Análise de soluções construtivas de envoltórias de edificações para as zonas bioclimáticas brasileiras quanto ao desempenho térmico – estudo para uma habitação do tipo loft

Abstract

The civil construction sector is one of the activities that causes the most negative impacts on the environment, especially due to high energy consumption during the building's use phase. Given this context, sustainable construction has been gaining prominence in recent decades. This work seeks to analyze the thermal performance of different configurations of the envelope (walls and roofs) of a loft, in addition to proposing the best solutions for each Brazilian bioclimatic zone. In a first step, the value of thermal transmittance and thermal capacity was calculated, according to the ABNT NBR 15220:2022 standard, for each type of envelope, considering various combinations, between normal coating mortar, insulating mortar and types of coverage with different thermal properties. After the calculations, an assessment of the thermal performance of the housing unit was carried out using a simplified procedure, in accordance with the ABNT NBR 15575:2021 standard. In the second stage, in a computer simulation, using the TRNSYS 17 program, the energy required for both cooling and heating of the internal environment of the hypothetical building was calculated over the course of a year, composed of the same envelope configurations considered in the firststage. After the simulations, another procedure, established in the NBR 15575 standard, made it possible to evaluate whether the analyzed loft envelope has thermal performance classified as minimum, intermediate or superior. The results demonstrated that, among the constructive elements and components studied, the type of roof was the variable that had the most impact on the thermal performance of the loft. Furthermore, it was found that the use of roofs with low thermal transmittance values and ceramic blocks are potentially more suitable solutions to obtain more thermally efficient buildings for the Brazilian context. By combining the best construction solutions, a significant reduction in energy consumption was achieved compared to the reference model. In all bioclimatic zones, configurations with lower U-value roofs were able to reduce at least 30% of the total annual heat load.