Question about setting up air cooled hoods?

[louie]

So I finally have a chance to install my new air cooled hoods and want to do it the most efficient way that I can. When cooling your hoods do you draw air from the outside of the house to cool them and vent that air directly outside as well (in a completely closed loop)? I am going to be running Co2, so I am guessing the best way to run my vortex fans are to have them blow so that Co2 isn't sucked out of any little unsealed areas of the hoods/ venting? How many lights (8" vented blockbusters 1000w) do you think I should run per 8'' vortex fan? Appreciate the knowledge!

 

[SuperSizeMe]

My room is not sealed, but it could be.

I have 1800 (3x600) on a closed loop with a 6" Vortex and a stand alone 12" with Can150(sized) for just scrubbing.I don't pull outside air, but I do use a 'lung area' for intake/fresh air etc.

I still alum. tape the seams of my hoods.Your setup sounds fine

 

[qbert]

Also not sealed, but I do push through the hoods as opposed to trying to seal them (to prevent sucking out unfiltered air). Sounds like you know what to do.

 

[louie]

Thanks guys. So I live in a climate that gets really cold in the winter, I am guessing that if I pull air that is 20 degrees through my hood I will be dealing with all kinds of condensation problems? Now lets say I didn't pull the air from directly outdoors, and instead pulled it from a lung room, I will obviously need a carbon filter hooked up to the beginning of the intake to scrub the air that will go through the hoods and eventually outside right? Will the filter being attached in this way drastically reduce the cooling effect on the hoods? Or should I just hook up a inline ozone generator right before the air is exhausted outside? What system would work better considering all variables (winter temps with outside air, and reduced air flow with filter in the other setup)? Any advice?

 

[Mighty Seed]

Thanks guys. So I live in a climate that gets really cold in the winter, I am guessing that if I pull air that is 20 degrees through my hood I will be dealing with all kinds of condensation problems? Now lets say I didn't pull the air from directly outdoors, and instead pulled it from a lung room, I will obviously need a carbon filter hooked up to the beginning of the intake to scrub the air that will go through the hoods and eventually outside right? Will the filter being attached in this way drastically reduce the cooling effect on the hoods? Or should I just hook up a inline ozone generator right before the air is exhausted outside? What system would work better considering all variables (winter temps with outside air, and reduced air flow with filter in the other setup)? Any advice?

Ok, first off you won't condensate going from cool to warm, it will steam but evaporate. Condensation forms going from warm, humid to cooler surfaces. You won't have to worry about that. Also, if you need extra heat in the winter just set your light exhaust on a dimmer so you can adjust the speed of cool air to use your lights as a heater. I suck fresh air from an adjacent room and exhaust it into my attic. I also have a passive intake for room air from the same room but I can seal that up when I get my minisplit for a sealed room.

 

[Mighty Seed]

Also not sealed, but I do push through the hoods as opposed to trying to seal them (to prevent sucking out unfiltered air). Sounds like you know what to do.

Always suck the air through. If you push the air, you pressurize the ducting and it will push tape off and hot air out the cracks in the light housing. If you pull air from one end you cool better and don't leak as much unwanted heat into the room.

 

[Marshall]

Always suck the air through. If you push the air, you pressurize the ducting and it will push tape off and hot air out the cracks in the light housing. If you pull air from one end you cool better and don't leak as much unwanted heat into the room.

I have aircooled a bit of lights and never had the ducts come off.

Pulling air allows stinky air to be pulled through cracks in the duct system. No matter how much you tape, hoods will leak.

 

[Mighty Seed]

I have aircooled a bit of lights and never had the ducts come off.

Pulling air allows stinky air to be pulled through cracks in the duct system. No matter how much you tape, hoods will leak.

Uh huh, if you read what I posted I was referring to blowing positive pressure into light ducting. If it gets warm enough it can push pipes apart and peel tape off. I have seen it happen and its how I know when someone has their fan setup wrong.

If you are saying pushing air works for you then grea for you but remember you are also pushing that heat right out those same cracks in your light housing making the actual cooling less efficient.

 

[Marshall]

Uh huh, if you read what I posted I was referring to blowing positive pressure into light ducting. If it gets warm enough it can push pipes apart and peel tape off. I have seen it happen and its how I know when someone has their fan setup wrong.

