stealth cabinet plan - ongoing plan!

[Jerry Maine]

Regarding the PC fans and use of a scrubber, Red Greenery has a single 64cfm fan working an undersized scrubber, and estimates that it exhausts at around 15cfm. I'd agree with YUKON and suggest you use two 150W HID's, but a 250W HID would get the job done and may be a little easier in some respects, less outlay, fans, ducting, etc. and if you cool it well enough you'll not lose any height either way. 150W HID's run cooler, but even my 250W barely warms my glass shield, I can hold the back of my hand an inch from the globe itself indefinitely, I'm sure plants could touch the glass without any problems. Admittedly I have a surprisingly efficient globe.

I still think you could power each with a 64cfm PC fan. And two 64cfm PC fans will push through a scrubber. I can feel a light draft coming from my scrubber, which admittedly is untested for odor, and I was using two fans running at 41cfm. They don't have the torque that centrifugal fans have, so they probably lose about 2/3rds of their capacity going through an adequate sized scrubber, but 128cfm worth of PC fans, if you had one 64cfm fan hooked up to each 150W cooltube, and then going through a decent sized scrubber should still get the job done, and exhaust at 40cfm or better. You're flower box is just over 12 square feet so at 40cfm you should be able to exchange the air 3 times a minute, which is perfectly adequate, but I think you can get that closer to 4 times a minute.

However, if you can think of a way, I'd try to cool the light(s) independently as you had originally planned. This way the air cooling the light, which is what's going to make the biggest difference for your temps, isn't restricted by the scrubber. The downside is you'll need to allow for separate intakes and exhausts, which I know can be a hassle, but if it can be done, it makes stealthing with PC fans easier. For a 250W I'd use three 64 cfm fans, 1 for the light, 2 for the scrubber. For 2 x 150W I'd still use 2 64cfm fans for the scrubber, but have two 33cfm fans for the lights. 120mm and 100mm PC fans are a good fit for 4 and 5 inch ducting.

Regarding scrubbers, one idea I've had is to use two 5 inch elbows with a cylindrical scrubber in between, and a PC fan on each end. You could probably do this, but again I think you will need to encroach on your mother room, whichever way you go, if you plan on scrubbing effectively. I did a search for durban poisons scrubber but couldn't find it, can you give me the URL? Perhaps he has the answer. You'll probably need to pass the air across 2 square feet or more of carbon, and I just can't picture how you'd do that in that little utility space, I'd consider making a third smaller compartment just for the scrubber, and just have the fans cooling the light exhaust via the utility box.

A few more things to chew on. But with that space you have some options, and whatever works for you is the right one. Frankly, if a little noise isn't a factor I would just go for a small inline fan, and a one-in-all ventialtion system like Yukon's would be easier, and give you more of an error margin for heat.

Jerry

 

[untamed]

Jerry Maine: thanks for that very great in depth post. you have given me a lot of information to think about and go work with.

Here is the link for a DIY scrubber durban poison (DurbanPoison) did:
http://www.icmag.com/ic/showthread.php?t=31679

I have been thinking about this for the last couple of hours, I cant really put a picture to this, but I will give a description as best I can:

- flower room will have 5 x 100mm (circle) inlet vents (covered by a sliding tray like NOKUY has done). there will be 2 x 80mm fans at top of the cabinet on each side of the cool tube to promote proer air circulation. cool tube will be 150mm (6") and have a fan sucking air through it.
- veg room will have 4 x 100mm (circle) inlet vents (covered by a sliding tray). there will be 2 x 80mm fans at top of the cabinet sucking air out and blowing it straight into the control room.
- cure room / storage will have 2 x 75mm (circle) inlet vents. there will be 1 x 80mm fan at top sucking air through straight into control room.

now, my control room is approx 17" tall (after revision). I am thinking of making 2 x 6" scrubbers (short length tho) and having 2 x 120mm PC fans sucking air through these. either that, or get a big inline setup and have 1 x scrubber.

how does that sound so far?

 

[untamed]

found an "inline fan" that a hydroponic shop near me sells.

150m, spectrum (brand I think?), 650 cubic meters per hour:

650 (cubic meters) = 22 954.5334 cubic feet
22954 / 60 minutes = 382 CFM (I hope my maths is correct)

thats a big output (probably a little too big / over rated)... wonder if there is a way to slow it down to 50% capacity to quieten it up!

