HVAC support

I am loking at a build and I have a question about my venting plan.



Will this work? the debate I have with my partner is that the manafolds wont work and the air wont pull evenly through the four hoods. I don't want to run the hoods in a line, the fourth hood would never get cool.
So any thoughts or ideas are greatly appriciated.
A little bit of info:
co2 enriched
a 12 site titan gro-n-flo system
4 k's
120 pint dehumid already here
can filter will be in place recirculating air
hoods are 8" xxxl sunsystems sealed

help a brother out

cerberus said:

I am loking at a build and I have a question about my venting plan.


View attachment 1867251
Will this work? the debate I have with my partner is that the manafolds wont work and the air wont pull evenly through the four hoods. I don't want to run the hoods in a line, the fourth hood would never get cool.
So any thoughts or ideas are greatly appriciated.
A little bit of info:
co2 enriched
a 12 site titan gro-n-flo system
4 k's
120 pint dehumid already here
can filter will be in place recirculating air
hoods are 8" xxxl sunsystems sealed

help a brother out

Click to expand...

If you put another output fan on the out manifold ....well it would have a better chance of working.
I dont think one fan against 4X1000w will be enough even if the manifold works, which I really don't know much about.

Or at least a 12' on the out side.

thanks for the input man.

cerberus said:

thanks for the input man.

Click to expand...

Wish I knew more about the manifold concept, you've got my interest.

Thanks, I can't see why it wouldn't work, other than CFM's not being enough (like you said) or the manafold idea doesn't.. manafold the air the way I think it will lol I know there are a few HVAC guys on ere I just need to get their attention. so thanks for the bumps


OH! and the arrow for the bottom manafold should be going the other way, all the air traveling the same direction..

Maybe this will give you some ideas:
I'm not a hvac guy but I have done some work with manifolds and plenums. It seems to me that the light on the left will have the best flow since it is nearly a straight shot. Imagine it is water leaking out of 4 holes in a pipe. the first hole will have the best pressure. There is one way to even the flow (that I know). You can use a damper of some kind at each opening or adjust the hole sizes. Use a ribbon tied above the holes to compare. Or alternatively you could provide so much suction that the last hole has adequate air flow.
I use a plenum or manifold to provide cool air to my room. I had to make the last hole smaller than the first to increase velocity at the end of the run. I also put vanes inside the plenum to direct some of the air past the first opening. Main thing is you will need a LOT of exhaust power to keep pressure high.

Hopefully a real hvac guy will help you out. A good hvac or duct man could design a plenum that be made easily out of P3 or insulation board.

word. I was thinking about channels in the manafold (I'm guessing that the same as a plenums) I was going to DIY so p3 was my medium of choice. I was also hoping that with the second box being smaller it would help create a suction. I'm thinking the final intake would be a 6 inch or even a 4..
either or, thanks for the thoughts on the project. its good sudgestions and acts as a bump for a real HVAC guy

subcool is hvac right? lol

a bump for the next day. any help on this manafold, i'm listening to all ideas.

thanks

I currently use one 8" fan to cool every 4 - 1000 watt lights in my bloom room. You can look at the link in my sig for tons of pics. Your idea will work. The last light will have the least air flow, though. This can be fixed by crimping the duct in the first couple lights. By slightly restricting air flow on the first lights you will ballance the air movement. The other (and better) option is to install the exhaust fan mid manifold...right between the input from lights 2 and 3.

Your real challange will be cooling a sealed room. A ductless mini split A/C would be best. Have fun.

You could modify your duct something like this to create an even flow throughout.
Add a center divider lengthwise with openings between #1 and #2, and another between #3 and #4. Then the exit would need to be between those 2 openings at the back or top. May not work in your AO but gives you another way of looking at it.
I've taken the liberty of doodling on your dwg if you wanna see what I mean.

*afterthought* you could make yet another parallel chamber inside to move the exit to the left end. draw back is it may start to get too wide for you

EvlMunkee said:

You could modify your duct something like this to create an even flow throughout.
Add a center divider lengthwise with openings between #1 and #2, and another between #3 and #4. Then the exit would need to be between those 2 openings at the back or top. May not work in your AO but gives you another way of looking at it.
I've taken the liberty of doodling on your dwg if you wanna see what I mean.

*afterthought* you could make yet another parallel chamber inside to move the exit to the left end. draw back is it may start to get too wide for you

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nice bro! that probably will equalize the preasure. It's early here so i'll look at it while I have my coffee. cheers!

collective gardener said:

I currently use one 8" fan to cool every 4 - 1000 watt lights in my bloom room. You can look at the link in my sig for tons of pics. Your idea will work. The last light will have the least air flow, though. This can be fixed by crimping the duct in the first couple lights. By slightly restricting air flow on the first lights you will ballance the air movement. The other (and better) option is to install the exhaust fan mid manifold...right between the input from lights 2 and 3.

Your real challange will be cooling a sealed room. A ductless mini split A/C would be best. Have fun.

Click to expand...

