There are two
systems:
Single-flow systems:
Fresh air of approx 20 à 30 [m³/h] (700 to 1,060 ft³/h) per person, enters a
room through the air vents fitted in the outside wall, in the window frames or,
as below, directly from the FCU.
Stale air is evacuated by a return network and/or by transfer to the sanitary
facilities.
Note that the air entry is possible owing to the depression of the rooms by
the extraction fans.
Single-flow ventilation
Dual-flow systems:
The clean air is treated in an air handling unit and delivered into the air
conditioned rooms, possibly directly through ceiling type fan coil units.
Stale air is evacuated by a return network and/or by transfer to the sanitary
facilities.
Dual-flow ventilation – Fresh air blown into ambient air
Dual-flow ventilation – Fresh air blown into FCU air inlet