The influence of envelope variables on energy consumption in buildings in Vitória, Brazil

Ana Carolina Alves Bernabé

Ana Clara Alves Bernabé

Cristina Engel de Alvarez

ABSTRACT: The awareness for energy efficiency in building sector has grown during the last years in Brazil and in the World. The new energy scenario brought to light the importance of energy efficiency in commercial buildings, encouraging discussions, studies and development of a new reality based on energy efficiency. This work aims to identify how some architectonic variables affect the energy consumption in commercial buildings, verticalized and artificially conditioned, in the city of Vitória, Espírito Santo. As methodology, a reference building was modelled based on the typical features of constructions located on the bioclimatic zone of study, which could be found in literature. Then, four variables of this building were altered: window to wall ratio (WWR), solar heat gain coefficient (SHGC), absorptance of opaque surfaces and orientation of façades. The modelling and simulation of the cases were performed on the software DesignBuilder, an interface to EnergyPlus, a widely used Building Energy Simulation tool. The analysis considered the results of annual energy consumption and assessed the variation of the amount spent with air conditioning. The Window to Wall Ratio showed the highest impact on the energy consumption (12.4%), representing an increase of 32.3% on air conditioning spent. The impact of the other variables on total energy consumption followed the order: SHGC (8.7%), façades orientation (7.5%) and absorptance (4.0%). The difference between the highest and lowest total energy consumption out of all the cases analyzed reached 16.8%.

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