how much cfm?

element2k10

element2k10

Well-Known Member
How much Cfm Would i need to cool a 400w Hps bulb in a cool tube that is 4" in diameter and 14" wide? its gonna get really hot in the room so im just wondering what kind of fan i should get.

can i buy 2 4" inline duct fans that have free air CFM of 40 and max boosted CFM of 80 and put one blowing air on the bulb and the other exausting it out into a duct tube that will lead to the outsuide?
 
BCtrippin

BCtrippin

Well-Known Member
It depends how much ducting you will be running. Also if your using a carbon filter you will want a vortex fan.

If I was you I would buy a 4" HO vortex fan, and a 4" carbon filter. BGHydro.com you can get 4" carbon filter with 12lbs of carbon for like $90. With one of those your grow will be Odorless. The 4" vortex fan can be a bit more expensive though, $150-200. It is worth it though, you will be able to run 4" ducting to wherever you need to get all that hot air out.

:peace:
 
element2k10

element2k10

Well-Known Member
i dont need a carbon filter because my grow box is in a place that no one has access too and it has venting to the outside i just wanna know how much i need to cool that bulb i already got my box vented
 
BCtrippin

BCtrippin

Well-Known Member
element2k10 said:
i dont need a carbon filter because my grow box is in a place that no one has access too and it has venting to the outside i just wanna know how much i need to cool that bulb i already got my box vented
Click to expand...
Like I said it depends how much ducting you are running. Any 4" vortex fan will be enough to cool the bulb. Im pretty sure 4" vortex fans are around 170 CFM without ducting.


:peace:
 
element2k10

element2k10

Well-Known Member
ill have about 3 ft of ducting for the exaust thats about it im not sure how much i need for the intake ill just hook up a simple computer fan to about 6 inches of ducting to blow on the bulb then hook up the exaust ducting which will be about 3 ft should the duct fan be connected directly to the cool tube or have about 1 ft of ducting then the fan and then the rest of the ducting? considerign this much ducting how much cfm would i need for the exaust if i hooked up a simple 40 cfm computer fan blowing on the bulb if thats enough? or do i need more?
 
BCtrippin

BCtrippin

Well-Known Member
element2k10 said:
ill have about 3 ft of ducting for the exaust thats about it im not sure how much i need for the intake ill just hook up a simple computer fan to about 6 inches of ducting to blow on the bulb then hook up the exaust ducting which will be about 3 ft should the duct fan be connected directly to the cool tube or have about 1 ft of ducting then the fan and then the rest of the ducting? considerign this much ducting how much cfm would i need for the exaust if i hooked up a simple 40 cfm computer fan blowing on the bulb if thats enough? or do i need more?
Click to expand...

You dont need the computer fan, just use passive intake. If you get a 4" vortex fan I would mount the fan somewhere sturdy, then run ducting from the intake of the fan to your cooltube, and more ducting from the exhaust of the fan out to where you will exhaust.

If you get a vortex fan it will have some real torque, and will be able to really get air moving. If you just leave the other end of the cooltube open, it will create low pressure in your grow cab, and that low pressure will bring in air (passively) from your intake hole, or any other gaps in the cab.


:peace:
 
element2k10

element2k10

Well-Known Member
the problem with that is there is alot of dust would i be able to run like 12 inches of ducting from the side u said to leave open and just put a filter on there to keep any particles from going in? but the thing with a vortex fan is they are really expensive would a 80 cfm fan work? if that is to little would a 6" inline duct fan that provides 160 cfm? only thing is i would have to fir a 6 inch duct onto the cool tube which would provide easier resistance and better air flow right?

the fan that provides 160 cfm is here from home depot and is cheap enough for me to afford

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100067594
 
BCtrippin

BCtrippin

Well-Known Member
element2k10 said:
the problem with that is there is alot of dust would i be able to run like 12 inches of ducting from the side u said to leave open and just put a filter on there to keep any particles from going in? but the thing with a vortex fan is they are really expensive would a 80 cfm fan work? if that is to little would a 6" inline duct fan that provides 160 cfm? only thing is i would have to fir a 6 inch duct onto the cool tube which would provide easier resistance and better air flow right?

the fan that provides 160 cfm is here from home depot and is cheap enough for me to afford

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100067594
Click to expand...
The problem with those fans is they are booster fans. I use them to boost my vortex fan when I run over 20ft of ducting or if there are a lot of bends.

That fan isnt going to have any real pulling or pushing power. I dont want to say it wont work, because every application is different, but once you start hooking up ducting to those the CFM drops drastically, and if you want a 4" to attach to it its going to drop even more.


You could probably make it work with a few of the cheap 4" boosters, but you will be a lot happier with the results if you invest in a 4" vortex fan.


If your worried about dust buy a pack of Honeywell Prefilter replacement pads for air purifiers, they are the ones everyone uses for DIY carbon filters, just use a prefilter pad and make a little filter with some ducting and it will keep any dust out of the cooltube.


:peace:
 
D

DR. VonDankenstine

Well-Known Member
element2k10 said:
the problem with that is there is alot of dust would i be able to run like 12 inches of ducting from the side u said to leave open and just put a filter on there to keep any particles from going in? but the thing with a vortex fan is they are really expensive would a 80 cfm fan work? if that is to little would a 6" inline duct fan that provides 160 cfm? only thing is i would have to fir a 6 inch duct onto the cool tube which would provide easier resistance and better air flow right?

the fan that provides 160 cfm is here from home depot and is cheap enough for me to afford

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100067594
Click to expand...
No because they don't work well under static pressure-If you look at the pic of the fan-you can see the space between the wall of the duct and fan blade---You need a fan that can work under load--look for a fan online----canfan----squirrel-cage---vortex.
 
element2k10

element2k10

Well-Known Member
ima get the 6" ducts and get that fan from homedepot which has 160 cfm it shoudl work considering it wont have alot of duct to travel through and like von said i need 80 cfm which 160 doubles so even if it drops a little it will be enough to mae it work and just for the hell of it i will install a intake fan to blow on the bulb and provide some more cfm.https://www.rollitup.org/members/dr-vondankenstine.html
 
BCtrippin

BCtrippin

Well-Known Member
element2k10 said:
ima get the 6" ducts and get that fan from homedepot which has 160 cfm it shoudl work considering it wont have alot of duct to travel through and like von said i need 80 cfm which 160 doubles so even if it drops a little it will be enough to mae it work and just for the hell of it i will install a intake fan to blow on the bulb and provide some more cfm.
Click to expand...

Think about how much you might be spending on all the stuff to make those 6" fans work, especially if you buy 2 or 3, and chords to wire them up. Its gonna cost at least $100.

I bet if you check ebay you can find a good deal.

2 seconds of searching...$140 with free shipping, and you will have way better results.

http://cgi.ebay.com/VORTEX-4-INCH-172-CFM-INLINE-POWER-FAN-FREE-SHIPPING_W0QQitemZ110328667400QQcmdZViewItemQQptZHydroponics_Seed_Starting?hash=item110328667400&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A50


:peace:
 
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