Rooms with high windows are likely to have comfort problems caused by cold airdowndraught, which are usually solved by placing heating appliances underneath thewindows. In the city of Zug, Switzerland, a highly insulated educational building with aconcrete core system for heating and cooling is planned. The purpose of our investigation wasto find out whether any measures are necessary in this building to compensate the effects ofdowndraught in the occupied zone. Special attention has been paid to the effect of passivemeasures like air flow obstacles or openings in the window sill.
The paper presents a mathematical model, implemented in a general computer code, that can provide detailed information on velocity and temperature fields as well as pollutants concentrations prevailing in three-dimensional buildings of any geometrical complexity, for given external meteorological conditions. The model involves the partial differential equations governing flow and heat transfer in large enclosures containing heat sources. Turbulent flow is simulated and buoyancy effects are taken into account.