Acoustical and airflow considerations concerning double-layered façades with openings for natural ventilation

Department of Building Physics and Building Ecology, TU Vienna, Austria

^* Corresponding author: amahdavi@tuwien.ac.at

Abstract

Numbers of factors such as noise exposure may constrain the use of natural ventilation, especially in the urban settings. Noise exposure was the motivation behind a previous research effort, recognizing that noise exposure hampers the operation of windows for natural ventilation. Thereby, specific designs of double-leaf façade solutions for concurrent natural ventilation and noise protection were empirically investigated. Tested variables included the position and size of the openings, the relative displacement of openings in the façade’s two layers, as well as acoustical dampening (sound absorption) in the interstitial space between the two layers. The study of the models estimated the resulting sound insulation level of double-layered façades as a function of the aforementioned variables. In the present contribution, we further examine the airflow implications of the aforementioned double-façade configurations via computational fluid dynamic application based on a generic single-zone space. Natural ventilation efficiency in the building is evaluated by means of computed mean velocity and age of air inside the zone. High-resolution 3D steady CFD simulations of single-sided ventilation are performed for 9 configurations (sizes and positions) of the openings in the double-layered façade. The results illustrate the effects of these configuration on air flow circumstances in the test space.