Air Exchange in sealed CO2 augmented grow room

[HighWaterMark]

MMJ Grow Space: I have ~10K cubic feet (20'x50'x ~10' ceiling). I wish to maintain 1200-1500ppm CO2 with a perpetual fresh air exchange.

My math is sort of failing me in calculating my air exchange.

There will be two systems. Three daisy chained 1000W HID lights initiating with an interior 8" ceiling oriented carbon Phresh filters>8"conduit>8" Baddass inline fans>8" Blockbusters/Hortilux>pulling air out ceiling oriented room exit. System two: filtered Clean Air Centrifugal Squirrel Fans pushing sufficient air in from ground port(s) to adequately circulate air.

Incidental: multiple wall mount Vornado Heavy Duty Oscillating Air Circulators.

What I need:
(1) cfm to bring in via Clean Air Centrifugal Squirrel Fans near floor.
(2) cfm to evacuate via Baddas Inline Fans/3 Conduits near ceiling.

If description is not clear, please ask questions. Thanks for reading.

 

[HighWaterMark]

Abbreviated: For a 10,000 cubic foot grow room augmented with carbon dioxide, how many cubic feet per minute of air would I have to exchange to maintain optimal fresh air for growing?

 

[JJ Bones]

How Much Ventilation Do I Need in My Grow Room?

 

[HighWaterMark]

JJ Bones, thanks for your reply. I read and reread it. It advocates a range of 2500% based on some fuzzy variables. That's why I tried to be so specific in my original post. I also studied: What Range Should I Maintain for my Growroom Humidity and Temperature?

I know where I want my carbon dioxide, temp and humidity at each point of grow cycle and likewise, diurnal light cycle. All of this will be monitored and controlled by computer. The fresher the air, the better but the more everything costs. I need a reasonable balance beyond which I'm just wasting money.

Please feel free to ask more questions.

 

[JJ Bones]

What do you mean when you say, "...a range of 2500%"

 

[HighWaterMark]

JJ Bones,

Thanks again. From your link, How Much Ventilation Do I Need in My Grow Room?, there's the following passage,

you will want your fan to exchange the grow room air 3-5 times in one minute, so for a room that is 40 cubic feet, a fan that is capable of moving 120-200 cfm (cubic feet per minute) is recommended. If you only want to replace depleted levels of co2 and are growing in a closet using fluorescents, one room change per five minutes (divide room size by 5) will be adequate.

The range spanned by the two bold phrases is 25x or 2500%.

Take Care

 

[shottafire]

Sealed means no air exchange. The lights can be cooled without exchanging air. Ambient co2 levels in the air will probably not get you the 1200-1500 ppms you desire. Get a good ac unit and a burner or a tank. thats what I suggest

 

[HighWaterMark]

shottafire,

Thanks for the advice. I sincerely appreciate it. I'm on the fence between painting my basement area with a mold resistent latex versus investing in one, possibly two of the GORILLA GROW TENT(s) - 10′ x 20′ x 6′ 11″ (w/ ext. 7′ 11″). In a sense I can get the best of both worlds with the tent(s), sealing the lights at both ends as I pull the air with an inline fan throught an activated charcoal Can-Filter (both ports outside the tent). But then I'm stirring around progressively staler air about the environment of the tent. There has to be a best way. If anyone has a super-hip hyperlink for ventilation/air scrubbing, do tell.

Another question: does activated charcoal filter carbon dioxide out of a given closed space or does it merely circulate it?

 

[JJ Bones]

There will usually always be air exchange. Whether with an A/C or with fans, somewhere lies an intake and out-take.

I highly recommend you just build out this room yourself, the size is too large for a grow tent, construction should be done here, unless it is not permitted for some reason.

For the lights if your going to have a lot, which I would guess you are based on space (maybe 16?) I recommend that you setup some sort of advanced duct line simply because cooling in a straight line does not become efficient once you get more then 6 lights in a run. Obviously the cold air from the beginning gets hotter as it goes down, making the "air-cooling" less efficient.

Think of a bigger office building and how it is handled. Each room has a vent, so the air for the building comes through a main vent and breaks off into other rooms. Use your growing as little rooms or sections. Six lights per 'section' gets its own vent, like an office building right?