HEY CG!

yeah I lurk all over your thread, I'll have to re-read and find the page with your lighting venting system. I live in a arctic tundra, so the intake on this system will break into two branches a) an inside the building but not the grow room opening and an alternative vent going outside. that way I can regulate the outside (super cold) air and introduce it to the light cooling set-up. I do plan on going mini-split come spring, that or a hydro-inovations water cooled system. then I could hit my 55 gal rez with cold too..

peace and thanks for the sudgestions!

fyi : its warming and in the low 20 now.. :/

i use inline duct fans & double them up to increase air flow my friend cools 4 1000w lights with a 8'' can-fan reduced to 6'' the only differences from your set-up is he uses ''y'' splitters instead of the manifold & his xxx reflectors have 6'' openings i would suggest a single 10'' fan reduced to 8'' being somewhat lazy we opted for the store bought parts instead of fabricating a manifold

one more note we were pulling air from outdoors & ran into condensation problems in our ducts so the intake was moved to an indoor location fixing the problem

cerberus said:

HEY CG!

yeah I lurk all over your thread, I'll have to re-read and find the page with your lighting venting system. I live in a arctic tundra, so the intake on this system will break into two branches a) an inside the building but not the grow room opening and an alternative vent going outside. that way I can regulate the outside (super cold) air and introduce it to the light cooling set-up. I do plan on going mini-split come spring, that or a hydro-inovations water cooled system. then I could hit my 55 gal rez with cold too..

peace and thanks for the sudgestions!

fyi : its warming and in the low 20 now.. :/

Click to expand...

I, too, grew once in a very cold environment. I used 2 large truck radiators, one inside and one outside. If it's cold enough (always freezing) you can just use one radiator inside and a large water tank outside. The idea is that the outside air cools the water and the water then cools your grow room. A radiator with a fan in the grow pulls alot of cold out of the water. This is a great way to use the cold outside air to cool the grow without any actual air exchange, making CO2 enrichment easy. It's also really cheap. All you need is some big ass used truck radiators, some powerful steel bladed fans to blow on them, a pump or 2, and a water tank.

BAMN! CG, I don't know if I have told you how much I like you, so dude, I like you, your cool.

I was thinking this samething plus a stainless steel brake line and a pump connected to a thermo for the nutrient rez what was your mix to keep the water in the tank from freezing? I'm thinking of either glycegin or maybe even good old radiator fluid but the idea of a poison so close to my medicine makes me feel uneasy..

thanks for the good info.

horrible, thanks for the info, I was thinking the same thing but my thought was if I was reducing the intake line it would do the same thing as necking down like your saying. thanks for the info on condensation! I hadn't thought of that..

I think the problem you're going to come across with the manifold idea is the air is going to just hit the back wall fluttter around and cause turbulence. In the hvac industry they'd use turning vanes for 90 degree turns like that manifold idea.

I think having an intake going into the front of the first reflector which has a fan pulling air at the back end and then have the duct make a U shape to go into the back of reflector#2. You and end this run once it exits the front of reflector#2 or you can make another u and go into the front of #3 and at the end of #3 have a fan pulling through and pushing out into another u that goes to the back of reflector#4. This second fan will act as a booster to help the air exit thru the front of reflector #4. Id personally have 2 duct systems and have 2 reflectors being cooled by one fan...intake from front of #1 and exhaust thru front of #2. Intake thru back of #3 and exhaust thru the back of #4. Snake like patterns. Put a 240cfm 6" inline in each loop at the end of the first reflector being cooled in the loop

You're right about the turbulence firsttimeARE. It takes more pressure in a plenum to overcome that. Also right about the vanes. They are pretty easy to add however,when the top is open and you can see everything.
It would be easy to check out your snake plan. I know it is done that way alot. Wouldn't take that long to hook it up. It is true you would need a helper fan. Trying to count the bends in my mind I can see at least 720 degrees, right? 4 -180s? Seems like that would scrub off some air as well. With the extra fans though it should really suck (literally).

@cerberus,
A lot of options huh? Advantages both ways I think. I personally will use a plenum when I can because they can cut way down on connections and transitions and they can be mounted neatly out of the way. They are quieter than flex duct too IMO.
I've scribbled on your dwg again to show where some vanes could be added to keep the air out of the corners and decrease turbulence as per firsttimeARE's comment.

damn guys! your killing it.. a bunch of stuff to think about, i'm going to re-draw with these ideas and throw it back up tomorrow. thanks for all the ideas gents

cerberus said:

BAMN! CG, I don't know if I have told you how much I like you, so dude, I like you, your cool.

I was thinking this samething plus a stainless steel brake line and a pump connected to a thermo for the nutrient rez what was your mix to keep the water in the tank from freezing? I'm thinking of either glycegin or maybe even good old radiator fluid but the idea of a poison so close to my medicine makes me feel uneasy..

thanks for the good info.

horrible, thanks for the info, I was thinking the same thing but my thought was if I was reducing the intake line it would do the same thing as necking down like your saying. thanks for the info on condensation! I hadn't thought of that..

Click to expand...

I just used RO water because the pass through the radiator in the grow warms the water. If it's THAT cold I would use regular coolant. The system is sealed indoors, so no danger to the meds.