5.1. Variation C2_S1,2
The contaminant removal efficiencies measured with
displacement flow are lower than with mixing ventilation
in the entire room Fig. 8 . The data of the lower region Ž .
Ž . 0.1 to 1.0 m indicate that the fresh air was supplied to all
axes, although the tracer gas concentration with displacement
flow increases towards the measuring axis 3 due to
recirculating room air contaminated from the ceiling see Ž. Ž
Fig. 7 ..
The uneven mixing of supply air and room air when
mixing ventilation was used is one of the reasons for the
relatively better air quality at all heights with displacement
ventilation. While the displacement flow resulted in contaminant
removal efficiencies of 0.05 to 1.1 0.1 to 1.7 m Ž
height , the corresponding values with mixing flow were .
between 1.1 and 1.4, with the higher values below the cooled ceiling area. This indicates for the tests with mixing
flow that the fresh air was not entirely being mixed with
the room air rising at the heat sources.