What are Series Fan Powered Variable Air Volume (SFB-VAV) systems?

A single air handler which provides central cooling, ventilation, and sometimes central heat to multiple ducted zones.

Each or some zones have a primary damper which opens to allow central air to enter the zone. A local zone fan is also enabled to assist in pulling this primary air into its space.

Some zones have a local zone reheat which heats the air from the plenum (above the zone) through a secondary damper to heat the space.