Ventilation performance measurement using constant concentration dosing strategy

Air change performances of an office with variable air volume (VAV) mechanical ventilation system and a domestic apartment with natural ventilation were evaluated using tracer gas techniques. Both the constant concentration and the decay method were utilized. Experimental results showed that the domestic apartment with opened windows performed better than the VAV system in terms of air-exchange efficiency, and maintained the highest air change rate. However, poor air change rate and air-exchange efficiency were resulted when the windows were closed in the home. By comparing the measurement results from the two tracer gas methods, it is found that the results obtained by the constant concentration dosing method were compatible with that obtained from the widely adopted tracer decay method. Several recommendations for conducting constant concentration dosing test were also discussed in this article.