Should I worry about airflow bottlenecks?

[Moonchild]

What I mean is, if negative pressure in my cabinet is the goal I'm shooting for, then don't I need to make sure that the area of the intake, on the bottom of the cabinet, is less than the amount of air that will be rushing through the two cooltubes?

I was thinking about this because I am just now cutting the holes to connect the lower part of the cab with the higher part, and two 4-inch holes just doesn't seem like a lot of area to me. Especially when I was hoping to use two 8"x8" darkroom louvers as my intake. I hope I'm not overthinking this (as I usually do), but it seems that I would be allowing way too much air into the cabinet that way, resulting in positive pressure, and odors leaking out of the cabinet. Should I just use ONE 8"x8" louver? Or would that even still be too much intake? Am I overthinking this?

I am basically making a Nimby-style dresser, but borrowing ideas from a few other people, mostly NOKUY, because he has the 2x150 setup that I am going with, and he uses cooltubes as well.

Everyone says that for negative pressure, the amount of air coming through the intake needs to be a bit less than the amount going out. Well, in my case, I'm going to have air coming in to the cabinet, then getting sucked through two 4inch glass tubes with mogul bulbs and sockets in them, THEN going to the dayton blower and out through the carbon scrubber via 4" hose.

I'm just one of those people who has to get things right the first time around, if anyone understands me. Sorry for asking so many questions!

Thanks.

edit: man, I don't even understand my own post, so I hope someone else will. I just want to make sure that I will still have negative pressure using 8x8 louvers for intake, and how many I should use for a cabinet that is 3 feet long by 1.3 feet deep. The air will enter through the bottom, go up through the plants, into the cool tubes (which will each have their own 4" hose going up to the next level in the cabinet, where the blower and the carbon scrubber will be, then out the back through one 4 inch hose.

Pictures are hopefully coming soon, as I really need some assistance.

 

[karl420]

i would do 2 or 3 x 3" hole that my 2cent :Oi know that the intake has to be smaller than the out-take for negative pressure.

what the height of this box ? you have to calcul the cubic feet.

~staysafe
-karl

 

[Moonchild]

Oh yeah, the height is over all 4 feet tall. The actual grow area is the bottom 2.5 feet. The top 1.5 is where the blower the the filter must be.

 

[minds_I]

Hello all,

I can tell you that the 8"X8" lovour does nto provide 64 square inches of opening... The louvers restrict airflow so going with two if them makes sense to me.

To keep odours inside the box you need negitive pressure but only just a little bit so you may be ok. What size is yoru Dayton...I would recommend a 265 cmf and a speed control. I truely have much greater control over my grow environment because of the speed control.

Good luck.

minds_I

 

[Moonchild]

^that's exactly the dayton I have... what is the speed control you mention? I was about to ask that question in the next few days, anyway... how can I control the speed of my dayton?

Thanks for your input, everyone!

 

[Moonchild]

I just had another idea, so tell me if this would work, anyone: I could have the air enter through the bottom of the cab (through two 8x8 darkroom vents), then go up through the two 150watt cooltubes (2.5 feet up), then each cooltube goes thru a 4-inch hole to the sealed-off top section of the cabinet where the dayton blower is SUCKING from a can-style carbon filter (as opposed to blowing) out of the back of the cabinet?

Would that work? (Sorry I still have no pics, and my microsoft paint skills are very weak). I was hoping to come up with a way to blow thru a carbon filter, instead of suck thru it, because I understand that blowing is quieter... (is this right?) But I'll suck thru it if it means I can contain everything inside the dresser. Especially if I can get a speed controller to lower the sound a little bit...

I can't wait to get this thing going... I've grown before, inside cabinets, but never needed to use a carbon filter before, so this is a fun new thing. Also the use of cool tubes is new to me, as well. I love micro-growing!!

If anyone can help me design this thing to where I can contain all of its parts within the cabinet, I will be their best friend. Thanks in advance!

Once again, it's a dresser, overall dimensions of a little over 4 feet tall, by 3 feet wide, by almost 1.5 feet deep. The bottom ~2.5 feet section is for growing, the top ~1.5 feet section is for everything else.

You guys are the best.