Tutorial Ventilation 101

[RomulusUSA]

Could you try running a duct from the flower chamber to the veg, so that air flow goes from veg to flower and then out the filter? That is what I would do if I didn't want to run 2 filters. I did similar with my whole room previously. Veg was open-air in the room, flower was in a DR120 with a ~400cfm filter combo exhausting back into the room. Worked great!

 

[Lathund]

Good idea Romulus. Do you think there will be a problem that the veg chamber is only one third of the size of the flower chamber?

http://www.head-nature.com/article/07159/Dark-Room-Twin-90

 

[RomulusUSA]

I think you should be fine. What do you do right now for intake to the lower chamber? How I did it with my DR120 was by using the 2 lower duct holes for some 6" silver flex duct, which went under the tray I had my pots in, and looped back 180* once they were on the ground, so they had 270* or more or bend. This prevented light from escaping/entering, and allowed plenty of airflow. I would suggest connecting the top/bottom chambers with 1-2 6" (~150mm) ducts, and see what happens. You just need to ensure there is over 180* of bend, 270* has been the sweet spot for me with 12" ducting (allows LOTS of light in!) and worked great with 6" too.

So in short - run 1-2x 6" ducts between the top and bottom, and ensure you have more than 180* of bends in them, and you should be good to go. And close up any other intakes of course.

 

[stealthed-up]

I think im almost there ... Struggling to understand everything but i guess it will take time, heard the best space for a Super sun 2 hood is 3x3 with a 600w, not too sure about the height & planning on going with two fans, one for the hood and one for the cab.

 

[Finklsteinshtkd]

Anybody have any experience with these?

http://www.harborfreight.com/8-inch-portable-ventilator-97762.html

Low speed is 1400 CFM and High Speed is 1575 CFM. For $75? Assuming this thing can handle running 12 hrs/day, how many 1K lights would this cool? Doesn't look that hard to modify for our applications. Think I may give it a try.

I imagine they're either loud and/or can't handle the static pressure of pulling through ducting, filtration or room. Negative, static pressure is a lot for a fan to handle when they're not designed for torque.

 

[yosun]

how about circulation fans? how would a small fan for circulation effect the negative pressure?

 

[St3ve]

how about circulation fans? how would a small fan for circulation effect the negative pressure?

it wouldn't at all. Circulation fans only stir the air. It doesn't effect air coming in or going out of the room

 

[purpLEsmoke]

Guys i want to make this as short and sweet as possible.

3x3x6 Tent, 600 watt electronic ballast with a super sun 2.

I have a few questions, will 150-200CFM be sufficient or too much to cool a Super sun 2 hood with a 600w HPS?

Will too much airflow through a Air cooled hood affect the light,bulb or colour spectrum?

How do i calculate how much loss of cfm or increased static pressure through ducting ?

Do you guys recommend using 150 cm - 125 cm reducer as such

Will a 125cm inline fan to 150cm duct be fine ? Will i have any advantages or disadvantages?

Appreciate any help possible. Thank You

PEACE

 

[RomulusUSA]

Are you running a scrubber? I'd go with 150mm fans and ducting.

 

[Snook]

Guys i want to make this as short and sweet as possible.

3x3x6 Tent, 600 watt electronic ballast with a super sun 2.
Ballast should be outside the tent. heat.

I have a few questions, will 150-200CFM be sufficient or too much to cool a Super sun 2 hood with a 600w HPS?
if you have ducting or scrubber, no it will not be enough.

Will too much airflow through a Air cooled hood affect the light,bulb or colour spectrum? No.

How do i calculate how much loss of cfm or increased static pressure through ducting ? ahh, here's the ducting! I'm looking for the same info. it's something like 10% for every foot of metal ducting and more % for elbows & flexible corregated ducting, I'd guess, is more of a drag on air.

Do you guys recommend using 150 cm - 125 cm reducer as such
View Image
Will a 125cm inline fan to 150cm duct be fine ? Will i have any advantages or disadvantages? running a larger than necessary fan at 3/4 speed is quieter than running one full out. those inline duct fans are supposed to be supplemental fans to boost exhaust airflow from a lager fan within a long run of ducting.

Appreciate any help possible. Thank You

PEACE

If you can afford it, a 4" centrifugal fan with a rheostat would be a better choice. For what it's worth, air flow and timeing of air flow has been the hardest task to get right. Each time an improvement is made to the grow space, the O2 requirements change. GL, hope this helps some.

 

[purpLEsmoke]

No scrubber for now Romulus, planning on using the inline fan on low to do the job & on high for when i get the carbon filter for the next grow.

Snook, ballast will definately be outside the cab.

