The effect of object positions on ventilation performance.

The effect of the change in object positions (i.e. office furniture) on the air quality in a room was studied using zonal purging flow rates. In relation to the zonal purging flow rate in a room, the transfer probability from the inlet to a certain zone can provide information on the amount of fresh air from the inlet to the zone. In this study, the probability obtained from Markov chain theory was used to analyze the ventilation performance.

Mean ventilation effectiveness - a sensitive parameter: an experimental study.

In order to improve the indoor air quality a change in the ventilation system is often one of the actions. The mean ventilation effectiveness or contaminant removal effectiveness is then often presented as a measure. Great care should however be taken when evaluating a system using these parameters. Measurements have shown that in displacement ventilation the mean ventilation effectiveness can fluctuate very much for the same air flow, the same cooling load, the same inlet - outlet devices and the same height of the tracer gas supply.