Flow measurements using rracer gas reclmiques were made on tile exterior doorway of a test house for indoor-outdoor temperature differetJces of 0.5-45 K. The time for door opening and closing was constant at 3.75 s, and fully open hold time varied from 0.5 s to 120 s. Predictions of a variable density sready flow model were in good agreement with the measurements when adjustmenrs were made for the time-varying size of the opening and for the effect of cross-stream mixing between the incoming and outgoing air streams.
The studies described in the present paper have been developed by the teams involved in the French National Research Programm "ARC Convection Naturelle dans l'Habitat" coordinated by CNRS-PIRSEM (Inte disciplinary Research Programm on Energy and Materials, National Scientific Reseach Center) and suported by AFME (French Agency for Energy Management). After a short description of the experimental facilities of each laboratory, we give some significant results on high Rayleigh number natural convection in rooms.
Tracer-gas techniques have become widely used to measure the ventilation rates in buildings. A tracer gas is an idealized substance used to tag volumes of air so as to be able to infer their bulk movement; the properties of a perfect tracer are discussed. The basic principle involved is that of canservation of mass (of both air and tracer gas) as expressed in the continuity equation; by monitoring the injection and concentration of the tracer, one can infer the exchange of air. This report will summarize the techniques in use.
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