Constant air volume (CAV) is a type of heating, ventilating, and airconditioning (HVAC) system. In a simple CAV system, the supply air flow rate is constant, but the supply air temperature is varied to meet the thermal loads of a space.

Most CAV systems are small, and serve a single thermal zone. However, variations such as CAV with reheat, CAV multizone, and CAV primarysecondary systems can serve multiple zones and larger buildings.

In mid to largesize buildings, new central CAV systems are somewhat rare. Due to fan energy savings potential, variable air volume (VAV) systems are more common. However, in small buildings and residences, CAV systems are often the system of choice due to their simplicity, low cost, and reliability. Such small CAV systems often have on/off control, rather than supply air temperature modulation, to vary their heating or cooling capacities.

This video is created by Danfoss Global learning.