closet questions

[neep32]

Long time lurker here, first post.

I just moved into a new place, and I have a spare closet in one of the bedrooms here that I would like to put to use.

The closet itself is I would guess about 8 ft tall, 6 ft wide, and 2 ft deep.

There aren't any windows nearby.

The only place I could vent exhaust to in this closet is the attic, and I am not sure of where or how I could get fresh air into the closet. Any tips?

I will be using a 400w with MH bulb for veg, HPS for flower. Will a 12 inch fan be sufficient for cooling the light, & providing enough circulation for that space?

I am new to all of this, and just want to make sure I don't screw up.

 

[green_grow]

the fresh air can come from the bedroom itself. as for the fan ... what kind of 12" are you talking about ? i am guessing it's an oscillating fan, which COULD possibly provide enough air exchange but you would have to fix it permanently to the ceiling, drawing air out of the closet and into the attic . you may want to buy an in-line fan instead. there are too many variables to say what will work in your application.

 

[neep32]

Thanks for your input!

I was thinking of maybe using an in-line fan, blowing through a carbon scrubber, vented into the attic. Does that sound right?

 

[green_grow]

yes. get your stuff set up, switch it on and see what your temps are . from that point you can do whatever fine-tuning is necessary.

 

[BonsaiBud]

Yeah, I have an "old" Vent Axia. It uses 67 watts. It has 4 inch flanges. It pumps 180 CFM with enough pressure to...well, suffice to say, it rules. When I bought it the hydro guy's buddy said that he knew someone who was air-cooling three 1k lamps with that very same fan. I don't doubt that it could. I think that is why they make the blades out of metal on a lot of them these days. Mine has fine plastic blades.

The Vortex is the best thing going these days. Just don't put it on any "fan controller" the only way to dial these babbys back is with a VFD, variable frequency drive, and they don't make those things for 120V AC single phase. If power went out, I would wake up, shit some bricks, then drag my APC over to my closet and plug the fan in to that...and go back to bed and say a little prayer that the power outage be brief.

 

[Mr. Bongjangles]

The Vortex is the best thing going these days. Just don't put it on any "fan controller" the only way to dial these babbys back is with a VFD, variable frequency drive, and they don't make those things for 120V AC single phase.

Could you elaborate about why one should not put a Vortex fan on a speed controller?

Never heard this before. I have one on a speed controller, and if there is a good reason I shouldn't be doing so I would consider it crucial information.

Thanks, and sorry to jump into the thread with something alternate..

 

[Mr. Bongjangles]

So I grew in a small closet for a couple of years, may as well contribute here in addition to my question.

About the air intake.. I recommend you replace the door with an unfinished door you can cut holes into, if stealth isn't a concern.

If the room still needs to pass a quick visual inspection or whatever, I recommend you cut a couple of inches off the bottom of the door to allow air through.

If you go that route and are concerned about light coming through the space, here's an idea that worked for me, and will help with the intake.

Basically, add a shelf for the plants, about a foot or two off the ground. Make the shelf solid, and cut an intake hole into it. Then put a small fan below the shelf and have it blow air from the bottom area into the plant area above.

You can cut another hole and pull cool air for your light from that area as well.

Hope that helps!

 

[BonsaiBud]

No problem Mr. Bongjangles.
I talked about this in other threads, but you are the first person to respond with any concern.
The Vortex uses the exact? same? motor as my Vent Axia. In any event, it is an induction motor. AC motors all have a certain RPM at which they are designed to run. 3 speed window fans and ceiling fans accomplish 3 different speeds by: example: full power: all 6 windings powered, medium: 4 of the 6 are powered, slow: 2 of the six are powered.
All the speed controllers I have seen being sold by the grow shops are just potentiometers (variable resistor) with a rudimentary "noise/harmonic filter" or something like that if you are lucky.
This is my VFD. Now, while it can be powered by single phase, and I will just get a 200 watt step-up transformer for it, It cannot drive a single phase motor. I do not know if a Vortex or my Vent Axia can be wired for 3 phase. I'm going to have an expert take a look at it pretty soon.

