Constant & Variable Air Volume Systems
Variable air volume (VAV) systems supply varied airflow at a constant temperature. However, constant air volume (CAV) systems supply a constant airflow at a variable temperature.
What is a Variable Air Volume System?
With variable air volume systems, the supply of cool air to a building increases as the cooling load increases, and it decreases as the load decreases. These types of systems are the most modern and energy efficient forms of air conditioning for comfort. Variable air systems use much less fan capacity than a constant air volume system as they only use the required air and nothing more - saving on energy. These have beneficial energy saving capabilities and are often used in larger buildings.
What is a Constant Air Volume system?
Constant air volume systems are generally small and serve a single thermal zone, but there are variations to these - which can serve multiple zones and larger buildings. These are more common in residential areas as they are simple and reliable.