Este trabalho é um estudo da aplicação de um sistema que utiliza a cogeração para hotéis localizados na cidade de Porto Alegre, RS, Brasil. Foi analisada a implantação desse tipo de sistema, também chamado de CHP (Combined Heat and Power), de um ponto de vista econômico e energético. A questão econômica foi determinada pela viabilidade através de métodos de análise quantitativa, neste caso, dando enfoque ao tempo de retorno do investimento. Para a análise energética foi realizado o estudo dos consumos e demandas anuais da operação do prédio através da ferramenta de simulação térmo-energética de edificações. O software escolhido foi o EnergyPlus. Essas análises, energéticas e econômicas, foram realizadas através de uma comparação entre o hotel sem o sistema de CHP e o hotel com o sistema de CHP. O hotel hipotético simulado foi definido através de um levantamento de informações a respeito do desempenho energético de hotéis que funcionam em Porto Alegre. Além dos estudos energéticos e econômicos, foram realizadas variações em parâmetros do hotel para tentar abranger uma série de possíveis cenários e verificar suas viabilidades econômicas. Foi visto que a cogeração pode trazer redução de custo operacional mesmo não tendo um menor consumo energético anual. Em alguns cenários o tempo de retorno do investimento apresentou valor abaixo dos seis anos, sendo considerado como uma boa opção de investimento. / This work is a study of the application of a CHP (Combined Heat and Power) system in hotels built in the city of Porto Alegre, RS, Brazil. This system was analyzed from an economic and energetic point of view. The economic matter on its viability perspective was determined through quantitative methods, in this case, with the focus on the time frame for the investment's return. For the energetic analysis, a annual energy consumption and demand study was performed utilizing a whole-building energy model with computer simulation. The chosen software was EnergyPlus. The analyses, energetic and economic, were performed through a comparison between the hotel without the CHP system and with the CHP system. The hypothetic simulated hotel was determined by a data survey on the energetic performance of hotels build in Porto Alegre. In addition to the energetic and economic studies, some parametric variations to the hotel were made to include a series of possible scenarios and check their economic viability. It was observed that the CHP can provide some operational cost reductions even without presenting a lower annual energetic consumption. In some scenarios, the time to return the investment showed figures lower than six years, being considered a good investment option.

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Being the major energy consumer of electricity and natural gas, buildings consume more than 70% of electricity and 30% of natural gas. On the way to green buildings and zero energy buildings, investigation and improvement of energy efficiency of the buildings will result in significant reductions in energy demands and CO2 emissions / make cost savings and improve thermal comfort as well. Key steps of a successful green, energy efficient building can be summarized as whole building design, site design, building envelope design, lighting and day lighting design and HVAC system design. Energy Plus&reg / software is mainly developed to simulate the performance of the buildings in the view of the above listed points. The design of a building or the analysis of an existing building with the software will show how efficient the building is or will be, and also helps finding the best efficient choice of the whole building system. Thesis focuses on the effect of changes in building envelope properties. In Turkey, topic of green buildings has recently started to be studied. Therefore, this thesis aims to present efficient technologies providing energy savings in buildings, to present green building concept and alternative energy simulation software. In the context of this study, design, methods and material guidelines are introduced to reduce energy needs of buildings and to bring in the green building design concept. Building and system parameters to enhance building energy efficiency and energy savings together with green building principles are summarized. Moreover, whole building energy analysis methods and simulation steps are explained / year-round simulation is performed for a sample building / as a result, energy savings about 36% is achieved.

Current designs of high performance buildings utilize hourly building energy simulations of complex, interacting systems. Such simulations need to quantify the benefits of numerous features including: thermal mass, HVAC systems and, in some cases, special features such as active and passive solar systems, photovoltaic systems, and lighting and daylighting systems. Unfortunately, many high performance buildings today do not perform the way they were simulated. One potential reason for this discrepancy is that designers using the simulation programs do not understand the analysis methods that the programs are based on and therefore they may have unreasonable expectations about the system performance or use. The purpose of this study is to trace the origins of a variety of simulation programs and the analysis methods used in the programs to analyze high performance buildings in the United States. Such an analysis is important to better understand the capabilities of the simulation programs so they can be used more accurately to simulate the performance of an intended design. The goal of this study is to help explain the origins of the analysis methods used in whole-building energy simulation, solar system analysis simulation or design, and lighting and daylighting analysis simulation programs. A comprehensive history diagram or genealogy chart, which resolves discrepancies between the diagrams of previous studies, has been provided to support the explanations for the above mentioned simulation programs.

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