If you are saying pushing air works for you then grea for you but remember you are also pushing that heat right out those same cracks in your light housing making the actual cooling less efficient.

I am pretty sure I understand what you are saying

Pushing will blow ducts apart and push hot air back into the room.

I say pulling will suck odor and co2 out through those cracks.

I have pulled on a 10k room

I tried pulling on 24 hoods in another op and I just could not stop the leaks, taped every seam, connection, glass on the hood etc. I wound up flipping the fans around and pushed. It was some pretty serious air movement but never blew the ducts apart.


I would rather push a little heat back in, then suck odor and co2 out. I guess its a preference issue

 

[louie]

Thanks guys! So as far as cooling the hoods in the winter; if I am pushing 20 degree cold air through the hoods, this will create steam inside the hoods right? And then that steam will eventually condense to water droplets once my hoods turn off? Does anyone have any experience with this? Am I better off just trying to use a lung room in the winter time instead of pushing in cold, dry air?

 

[Mighty Seed]

I am pretty sure I understand what you are saying

Pushing will blow ducts apart and push hot air back into the room.

I say pulling will suck odor and co2 out through those cracks.

I have pulled on a 10k room

I tried pulling on 24 hoods in another op and I just could not stop the leaks, taped every seam, connection, glass on the hood etc. I wound up flipping the fans around and pushed. It was some pretty serious air movement but never blew the ducts apart.


I would rather push a little heat back in, then suck odor and co2 out. I guess its a preference issue

Not really, hvac guys say to always use negative pressure. The primary purpose of the hoods is to cool. If you have smell issues, those are best dealt with in the room. Fans are more (I think its around 20% more) efficient sucking. There's no sense designing a cooling system to work less efficiently. The dollars on AC are saved on a properly designed light vent.

 

[Mighty Seed]

Thanks guys! So as far as cooling the hoods in the winter; if I am pushing 20 degree cold air through the hoods, this will create steam inside the hoods right? And then that steam will eventually condense to water droplets once my hoods turn off? Does anyone have any experience with this? Am I better off just trying to use a lung room in the winter time instead of pushing in cold, dry air?

The steam will not be an issue if you are pulling rather than pushing air. A fan speed controller is all you need, the colder the air, the less the speed.

 

[Marshall]

Not really, hvac guys say to always use negative pressure. The primary purpose of the hoods is to cool. If you have smell issues, those are best dealt with in the room. Fans are more (I think its around 20% more) efficient sucking. There's no sense designing a cooling system to work less efficiently. The dollars on AC are saved on a properly designed light vent.

Just curious are you just repeating what you have read? Or have you actually tried cooling 10KW + in lights?

I have personally designed and installed air cooling on 2 ops, one with 10K, one with 30K. I have hands on experience. a few others too but those two I ran for a while

yes HVAC guys do say fans are more efficient at pulling, than pushing. But most HVAC guys (except the ones here) are not trying to cool lights in a indoor marijuana grow op, and priorities get a little rearranged.

There is no way to eliminate smell 100%. If you pull, you are going to pull odor out. No way around it. You can put a filter at the end but there goes any efficiency advantages

The amount of heat that gets pushed back in compared to ballasts, dehumidifiers, co2 generators is minimal. And you are still removing a tremendous amount of heat. Even a small amount of odor leaking out can be catastrophic

If you are state legal, sure pull.

If you are not legal, push


BTW I will be installing a 12" max fan 1700 CFM this week to cool 4kw, manifold design. 2 12" ducts to two 6" ducts. Each 6" run will cool 2 1000k's in a row. SHould be lots of air, will see if the ducts blow apart.

 

[Mighty Seed]

Just curious are you just repeating what you have read? Or have you actually tried cooling 10KW + in lights?

I have personally designed and installed air cooling on 2 ops, one with 10K, one with 30K. I have hands on experience. a few others too but those two I ran for a while

yes HVAC guys do say fans are more efficient at pulling, than pushing. But most HVAC guys (except the ones here) are not trying to cool lights in a indoor marijuana grow op, and priorities get a little rearranged.

There is no way to eliminate smell 100%. If you pull, you are going to pull odor out. No way around it. You can put a filter at the end but there goes any efficiency advantages

The amount of heat that gets pushed back in compared to ballasts, dehumidifiers, co2 generators is minimal. And you are still removing a tremendous amount of heat. Even a small amount of odor leaking out can be catastrophic

If you are state legal, sure pull.

