Examination of the Space with Cross Ventilation by Tracer Gas Technique and Zoning Concept of the Space with Unevenness

It is difficult to evaluate the effect of cross ventilation quantitatively, because the indoor environment under cross ventilation is uneven and changes with the outside conditions. In this paper, the decay process of tracer gas is measured in uneven space under cross ventilation, and the property of spatial unevenness is examined by the concentration decay and velocity distribution. And zoning concept of the uneven space is shown based on the approximated expression of average concentration, and the relation between the mixing property and the volume of two-zone and exchange rate is examined.