Experimental PIV techniques applied to the analysis of natural convection in open joint ventilated facades

摘要

In recent years, opaque ventilated facades have been widely used as passive constructive elements, specially in warm climate areas. Considering their increasing relevance, the present article focuses on the study of the thermal and energy behaviour of the open joint ventilated facades (OAT). The study of the fluid flow has been carried out by application of 2D Particle Image Velocimetry (PIV) techniques to a facade model specially designed for laboratory measurements. In this work, instantaneous and time averaged velocity fields along the ventilated cavity have been obtained for five different radiation conditions. These results have allowed to obtain a good description of the flow structures. It has been observed that under radiation conditions, the natural thermal convection produces a chimney effect that forces external air to circulate along the air cavity allowing to remove part of the heat of the facade, and thus reducing the heat transferred to the building.