Natural Ventilation of Buildings by Using Venturi Devices Placed on the Rooftops

A Venturi channel is considered when assessing the viability of using such a device as a component of a hybrid ventilation system. The model of the Venturi channel at a scale of 1:2 was placed in a parallel air current, and tests were performed in order to settle down the optimum section of the narrowed area of the channel, where a ventilation tube should be placed. The best results were obtained for the air approach velocity of 2.2 m/s, corresponding to 6.4 m/s in the narrowed section and 2 m/s in the ventilation tube. According to these data, an indoor space of 80 m² was considered for natural ventilation. In order to provide a rate of 2 air changes per hour for the considered volume, 6 Venturi devices are required. If higher values for air current are considered, both reducing the number of devices for ventilation and installing an AeroMine wind turbine for energy harvesting can be considered.