<-- there is a pic of it at the bottom, check it out.. let me know what you think.

 

[untamed]

and I just found another inline fan:



I might have to go with one of these i think? if it gets too loud, I will just make a small muffler at the back of the cabinet to shut the sound up a little!

 

[stevr59]

:quote:stevr: what wattage HPS are you using in your cab to get the temps that high? also, what ventilation system have you got going?:quote: well i am running one 150 hps with a Dayton 145 cmf blower, but my ventilation system need to be up graded, even still don't matter if you room temps are to high and with out ac i am in big trouble. thank god its still cool at nite for now. but even that fixing to end summer nite time temp here can be any where from 75 to 89 at nite and i run my box at nite to help keep it cool as i can but i think this will be my last run using the swc getting tired of fighting the rez temp which is now out of control and root rot should be setting in soon. but my next run i will be growing in coco coir and that will cure my root rot problems. yesterday was my highest room temp it hit 89.6 and the highest box temp was 87.5 and the rez temp hit 79 way to high. and before i had the air cooled hood and was running a 85 cmf bath room fan it hit 105 box temp lol can you say Easy bake oven.

 

[untamed]

wow, they are high temps.. I'm growing pure organinc in a soilless mixture, no rez probs to worry about, although I will have PH and nute levels to maintain.

 

[untamed]

well, it looks like I have found a good exhaust fan:

170ltrs per second, which equates to roughly 360 CFM. 150mm (6") which will conect straight to the carbon filter!

 

[minds_I]

well my cab is a working copy of the ngb and it does work well but my main problem is still heat even with a air cool hood right now the ambient room temp is 87 and fixing to be in the 90s any day now. and i am having a hard time keeping my rez cool today the rez hit 79 which is not good yeah my ac no longer work and my trailer is fixing to turn into a oven. i am trying to hold out 2 more week till harvest then i am shutting it down till i can get my ac fixed. nokuy there not a thing wrong with borrowing some one ideas. but your version of the box so far has been the best i seen. but me i would do a way with the pipes my self and vent each cab speratedly and install dark room vents and copy minds idea of a adjustable vent , but i am curious nokuy how many grams you pulling from ur box so far best i have done was 200 grams with 2 plants.

here is last year crop the one i pulled the 200 grams its a ak47 by bubble berry

Hello all,

I just wanted to say that since I made the vent modifications my temps have been much better.

Lately, as the outside temp is going up, my cab temps have also gone up. OK, so I turn on the AC and bring the room the cabinet is in to 72*F.

Now when I first did the mods my temps were 4-5 degrees above ambient. Well lately they have been climbing to 82*F. I turn up my fan and get a little relief but not as much as was getting.

What could be causing this I have been wondering for about a week now....I said to myself, it must be the light traps have gotten clogged with dust and debris....

ANyway, so I remove the lighttraps and clean them...temps back to normal.

What was a problem was I initially used latex caulk to fasten them to the bottom of my cab. I had to use a razor blade and cut them off.

I am mentioning this because it is a design change I would make...make your lighttraps removeable for cleaning as they get clogged.

I change my home AC filters monthly, I do not know why I did not think about it.

So, again, make your inlets removable for cleaning if they are susceptable to clogging.

Untamed, good luck with your cab...mine has been a pleasure to run.

minds_I

 

[untamed]

minds, thanks for stopping in

good advice on the cleaning of the system.. I will have to factor that into my plan..

thanks for all the input guys, this thread is going to be great!

hope to have my plans finalised by this weekend so I can start assembling it and get my bagseed seedlings a better home!

 

[untamed]

I am a little stoned and have been thinking heaps about my exhaust system.

if you go back to the last page, you will see what I had planned:

- flower room will have 5 x 100mm (circle) inlet vents (covered by a sliding tray like NOKUY has done). there will be 2 x 80mm fans at top of the cabinet on each side of the cool tube to promote proer air circulation. cool tube will be 150mm (6") and have a fan sucking air through it.
- veg room will have 4 x 100mm (circle) inlet vents (covered by a sliding tray). there will be 2 x 80mm fans at top of the cabinet sucking air out and blowing it straight into the control room.
- cure room / storage will have 2 x 75mm (circle) inlet vents. there will be 1 x 80mm fan at top sucking air through straight into control room.

ok, so I ill have 2 x 80mm fans pushing air from each chamber into the exhaust area (bar the flower room which will also draw through the cool tube which will have a 150mm fan sucking air through).

what I have been thinking, is these fans are rated to certain CFM levels, from memory it was about 40-50 CFM each fan. With this big can fan I'm looking at buying for my scrubber / exhaust (approx 350 cfm), will there be bottle necks in the system I have planned?

