Plenum Fan
Plenum Fan
(OP)
Never used this type of blower before, I was going to use a DWDI blower. I am very concerned about system effects. Does this 1200 cfm blower configuration make sense to all those with experience with this type of blower ? (See attached pic)





RE: Plenum Fan
The plenum fan is typically more compact and appears to provide reasonable efficiency in the instances I have seen.
RE: Plenum Fan
Patrick D. Propst, P.E.
http://www.pro-engr.com
RE: Plenum Fan
RE: Plenum Fan
VFD or ECM motor is highly recommended. Just the sound reduction is worth it in many cases, the energy is a extra bonus.
RE: Plenum Fan
As you can see, the installation is tight and I want to minimize system effects.
Like many of you mentioned, I am seeking noise reduction which I am hoping the backward curved blades and direct-drive motor offer.
Once it's done...I'll give you all feedback.
Thx again all !!!
RE: Plenum Fan
RE: Plenum Fan
RE: Plenum Fan
I cannot put the coil after the fan because there is no room. I am hoping that by ensuring that the air flows through the coil at a speed of < 450 fpm, I will ensure that I don't entrain water droplets downstream during cooling.
Might you have arranged the components differently ? Then how so ? Keep in mind I cannot redo the ductwork around the air handler sinced it is fixed through walls. Therefor I am constrained by the existing ductwork.
Please see an alternative arrangement I elected not to use. This arrangement made use of a DWDI blower.
Regards
RE: Plenum Fan
Given the mosture I suspect all that I would have removed as much of the electrical connections to being outside the housing as possible (extend all leads, wiring and controls outside the plenum). If the humidity could be great in the fan/motor area then perhaps I might have used a motor rated for external exposure so that it would not be affected by the water.
I agree with slowing the air down to minimize droplet throw. If that is still an issue there are mist eliminators that are very low dP that could work to help with that (Basically they are stainless still brillo pads, about 1" thick which attach hard to the discharge face of the coil. Any condensation that forms attaches to these pads and drains down.)
RE: Plenum Fan
Plenum Fan + N-Coil +Discharge Plenum.
Following everyone's suggestions,
1.I placed the N-Coil after the Fan Motor so as to remove the risk of a damp Fan-Plenum environment.
2.I use a Discharge Plenum so as to do away with transitions such as elbows, pant fittings, offsets, etc.
Concern : I seem to be pressurizing 2 Plenum chambers, the Fan Plenum and the Discharge Plenum. Is this a problem ?
Any other comments on the present configuration ?
Thx in advance !