Numerical and experimental study of an airing device for controlled natural ventilation of a building

The rationale of an advanced natural ventilation system should be to control airflows and air temperature during winter, and to avoid unnecessary energy losses and local draught, while maintaining an adequate ventilation rate. On the other hand, natural driving forces (pressure head due to buoyancy and wind) vary significantly during the heating season. A prototype of a new device for controlled natural ventilation of buildings has been designed with the aim of avoiding cold draughts and excessive energy consumption during the coldest periods as well as ensuring the right amount of airflow even during mid-seasons. The device has been numerically studied by means of a commercial Computational Fluid Dynamics (CFD) code and has subsequently been built and experimentally tested. The CFD calculations were validated and used to assess the practical possibility of controlling the very low airflow rates typical of natural ventilation. Results will be used to investigate the comfort conditions in a room equipped with such a device during a normal heating season.