Computational modeling of natural ventilation in low-rise non-rectangular floor-plan buildings

Abstract

Natural ventilation (NV) is a relevant passive strategy for the design of buildings in seek of energy savings and the improvement of the indoor air quality and the thermal comfort. The main aim of this work is to present a comprehensive NV modeling study of a non-rectangular floor-plan dwelling. Given the arbitrary shape of the building, recourse is made to computational fluid dynamics (CFD) to determine the surface-averaged pressure coefficients (Cp¯). The CFD model was calibrated to match experimental data from an extensive wind tunnel database for low-rise buildings. Then, Cp¯ computation via CFD is used to feed the building performance simulation software EnergyPlus, in replacement of the built-in Swami and Chandra parametric model that is only valid for estimating Cp¯ in rectangular floor-plan buildings. This computational tool is used to investigate the effect of NV on the thermal performance and the airflow rate in a social housing located in the Argentine Littoral region. Simulation results of the considered building show that NV enables to reduce even more than 65% of the cooling degree-hours. Furthermore, regarding to the Cp¯ source (either CFD or Swami and Chandra’s), it is also found that this data has a considerable effect on the airflow rates, but a little effect on the thermal performance.