CFD model of air movement in ventilated fa ade: comparison between natural and forced air flow

This study describes computational fluid dynamics (CFD) modeling of ventilated fa ade. Ventilated fa ades are normal fa ade but it has an extra channel between the concrete wall and the (double skin) fa ade. Several studies found in the literature are carried out with CFD simulations about the behavior of the thermodynamic phenomena of the double skin fa ades systems. These studies conclude that the presence of the air gap in the ventilated fa ade affects the temperature in the building skin, causing a cooling effect, at least in low-rise buildings. One of the most important factors affecting the thermal effects of ventilated fa ades is the wind velocity. In this contribution, a CFD analysis applied on two different velocity assumptions for air movement in the air gap of a ventilated fa ade is presented. A comparison is proposed considering natural wind induced velocity with forced fan induced velocity in the gap. Finally, comparing temperatures in the building skin, the differences between both solutions are described determining that, related to the considered boundary conditions, there is a maximum height in which the thermal effect of the induced flow is significantly observed.