Ventilation of auditoriums
A common method of supplying air to auditoriums is to supply air under the seats in the belief that the air will float slowly upwards, thus achieving a displacement effect. This is not correct however. The air behaves like water and "flows" downwards where it collects before it flows slowly upwards towards the rear outlet. The supply air mechanisms could just as easily be installed at the front of the auditorium.
Regardless of the location of supply air mechanisms, experience shows that is difficult to achieve any real displacement effect. Measurements and computer simulations for a solution as outlined above indicate a ventilation efficiency of roughly 100%, which entails complete agitation of the air.

Tests have also been carried out for traditional ventilation with (vortex) diffusers in the ceiling. This works satisfactorily, provided the outlet is located towards the rear. Locating the outlet in other spots may easily result in full short circuiting.

Suggestions for sensible ventilation of auditoriums:

1. Ventilation by diffusion with air supplied from the ceiling/rear by, for example, vortex diffusers. Outlet at the rear.

2. Diffuse supply of air under or in front of seats. Supply of air beneath the seats has not other significance except that it is often practical to use the space below the seats as a supply chamber.

3. In addition to the above, the rear of the auditorium should be ventilated separately. This is particularly the case when it serves as an entrance area so that users are not met by a "wall" of hot, polluted air.

Pictures from our applicaiton.(Turkish Parlement Hall )

Design of the supply air systems in ventilation by displacemen For displacement-type ventilation at premises with normal heat sources in the form of people, light, etc., experience shows that the temperature change between floor and ceiling is roughly as shown in the figure below: