Return Air Box
The return air box is an optional component for the return air plenum, which is connected to the air handling unit (AHU). It is acoustically lined with half-inch sound absorbing insulation. It can also be us
ed as a transition and mixing box for the return air. It has a 25mm filter (if not using the optional air purification module).
Return Air Grille
A single central return air grille is positioned discreetly in a central location e.g. in the corridor of an office complex. The grille size matches the return air duct and air speed requirements. The shape of the grille is not important providing the free air dimensions are at least equivalent to the cross section of the return air duct.
You can design your own return air grille. It can be any size, shape or design as long as it meets the minimum requirements for return air flow.
Sound attenuated flexible duct or baffle is used for solid return air duct. If a shadow gap or ceiling void plenum is used, a return air duct is still recommended for sound attenuation.
Multiple returns can be used if required. Mechanical heat recovery ventilation can be added to the return air path.