Avaliação de desempenho térmico de edifício estruturado em aço : o caso sede da Prefeitura Municipal de Mariana, MG.

The evaluation of building thermal performance, by numerical simulation, can greatly contribute to improving the thermal comfort of built environments and a reduction in energy consumption, in the heating and / or cooling of environments, providing means to optimize projects in the energy performance of buildings. So when conditions for human comfort within the built environment can be investigated by numerical simulation, even during the pre-design, architectural and bioclimatic strategies can be set so as to minimize the gains of heat and improve the performance of the building. In this research, to evaluate the thermal performance in building, was use as object of study, the city hall of Mariana, structured in steel construction, which presents problems of thermal comfort to its users, particularly in periods of summer, due to the high internal temperatures. It is used a computer program EnergyPlus to perform the simulations with emphasis on thermal analysis and proposes to some architectural strategies for improving the performance of the heat building. It is a condition that naturally ventilated building and apply the method of natural ventilation through the thermal areas (rooms) of the computer program. It was proposed architectural strategies such as replacing the existing coverage in policabornate by a ceramic tile and / or tile metal type sandwich, an increase of openings in the central corridor of the building and placement of sheds in the central part of the coverage. The results indicate that the strategy that replaces part of the coverage in policabornate and that minimizes the direct solar radiation by the coverage, and the placement of sheds, which assists in the ventilation building, provide an improved performance in the heat of the building of 25 to 35% , for the current architectural setting. In this context, the numerical simulation represents an important tool, however, it is necessary that they have a correct definition of the relevant variables in interactions between the thermal building (characteristics of the project as volume, solar orientation, closing systems and coverage, profile occupation desired) and the external environment (the local climate).