Trombe Walls and solar chimneys are passive building
elements which rely on solar-induced buoyancy-driven convection.
In contrast to fan-driven (forced) convection, buoyancy-
driven (natural) convection components are more difficult
to analyse and it is more difficult to predict their performance,
not least because mass flow depends on the heat input and also
on the geometry of the system, and therefore it is not easily
controlled