If you are not legal, push


BTW I will be installing a 12" max fan 1700 CFM this week to cool 4kw, manifold design. 2 12" ducts to two 6" ducts. Each 6" run will cool 2 1000k's in a row. SHould be lots of air, will see if the ducts blow apart.

Yes, legal state, yes, I have setup 10+ light grows, yes, I duct my own 4.6kW in HPS this way. You are wrong about smell though. The best way is to duct light heat into an attic or crawl space. Also, with my Phresh filter and a little ozone I could walk you into my flower room and you wouldn't even detect MJ. I am not trying to be a dick here but maybe you have been doing things wrong. I have NEVER seen anyone willing to push heat into their flower room. If you have designed and built enough rooms you know, positive pressure will eventually unstick tape and leave stuff dangling. If you suck the tape inward, you never have to come into your grow room and see it at 110 degrees because your duct collector manifold came off a main pipe.

 

[Mighty Seed]

Just curious are you just repeating what you have read? Or have you actually tried cooling 10KW + in lights?

I have personally designed and installed air cooling on 2 ops, one with 10K, one with 30K. I have hands on experience. a few others too but those two I ran for a while

yes HVAC guys do say fans are more efficient at pulling, than pushing. But most HVAC guys (except the ones here) are not trying to cool lights in a indoor marijuana grow op, and priorities get a little rearranged.

There is no way to eliminate smell 100%. If you pull, you are going to pull odor out. No way around it. You can put a filter at the end but there goes any efficiency advantages

The amount of heat that gets pushed back in compared to ballasts, dehumidifiers, co2 generators is minimal. And you are still removing a tremendous amount of heat. Even a small amount of odor leaking out can be catastrophic

If you are state legal, sure pull.

If you are not legal, push


BTW I will be installing a 12" max fan 1700 CFM this week to cool 4kw, manifold design. 2 12" ducts to two 6" ducts. Each 6" run will cool 2 1000k's in a row. SHould be lots of air, will see if the ducts blow apart.

Yes, legal state, yes, I have setup 10+ light grows, yes, I duct my own 4.6kW in HPS this way. You are wrong about smell though. The best way is to duct light heat into an attic or crawl space. Also, with my Phresh filter and a little ozone I could walk you into my flower room and you wouldn't even detect MJ. I am not trying to be a dick here but maybe you have been doing things wrong. I have NEVER seen anyone willing to push heat into their flower room. If you have designed and built enough rooms you know, positive pressure will eventually unstick tape and leave stuff dangling. If you suck the tape inward, you never have to come into your grow room and see it at 110 degrees because your duct collector manifold came off a main pipe.

Maybe your tape holds, maybe it doesn't get hot enough to get gummy and come loose, maybe you don't have enough pressure to make pushing a problem. It doesn't change the fact that your system could be designed much more efficiently.

 

[supersmallgiant]

Why does every one ignore the fact that you can have the carbon filter at the end of the system? Then it doesn't matter if you suck or blow.

 

[Mighty Seed]

Why does every one ignore the fact that you can have the carbon filter at the end of the system? Then it doesn't matter if you suck or blow.

Well, if you blow into a carbon filter you are going to push a hell of a lot more heat out your lights.

Just for fun I am going to turn off my carbon filter and see if I can detect any smell from my light exhaust. This is with 40 plants, some in 10 gallons, in bloom. I really don't think that sucking air at 900 cfm from outside my room and venting it outside my room I would be smelling that at all.

 

[gonzo`]

mine is : carbon filter --> light --> fan (pulling)

 

[cjk]

i definately pull air. it goes through a filter then hoods then fan then out of a vent. the key is to get hoods that seal really well. i have no tape or anything on my hoods and i have no smell leaks. my hoods have a hinge, clamps, and a rubber gasket and seal up very well.

 

[In~Plain~Site]

I've always had good luck pushing air, keeps my fan nice and cool as well.Admittedly, I've never attempted to 'pull' air through my system, as just about everything i've read suggests against it.

I also use a large fan/filter (stand-alone) that just scrubs while the lights are on a closed loop w/no filter(only for particulate @ intake source)

Whatever works