Variable air volume, or VAV, is a type of heating and cooling strategy which is used to adjust or vary the amount of air that is pumped into an enclosed space, based on factors such as ventilation or the energy required to maintain the desired temperature within the space. There are different ways to manage variable air volume, with some systems very simple and straightforward but with limited options, and more sophisticated systems that can be programmed to adjust the volume to meet a wide range of heating and cooling situations.
One of the simplest variable air volume approaches is a system that simply turns off and on when the desired temperature is reached and maintained for a specified period of time. With this approach, the velocity of the air pumped into the space is more or less constant as long as the system is active. A thermostat measures the temperature and signals the air conditioning system to cease operation when the room is within the right temperature range, then sends a second signal to begin delivering air to the space when the temperature moves out of that desired range.
Many of the air conditioning systems used in commercial spaces also make it easy to adjust the variable air volume in terms of speed as well as temperature. Rather than simply shutting down when the desired temperature range is reached, systems of this type will decrease the amount of air flowing into the space when and as needed. This makes it possible to continue pumping fresh air into the space while also allowing the temperature to remain within range for a longer period of time. A system that regulates the variable air volume with this approach is often cost efficient, since the adjustment is automatic and does not require manual intervention.
There are other systems today that offer additional controls and options for managing variable air volume within a given space. With these options, the ventilation system may be configured with multiple points of entry and exit, creating a more efficient flow of air to and from various points within the space. Many of these types of systems today are operated with the use of software technology, making it possible to alter the flow of air from specific vents as well as adjust the temperature of the air flow at different points within the space. This can be especially important in a manufacturing setting, where the temperature near one area of the floor may need to be different from the temperature at the opposite end of the space, owing to machinery or computer equipment that is placed within the area.