What cfm would be efficient for a 40 " ducting with one bend coming out the cab ? I can get a inline line with 271cfm at 0 Pa, has 6" hole

Planning to use this for the cab

which is also a 6" but pushes out 360 cfm at 0 Pa.

Could you maybe paste me the link to the how you got those estimates of 10% percent through ducting ?

Running it lower for now that i have no carbon filter & low ambient temperatures it should be good i hope.

So you think these inline fans wont be good enough for short run ductings ? As i mentioned above 40" ?

The second inline i pasted comes stand alone or you get a package that comes with ducting & a smaller inline fan at the end to help boost airflow.

Centrifugal do you mean one of this sort :

Just one that has a rheostat ofcourse?

Very kind thanx for your help !

Peace

 

[purpLEsmoke]

Centrifugal like this i meant.

 

[messn'n'gommin']

Will too much airflow through a Air cooled hood affect the light,bulb or colour spectrum?

It can, but that doesn't mean that it will. To be sure, you would have to have a lot of air flow to have that happen and I won't venture to say how much exactly, as I don't know.

Manufacturers have fairly exacting specs and one of them is a small range of optimum operating temperatures. Altering this temperature range independently does in fact cause a subtle shift in color spectrum.

Taken from a pdf at Lithonia's web site:

Lamp Color: Almost all lamps exhibit color shift
when dimmed. Incandescent lamps shift toward the
red end of the color spectrum. Metal halide lamps
shift in the opposite direction, toward the blue. This
shift is a result of additives falling from the arc stream
as the operating temperature drops.

Taken from Fins Depot, an aquarist site:

Lamp Life
The median life of metal halide lamps is statistically determined under controlled conditions on a 11 hours on, 1 hour off, cycle. Environmental factors including the lamp housing, reflector, power supply, and lamp cooling will affect lamp life considerably.

hth

 

[purpLEsmoke]

Does make a whole lot of sense man, they are made to run a certain temperature, although do you think the manufacturers release these details on the specification sheets ?

So is cooling the lamp suggested ? or should you just extract the heat build up slowly ?

 

[messn'n'gommin']

Does make a whole lot of sense man, they are made to run a certain temperature, although do you think the manufacturers release these details on the specification sheets ?

So is cooling the lamp suggested ? or should you just extract the heat build up slowly ?

Am not very well versed in thermodynamics, to say the least. But, I will say that if you follow the equations on the OP, you shouldn't have any trouble. Like I say, it will take a lot of air flow; it's not really a case of either/or.

 

[Snook]

No scrubber for now Romulus, planning on using the inline fan on low to do the job & on high for when i get the carbon filter for the next grow.

Snook, ballast will definately be outside the cab.

What cfm would be efficient for a 40 " ducting with one bend coming out the cab ? I can get a inline line with 271cfm at 0 Pa, has 6" hole View Image
Planning to use this for the cab View Image which is also a 6" but pushes out 360 cfm at 0 Pa.

Could you maybe paste me the link to the how you got those estimates of 10% percent through ducting ?

Running it lower for now that i have no carbon filter & low ambient temperatures it should be good i hope.

So you think these inline fans wont be good enough for short run ductings ? As i mentioned above 40" ?

The second inline i pasted comes stand alone or you get a package that comes with ducting & a smaller inline fan at the end to help boost airflow.

Centrifugal do you mean one of this sort :
View Image
Just one that has a rheostat ofcourse?

Very kind thanx for your help !

Peace

I'm pretty sure those percentages for airflow restrictions is in this thread somewhere but I'm not smart enough to find it.. I start looking and then start reading something else and next month I'll try to remember to look again.. gaining on it though.. 3 years later.. tril and error....someone should be along point us in the right direction...

 

[purpLEsmoke]

I guess then 150 cfm should do good, ill make it 200 with the ducting.

I want to run a few tests pulling and pushing.

M`n`g dude, now that ive changed to use a single fan setup, the 150 - 200 cfm doesnt work, like i said the 360cfm fan is an option but will it pull enuf to push through the hood and 20-40" with a booster fan on the end ?

 

[zeke99]

Any ideas on rigging up a duct fan to a sliding window?

I'm moving into a new space and need some assistance with carbon filtered exhaust.

There is a dryer vent that I can hook up to but I'll need to use two fans during the Summer.

I've exhausted out of a window before, but that one was hidden, this one is exposed on the exterior side. Any ideas on something I could put over the exterior side of the window to hide the exhaust hole and make it look non suspicious?

 

[zeke99]

Well one thing I thought of today is to connect the duct tubing to a Portable Air Conditioner window bracket device...But still how to conceal this on the exterior side? The window is at eye level.

 

[gdbud]

Find a old window ac unit gut it out. Set the shell in the window the run the ductwork to it.

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