Functional Aerodynamics for the Optimal Temperature and Energy Regime of the Double-Skin Transparent Facade

Boris Bielek

Slovak University of Technology in Bratislava, Faculty of Civil Engineering, Slovakia

Abstract: Double-skin transparent façades of buildings, using a renewable energy source of solar radiation, have a wide application in modern façade building technology. Functional aerodynamics is necessary for its correct function, i.e., to ensure the constant flow of the air through its cavity in every climatic condition. This article deals with the dynamics of air flow through the cavity, based on effect of the wind, natural convection and its combination. In a windless climate conditions, where the airflow dynamics in the cavity is based on natural convection, the important aerodynamic parameter is the overall aerodynamic resistance of the cavity, which is the sum of the friction resistance and local resistances alongside of the air movement trajectory through the cavity. The value of the total aerodynamic resistance of the cavity shall be less than the force of the convective buoyancy of air in the cavity. Under of the effect of the wind, the air flow rate in the cavity and also the temperature and energy mode of the cavity are dependent on the value of the highly variable external pressure coefficient, quantification of which is the typical task of aerodynamics of buildings solved on rigid model in wind tunnel.

Key words: double-skin transparent façade, temperature and energy regime of the façade, aerodynamic resistance of the cavity