CFD Simulation Supported Development of Wind Catcher Shape Topology in a Passive Air Conduction System (PACS)

Abstract

New studies and reports are published on a daily basis about the dangers of climate change and its main causes: humanity’s constantly growing population, the built environment and resource consumption. The built environment is responsible for approx. 40% of the total energy consumption, and a significant part comes from maintaining an appropriate indoor comfort environment by heating ventilation and air conditioning. Though contemporary studies have achieved a wide knowledge about natural ventilation and passive air conducting systems (PACS) and their applicability, further investigations are necessary to deepen the aerodynamic topology of air conducting building structures’ shape properties. Hence, in our current research we conducted a series of tests applying different wind catcher geometries. The methodology of this work is based on the authors’ previous work, where passive air conduction systems were compared with different airflow directions via computational fluid dynamic simulations (CFD). After finding the better performing PACS (a downdraught system), this research evaluates whether further improvements in ventilation efficiency are possible due to the aerodynamic shaping of the roof integrated inlet structures. Four different wind catcher geometries were examined to determine the most advantageous dimensional settings in the natural ventilation system’s given boundaries. After multiple series of basic and developed calculation runs, diverse shape designs of the passive air conduction inlet (PACI) were examined, including wind deflector geometries. The initial reference wind catcher’s air change rate was increased by approx. 11%. The results deliver the potential measure of improvements achievable in the aerodynamic shape design of structures under identic conditions of the same building domain. As a consequence, more sophisticated natural ventilation structural solutions will be possible in more operation cost- and performance-effective ways.