Research of Design Features that Influence Energy Consumption in Office Buildings in Belo Horizonte, Brazil

Buildings in Brazil in the residential, commercial and public sectors represent, according to the National Energy Balance in 2015, 50% of the total electricity consumption of the country. According to the National Energy Plan 2030, buildings energy consumption is projected to grow 3.7% per year by 2030. Thus, understanding of the architectural variables that influence the consumption of buildings has significant importance to contribute to the reduction of the expected energy demand for these buildings. The aim of this work is, therefore, the analysis of the architectural variables in the 102 office buildings of medium and large electricity consumption in the city of Belo Horizonte for which the monthly consumption per square meter was obtained. Then, the sample was segmented considering the following parameters: air conditioning system type, window-to-wall ratio, existence of glass facades, average absorptance of the walls, type of glass, existence of solar protection and construction decade. This segmentation was statistically treated using the frequency of occurrence of the listed building features and their influence on consumption of the sample was analyzed. The results indicate that naturally conditioned or mixed-mode air conditioned system buildings consume up to 58.7% less electricity per area in comparison with buildings with central conditioning systems in the city. This is explained by the fact that Belo Horizonte is a city with a mild climate with high percentage of comfort hours when natural ventilation is used. This discussion becomes important once it is believed that the analysis of such data can contribute to presenting guidelines to designers and legislative bodies to improve the building design decisions in order to achieve lower electricity consumption in buildings.