How's this for a 4 x 8 flowering chamber vent setup?

[nachoconqueso]

I have an idea to put the scrubber (can50 w/ 8" max fan) on the floor of one end and put intakes with darkroom vents on the opposite side to create a sort of cross flow. Oscillating fans will be placed on the intake side and the max fan would blow through 2 1000w hoods to an exhaust hole above the intake. Is this cool? What size intakes in consideration of the darkroom vents airflow restriction?

I'm looking for door suggestions too. I got a 4' x 7' doorway that needs to be light proofed. Thanks!!

 

[M.R.GT]

how tall? 4x8x8=256 sq ft air exchange every 2 min 128cfm. just for the box. I use 500 cfm as a base unit per 1 k light. so for me with no other heat load and atleast 50 sq inches of passive intake I would use 1150 cfm to create neg pressure. most 8" fans move 600 to 700 cfm so I would use at least 2 for 2 1kw lights.

all these are variable based on climate. in an area with high ambient temps and rh I would consider A/c. Will intake air be cooled? Other heat loads ie glass in the doors, windows...duct run length and static resistance all will play a part so there are a lot of variables.

Just hook it up and run it. check temps I like 78 lights on 68 lights off if your in the zone your good.

For door 20 mil black plastic and Velcro.

 

[RonSmooth]

"Scrubbing" ususally refers to sucking air through a carbon filter and blowing it out of the attached fan right back into the room.

If you are running the filter > fan > hood > out (exhaust)

I would run it :

Filter > hood > fan > out

I would pull the air, not push it. This is more efficient and will create a better negative pressure. The negative pressure will in turn draw air in through the passive intakes.

Mounting the filter high in the room will have it drawing the hottest air out first. Also the air coming in through the intakes on the opposite side floor will have to travel across the whole room before being sucked up and out. This will provide good circulation.

The intakes should be at least twice the size of the exhaust. With an 8" exhaust, you'll need at least 100 sq in of intake. The darkroom vents will add resistance so you'll need to account for that.

Oscillating fans are good for blowing air around the room. They help avoid any areas where stagnant air might accumulate and make it harder for molds and pests to get a foothold. They won't increase the air coming in from the intakes. I would use as few as possible. You could probably get away with one 16" wall mounted blowing at the hoods.

For my doors, I use b&w poly and double sided velcro tape. I have used magnets but found that the velcro holds better as the vacuum created by the exhaust pulls on the poly. Has to be secure. I also run foam weather stripping around the inside of the door frame to catch any stray light leaks.

 

[M.R.GT]

I agree with Ron and he's right 100" intake, I should have doubled that 50. it was early and I hadn't had my coffee.

 

[nachoconqueso]

@ Ron: with your setup aren't you pulling in unfiltered air through the seams of your hood?

 

[nachoconqueso]

how tall? 4x8x8=256 sq ft air exchange every 2 min 128cfm. just for the box. I use 500 cfm as a base unit per 1 k light. so for me with no other heat load and atleast 50 sq inches of passive intake I would use 1150 cfm to create neg pressure. most 8" fans move 600 to 700 cfm so I would use at least 2 for 2 1kw lights.

all these are variable based on climate. in an area with high ambient temps and rh I would consider A/c. Will intake air be cooled? Other heat loads ie glass in the doors, windows...duct run length and static resistance all will play a part so there are a lot of variables.

Just hook it up and run it. check temps I like 78 lights on 68 lights off if your in the zone your good.

For door 20 mil black plastic and Velcro.

7' tall. So if you ran two then using Rons setup would you just place each fan on the exhaust side of each hood? I'm sorry I just don't get ventilation at all. I've tried and tried.

Also, my environment is cool and dry. The plants get way too cold come winter time. It's a nice problem.

 

[M.R.GT]

yes pull the air. filter, hood, hood, fan, exhaust. just like Ron said from the top of the chamber.

If heat is no issue then the single 8" fan may work for you

mount your filter up high. run flex pipe from filter to your first hood from there to your next hood then to the suction side of your fan. pipe the blowing side of the fan to external exhaust. fire it up and see what your temps are.

I would run it the same either way single or double.

the 8" will for sure handle the 4x8x7 and 1 light I'm just not sure if it will handle the second 1kw hood without a heat build up. Try it and see.

you need the 128 cfm to exchange the air in the cab and create neg pressure so smell is pulled through the filter and not escaping into your surrounding areas. you need that much suction at your filter. keep your pipe runs short as you can.

 

[Devilman]

@ Ron: with your setup aren't you pulling in unfiltered air through the seams of your hood?

Quoted for truth... While many of you are spouting the fact that pulling is better than pulling, you all gloss over the fact that pulling air, and the slightest little leak, or seam in the hood, or ducting and it will be pulling UNFILTERED air straight from the plants and throwing it outside for the whole world to smell..

Not to mention that a lot of fans are not rated for the sort of exhaust temps that come out of a HID lamp inside a ventilated hood and may reduce the lifespan of your fan (or kill it entirely).

Think very carefully about how you want to setup ventilation.. I for one would rather have a bit of air being leaked INTO the tend from a fan that is pushing, than unfiltered air being leaked OUT of the tent because of the seams in the hood, the ducting and what-not.

 

[M.R.GT]

Quoted for truth... While many of you are spouting the fact that pulling is better than pulling,

aren't they the same. if your going to come off like that at least proofread your post.

assuming your using a fan rated for the job you should be good .
don't use a fart fan and expect it to work.

I agree with devilman about filter placement. I run my filter on the exhaust side but it can be done either way. on the exhaust side is more efficient but it has to be big and free breathing to prevent back pressure on your fan and cut down on your suction side cfm causing premature fan failure.

mine is set up
hood>fan>filter>exhaust

 

[nachoconqueso]

Another question, if I'm adding extra fans to increase cooling then am I causing too much air exchange in the chamber thus stressing the plants out?

 

[nachoconqueso]

Bump

 

[5th]

if your going to come off like that at least proofread your post.

I read his post twice. What don't you understand?

If there is any chance you are pulling in unfiltered air after the the filter in your circut...you set it up differently. Period.

Inquire about your filter before purchase. The cfm spec's they give are assuming you are sucking through...not pushing.

Cooltubes for example are hella easy to seal...so scrubber>tube>tube>fan ....no worries. If your hoods are prone to leaks. prefilter>hood>hood>fan>scrubber.

 

[nachoconqueso]

I don't know. There's a lot of conflicting info here. Is there a setup other than "intake>filter>fan>hood>hood>exhaust into hole in wall" that allows for circulation of fresh air as well as no smell leaks?