Ventilation design for new room... opinions?

[growclean]

New room - 10x20 wtih 12' ceilings inside of a warehouse. I am trying to design something that will be useful now (12 plants) and for the future....

I have put a diagram in below, which needs some explaining, referencing the diagram:

1. This is a diy carbon scrubber as described in this forum thanks to DurbanPoison. It would be hooked to a 8" S&P TD-200 fan (538 cfm - http://www.hvacquick.com/products/r...Remote-Fans-for-Bath/SP-TD-Series-Inline-Fans ). It would currently be exhausting out of the room into a common warehouse. The dashed lines show where later the veg/mother room exhaust would be routed to take up the hole left by this when we switch to a fully sealed room and co2.

2. Same 8" S&P TD-200 fan (538 cfm - http://www.hvacquick.com/products/r...Remote-Fans-for-Bath/SP-TD-Series-Inline-Fans ) pulling through lights and venting into warehouse.

3. HELP here! I want an intake from our "entry way" area that would lead the veg and flower rooms. I am not sure of the best way to do this. I would like something like an air return, so it blends in the surroundings from the entranceway. I would like it to be filtered and the somehow be able to split into the two sets of ductwork. I have looked at filtered returns online ( http://americanhvacparts.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Reg-8 ), but am not sure how they work or how to integrate it, and have thought of just using a regular air return and a box built on the inside of the veg room that would contain the duct work capped by a cone hepa filter ( http://www.growlightexpress.com/air-purification-50/organic-air-8-hepa-filter-337.html ). I would like it to be as clean as possible, but understand that restricting airflow may cause issues. Any ideas? Please help...

4. This would just be a passive style intake through the filter. 6"? I would like the same 8" fan pulling eventually through the opening where the carbon scrubber currently is, but that will be down the road.

Just to be clear, the dashed lines represent future improvements. Eventually 4 1000w reflectors in the flowering room. Sealed, with co2.

Does this make sense? Does it look good? Again this is new construction, so I can do whatever I want.

Thanks Again!

 

[growclean]

Bump for a little help. If you need a better explanation of what is going on or I am just a complete idiot... just let me know!

 

[EvilTwin]

Hi Growclean...
I'm just bumping your thread for you. I think you're getting into minutia when you should be thinking in more broad general strokes. At least for the purposes of trying to get help.

Your post is just too hard to understand and the picture isn't clear. That's just my opinion on why people aren't posting.

So for your 12 plants in flower initially...how will they be grown and under what lights? Will you be starting with two 1000s and then doubling that later?
ET

 

[growclean]

Your post is just too hard to understand and the picture isn't clear. That's just my opinion on why people aren't posting.

So for your 12 plants in flower initially...how will they be grown and under what lights? Will you be starting with two 1000s and then doubling that later?
ET

Yeah, I hear ya. I think it is maybe a little too hard to understand what I was thinking. So here goes a simplified version.

We will start with only 1 1000w Magnum XXXL and would like to expand up to 4 soon (hopefully!) Will that 8" fan be good enough to cool those 4(Starting wih one now and a speed controller)? Is that same fan good for a carbon scrubber for the 10x12x12 flowering room? In the 10x8x12 veg room, is that same fan good for exhasut with a passive intake?

Thanks for trying to understand!

 

[Dr. Conjuror]

What is the CFM of the fan being considered?

But the quick answer to your question (if I understand it) is that you would need about 1200CFM to cool 4000w of lighting if it is being air-cooled separately. Static pressures will greatly affect if you need more.

Ok from what I understand. you will need about 300cfm per 1000 watts of lighting with its only cooling region (ducts and air cooled hoods) to have a 10 degree difference between ambient temp and exhaust temps for the light cooling system and would barely affect your growing area temps.

This is the best thread I have come across for understanding ventilation...

Ventilation 101 by redgreenery

This is the formula to use assuming you have adequate intake area for the exhaust size:

CFM=3.16*Watts/DeltaT



I think it will help you find your answers.

Dr. Conjuror

 

[EvilTwin]

growclean,
Just pondering your situation again, it seems like you're neglecting the veg room. Since you're starting from scratch, you may as well incorporate the two into a system of ventilation.

Also, and I've never used CO2, but is a sealed room isn't the only way to go. Many people use timers that shut off ventilation while CO2 is being administered. Then...after an interval, the ventilation system is turned back on. Since you're going to the trouble of installing a complex ventilation system...perhaps you should consider the timed CO2 idea.

This is how I ventilate my rooms. I have passive intake into the veg room and then have a fan that vents from veg into the bloom room. Then I run an exhaust pump (bigger then the intake) that runs through the scrubber and the lights (or rather will incorporate the lights once finished) and then out of the room.
ET

 

[growclean]

Dr. Conjuror,

Thanks for the help. The Ventilation 101 thread and alot of the formulas are what I do not understand though. Maybe I just have not devoted enough time to trying, but I have read through it. My problem is that I am on a deadline to get this room built, due to where we are and other circumstances, and I still have my regular job, and I am trying to research every stage of this. I think I am a little overwhelmed in regards to ventilation....

