Variable Air Volume Control System Variable Air Volume (VAV) is a type of heating, ventilating, and/or air-conditioning (HVAC) system. … The VAV Zone Controller has a built-in actuator and maintains zone temperature by operating the terminal fan and regulating the flow of conditioned air into the space.

What control variable is used to modulate fan speed in a VAV system?

As a result, the total supply airflow provided by the central air handling unit must also vary to maintain sufficient airflow through each VAV box. Airflow is typically controlled using a variable frequency drive (VFD) to modulate supply fan speed and vary system airflow.

Which damper used in VAV?

A VAV terminal unit, often called a VAV box, is the zone-level flow control device. It is basically a calibrated air damper with an automatic actuator.