An important element in the natural ventilation design procedure is the flow-pressure characteristics of a window with a given opening area. The flow in the room is another important element that is often ignored in the design phase due to lack of relevant information on the air movement. This paper shows the outcome of experiments with the room air distribution. The results show that the velocity distribution in the occupied zone can be described by a semi empirical model. The buoyant cold flow from an open window will drop into the floor region of the room and cause a radial flow along the floor. It is possible to show that this flow behaves like the flow from wall mounted diffusers for displacement ventilation. The velocity distribution can be described in the entire occupied zone as a function of the opening area, flow rate and temperature difference.
Characteristics of buoyant flow from open windows in naturally ventilated rooms.
UK, Oxford, Elsevier, 2000, proceedings of Roomvent 2000, "Air Distribution in Rooms: Ventilation for Health and Sustainable Environment", held 9-12 July 2000, Reading, UK, Volume 2, pp 825-830