What is the term for an air compartment that forms part of an air distribution system?

The term for an air compartment that forms part of an air distribution system is the furnace plenum. This component is designed to distribute heated air from the furnace throughout the ductwork and into the living spaces of a building. The plenum serves as a central hub where conditioned air gathers before being directed into various ducts, ensuring even distribution and effective heating or cooling of a space.

A furnace plenum typically has a larger volume than the ducts leading from it, allowing it to efficiently equalize air pressure and promote better airflow. It is an essential part of HVAC systems, as it helps in managing the distribution of air to different zones or rooms within a structure. Understanding the role of the furnace plenum is crucial for maintaining efficient heating and ventilation systems.

Other terms in the options refer to different components or concepts within HVAC systems, but they do not specifically describe the air compartment serving this distribution function.