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Abstract(s)
O objetivo principal desta dissertação é o estudo da aplicabilidade que os sistemas de aproveitamento de energias renováveis têm na reabilitação de edifícios de habitação. Para tal, analisou-se qual dos sistemas usados com mais frequência é o mais vantajoso, considerando a relação entre a classe energética e o investimento monetário necessário. Utilizou-se uma fração de um edifício de habitação como caso de estudo, situada numa zona urbana, a uma distância muito curta da costa marítima, no distrito do Porto. Iniciou-se este estudo com a caracterização do edifício e respetiva determinação das necessidades nominais anuais de energia para aquecimento, para arrefecimento, para preparação de águas quentes sanitárias e por fim, as necessidades nominais de energia primária. Com isto, obteve-se a classe de eficiência energética da habitação sem a utilização de qualquer tipo de sistema de aproveitamento de energia renovável. Verificou-se assim que o edifício em análise possuía a classe B - sendo superior à classe mínima exigida pela legislação para grandes reabilitações, a classe C. De seguida, procedeu-se ao estudo dos sistemas de energia renovável, apresentando sistemas aplicáveis na habitação e obtendo as novas classes de eficiência energética, com a utilização de cada sistema. Os sistemas solar térmicos, termossifão e circulação forçada, são os que conseguem baixar mais o rácio da eficiência energética, em cerca de 30%, e o sistema solar fotovoltaico apenas o diminui em pouco mais de 10%. Foi assim possível retirar algumas ilações sobre os sistemas mais eficientes, ou seja, os sistemas que tem como função preparar águas quentes sanitárias, pois, iriam mitigar necessidades nominais de energia, enquanto que o sistema de produção de energia elétrica iria contribuir mais para uma melhoria energética. Foi também realizada uma simulação com a implementação de dois sistemas (térmico termossifão e fotovoltaico), onde se verificou uma melhoria bem significativa da classe energética da fração. Finalmente, efetuou-se uma análise dos investimentos necessários para a implementação destes sistemas e foi estimado o período de retorno destes investimentos. Assim, obteve-se os sistemas mais viáveis a implementar na moradia. No ponto de vista de melhorar a classe de eficiência energética, seria o sistema solar térmico do tipo circulação forçada para produção de águas quentes sanitárias. Do ponto de vista financeiro face às diminuições percentuais do rácio de eficiência energética obteve-se o sistema solar térmico do tipo termossifão, apresentando também o menor período de retorno (5 anos e 7 meses). Já o sistema solar fotovoltaico, é o que necessita mais investimento do ponto de vista de diminuir o rácio de eficiência energética e tem o maior período de retorno (11 anos). No entanto, o investimento nos dois sistemas de energia renovável em simultâneo teria um período de retorno de 9 anos.
The main objective of this dissertation is the study of the applicability that renewable energy systems have in the rehabilitation of residential buildings. To this end, it was analyzed which of the systems used most frequently is the most advantageous in the relationship between the energy class and monetary investment. A residential building was used as a case study, located in an urban area, a very short distance from the seacoast, in the district of Porto. It started with the characterization of the building and the respective determination of the nominal annual energy needs for heating, for cooling, for the preparation of domestic hot water and finally, the nominal primary energy needs. With this, the energy efficiency class of the house was obtained without using any type of renewable energy use system. After this, it was found that the building under analysis did not have a very efficient class, class B-. Still, higher than the minimum class required by the regulation, C. The advantage of the building having this class is that the implementation of renewable energy systems could considerably change the class, and therefore, it was possible to derive a correct deduction from which better to promote energy efficiency. Then, we proceeded to the study of renewable energy systems, presenting systems applicable to housing, and calculating the new energy efficiency classes, using each system. The solar thermal, thermosyphon and forced circulation systems are the ones that decrease the energy efficiency ratio the most, by about 30% and the solar photovoltaic system only decreases 1%. Consecutively, lessons were learned from the most efficient systems, that is, the systems that have the function of preparing domestic hot water, as they would mitigate nominal energy needs, while the electricity production system would contribute more to an energy improvement. A simulation was also carried out with the implementation of two systems (thermosiphon and photovoltaic thermal), where there was a very significant improvement in the energy class, rising to A. Finally, an analysis of the investments required for the implementation of renewable energy systems was carried out in view of the percentage decreases in the energy efficiency ratio. Still linked to the economic analysis, the payback period for each system used was estimated, to predict how long it would take to obtain a profit from the investment made. Thus, the most viable systems to be implemented in housing were obtained. From the point of view of improving the energy efficiency class, it would be the forced circulation solar thermal system to produce domestic hot water. From a financial point of view, in view of the percentage decreases in the energy efficiency ratio, the thermosyphon solar thermal system was obtained, also presenting the shortest payback period (5 years and 7 months). The solar photovoltaic system, on the other hand, is the one that needs the most investment in terms of reducing the energy efficiency ratio and has the longest payback period (11 years). However, investment in both renewable energy systems simultaneously would have a payback period of 9 years.
The main objective of this dissertation is the study of the applicability that renewable energy systems have in the rehabilitation of residential buildings. To this end, it was analyzed which of the systems used most frequently is the most advantageous in the relationship between the energy class and monetary investment. A residential building was used as a case study, located in an urban area, a very short distance from the seacoast, in the district of Porto. It started with the characterization of the building and the respective determination of the nominal annual energy needs for heating, for cooling, for the preparation of domestic hot water and finally, the nominal primary energy needs. With this, the energy efficiency class of the house was obtained without using any type of renewable energy use system. After this, it was found that the building under analysis did not have a very efficient class, class B-. Still, higher than the minimum class required by the regulation, C. The advantage of the building having this class is that the implementation of renewable energy systems could considerably change the class, and therefore, it was possible to derive a correct deduction from which better to promote energy efficiency. Then, we proceeded to the study of renewable energy systems, presenting systems applicable to housing, and calculating the new energy efficiency classes, using each system. The solar thermal, thermosyphon and forced circulation systems are the ones that decrease the energy efficiency ratio the most, by about 30% and the solar photovoltaic system only decreases 1%. Consecutively, lessons were learned from the most efficient systems, that is, the systems that have the function of preparing domestic hot water, as they would mitigate nominal energy needs, while the electricity production system would contribute more to an energy improvement. A simulation was also carried out with the implementation of two systems (thermosiphon and photovoltaic thermal), where there was a very significant improvement in the energy class, rising to A. Finally, an analysis of the investments required for the implementation of renewable energy systems was carried out in view of the percentage decreases in the energy efficiency ratio. Still linked to the economic analysis, the payback period for each system used was estimated, to predict how long it would take to obtain a profit from the investment made. Thus, the most viable systems to be implemented in housing were obtained. From the point of view of improving the energy efficiency class, it would be the forced circulation solar thermal system to produce domestic hot water. From a financial point of view, in view of the percentage decreases in the energy efficiency ratio, the thermosyphon solar thermal system was obtained, also presenting the shortest payback period (5 years and 7 months). The solar photovoltaic system, on the other hand, is the one that needs the most investment in terms of reducing the energy efficiency ratio and has the longest payback period (11 years). However, investment in both renewable energy systems simultaneously would have a payback period of 9 years.
Description
Keywords
Energias renováveis Classe de eficiência energética Rácio de eficiência energética Necessidades nominais de energia Renewable energies Energy efficiency class Energy efficiency ratio Nominal energy needs