, the shares of total consumption being 20% for toll systems, 20% for acclimatization and 60% for lighting. Having completed the first stage, it became necessary to study the current situation in order to further present energy efficiency proposals. The research focused on LED lighting technology as it is cheaper by comparison and it has a longer useful life, therefore reducing the costs of maintenance, establishing itself as an economically viable alternative for the public lighting of the toll area and connections roads. Focus was also on solar tubes lighting technology, a form of completely clean energy as it uses solar irradiation as its source. However, this alternative was not viable, because of the complex civil engineering works required for its installation in the existing structures. Finally, focus was on self-consumption energy production using photovoltaic panels. In Portugal, this is the third source of renewable energy and the one with the largest growing rates in recent years. The photovoltaic system has significantly evolved, presenting now more efficient with the monocrystalline cells. Furthermore, recent amendments to the Portuguese legislation have enabled the use of these systems for the production of self-consumption energy and the selling of the electric energy surplus to the national electrical network. Finally, improvement measures were identified, some of which have already been implemented as others are still to implement. The identification of improvements extends to all consumption groups mentioned above, being the most relevant the optimization of tolling equipment, the identification of maintenance procedures that improve the efficiency of acclimatization systems, the replacement of sodium vapour lamps used in public lighting with LED and a self-consumption energy production project. In order to ensure the implementation of the proposed measures, local tests were conducted, in the context of real working conditions as far as public lighting and evaluation of the conditions required to implement self-consumption energy production projects are concerned. The scaling of the self-consumption energy production project was conducted based on professional simulation software, according to a methodology in line with the current state of the art of the subject studied. The above-mentioned methodology consists of the following stages: determination of the location for the photovoltaic plant installation, its analysis and description; selection of the photovoltaic modules; selection of the inverter; configuration of the system’s layout and definition of the total capacity for the network connection. To conclude the analysis of the viability of the solutions proposed, an economical study was conducted, in which the payback time for a return on investments, the internal rate of return and the net present values for the replacement of public lighting and selfconsumption energy are presented.
Description
Keywords
Eficiência Energética Iluminação LED Dimensionamento de Sistemas Fotovoltaicos Investimento Responsabilidade Ambiental Ascendi Energy Efficiency LED lighting Photovoltaic System Project Investment Environmental Responsibility