Dual Duct System

[dallas]

We have a dual duct HVAC system in our plant. A problem we are having is that one of the mixing boxes is not "mixing" the air. The ductwork is configuered in a way in which it branches right after it leaves the mixing box. What we beleive is happening is that cold air is shooting through the mixing box and going through to one branch while hot is going through to the other. Are there any devices (vanes) which mix air after the mixing box? Thanks

 

[stevenw]

The device is called an air blender.
It mixes the air. Often used to mix r/a and o/a at the ahu.
it looks like a supply air grille perp. to the airflow.
The big AHU mfg. offer them and some third party companies mfg. them.

 

[Goorah]

Right on: You are experiencing "stratification" ; which is why a certain number (4?) of duct diameters before any branching is recommended.

If you have the space, I'd extend the ductwork.

Buddha's advice 2,500 yrs ago (I'm Christian!!???!!): "After deep, careful observation/analysis; and it agrees with reason, is conducive to the common good: accept it and live up to it."