But to answer, those fans are 538 cfm.

EvilTwin,
Thank you again. I did not think about venting from the veg into the flower room. That seems like a good idea. I was just going to vent straight out of the veg room. Are there any disadvantages to having it set up that way?

Also, in regards to co2. I have only done minimal research on the systems, as I know it is out of our league at the moment. But are you saying that we would basically run a close room during daylight and still do our regular vent during night when they don't need the co2?



Too anyone else: do these 538 cfm fans seem sized right to 1. cool from one light up to four? 2.operate as our carbon scrubber fan? 3. Be an exhaust from the veg room with a passive intake?

Thank you again for the help everyone!!!

 

[Dr. Conjuror]

Sorry I missed that you had listed the cfm of your fan. If you only had the fan ventilating the light system, you would need 600cfm for 2 X 1000w lights to maintain that 10F* difference in incoming air and the exhaust. So if you had the right fan to overcome the static pressure of the system with hardly any loss of cfm's, your temperature difference (DeltaT) temperature difference would be slightly higher than 10F* above ambient. Let's use the formula...

CFM=3.16*Watts/DeltaT

(538cfm) = 3.16 * (2000w)/DeltaT
DeltaT = (3.16 * 2000) / 538
DeltaT = 11.75F*

You have not made your scrubber yet, have you? It will need to be based on the fan extracting any air that you want scrubbed.


But to practically eliminate the static pressure for the intake, the total area of the incoming vents needs to be larger than the area of the exhaust of the fan.

I know it can be easy to be lost in the minutia of it all, but also planning it on paper can save you money in buying what it is you need for now and later on.

Dr. Conjuror

 

[growclean]

Sorry I missed that you had listed the cfm of your fan. If you only had the fan ventilating the light system, you would need 600cfm for 2 X 1000w lights to maintain that 10F* difference in incoming air and the exhaust. So if you had the right fan to overcome the static pressure of the system with hardly any loss of cfm's, your temperature difference (DeltaT) temperature difference would be slightly higher than 10F* above ambient. Let's use the formula...

CFM=3.16*Watts/DeltaT

(538cfm) = 3.16 * (2000w)/DeltaT
DeltaT = (3.16 * 2000) / 538
DeltaT = 11.75F*

You have not made your scrubber yet, have you? It will need to be based on the fan extracting any air that you want scrubbed.


But to practically eliminate the static pressure for the intake, the total area of the incoming vents needs to be larger than the area of the exhaust of the fan.

I know it can be easy to be lost in the minutia of it all, but also planning it on paper can save you money in buying what it is you need for now and later on.

Dr. Conjuror

Dr. Conjuror,

Thank you again for your patience. I just got home from working on the room. It is coming together nicely! I am going to post some pics in another thread here in a minute if you are curious to see. Anyways, I am still not sure what you are saying. Is that 3.16 a constant? If so, that would mean that DeltaT (temperature difference?) would actually increase when wattage increased right?

(3.16 * 4000) / 538 = 23.5

Thank you for the advice on the scrubber, I did print off the form for the DIY scrubber on here and was planning on tackling that project by the weekend. I will match it to the fan. Do you think the fan itself is the right size for the room?

Thank you more than I can say!!

 

[Dr. Conjuror]

Yes you have it right, 3.16 is the constant (conversion factor?). So if you are using a set known 538cfm, then as the wattage increases, so does the increase in temp. That is why if you cool the lights with air in its own separate ventilation system, then you are mainly heating that air and not the air in the rest of the room. You can use another fan for your fresh air source via a passive intake and then scrub the air before expelling.

So if you are using a fan for air exchange and scrubbing, you need to be exchanging the entire volume of the air any where from three times a miunte to once every five minutes (I have read varying things from different members). Take the total volume of air of the room 1440 cubic feet(In your case I think you are saying you want it to be 12 ft long by 10 foot wide by 12 foot high) and divide by the length of each air exchange you desire in minutes to get the cfm of the fan you need. Say you want to exchange all the air in the room once a minute. 1440cf / 1 minute = 1440 cfm. For an exchange rate of once every two minutes, you would take 1440 cf / 2 minutes = 720cfm.

You then have to take into account the resistance your scrubber will cause, make sure that it can handle it and still produce the desired cfm's.

I really stink at explaining this. I will improve. Feel free to ask questions. If I can help I will try. And I will gladly tell you when I am unsure or just do not know.

And of course do point me toward any pics you might post.

Dr. Conjuror

 

[EvilTwin]

Growclean,
I was sort of forced to use that approach since my floor heat register was in the veg area and I needed to get heat into the flower room. It works great though I had to increase my fan size. Haven't noticed any down side. Both rooms get fresh air and both get do-odorized...without duplicate systems (the big advantage).

Glad you're getting some help with the technical stuff. Hope it all comes together...
ET