VAV control principle - Variable air flow
VAV allows for two-stage airflow control in each zone.
This allows ventilation to be controlled according to when individual rooms are in use, though not how much they are loaded during their times of use.
VAV is typically used when:
- Rooms are used periodically
- There is low variation in loading from persons in the room
- There is low variation in heat load
Example: North-facing classrooms, offices.
A timer and weekly plan control the basic ventilation
A switch or motion sensor turns up the ventilation in the individual rooms
A controller maintains constant pressure in the duct system, ensuring correct airflow distribution. |
Ventilation of rooms in use only |
Same airflow in the room regardless of number of persons
Updating of weekly plan in event of changes to pattern of use |