Return Air Plenum Pressure Drop
Return Air Plenum Pressure Drop
(OP)
Can anyone explain how to account for the pressure drop through a return air plenum above the ceiling? Some say, just add 0.5", but I want to know how it is actually calculated. In this return plenum, there are walls that go to deck, so I will have to put in transfer ducts and rectangular openings in the walls above the ceiling. In addition, if anyone has any literature that could explain it, that would be great too.
Thanks
Thanks





RE: Return Air Plenum Pressure Drop
RE: Return Air Plenum Pressure Drop
Thanks for the help.
RE: Return Air Plenum Pressure Drop
(Assuming you have a return air AHU with filters and some form of heat recovery).
Anyway, what I'm trying to say is that it is worth thinking about the scale of things and seeing where it matters (large factors) and where it doesn't (small factors).
Have a look at the airvelocity in the plenum and it will probably be very low.
And since pressure losses relate to "velocity squared", small velocities will result in very very small pressure loss.
RE: Return Air Plenum Pressure Drop
RE: Return Air Plenum Pressure Drop
Given a poor initial balance, anything that now changes pressure drops in the ceiling space will make air delivery worse.
RE: Return Air Plenum Pressure Drop