What is a VAV box and how does it work?
A Variable Air Volume (VAV) box, is a part of an HVAC system in commercial buildings. A VAV box is integral to the ductwork connecting primary ductwork to secondary ductwork. In many cases, a Variable Air Volume box is nothing but an assembly of a sheet metal box with a damper and controls inside a control panel.
What is the basic difference between CAV and VAV box?
VAV stands for variable air volume. VAV is also known as VAV box which the full form is variable air volume box. VAV is used to maintain a more precise room temperature by regulating the amount of airflow supplied to the room.
How does a VAV box work through Ahu?
Whereas, the VAV. box provides variable air inside a building. The temperature of the air is constant and similar as the control unit delivers. What does a VAV do? VAV stands for Variable Air Volume. In its simplest form, VAV systems use varying airflow at a constant temperature to heat and cool buildings. This is opposite of a CAV (or Constant Air Volume) system, which …
How do VAV boxes work?
A Variable Air Volume (VAV) box, is a part of an air conditioning system. It is located inside the duct work. It is designed to control the air flow to a specific area, called a "zone." Click to see full answer. Subsequently, one may also ask, how does VAV …
What is the purpose of a VAV box?
A variable air volume (VAV) box, is a part of an air conditioning system. It is located inside the duct work and is designed to control the air flow to a specific area, called a "zone."Sep 13, 2021
Where are VAV systems used?
VAV systems achieve their full potential in applications where there a multiple zones with variable load. Some examples are malls, hotels and office buildings. VAV boxes have a role similar to the duct heaters used in a CAV system.Feb 7, 2021
What does vrv stand for in air conditioning?
variable refrigerant volumeVRV (variable refrigerant volume) and VRF (variable refrigerant flow) are two different terms for the same technology.
Do Vavs Have filters?
Each VAV terminal box is connected to a supply air source. This is a ducted connection that provides air from an AHU. Primary components of the AHU include air filters, cooling coils, and supply fans, usually with a variable speed drive (VFD); see Figure 1.
What does VAV mean?
VAV system means air flow rate will be different at a constant temperature. It can use for the single zone as well as multi-zones, however, efficiency is more in case of a single zone. It can use for the single zone as well as multi-zones, however, efficiency is more in case of multi-zones.
What is the heating function of a VAV system?
Heating is the core function of a furnace that is present in the VAV system. Specifically, there are heating coils that are located in the ducts which provide effective heating. Cooling action. Thermal comfort has a fair share of the cooling aspect, and the VAV system distributes it according to the demand.
What is ductwork in a VAV system?
The ductwork comprises different parts that help in the overall process of the VAV system. Mainly it has a system of ducts, dampers, and connectors. The processes involved are air conditioning, heating, and ventilation.
What is a fire damper?
Fire Damper. This is safety equipment installed in the VAV system. The fire damper has an efficient function that provides automatic blockage to the smoke and fire if it happens. It is required in those places where the duct is in the vicinity of a fire-rated shaft, a firewall, or other fire-prone areas.
What is all round analysis of VAV?
The all-round analysis of the VAV system provides all the information. Being one of the most advanced and proven temperature modulation systems, one can get optimal benefits. With this information, you will get a holistic view of the different terms associated with VAV systems. In addition to that, the applications of this system help to use vividly. The advantages and disadvantages are the foremost information that holds the crux of the system.
What is a chiller in a VAV?
The chiller or condensing unit is among the vital parts of the VAV system that provides a compelling advantage by providing a compressive refrigeration cycle. This helps to chill the water that helps to cool the desired zone.
What is an air handler?
The air handler is a set of machineries that contains different equipment, which helps the inefficient distribution of conditioned air in the specific zone. It generally comprises filters, fans, etc.
What is a VAV box?
VAV boxes are usually designed for use in larger systems, where cooling needs vary in each zone of the building. The system has a large air handling unit and multiple VAV boxes, allowing a far greater degree of control than a simpler system. With the ability to run the system on part load when not in use, or to have a higher level of independent room control, the VAV box are used in a variety of locations including retail stores, auditoriums, office spaces and some larger homes.
What are the different types of VAV boxes?
Types of VAV Boxes. There are three types of VAV boxes: traditional, fan-powered and VAV with reheat. The traditional VAV box consists of VAV box with an integral damper and is controlled by thermostat. This is the most basic type of VAV box and is also called a single duct terminal unit.
What is a VAV with reheat?
A VAV with reheat also is built the same as the traditional VAV, but it contains an electric coil designed to reheat the air when the damper reaches a predetermined position. This feature allows heating in the specific zone instead of having to heat the whole building, which improves the efficiency of the entire system. Advertisement.
How does a VAV control air?
The VAV regulates the volume of the air to the zone by opening or closing the damper, thus controlling the amount of conditioned air directed to the zone. Each zone in a building has a thermostat that controls the VAV, telling it when to open or shut the damper based upon the needs of the zone. Tip.
What is the inlet of a VAV box?
The casing is the outer box or shell, usually made from 22 gauge galvanized steel. The inlet is the connection to the duct coming from the air handling unit. The outlet is the connection to the duct leading to the zone.
What is an outlet in a duct?
The outlet is the connection to the duct leading to the zone. Advertisement. Inside is the damper, or the metal door which opens or closes to control the amount of air flow needed. The damper controlled automatically by a motor, which is controlled by the thermostat.
What does VAV stand for in air handling?
If you aren't familiar with VAV, this is a quick intro to the basics so that they won't seem so overwhelming. VAV stands for variable air volume ; this means that the AHU (air handling unit) can vary the amount of air output to suit the amount of air needed for the areas served.
What happens when a VAV terminal is open?
As VAV terminals open, the static pressure in the supply duct decreases, and the blower increases air volume to maintain the static. As the air volume increases, the system cooling capacity also needs to increase to maintain the supply air temperature.
How does a VAV box work?
Control of the system's fan capacity is critical in VAV systems. Without proper and rapid flow rate control, the system's ductwork, or its sealing, can easily be damaged by overpressurization. In the cooling mode of operation, as the temperature in the space is satisfied, a VAV box closes to limit the flow of cool air into the space. As the temperature increases in the space, the box opens to bring the temperature back down. The fan maintains a constant static pressure in the discharge duct regardless of the position of the VAV box. Therefore, as the box closes, the fan slows down or restricts the amount of air going into the supply duct. As the box opens, the fan speeds up and allows more air flow into the duct, maintaining a constant static pressure.
What are the advantages of VAV fan control?
Another advantage is energy savings and reduced wear. VAV fan control, especially with modern electronic variable-speed drives, reduces the energy consumed by fans , which can be a substantial part of the total cooling energy requirements of a building.
