Análise comparativa de simulação de ventilação em contexto urbano com coeficientes de pressão tabelados e oriundos de CFD

Abstract

The limited availability of natural resources raised a global awareness to the necessity of optimizing the consumption of these resources in the civil construction. Thermal comfort is an important factor in the pursuit of making sustainable buildings since active conditioning systems are quite responsible for the high energy consumption in buildings. A properly designed natural ventilation is capable to provide thermal comfort during most of the time in the many climatic regions of Brazil. The use of thermal simulations assists the design process of natural ventilation, in which the context where the building is inserted must be considered. The aim of this research is to evaluate the influence of the pressure coefficients in the natural ventilation of an isolated residential building located in a specific context created in the city of Porto Alegre. The pressure coefficients are relevant components of the equations that evaluate the natural ventilation in the computer simulation. The method applied in this research relied on a Computational Fluid Dynamics simulation to obtain pressure coefficients specific to the context created and compared to the widely used AIVC pressure coefficients. In order to analyze the impact of the different pressure coefficients, the housing unit was modeled in an energy simulation software. Hence, it was simulated with the CFD pressure coefficients and the AIVC database pressure coefficients. The results found indicated overpredicted levels of air exchange for the AIVC pressure coefficients, considering the context evaluated. Differences in hourly operative temperature reached 1.05º C between the two models.