The CCD is designed to handle
both supply and return air requirements in a single unit.
Conditioned air is supplied
at the outer parameter, while the return is extracted through the
The center core which is the return part
is made of extructed aluminium a may be supplied with performed
core pattern which is shown in the picture.
The size can be determined according to the supply
and return air flow requirement. The return occupies merely
the center core of the diffuser, which is usually of a negligible
The minimum size of the center core is 75mm,
while the maximum size is equal to nominal size of the CCD minus
75mm. Nevertheless, the size of the core must be in the steps of