Help with ventilation

[iSmokeTrees]

With the concept of positive pressure in mind, should I have the inlet fan of my light cooling be smaller than the outlet fan? i.e. 6" inlet fan and 8" outlet. Or can I go with two 8"?

Also for the room ventilation, should I have a larger outlet fan than inlet fan? i.e. 8" inlet and 10" outlet? Or is it ok to go with two of the same, like two 8".


Thanks for help!

 

[HeadyPete]

why positive pressure?

A fan sucking through a carbon filter then your light is the way to go. Biggest fan you can live with on the exhaust (put it on a speed control to adjust temps) and a larger intake duct than exhaust to ensure no air restriction. Put a furnace filter on the intake to keep out pests and problems.

If you mismatch fan sizes one will work harder and burn out faster.

 

[iSmokeTrees]

I thought it was best to always have your exhaust fan to be larger than your intake fan, to prevent positive pressure and inflating the ducting/room/etc.

 

[FreezerBoy]

Intake fans are for people who really know their stuff. If you're here asking these questions, you're not one of them. Punch 3 equal sized holes, two at bottom, one at top for the exhaust fan and be done.

 

[iSmokeTrees]

Condescending jack ass, I'm making a sealed room. From my understanding if the intake fan is larger than the exhaust fan, you create positive pressure which is no good. You want negative pressure, so you have the exhaust fan larger than the intake fan. The air can never exit faster than it enters, and you never have positive pressure problems.

 

[masterKahn]

Negative pressure is the goal. With carbon this is all more important. You want no air escaping EXCEPT through your carbon then exhaust fan and out of the grow area. If your exhaust is powerful enough to make negative pressure all gaps where smell might leak out are effectively "sealed" because air is rushing in and can not escape.

i am a fan of passive intakes alot less fuss and mess to deal with. This can't work for everything unfortunately but it's simple and effective. If your asking about the intake fan for an aircooled hood an inline duct fan can be a good option. They are great for "boosting" air flow in ducts and a 4" in line duct fan will pull 80-100 cfm while a true in-line fan like a vortex or what ever it's called would pull closer to 250cfm. In line duct fans can be had on the cheap and come in sizes up to 12"

 

[FreezerBoy]

There's only one way to get positive pressure and thats intake fans. If you want to spend extra time money and effort on something you don't need simply to increase your chance of arrest, have at it. My apologies for trying to keep you out of jail. Won't happen again.

 

[iSmokeTrees]

Well is one fan enough to air cool 2000W pulling it 10 feet? Seems like it would struggle.

 

[smokinshogun]

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[iSmokeTrees]

Why can't my room have air cooled lights with air from outside the room, while the room remains sealed?

 

[smokinshogun]

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[hoosierdaddy]

Condescending jack ass,

Nice touch, asshat.

 

[phr3d0m2gr0]

iSmokeTrees: Coming here and talking shit to someone like FreezerBoy, who obviously knows his stuff if you look at his threads, will not get you much help or respect. Calm down.

Also you need to be more specific in your post, for example:

Well is one fan enough to air cool 2000W pulling it 10 feet? Seems like it would struggle.

Yes one fan is enough but it depends on the fan. A PC fan will NOT work, but a inline blower/squirrel cage fan of proper size WILL work. What fan are you planning on using? It's all in the details man.

The easiest way to set up your ventilation would be:
1 Fan exhausting air through the light (cooltube?). This would take air from outside the grow area via a passive intake connected to the light via ducting.

1 Fan, probably a smaller than the one exhausting your light, pulling through a carbon scrubber and then exhausting out of the room. The air would come in through a passive intake someone in the room. You want enough airflow so that the entire cubic area of the room is exchanged with fresh air every few minutes.

Example:

Let's say the room is 2' wide, 3' deep, and 5' tall. The cubic area is 2x3x5=30 cubic feet. To exchange this every three minutes you would only need a 10 cfm (cubic feet per minute) fan. Of course you have to take the carbon scrubber (these can hurt the cfm a lot, but most scrubbers you can buy at the store have a cfm rating. Get one that is rated at the cfm you would need for adequte ventilation. In this example a 10cfm scrubber would be adequate.) and ducting into account. This would lower the effective cfm of the fan. So probably go for 100cfm fan just to be safe.

These numbers are off the top of my head and you would need to use your own to find the correct equipment for your particular situation.

-Phr3

 

[iSmokeTrees]

Well its two 10x10 rooms sealed with a lung room between them set up on a flip flop. Each room is gonna have two 8x4 trays with two 1000w lamps above each tray. Each room will have a 12" ecoplus supreme inline fan @ 1060 cfms for intake and exhaust to and from the lung room. I figured along with A/C I would air cool my lamp hoods but I suppose that is a bad idea according to everyone. Oh well, saves me $2300 on fans.