For ventilation in auditoriums, theatres, movie-theatres etc., where many people sit close, it is a great advantage to use the displacement principle and units especially for that purpose.
Typically units are either placed in the stairs or in the floor under the rows of seats. Normal small airvolumes (10-14 l/s) are supplied with a limited cooling temperature, usurally distributed in the ratio of one unit per person. This ensures the best division of layers. An added bonus is that the thermal load from the people is removed.
The velocity of the air in the units near-zone is an important parameter in planning. Normally 0,20 m/s at a temperature gradient of 1,5 K is acceptable. The velocity depends on how much air is supplied per meter of chair-rows in the room, in addition to the air diffusion. Usually air diffusion pattern is directed so the air is supplied in the direction of the chairs. This ensures a reduction in the velocity before the air is spread throughout the room.
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