Ventilation requirements (Diagram included)

[TomatoPie]

Long time lurker, first time poster here, I'd like some opinions.

In a 78 cubic foot closet, I'd like some input on whether I should use a 6" 440 CFM or 4" 167 CFM can/vortex inline, pulling through a DIY Carbon scrubber and exhausting directly outside the room. I'm also wondering whether or not a cooled hood/tube would be necessary with a 430W HPS.

As you can see there'll be a 1/2 sq. foot intake port from a cooler concrete cellar. Two fans for circulation will be used inside, and I may add two cool 23W or 45W cool CFL's for uvb/light supplementation.

So, 4" or 6" fan? Cooled hood? I'm on a very strict budget putting this together, I'd like to know whether I will NEED a hood.

Here's a scaled sketch of the room, thanks in advance. Going to be doing DWC, so res temps are also key.

PS: Thank you 420magazine for all the bud/grow porn! Might convince our medical patient here to make a journal out of this!

 

[BWC BayArea]

It really depends upon ur filter size. How many lbs of activated carbon u use to make ur scrubber? I'd be more inclined to use the higher CFM fan based on info provided.

 

[TomatoPie]

Changing all my rooms (78c feet) air 4 times a minute with 440CFM minus the slight impedance of the scrubber won't be too much?

 

[BWC BayArea]

As long as u have a comparable intake to replenish the air as needed and ur not having pressure issues I wouldn't worry. Then again I'm no expert and am still learning like most. Hope this helps some.

 

[DroJo]

Changing all my rooms (78c feet) air 4 times a minute with 440CFM minus the slight impedance of the scrubber won't be too much?

4 times a minute is perfect in terms of air movement, but that figure is before you add the carbon scrubber, its hard to guage what your actual cfm will be once you add the carbon filter. I would add another 30w 170cfm(advertised as 250) suncoast duct boosters to help out with the air movement

 

[TomatoPie]

Here's what this became

 

[BWC BayArea]

Way To Go

I saw the journal u started based on this thread, nice utilization of space. Can u take a pic of the ventilation and lighting setup to post here so we can compare it to the diagram to get a feel for what exactly was done here?

 

[TomatoPie]

I'll do that right now in my journal, see my sig.

I basically switched a few things around. Where I marked intake, is now where my exhaust duct goes, where I had the fan exhausting on the diagram, is my intake.

I'll explain more with the pics in the journal.

 

[MisterPeabody]

I dig the blueprint. The fan and scrubber look functional. You might think about venting your hood outside. I'll be following along with your project. Good luck!

 

[TomatoPie]

Check out my grow (link in my sig), somewhere on page 2 or 3 I have pics of what I actually built.

I vent to my mom/clone room, which then vents to the "machine room" which has concrete everything, so it acts as a heat-sink.

On second thought, can you send me one of those cabs?

 

[MisterPeabody]

Here is what I am up against at the moment. I have a 170 cfm inline turbine fan exhausting my passive grow cab. Mine is 18x36x72. I have about 3.5 sq ft of passive air inlets via darkroom registers. Without the carbon filter, the 170 cfm fan keeps cab temps at about 2-3 deg above indoor ambient. With the 4" Phresh carbon filter connected, cfm drops to about 50% of the rated 170 cfm of the motor, and temps reach in excess of 90 deg. I have built a high flow carbon filter, and am now in the process of attempting to improve it some more, i.e less restrictive. I am now looking at getting a 6" turbine fan delivering about 400 cfm/200 with carbon scrubber. In my humble opinion, I'd opt for the 6" so you don't end up kicking yourself like I have done. Good luck with your grow!