Tutorial Ventilation 101

[r2k]

Is it worth it to read past the first pages?

If you are serious about this stuff, then I would recommend it. People in this thread are good at recalling specific facts but they refer to it in conversation but don't post the link to what they are talking about. If you haven't read the whole thread, you are missing lotta good info and also don't have the background to understand references that people make today.

I read the whole thing (took a couple sessions) and I still have trouble recalling certain things that come up. I don't think I ran across anything that I disagree with at some level. No matter how you grow, air movement is a big piece of success. There are rules and strategies to air movement and this thread does a pretty good job at addressing them. IMO, It's worth the read.


-r2k

 

[JohnKimble]

Can you use one vortex fan to cool the hood while also scrubbing the air with a carbon filter, or would all the air suction to the filter be lost on the hood?

I was thinking something like this:
Have the air cooled hood ducting at 4", while the carbon filter ducting is 6", air flow to the hood would be more restricted allowing the path of least resistance to the carbon filter.

 

[Nomad28743]

Some times too much thinking is a bad thing...however here I go.
By products from a gas clothes dryer are water vapor(increases humidity) and CO2 which might be favorable in a grow room?
Any ideas or comments?

 

[Jhhnn]

Can you use one vortex fan to cool the hood while also scrubbing the air with a carbon filter, or would all the air suction to the filter be lost on the hood?

I was thinking something like this:
Have the air cooled hood ducting at 4", while the carbon filter ducting is 6", air flow to the hood would be more restricted allowing the path of least resistance to the carbon filter.
View attachment 330138

I'm sure that could work with an adjustable damper on the reflector & a fairly powerful fan. Set the damper so as to best control the temp in the chamber.

Lots of variables in that so it's not possible to recommend any specific hardware.

 

[KangarooLover]

how does ventilation work I was just reading something on 1:4 ratio and it says u want 1 part air coming in and 3 parts coming out did I misunderstand it and its opposite or what are they talking about when they say u want 1:4 ratio

 

[newGroath]

Pretty much you want your intake to be smaller than the exhaust and that ration would be for the size of the holes

 

[KangarooLover]

Pretty much you want your intake to be smaller than the exhaust and that ration would be for the size of the holes

Okay so say I have 6x9 room what size do I want coming in and wat size do I want coming out I'm thinking 6 in and 12 out which I guess wouldn't work ?

 

[newGroath]

I think you should find the cubic feet measurement. I've read that all the air should be cycled out every 5 minutes or so.

 

[Granger2]

newGroath,
You info is incorrect. Read this sticky. -granger

 

[r2k]

Some times too much thinking is a bad thing...however here I go.
By products from a gas clothes dryer are water vapor(increases humidity) and CO2 which might be favorable in a grow room?
Any ideas or comments?

Don't do that.

Venting your gas dryer or furnace will also introduce carbon monoxide, unburned gas (a little, but it is there), any soot products from partial burning, some sulfur based byproducts (burning the mercaptan oder in the gas means sulfur compounds must go somewhere), and probably some other things. And don't forget the heat...

Besides that, you will probably create backpressure in the dryer and this will affect dryer performance. It may even effect how the gas burns, which you surely don't want to do.

-r2k

 

[jsomhintdh]

I've recently gotten back into the craft, in doing so i've had limits of medium/large size closet space i'd like to convert to use.

Closet is 4ft deep/8ft high/10ft or so in length.

I was originally gonna go with a 4x4x8 veg and 5x4x8 flower and construct seperate rooms inside the closet, but decided to go for just keeping the 4x4 for grow stuff and dirt mixin and the 5x4 for flower and make a seperate veg box outside the closet.

While playin and constructin trial and error with two seperate rooms i had a single 6" ventech inline fan to play with for exhaust. This closet isn't insulated from the outside so summer temps reak havoc on it, but with using the fan i tried to dial in negative pressure, small things like a oscillating fan and passive intake size played huge rolls with pressure.

Anywho long story short, when dealing with keeping negative pressure do surrounding wind pushing devices affect the pull of inline exhaust? Seems like slightest tweaks of fans would cause pressure changes on exhaust fan. optimally i'd like just an exhaust fan pulling air to cause a slight breeze, but if i can use a tiny clip fan to circulate that'd be cool compared to a 12in deskfan that causes pressure issues in small cab like a box fan on 1 to 3 setting messes with exhaust pressure in larger closet.

rant...ended

 

[Nomad28743]

OK here's where I am stuck(hung up) in my mind.