So now a powerful fan is pushing in cold air to a huge duct, which then distributes air to lines of lights, 6 of them. On the other end the line of lights ducting meets with another huge duct for the exhaust. This is just one idea for you to cool your lights, others may have different ideas.

Carbon filter won't harm CO2, however keep them on opposite corners of each other.

 

[HighWaterMark]

JJ Bones,

Ideally, I want two rows of six 1000W lights, each over a 4'x4' castered stiff tray (with a bit of room to walk around). I'd like three 400W MH lights hanging vertically between the rows. Hence, I have choices to make so that I can rotate all the plants at regular time intervals.

This doesnt help my heat evac situation. Please tell me what you mean by an "advanced duct line"? Do you thing a single industrial space is better than two large Gorilla Grow Tents, for example. Is a pair of sealed air duct lines enough in your opinion to cool six 1000W lights each? I got these ideas from an atricle entitled Ultimate Lighting.

Please feel free to offer more suggestions. I read them carefully.

 

[TanR]

Hi HighWaterMark,

I'm new to indoor growing and attempting to learn as much as possible by following questions like your's and read the various responses. So please forgive what may be question born of my lack of knowledge - but wouldn't any exchange of fresh air in your grow offset the benefit of (and money spent on) the creating the CO2?

From what little I've read on the topic, your stated desired range of 1200-1500 ppm is roughly 3 to 4 times the level of normal outdoor air. So as fast as your generating the CO2 to acheive this level, you would be diluting it with the fresh air, requiring you to generate even more CO2 to maintain your desired range.

What am I missing in the concept. Again, please forgive me if there is an aspect of which I'm not aware.

Thanks,

TanR

 

[HighWaterMark]

TanR,

Sorry for the delay in responding. Honestly, were on the same place on the slope of the same curve where it comes to room design. You are correct: ambient air approximates 300ppm CO2. Activated charcoal filters will remove carbon dioxide, but remove other molecules as a function of size and polarity. So if you just had an intake screen in the corner of your hypothetical cube and an activated charcoal filter in the opposite corner, the resultant air will still have right around 300ppm CO2, 78% N2, 21%O2, trace noble gasses and diminished pollutants. What your really looking to remove are the comparatively large and extraordinarily strong smelling terpenes and terpenoids, dominated by beta-Caryophyllene, a sesquiterpene with the molecular formula C15H24. There are over 120 terpenes and terpenoids synthesized by cannabis and stored by the trichomes. They are filtered much more efficiently by activated charcoal filters. Good thing too as they are what cause your neighbors to perk up on their morning walk and think, "aha, grow house!".

I'm remembering Organic Chemistry from 20 years ago, so if there are any gross errors in the above paragraph, please feel free to correct them with liberty.

 

[JJ Bones]

JJ Bones,

Ideally, I want two rows of six 1000W lights, each over a 4'x4' castered stiff tray (with a bit of room to walk around). I'd like three 400W MH lights hanging vertically between the rows. Hence, I have choices to make so that I can rotate all the plants at regular time intervals.

This doesnt help my heat evac situation. Please tell me what you mean by an "advanced duct line"? Do you thing a single industrial space is better than two large Gorilla Grow Tents, for example. Is a pair of sealed air duct lines enough in your opinion to cool six 1000W lights each? I got these ideas from an article entitled Ultimate Lighting

Please feel free to offer more suggestions. I read them carefully.

This is what I was attempting to describe:



A large duct line brings in cool air, which is then sent off to be split amongst other lines of lights. 6 lights in a line, then a big ducting is setup for the exhaust for them.

If you air-cool more then six lights in a row what tends to happen is heat builds up, which serves your air-cooling as useless. By doing it this way each line of lights gets cold air.

 

[HizzyB]

I'm trying to figure out a way to have an air exchange so at times I can dump the rooms co2 so I can work without feeling ill, maybe even if something like some kind of spray is used and is just to strong smelling to be comfortable. I've even heard at lights out to completely exchange the rooms air so it's all fresh and ready to ramp up the plants next morning.
My "new redo" is completely sealed up, maybe some sort of flap that stays shut until air flows so it's reletivly sealed when the fans off

Sorry for not knowing and using the proper terminology, this sealed style of growing is a new venture for me