The neutral height in a room with displacement ventilation.

This paper investigates the relationship between the neutral height for air distribution and the ventilation load in a room with displacement ventilation. An environmental chamber equipped with a displacement ventilation system has been used to carry out the neutral height measurements with the presence of a heated mannequin and other heat sources in the chamber. The total room load used was varied from 104 W to 502 W, i.e., corresponding to a ventilation load from 10 W/m2 to 60 W/m2. The prediction of the neutral height was based on plume theory. Comparison between the experimental data and the predictions showed good agreement. The predictions also showed that a human body could draw uncontaminated fresh air from the lower zone that improves the air quality in breathing zone.