Using passive fresh air intake from the outside where the temps are midsummer high 80's to high 90's and you want to exchange 100% of the air in the room every few minutes. How can an AC unit keep up with cooling the air if it's exchanged so fast?

 

[Granger2]

It can't. That's why, if you want to use AC, you should seal your room, dehumidify, and add CO2. Either that or just forget AC, dehu, and pull as much air thru the room as you can, up to twice/min. Good luck. -granger

 

[Nomad28743]

Thanks again Granger.

 

[bluntdcat]

Question about intake alternatives

Question about intake alternatives

I have a small tent made of black white poly and am gonna have a 347 cfm as the exuast. Can I cut out holes in the black white poly where I want the intake and use a window screen or, and air filter. Or something light. I tried the DIY new-take on intake aluminum right angles link but it way too hard anything simpler?

 

[oo2be]

Many Thanks

Many Thanks

I realise this is an old thread but wanted to say thank you to Red, Hossier and everyone who's contributed to this info. I'm a long long way off understanding it but keep returning every few days and reading it again, slowly but surely little bits are sinking in.

Before you read any further I'll apologise in advance for the long winded slavering post - enthusiasm/OCD got the better of me and there's no one in the real world I can discuss with who actually can tell me the correct answers.

As for me unfortunately I went all "boys toys" in the ordering of equipment and was seduced by the idea of oversized filter and fan to try to prevent any heat/smell issues. Stealth is of paramount importance for most of us but my particular groom CANNOT leak any aroma.

I'm not gifted when it comes to Maths/Arithmetic and find myself gettting confused between cfm and m/hr!

My set up (or in the process of setting up - was steadfast before reading this thread about a one stage ventilation system. e.g.

Filter (straight onto monster filter) ducting /cool hood/ducting/attic exit but now I'm concerned as my knowledge is throwing anomalies that are wrong and that's even before a bag of dirt is even entered into the picture. For example "wind tunnel" effect on plants and also even I read recently that carbon filters should be run at a minimum of a quarter of their capacity i.e. 800 m/hr should have a minimum of 200 m/hr passing through it to ensure pressure and performance

Groom/Cupboard =
0.55 x 0.88 x 2.3 m =1.1 (x 1.33 Cf) = 1.48
(2 x 3 x 7 ft = 55.86 x 1.33 = 74.3)

Equipment -
250 - 600 W Dimmable digital ballast
5"/125 mm Gold Star Air Cooled Hood
6" accoustic ducting
S&P TD Silent 350/125 High 350 m/hr low 250 m/hr
Rhino Pro 200/400 (800 m/hr)
No active
at present 250 mh bulb but was planning on seeing how much of the 600w's capacity I could use depending on temps but now beginning to wonder if 400w will be the top limit - (footprint 2 x3 = 6: 400/6 = 66.7 w/sqft)

Was hoping to use passive intake of 400 mm x 70 mm rectangle cut into the bottom of one wall as a starting point which would be lightproof baffled. The groom is inside an enclosed cupboard and was planning on taking air from there, the cupboard is well ventilated as is serviced by a permanently open window.

What my long winded post is asking is ;

1) Will adding a fan controller to dial down the speed of the fan ensure that the I can slow down air circulation/exchange for the plants but keep the CF at an efficient performance to counter the lovely stench?

2) Should I start of going with low speed setting on the fan 280 instead of 350 m/hr?

4) Will the baffled hole for passive intake be sufficient?

5) Even although groom has some way to go before being operational I couldn't resist playing with my new toys - bad news - I'm an ass and dropped the fan on first opening it - still works although a bit of the lip broke so it can't be returned!!!!

I also read somewhere that if you add a meter of ducting to the intake of the fan it can assist with noise - something about it balancing the pressure at either end, at present the fan and filter work with fan sticking out the top of the CF, but there is not much suction at the CF end - I smoked a cigarette beside to see what the draw of smoke is - when right next to it pulls but say a couple of feet away the smoke was drawn towards the open window (also two feet away) finally i noticed that the fan does seem to be em ..... well lets just say the tone of the fan has gone up, the final placement will be behind two doors so I'm sure this will be negated when its in its final position.

Sorry for my wandering post, it's really satisfying to feel like I'm beginning to understand stuff I thought was black magic.

Hope everyone is in rude health and effervescing with life

 

[oldbean]

I realise this is an old thread but wanted to say thank you to Red, Hossier and everyone who's contributed to this info. I'm a long long way off understanding it but keep returning every few days and reading it again, slowly but surely little bits are sinking in.