I'm thinking the exhaust room is going to be trying to draw through a big load more air then the PC fans can emit, will this cause back pressure problems at all?

Am I on the right track here with what I'm thinking? or will it be irrelevant?

Any experience/feedback/opinions would be appreciated guys..

and once again, thanks for stopping in!

 

[NOKUY]

I am a little stoned and have been thinking heaps about my exhaust system.

if you go back to the last page, you will see what I had planned:



ok, so I ill have 2 x 80mm fans pushing air from each chamber into the exhaust area (bar the flower room which will also draw through the cool tube which will have a 150mm fan sucking air through).

what I have been thinking, is these fans are rated to certain CFM levels, from memory it was about 40-50 CFM each fan. With this big can fan I'm looking at buying for my scrubber / exhaust (approx 350 cfm), will there be bottle necks in the system I have planned?

I'm thinking the exhaust room is going to be trying to draw through a big load more air then the PC fans can emit, will this cause back pressure problems at all?

Am I on the right track here with what I'm thinking? or will it be irrelevant?

Any experience/feedback/opinions would be appreciated guys..

and once again, thanks for stopping in!

I'm thinking you won't need any fans except for this (1) (350 cfm)...it should be more than adequate by itself if you have the rest of your ventilation in check.

I might be canfused as to why you think you need the additional (2) smaller ones

what carbon scrubber are u thinking of going with (for one rated to that much CFM it's gonna be pretty big)

I used this link to make mine:

http://www.icmag.com/ic/showthread.php?p=509470#link

for my fan (160cfm)...the exact one "durban poinson" made in the thread was perfect inch for inch

but he has the formulas posted for making your scrubber the right size to avoid any "backflow" issues.

heres the formula and some explanation, there is more disgussion on all this in his thread tho:

To figure out the size filter you will need for your fan, use this formula:
[If you need a larger diameter filter than listed in the tutorial, then you need to upgrade the duct sizes in the list and update the instructions.] Also keep in mind that if you're running some ghetto fan, expect ghetto results. Spend some decent money on your fan and it will perform. Some cheaper fans will give inflated figures too as to what the true CFM ratings are. My sig has a link for great pricing on vortex fans. I'm using the 4" 175CFM.

D = Diamter of Filter Inner Core (Inches)
H = Filter's Height (Inches)
I = Inner Core Surface Area Square Inch

CFM D H I
150 4 9 113
200 4 12 151
275 6 12 226
375 6 16 302
400 6 24 603
550 8 24 603
650 10 24 754

See the relation there?
Just take the CFM of your fan and choose the diamater of core you want and divide it accordingly. For example: I have 175 CFM and intend to use a 4" Diameter core. So I can look at the list above and figure;
150(CFM) divide 9(H) = 16.6 (Approximately)
Then I can take my 175(CFM Fan) and divide it by 16.6 to get 10.5". Therefore, my 175 cfm fan with a 4" Diameter would need a core height of 10.5".

I dont know if thats any help, but I thought it might be.

 

[untamed]

Hi nokuy

Thanks for repling.

The reason I was thinking of putting smaller fans was for better air exhange and to promote air movement from within the cabin. air flow will take the best and most easiest route to go from the inlet to the outlet. I have also read (cant remember where) that having smaller fans promote good air flow.

I guess guys like yourself have done it with one big fan so it should be ok with out the smaller ones.

I have seen that scrubber design and formula, if I get that big fan, I'm going to need to go this scrubber spec:

CFM D H I
375 6 16 302

Rougly needs to be 6" high and ~15.5" long if my calculators are correct.

 

[Jerry Maine]

That formula for the scrubber is probably for the inner core. If so you have to allow an extra few inches for the carbon packed around that, and some more again for clearance so it can exhaust. Assuming you go for 1.5 inch thick layer of carbon, and a 1.5 inch clearance around the scrubber, you'll need a space approximately 1'x1'x2' to house the scrubber, once you've allowed for an elbow, fittings, cap etc.

