2k Watt Ventilation

J

joe macclennan

Well-Known Member
sure, you could probably get away with One six inch fan for all of em honestly. Just size your inlet and outlet appropriately.

I know a guy who vents 8k of lights with one 8" fan...works fine.

edit: oh and you will probably want a couple of dampers to balance the airflow unless your runs are close to being identical.
 
NorthofEngland

NorthofEngland

Well-Known Member
effect said:
to common sense? hahahahaha. weed forums. what is your argument? that you don't understand hvac or can't do math? the area of an 8 inch circle is about 100", so a window of about 30" wide would need to be open 6-9", to ya know, have a chance of keeping up with the several hundred cfm of air you're ideally blasting out it. that fan is pretty windy right? it blows on your hand pretty hard? well if you don't have as much air flow coming in, you're going to have vacuum right? and how does working in a vacuum effect fan performance? it lowers performance because the air is thinner, and the fan cannot spin faster. OK, so it's sub optimal to have excessive vacuum. it'll work, but the fan is working harder for less. the 2x-3x thing isn't some forum rule some guru came up with, it's just an off the cuff figure in this case to illustrate that you need a good bit more to compensate, look up ANY hvac shit on google.

i'm not linking to anything because i wrote that myself just now as a forum contribution. you wana try it?
Click to expand...
Gases DO NOT get blocked out due to BOTTLE NECKS.
It may be your 'common sense' but it makes absolutely no sense, to me.

Show some supporting evidence.
I just contributed by making sure your 'off the cuff' equations were exposed as 'sub optimal' (aka - made up).
 
NorthofEngland

NorthofEngland

Well-Known Member
2000w over a 8' x 10' footprint = 25watt per sq ft.
There's something hinky about this entire thread.
Almost like it's a fictional grow room....???
 
fir3dragon

fir3dragon

Well-Known Member
With everything that has been said I still believe it's false that it has to be 2-3 times bigger then the out take.
 
jrainman

jrainman

Active Member
fir3dragon said:
With everything that has been said I still believe it's false that it has to be 2-3 times bigger then the out take.
Click to expand...
Understandable , let me put it in something you can understand an experiment with, Go outside to your car cover 3/4 of your radiator with car board ,then get in your car and drive it for about 45 min and come back here and tell us what happens
 
NorthofEngland

NorthofEngland

Well-Known Member
I use a 6"Ruck & 6" Ducting as Extraction
and a 6ft length of 6" Ducting as a passive intake.

It has worked fine since day one
Not the least sign of negative pressure.

Talking about Car Radiators and 'sub optimal' performance are mere distractions from the obvious incorrectness of the comment.

He'd back it up with a sourced quote if he could
But he can't.
So he's desperately attempting to use sophistry to justify the unjustifiable.
 
jrainman

jrainman

Active Member
here is something that may help you understand ,let take a normal window A/c unit , why is the area where the air gets drawn in to the unit ( Condenser coil) 2 x the size of where the cold air exits from
 
jrainman

jrainman

Active Member
NorthofEngland said:
I use a 6"Ruck & 6" Ducting as Extraction
and a 6ft length of 6" Ducting as a passive intake.

It has worked fine since day one
Not the least sign of negative pressure.

Talking about Car Radiators and 'sub optimal' performance are mere distractions from the obvious incorrectness of the comment.

He'd back it up with a sourced quote if he could
But he can't.
So he's desperately attempting to use sophistry to justify the unjustifiable.
Click to expand...
So then why is there a CFM rating on all fans , CFM cubic feet of air movement per min
 
NorthofEngland

NorthofEngland

Well-Known Member
jrainman said:
Understandable , let me put it in something you can understand an experiment with, Go outside to your car cover 3/4 of your radiator with car board ,then get in your car and drive it for about 45 min and come back here and tell us what happens
Click to expand...
This analogy is irrelevant.
Car radiators have to cope with the constantly expanding and shrinking water/gas combination.
AKA Steam combustion - potentially explosive due to built up pressure??

Can you understand that?

Let me phrase this in a way you can understand:

CAR RADIATORS WORK NOTHING LIKE GROW ROOM PASSIVE INLINE FANS
NOTHING!
 
jrainman

jrainman

Active Member
Do you understand that A 6'' round duct can only handle 150 cfm at best so if you attach that 6'' duct to a 300cfm fan you can not achieve your per min cycle
 
NorthofEngland

NorthofEngland

Well-Known Member
I understand that, unless working within a vacuum, a 6" passive intake WILL ALLOW enough air to return into the space to compensate for the 6" Extraction.

Or else why would SO MANY GROWERS use such a system without experiencing NEGATIVE PRESSURE?

You made a false statement.
When confronted you made a partial confession (with a lame excuse).
Now you're clinging on to the principle and attempting to over complicate the issue through pure embarrassment.

I KNOW what works in my grow.
And I don't need 3 x 6" for a passive.
I need a 6"
(Same as the extractor).

If all of the facts you state are true it should be incredibly easy to find quotable sources.

Go on - Quote a Professor or something
Someone who's academically published.

Expose me as being wrong....
 
J

joe macclennan

Well-Known Member
~ sighs~ another internet expert...whose only experience on the subject is hooking a fan up to a reflector.

no real world experience..

do what your gonna do england

obviously you know everything on the subject :roll:


oh and jR didn't say it needed to be 3x larger...superstoner did.

as I said 25% larger is adequate for PROPER air flow.

Key word bolded there^^

will it work with a six? sure. and it'll be less efficient, louder, and probably make your hoods leak a bit.

size your duct appropriately and all of these things will vastly be reduced. If not eliminated. You'll probably find you can cut the fan speed by half thereby dropping usage a bit.

but don't take the advice from a couple of guys who do hvac for a living or anything.


knucklehead
 
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