Natural ventilation induced by combined wind and thermal forces in a two-zone building.

When buoyancy forces, wind forces and envelope heat losses interact in a naturally ventilated building, the behaviour of the flow rate as a function of these parameters can be quite complex. This paper derives the equations for the flow rate in a two-zone building where one zone is above the other, and where each zone has a high and a low opening. When the wind force opposes the buoyancy force, several solutions for the flow rate can be found for a given set of parameters, and a wide variety of behaviours for the flow rate is possible, some of which are not possible for a one-zone building