Impacto do método de modelagem de modelagem de pontes térmicas: estudo em edifício residencial na zona bioclimática 2.

Abstract

The impact of thermal bridges and it’s consideration in calculations of thermal transmittance is a subject that has been discussed in several countries in the world and in regions of cold climate in Brazil. The presence of vulnerable points in the envelope of the building may influence the thermal energy performance, and may also have consequences for the envelopment of the building, such as favoring conditions for the formation of filamentous fungi. Globally, several countries already have standars or regulations on the subject, in Brazil, none of the regulations deals with this topic. This work aims to evaluate the impact of thermal bridges of reinforced concrete structure on the thermal energy performance of a residential building in bioclimatic zone 2. The modeling of the thermal bridges in the EnergyPlus simulation software was configured considering five approaches. Approach 1 treats the modeling of the building as it occurs in a real building, separating the thermal bridges and adopting different materials and thermal transmittance for thermal bridge in the structure and for the rest of the vertical closures; the approach 2 considers a simplified modeling, through an equivalent wall, where the horizontal closures are composed of a single plane with no differentiation of materials and thermal transmittance between structure and wall, as buildings are usually modeled for computational simulation. Approach 3 considers a simplified modeling, but with the weighting between the structural areas and vertical closures to configure thermal transmittance and thermal capacity. Approach 4 considers an equivalent wall modeling, but with the thermal transmittance of the horizontal closure increased considering the ISO 10.211 with the help of THERM 7.4 software, considering the thermal capacity of the ceramic. And the approach 5 uses the same thermal transmittance values adopted for approach 4, but with the thermal capacities of the concrete and ceramic wall weighted. The results show that the type of model influences the values of energy consumption in the building. The different models can reach a consumption difference of up to 13% when compared to the approach that disregards the thermal bridges with those that consider thermal bridge calculation. The level of envelope insulation also interferes with differences in consumption observing the 5 approaches.