Characteristics of air flow through windows.

This paper describes the first results of a series of laboratory investigations that is performed to characterise three different window types. The results show the air flow conditions for different ventilation strategies and temperature differences. For one of the windows values of the discharge coefficient are shown for both isothermal and non-isothermal flow conditions and the thermal comfort conditions are evaluated by measurements of velocity and temperature levels in the air flow in the occupied zone. It is demonstrated that different window types have quite different characteristics. A combination of different window types in the same natural ventilation design can by using their strong sides improve both ventilation capacity, thermal comfort and IAQ.