Having a few fans randomly blowing air around your growbox will help strengthen stems, and I think it helps reduce hot spots and mould too. But yeah, I agree with Yukon that with that jet engine you'll not need any ie. inlet fans, so long as you plan out your ventilation system.

However I'd suggest you find a smaller quieter fan, something around half that capacity will be ample for that box by itself. Frankly 350 cfm is overkill, will use more power, require a large scrubber, and your box will be noisier. Yukon is using a 160cfm fan from memory. I'd recommend something closer to 200cfm instead.

Jerry

 

[untamed]

Jerry, I think you are right, that fan is probably overkill!

Here is an inline one I came across from a local hydro place:

EDIT: REMOVED

they say its approx 90litres per second which roughly equates to 190 CFM. they also said to me that it will work with a carbon filter, but wont be the "best" and to use a smaller carbon filter.

what do you think?

Sorry about all these questions about the exhaust, but I jsut seem to be having issues figuring out this area for my cab and its getting frustrating

 

[Jerry Maine]

Yeah, I'd think 190cfm would be fine. It has a rating of 53 dB(A) which is decent, probably only hear it if you're listening for it or right next to the box.

I understand your frustration, but it's best to throw a few different ideas around and then settle on something rather than rush into anything. Like you I used google sketchup, and designed three different boxes, and a series of different setups. Best to ask questions now, than have to make difficult modifications later.

Regarding the scrubber, you'll still need to have a 6 inch core to match that fan, so you'll still need to allow about 1x1x2 for your scrubber. Definitely have a look at the odorsok, I think that would work well in your setup, they are a bit skinnier than most scrubbers, reasonably cheap, and you can get them in Australia.

Jerry

 

[untamed]

Thanks for all the help Jerry, its good to have some great opinions on board.

I have probably scrapped 5 ideas in sketchup already This one I have now is probably one of the better ones!

When I get home from work tonight, I will post up my latest pic of where the cab is at.

Regarding inlets, would it be better to have say 8 3" inlets or 3 or 4 6" inlets? Also, having a sliding draw OVER the intakes like NOKUY, will this impede air flow?

 

[minds_I]

Hello all,

Untamed, no matter what size fan you go with, it is always better to oversize and use a speed control.

Having control over your vent system is key to low temps and a proper grow environment. Having control over each leg of your system will pay off big time in environmental control and ultimately the quality of your buds.

minds_I

PS: as for flow resistance... the faster you have to move your airstream...the more resistance and hence flow loss you will realize. That is, multiple vents will move smaller amounts of air faster and casue more flow resistance. WHne you add it up, you will likely have better flow with a single large vent. So, I am suggesting that one or two big vents are better then many smaller ones.

 

[untamed]

hi minds,

thats some food for thought.

I think the "best", or easiest fan control I have seen is using PC fans connetected up to a variable voltage output, i.e. 240V AC -> 12/9/7.5/5V DC adapter.

I will certainly have a look into it minds, thanks for the heads up.

 

[Jerry Maine]

Agreed.

When I designed my ventilation system I deliberately chose a low rev fan, and designed it in such a way I could add fans to the system if necessary. So I could add two more fans to my scrubber, and another fan to my light hood, if necessary. I can also replace the low rev (low noise) models I have with mid or high rev higher capacity models. However PC fans are considerably cheap to replace, especially in Japan. I've actually got mine on a voltage adapter and slowed them down, but the true test won't be til the summer months,.

If that 350cfm fan is going for a song get that and a fan controller. You'll probably only need run it on half speed, even less, but if you need more you're covered. Alternatively perhaps look for a fan closer to 200-250cfm, this will give you a bit more breathing space, help you overcome any flow resistance.

I think the fan you listed will do the job however, so you could still just go with that. If you lose half its power due to resistance from the scrubber and flow restrictions you'll still be exchanging air at 4 times a minute, which is pretty good.

Jerry

 

[untamed]

4 times a minute is sufficient, I will just go with that. I'm actually retuning a few things to that store as they didnt suit my needs, so its costing me $30 total (after the other items are sent back).

so that fan will do the job and thats what I will get