Large ducted systems with many outlets has one big challenge: Balancing air grilles to ensure that the right amount of air gets out there.
However, there is a trick that many designers don't understand and that is the fact that pressure drop through an orifice is logarithmic.
This phenomenon can be actively exploited by a good designer and if done correctly, it will create a self balancing effect in any system (air or water) without any additional dampers or balancing valves.
In this case the flow and pressure drop is determined by the slot width. If you have the flow, pressure drop and grille size, the grille can be calculated by varying the width, length and number of slots on a certain face size. This has been empirically determined.
Grilles have quite complex manners, and the method used here has limited application because the air distribution cannot be directed like with some other products. This is not a problem if the fresh air is tempered and enters the room at about the same air temperature as the room.
Where this product is suitable, the advantages are enormous.
- It is cut from 1.2mm aluminium sheet, so it is can be well priced - especially for small grilles.
- It is fast to make. Large jobs can be done on a 2 or 3 days lead time.
- It is self balancing - the contractor can fit and forget. This saves an enormous amount of commissioning time.
- It is silent.
- Architects loves the subtle look it has on a round duct. It disguise so well that one has to look for it to see it.
- It follows the curve of a round duct.
This method can be easily be used to replace OBD dampers.