Presented report is an analysis of performance of diffuse ceiling ventilation system and both experi-
mental and numerical analysis are included.

Experimental part involves full-scale measurements on the DCV. Number of experiments are
carried out under different thermal and air flow conditions. One of the main issues, which is in-
vestigated, is influence of the heat loads location in the room on the airflow pattern. It is checked
how much conditions in the room will change depending on the heat loads distribution- equally dis-
tributed heat sources, point heat sources in different locations or heat sources only on one side of
the room. Influence of vertical heat loads location is tested as well. With equally distributed heat
loads a problem with unstable airflow pattern may occur and it is tried to investigate its nature. An-
other broad field of interest is the importance of the supply area of the ceiling. All of the results are
recalculated to a design chart, which enables to find maximum acceptable q and ∆T values, which
ensure that draught risk in the room is in the acceptable range. What is more a pressure loss across
the real ceiling is measured and it is investigated what is the influence of ceiling’s construction on
the pressure drop.

Second main part of this report is CFD modeling and a Star CCM+ software is used to create a
model of the test room. One of the cases, which is tested in the real experiment is a base for the
model’s geometry and boundary conditions. Next it is tried to validate the model by comparing
results of the simulation with measurements results. Finally the test room’s model geometry is
changed by decreasing the height of the room to be able to see, what is the influence of the room’s
height on the buoyancy forces in the room, as these are the main forces generating airflow for DCV
system.