A Numerical and Experimental Evaluation of a Natural Wind Driven Suction Cylinder for Building Ventilation

The suction cylinder described in this paper is a device to increase the ventilation flow rate, especially in naturally ventilated buildings. Outdoor wind is the driving force. The principle of operation is the development of a pressure drop created by the relative increase in flow velocity as wind driven air flows through a nozzle. This paper basically describes how this pressure drop and resultant momentum can be used to provide exhaust ventilation. The suction cylinder is particularly designed for natural and hybrid ventilation systems, especially for times when the temperature gradient between inside and outside is not enough to drive stack driven ventilation. A 1-dimensional analytical flow model was derived to establish a relationship between the volume of air entering through the inlet and the volume of air sucked by the suction cylinder. The commercial Computational Fluid Dynamics (CFD) code, Fluent, was used to visualise the flow system inside the suction cylinder. A corresponding wind tunnel experiment was also made. Preliminary results show advantages in using a suction cylinder for building ventilation.