Tutorial Ventilation 101

[chase]

cooling help

cooling help

Hello everyone ,im going to try a new set up .
please tell me if this will work.

1000 Watt H.P.S 10000 btu portable ac , & I intend to air cool the light with an 8 inch vortex pulling from the room , & blowing into the same room , through a carbon filter , recycling the hot air.


Will the ten thousand btu ac keep everything cool ? Any info would be apreaciated.
\
Also I cant duct out , only a small laundry duct for my ac.

 

[chase]

??

Hello everyone ,im going to try a new set up .
please tell me if this will work.

1000 Watt H.P.S 10000 btu portable ac , & I intend to air cool the light with an 8 inch vortex pulling from the room , & blowing into the same room , through a carbon filter , recycling the hot air.


Will the ten thousand btu ac keep everything cool ? Any info would be apreaciated.
\
Also I cant duct out , only a small laundry duct for my ac.

This will be a 4x4 room , & the lights will be 12/12. Also the electronic balist will be in the same room but outside of the polysheild that I will be flowering in , I will have an oscelating fan also.

 

[johnnybravo]

anybody got some idea how to mount/hang a fan like this:

 

[Primate]

Hi everyone.

Really confused the crap out of myself with all the different post i've read regarding how often you should replace all the air in your room. Read anything from every 2 minutes, to twice a minute. 0.3 cfm/w to 3cmf.

Basic question. Is replacing the air in my room every 2 min 25sec good enough.

I have a space that has a volume of 39.05m3 but i'm only growing in about 20m3 using 2400watts of HPS lighting and 600 watts of CFL lighting, so total 3000 watts of light, and i'm replacing the whole volume of the room including unused space every 2min25sec as i said above.

Is this close enough or am i far off?

Any help will be much appreciated.

 

[Primate]

Or wait....

Does the fact that i'm growing in half the volume mean that i am then in theory replacing the volume of air in the grow space in half that time, comparatively?

So 145 seconds / 2 = 72 sec?

 

[Spok]

two stage vent system.

two stage vent system.

ive got a two stage ventilation system, one for the light and one for the cab. however i forgot to cut two outake holes, therefor ive only got one.

If i channel both ventilation systems into one outake, will that cause a problem? Or in other words, is this plausible? I think it would cause a reduction in the airflow, but i dont know if its significant enough to impact the grow.

any help would be nice, thanks.

 

[St3ve]

ive got a two stage ventilation system, one for the light and one for the cab. however i forgot to cut two outake holes, therefor ive only got one.

If i channel both ventilation systems into one outake, will that cause a problem? Or in other words, is this plausible? I think it would cause a reduction in the airflow, but i dont know if its significant enough to impact the grow.

any help would be nice, thanks.

It all depends on how big the vent is. Both streams of air will cause friction as they run into each other so you have to account for that by an oversized vent.

 

[barth]

Hey ICMAG, Long time no see.

I have a 6" Inline Fan rated at 424 CFM runs 24/7 and a 4" Inline fan fan rated at 178 CFM that runs for about 15 mins an hour for an a/c box. This currently just vents into the Attic space. I live in a very dry area and mold hasnt been a problem and i use a humidifier.

However I would like to vent outdoors to keep the area cooler. I am going to install a roof vent.

Could i use an 8 inch vent to 6 " reducer T and connect the 4" and 6" flexible duct to it thus venting outdoors. Any roof vent ideas or experience would be helpful.

 

[vta]

Hey ICMAG, Long time no see.

I have a 6" Inline Fan rated at 424 CFM runs 24/7 and a 4" Inline fan fan rated at 178 CFM that runs for about 15 mins an hour for an a/c box. This currently just vents into the Attic space. I live in a very dry area and mold hasnt been a problem and i use a humidifier.

However I would like to vent outdoors to keep the area cooler. I am going to install a roof vent.

Could i use an 8 inch vent to 6 " reducer T and connect the 4" and 6" flexible duct to it thus venting outdoors. Any roof vent ideas or experience would be helpful.

Maybe one of the vent pros will chime in but until then check this out, it might give you some ideas.

I have 2 fans, 1 is on 24/7 the other, 12 hours. They go to a Y and out the roof via a vent. My concern was noise...so in made my own muffler. Before the 2 meet up at the Y, I have a back draft damper in place for the 12 hour fan.

The fans are 6" but the ducts are increased to 8" before the 8" Y. Then onto the garbage can muffler. The top of the can is connected to a 12" collar that is secured to the underside of the roof. Hole then vent on top.

By the time the air stream makes it outside...it has slowed down and is silent....zero noise.

So instead of restricting, I went the opposite direction. You might want to turn down the speed of your 8" fan...then reduce the duct to 6" and into a Y. Your 4"...increase to 6" then put in a damper, then to the Y and out... Good luck!

Here is the vent I got from Home Depot...16-3/4-in x 15-in

 

[barth]

Thanks VTA this is exactly what i was looking for. I even found that DIY muffler. This is my next weekend project.

 

[Ohmless]

I would think you would need a baffle to prevent backflow of hot air back into the garden if the two fans weren't working at the same time. GL

 

[vta]

I would think you would need a baffle to prevent backflow of hot air back into the garden if the two fans weren't working at the same time. GL

Yes you do. back draft damper...