Before you read any further I'll apologise in advance for the long winded slavering post - enthusiasm/OCD got the better of me and there's no one in the real world I can discuss with who actually can tell me the correct answers.

As for me unfortunately I went all "boys toys" in the ordering of equipment and was seduced by the idea of oversized filter and fan to try to prevent any heat/smell issues. Stealth is of paramount importance for most of us but my particular groom CANNOT leak any aroma.

I'm not gifted when it comes to Maths/Arithmetic and find myself gettting confused between cfm and m/hr!

My set up (or in the process of setting up - was steadfast before reading this thread about a one stage ventilation system. e.g.

Filter (straight onto monster filter) ducting /cool hood/ducting/attic exit but now I'm concerned as my knowledge is throwing anomalies that are wrong and that's even before a bag of dirt is even entered into the picture. For example "wind tunnel" effect on plants and also even I read recently that carbon filters should be run at a minimum of a quarter of their capacity i.e. 800 m/hr should have a minimum of 200 m/hr passing through it to ensure pressure and performance

Groom/Cupboard =
0.55 x 0.88 x 2.3 m =1.1 (x 1.33 Cf) = 1.48
(2 x 3 x 7 ft = 55.86 x 1.33 = 74.3)

Equipment -
250 - 600 W Dimmable digital ballast
5"/125 mm Gold Star Air Cooled Hood
6" accoustic ducting
S&P TD Silent 350/125 High 350 m/hr low 250 m/hr
Rhino Pro 200/400 (800 m/hr)
No active
at present 250 mh bulb but was planning on seeing how much of the 600w's capacity I could use depending on temps but now beginning to wonder if 400w will be the top limit - (footprint 2 x3 = 6: 400/6 = 66.7 w/sqft)

Was hoping to use passive intake of 400 mm x 70 mm rectangle cut into the bottom of one wall as a starting point which would be lightproof baffled. The groom is inside an enclosed cupboard and was planning on taking air from there, the cupboard is well ventilated as is serviced by a permanently open window.

What my long winded post is asking is ;

1) Will adding a fan controller to dial down the speed of the fan ensure that the I can slow down air circulation/exchange for the plants but keep the CF at an efficient performance to counter the lovely stench?

2) Should I start of going with low speed setting on the fan 280 instead of 350 m/hr?

4) Will the baffled hole for passive intake be sufficient?

5) Even although groom has some way to go before being operational I couldn't resist playing with my new toys - bad news - I'm an ass and dropped the fan on first opening it - still works although a bit of the lip broke so it can't be returned!!!!

I also read somewhere that if you add a meter of ducting to the intake of the fan it can assist with noise - something about it balancing the pressure at either end, at present the fan and filter work with fan sticking out the top of the CF, but there is not much suction at the CF end - I smoked a cigarette beside to see what the draw of smoke is - when right next to it pulls but say a couple of feet away the smoke was drawn towards the open window (also two feet away) finally i noticed that the fan does seem to be em ..... well lets just say the tone of the fan has gone up, the final placement will be behind two doors so I'm sure this will be negated when its in its final position.

Sorry for my wandering post, it's really satisfying to feel like I'm beginning to understand stuff I thought was black magic.

Hope everyone is in rude health and effervescing with life

I think your carbon filter is too big for your fan,or fan not powerful enough for the carbon filter.

Peace

 

[Koondense]

Instead of opening a new thread I'll ask a questions here.

I want to purify the air in my tent(60x120cm or 2'x4') which has passive intake.

Can a HEPA filter be used for passive intake?

I was thinking of using a hepa for dusters and putting it on the intake tube.
Extraction will be standard carbon filter and silent fan.

Thanks for any answer

 

[Jhhnn]

I think your carbon filter is too big for your fan,or fan not powerful enough for the carbon filter.

Peace

In general, bigger filters have lower restriction & need less fan power & noise to filter the same amount of air. Contact time between the air & filter is also greater due to lower velocity thru the filter resulting in better performance.

 

[Jhhnn]

Instead of opening a new thread I'll ask a questions here.

I want to purify the air in my tent(60x120cm or 2'x4') which has passive intake.

Can a HEPA filter be used for passive intake?

I was thinking of using a hepa for dusters and putting it on the intake tube.
Extraction will be standard carbon filter and silent fan.

Thanks for any answer

Hepa filters are quite restrictive so more fan power is needed to overcome that & to maintain proper temps.

I've just resigned myself to periodic cleaning of reflector glass. My grow space draws air from my workshop where I do woodworking so resistance is futile.