The aim of this study is to assess the performance of the mechanical ventilation system and air quality in an office building. The perfluorocarbon tracer (PFT) technique was used to measure air flow in an air handling unit and to estimate flow rates supplied to the office. In order to validate the PFT technique as a viable means of measuring air flow in the mechanical ventilation system, the PFT measurements were compared with measurements made using a pitot-static tube. Air exchange range, ventilation effectiveness and age of air were examined.
Tracer distribution measurements were performed to assess pollutant transport from basement garages situated in a commercial building and in two residential buildings, in which the occupants had reported typical garage odors and complained about bad indoor air and typical SBS symptoms. A tracer gas technique (tracer gas SF6, infrared detection) was used in all three buildings to study the contaminant distribution in the buildings. In the commercial building, a leaky HVAC system distributed contaminated air from the garage to other zones of the building.
The first part of the paper will show some aspects of experimental research on air distribution in ventilated rooms. The study has been carried out to get an understanding of the air movement and the ventilation effectiveness by means of tracer gas measurements. It has been investigated the velocity and the distribution of the concentration in a two-dimensional isothermal flow issue of a linear supply opening. The second part of the paper will describe a proposed zonal model in 9 zones.
Tracer gases are commonly used to evaluate the performance of ventilation systems. One way to reduce the time, complexity, and cost of such experiments is to use the carbon dioxide generated by occupants as a tracer gas. In this paper, a method for using the carbon dioxide generated by occupants as a tracer gas for determining the effective supply air flow rate to a zone or the relative air-change effectiveness of a zone is described. The approach is to make use of a model of the accumulation dynamics and a model of the way that occupants generate carbon dioxide.
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