Now, back to your question:
To slow down an induction motor, or to efficiently vary the speed of a single speed brushed AC motor, you need to change the frequency of the AC power. A resistor won't do that, a transformer won't do that. You need a variable inverter. In times gone by, one would have plugged an induction motor into the wall, hooked a pulley to it, put a larger pulley on a brushed AC motor and connected the two with a belt. But you aren't done yet. All that gets you is a source of, say, 40 Hz and the corresponding lower voltage. So, you take the wires from the driven brushed motor and connect that to your Vortex and wa-la! A quiet Vortex fan that also doesn't move as much air or put out as much pressure.

But I still haven't answered your question.
Vortex motor: there is a capacitor for "soft start"
In AC current, a capacitor will limit the current flow.
so we have a C in the circuit
there are the primary windings to produce a magnetic field to drive the "rest of it"
this is the inductor L
Hook up the inexpensive kind of speed controller (R) and dial it back until it is nice and quiet and your Can Filter gets the proper 1/10 second or more contact time...by any chance to you hear a "wa waa waaa waaaa waaaaa waaaaaa waaaaa waaaa waaa waa wa waa waaa..."?
That would be constructive interference from the RLC circuit you just created. congratulations, you fan is using about twice the rated power and blowing half as hard. I gauged it with an inductive ammeter. The extra energy is being dissipated in the form of vibrations in the coils of the motor (that is the wa waa noise you hear), heat from all the extra current bouncing back and forth, and, I bet, a whole bunch of electro magnetic radiation.

tl;dr
Your fan won't last 10 years.
You are using more power than at full blast. (possibly twice as much)
The capacitor might blow...I don't know what would happen then.
If you need to reduce flow to make your Can Filter work then add a restrictor somewhere.

I covered the intake with my hand one time and the fan sped up to what sounded like exactly twice it's normal speed (2500 RPM to 5000 RPM). I did not test the current draw when I did that. I do not know what happens to current consumption when a restrictor is added to the intake side. My guess is that if you just partially restrict the intake side the fan will spin at the same speed and use less power because the air is rarified and causes the blades to see less resistance. Add a restrictor on the output side and the fan will draw more power? I'm not sure if it can do that due to the capacitor.

None of those above tips will result in less noise. They will just help you dial in the flow rate.

If you duct it properly: Can Filter to fan suction, then most of the noise comes from the output side. A few feet of rigid metal duct (not that lightweight aluminum stretchable stuff) on the output side will help muffle it. Exhausting over a cool tube or well-sealed lamp should help muffle it. You can build or buy a "fan muffler". That will add resistance and reduce flow.
tl;dr
Use galvanized steel ducting on your exhaust ducts. Wrap it in insulation for extra dampening.

As for noise coming off the fan body: I would build a little MDF box...you could just find a subwoofer box that your fan fits into...and line it with the foam material you find inside. If you just get an empty MDF box, or build one, then go to www.partsexpress.com and line it with acoustic asphalt tile, then glue that foam egg-crate stuff to the acoustic asphalt.

While you are ordering from Parts Express, you might want to try out their nice line of 3 and 4 inch light trap parts (speaker vent ports). It is black plastic and comes with nice, aerodynamic flares for the ends and they even have 90 degree elbow pieces and long straight pieces. They are all black, inside and out. You just glue them together. A little more expensive than getting PVC pipe parts and painting the inside flat black, but hey: its perfect for our needs. I bet the acoustic flanges will also make less noise. They are probably less heavy than PVC which is a plus for a portable grow box.

 

[BonsaiBud]

Yeah, pretty much all homes with modern centralized air need to have the bottoms of the doors trimmed for better air flow back to the main intake. Way back in the day, Each room it's own intake. When they decided to economize on the ducting they forgot to allow any way for the air to get back to the HVAC unit. Just think of the gas/oil/electric bills that could be halved and the coal plants that could be taken off line if everyone just trimmed the bottoms of their doors.

 

[Guest]

Really?