What is a Constant Air Volume HVAC System?

A constant air volume (CAV) system is an HVAC system where the air flow rate is kept constant, but the air temperature is varied. The most common type of CAV system is a small forced-air system with on/off control.

How Does a CAV System Work?

A constant air volume system constantly moves a set amount of air through the building. To heat or cool the building, the temperature of the air is changed. When the building needs to be heated, the air is warmed before it enters the building. In cooling mode, the process is reversed and the air is cooled before it enters the building.

Advantages of a CAV System

One advantage of a CAV system is that it can provide a more even temperature throughout the building. Another advantage is that, because the air flow rate is constant, the system can be easier to design and install.

Disadvantages of a CAV System

A disadvantage of a CAV system is that it can be less energy efficient than a variable air volume (VAV) system. In a VAV system, the air flow rate is varied to match the heating or cooling needs of the building, which can save energy. Additionally, because the air flow rate is constant in a CAV system, any leaks in the ductwork will result in reduced air flow and decreased efficiency.

What is a VAV System?

A variable air volume (VAV) system is an HVAC system which supplies air at a variable temperature and airflow rate from an air handling unit (AHU). The temperature and airflow rate can be controlled independently or together to maintain the space temperature set-point. VAV systems are used in office buildings, schools, hospitals, and other commercial buildings.

CAV vs VAV HVAC Systems

The main difference between CAV and VAV systems is the way they control air flow. In a CAV system, the air flow rate is constant, while in a VAV system, the air flow rate is varied. Additionally, CAV systems are typically less energy efficient than VAV systems.

Related Links

Constant Air Volume (CAV) | HVAC Selection

Constant air volume

CAV vs VAV HVAC Systems

Rectangular Constant Air Volume Dampers

Constant Air Volume Boxes and CAV Terminal Units

Constant air volume CAV – Designing Buildings Wiki

Variable Air Volume vs. Constant Air Volume for Commercial HVAC System

Constant Air Volume -CAV

Related Videos