I'm installing a Daikin VRV system, 4 low static ducted hide away units and 3 floor mounted, vertical discharge units.

My question is how do I size the return air grille and the supply air grille. The client has requested the linear type.

I understand I need to start with the airflow of the particular unit on high speed but from there I have no idea how to proceed. Fortunately there is only on supply grille per unit.

Any assistance will be greatly appreciated.

PS. If I could have the examples in metric it would be greatly appreciated.