Heat transfer through a horizontal aperture connecting two non isothermal rooms.

This paper deals with the convective flow through a horizontal aperture connecting two superimposed large enclosures which are kept at different temperatures. The lower room is warmer than the upper room and this unstable thermal configuration generates a natural them1osyphon flow, between both volumes. This type of flow can occur inside buildings: stairwell flows or natural ventilation flows through horizontal openings. In the literature, very little information is available concerning this domain of applications. We carried out a full-scale experimental study in order to determine the heat transfer rate and to point out the influence of the aperture area, the aperture location, the aperture thickness and the presence of a stairwell.