🔄 VAV (Variable Air Volume) – Operating Principle
- Airflow varies depending on the thermal load of each zone, but supply air temperature remains constant.
- A temperature sensor in the zone measures room temperature and signals the VAV box to modulate the damper—opening or closing it—to adjust airflow accordingly.
- Common in areas with fluctuating occupancy or heat gain, like conference rooms or offices.
Example: When more people enter a meeting room and temperature rises, the VAV box increases cool air supply by opening the damper wider, then reduces it as temperature stabilizes.
➖ CAV (Constant Air Volume) – Operating Principle
- Airflow remains constant, while supply air temperature is adjusted to meet thermal demands.
- The AHU (Air Handling Unit) or central control adjusts the temperature of the supply air, not its volume.
- Often used in server rooms, classrooms, or open-plan areas where consistent ventilation is required.
Example: In a server room, airflow stays steady. When temperature increases, the system lowers the temperature of the supplied air—without changing its volume.
