What is the primary function of a plenum in HVAC systems?

What is the primary function of a plenum in HVAC systems?

• A. To filter air before it enters ductwork
• B. To serve as a supply air chamber connecting AHU to ductwork
• C. To house electrical components
• D. To exhaust stale air to outside

Answer: (B)

The main function of a plenum is to act as the supply air chamber that connects the air handling unit to the ductwork. It provides a relatively large, low-velocity space for the conditioned air to enter the distribution system, helping distribute air evenly to the branches, dampen noise, and absorb pressure fluctuations from the AHU. Filtration happens either in the AHU or in a dedicated filter housing, not in the plenum. It’s not used for exhausting stale air or housing electrical components as its primary role.

The main function of a plenum is to act as the supply air chamber that connects the air handling unit to the ductwork. It provides a relatively large, low-velocity space for the conditioned air to enter the distribution system, helping distribute air evenly to the branches, dampen noise, and absorb pressure fluctuations from the AHU. Filtration happens either in the AHU or in a dedicated filter housing, not in the plenum. It’s not used for exhausting stale air or housing electrical components as its primary role.