A VAV system, also known as a variable air volume system, is a type of heating and cooling system that uses a large air handler and central duct system. According to High Performance HVAC, this setup allows an engineer to accommodate very large areas that need to be regulated by a single cooling or heating system. Variable air volume system setups tend to vary depending on each building's needs.
Professional buildings like factories and offices often have large rooms that need to be regulated with a single temperature control system. Variable air volume systems are designed to handle the logistics of regulating the temperature of large areas.
Depending on the temperature that is set, a variable air volume system allows its damper to open or close to allow more or less air flow. When cooling, more air flow is required. Usually, these systems also have a sensor that can detect the air flow through the duct system. This is used in conjunction with an air handler blower fan that can move the heated or cooled air through the ducts and spread it throughout large spaces. Because these systems are specific to individual workplaces, not all variable air volume systems have the same number of sensors or fans.