whether the cooled ceiling supported this air movement
additionally. Unlike the variations with only one half of
the ceiling being cooled, the fresh air was mixed very well
with the room air, causing contaminant removal efficiencies
of 1.0 to 1.1 at all places for all variations with
entirely cooled ceiling area.
The rather uniform air temperature profiles presented in
Fig. 12 prove that, the supply air was mixed with the room
air very well, although displacement ventilation was operated.
Only very close to the supply air inlet lowest points Ž
at axis 1 , a significantly cooler air temperature was mea- .
sured.
The vertical air temperature differentials between 1.1
and 0.1 m with entirely cooled ceiling area and displacement
ventilation were always below 1.5 K pointing at good
thermal conditions. The dominating characteristic of the
cooled ceiling equalized the airflow pattern, so that almost
no local differences appeared. The arrangement of the heat
sources did not influence the temperature distribution significantly.
6. Discussion
The results presented make clear that when the air
quality provided with displacement ventilation and a cooled
ceiling is compared with the one achieved with mixing
flow and a cooled ceiling, one has to consider the thermal
conditions as well. By evaluating the data of both the
contaminant removal efficiency and the vertical air temperature
rise of the many different results for the variations
with displacement ventilation, an interaction between these
characteristics becomes apparent.
As mentioned before, the portion of the cooling load
removed by the cooled ceiling strongly influences the
airflow pattern in a room with a displacement ventilation