Upward flows in a multi zone building with subfloor plenums and solar chimneys.

Solar chimneys are often used to extract air from a building by thermal stacks, while subfloor plenums are used to passively cool air before it is supplied to a building. This paper examines the overall flow pattern in buildings with both solar chimneys and subfloor plenums. For a multi-zone flow system in which each zone has only two effective openings, an analytical solution is derived. A sufficient condition for upward flows to occur is derived from the analytical solution. A two-room building with two solar chimneys and two subfloor plenums at two different heights, and an internal large opening is also considered. No analytical solutions exist for this configuration. A multi-zone natural ventilation program considering bidirectional flows is used to solve the problem numerically. Much more complex flow patterns are identified and analysed.