 

[LyryC]

Whats better. The scrubber in the Box and an Exhaust fan pulling the air out of the grow box. Or the Scrubber outside the box and the exhaust fan pushing air out of the room?

Thanks!

 

[Trewarin]

I'm sorry, I've tried reading this thread a few times... but it's not in language I can understand.
I was hoping someone could have a look at my math...

2ftx3ftx5ft box = 30 square feet

I have two 6in inline fans, not centrifugal... they claim about 250cfm each.

now for the problem: a 600watt bulb hanging vertically in this cab.

I have a 6inch intake hole at the bottom that can be made to be a square hole 2x that size roughly... should I run it with an intake AND outtake fan or run both exhausting out the top and have passive intake at the bottom?

Will this be possible, or should I wait a few months and downsize the bulb?

 

[b_all_in]

Is this correct?

Is this correct?

-Aprox. 32sqft/224cuft flowering room
-2 600watt hps in air cooled hoods
-1 fan for both lights with flex duct: 6in inline axial @ 250cfm via 12sqin intake
-Exhaust: 6" 340cfm thru 400cfm scrubber via 12sqin passive intake.
-Run light fan when lights are on (duh)
-Run exhaust fan 24/7???

Overkill? Not enough?

PLEASE HELP! This thread, while enlightening me greatly, has made me realize how ignorant I am!

THANKS!

 

[Superklass]

Very informative and good thread

 

[bEasty]

Steve, from what I can gather, the OP mainly focused this article on what he grows in, micro cabs. He states that any airflow more than this will stress out the plants............which may be the case if you're growing in a rubbermaid and there's a vortex going on inside.

I don't really think that's applicable for larger apps, as you can exhaust your air much more quickly (I can go up to 1X per minute in my 1200 CF grow room) without my plants even knowing anything's going on

He talks about it in the first post (although it's from more than two years ago).

Ventillation means in practice, that you suck out air from your grow area (and replace it with fresh air of course).
Although its only one thing, the air speed, witch you can control, ventillation has three purposes:
a, sucking in fresh air, containing co2 for photosythesis
b, sucking out hot air, to have room temperature between 25-30 *C (around 80 *F) - where photosytesis at its best, and
c, lowering humidity - by sucking it out, with the air of course

in a plants life low humidty is like when your throat dries out: you will get thirsty, and you will drink a lot (that was mentioned in the first post). But if you drink a lot, then you'll need to piss, which in plant life means transpiration(water evaporating through the leafs through stomatas).

sorry for the lame metaphore, but I think this is important to understand, as this is the point of this thread. If you let out the humidity factor out of ventillation, you should just go with the "ventillated hood with scrubbers setup", as it lowers the temperature in the chamber effectively, and you get plenty of fresh air.

Too fast transpiration is not always bad, or at least its not a knockout.
Plants have much more experience at evolution , they can survuve much more then we could. The point is, to have a reasonable yield, the fastest as possible, and at the lowest cost. For that, we want to give our plants the OPTIMUM of all factors, including transpiration.
Differing from the optimum(by any factors) means that your plants will grow or mature slower (in extreme cases it can lead to defficiencies), and it can cost a lot: more energy consumption (by the elongated grow cycle), more nutritinet counsumption(by the grown water consumpiton), and less yield.

And these are facts, and not depending on the grow room size.
But that leads to an other topic, which is:

How you could count the proper air change?

At soilless greenhouses, where co2 added seprately, ventillation controll is based on the temperature, and the humidity.

When designing a grow room, ventillation usually made for eliminating odors, and cooling our bulbs(to have our room temperature o.k.) at the first place!
And fresh air are usually just a spin-off, not mentioned the humidity.

But now, if you want an exact answer: how to count the air change - i have to dissapoint you: i dont know.
to be honest, i think there is no exact number.

I think ventillation controll sould be based on the humidity and the temperature, and the cooling line for the bulbs should be seperated from our grow chamber - as redgreenery showed us at the first post.
Odor contorol can be done also by VaporTek Optimum 4000 for example.
but theese are just thoughts, not facts!

And thanks for this very informative thread, it enlighted me a lot!

 

[Farmerco]

I just purchased a dr120w it has 1 6in exhaust and 2intake and is 2x4x5. I am planning on running a 600 air cooled hood and now need a filter for smell. My plan is to keep everything in the tent if possible. I have a 165cfm inline 4 and that is just short for the 190cfm to vent it to within 10*f. So I would like to do a 2 stage system for space saving. My hood has 4 in openings.
Now for my questions.
I assume I need to up my fan to a 6in to get to the proper cfm to add a scrubber and hood. Since heat can supposedly make scrubbers work less efficient how should I run this. A wye to pull from the air and the other side connected to the hood? Pull directly through the hood (which seems very inefficient)?

The intake spaces are already doubled since I have 2 at 6 inches but isn't it more based on how much is being expelled?

I was running a 2 600's in a 4x4 with the ambient house temp at 70 and venting them with the 4in. And then a 6inch open and exhaust for plant maintenance. This kept the inside temp at 80.



Sorry about the randomness just trying to get things dialed in before I get to far.

 

[thelaughingman]

what about an intake fan and exhaust fan?

 

[GrowNut]

great reference thread, thanks