Help with carbon filter/fan setup please
- Thread starter Cereall
- Start date
Serapis
Well-Known Member
OK, first things first, a little math to determine the area of air that we need to move..... I'm assuming an 8' ceiling, but will expose the math so you can sub a number if needed....
You have 64 square feet. That is 8' x 8' walls, 64 single foot squares. In order to determine volume, we have to multiply the square footage by the height, so 64 * 8' gives us 512 cubic feet. Now that we have the volume, we need to determine how many times per minute we need to replace that air. If you are using a sealed room and plan to introduce CO2, you'll want a fan that can cycle the room air 5 times per minute, so it can quickly clear the area when cycled on. A 24 hour exhaust fan to maintain negative pressure and control odor probably needs to cycle the air 3 times per minute.
How ever many times you want to exchange the air per minute is up to you. 3-5 is recommended. So let's look at the formula...
l x w x h = cf / pm = cfm
Length times width times height = cubic footage divided by cycles per minute equals desired cfm of exhaust fan.
We already have the volume, 512 cf so we divide by the number of cycles, for example 3, we get 170 cfm. Keep in mind that this doesn't reflect pulling air through lights or a carbon filter. This formula is simply for air exchange.
When you add the light (approx 350 cfm per 1kw), you can now account for heat exchange as well. So using the same example as above, if you had 2k watts of light (2 1k in an 8'x8') You are looking at a requirement of 870 cf/m, and we haven't factored in duct loss and back pressure yet.
You'll also need to take into consideration the resistance from the charcoal filter/scrubber. In our example, I would use a fan with a cfm rating of about 1100 cfm. Fans that size require 12" ducting, so it maybe ideal to split the requirement and run two exhaust fans, however you'll need two controllers and two scrubbers.
I hope this info was handy.
You have 64 square feet. That is 8' x 8' walls, 64 single foot squares. In order to determine volume, we have to multiply the square footage by the height, so 64 * 8' gives us 512 cubic feet. Now that we have the volume, we need to determine how many times per minute we need to replace that air. If you are using a sealed room and plan to introduce CO2, you'll want a fan that can cycle the room air 5 times per minute, so it can quickly clear the area when cycled on. A 24 hour exhaust fan to maintain negative pressure and control odor probably needs to cycle the air 3 times per minute.
How ever many times you want to exchange the air per minute is up to you. 3-5 is recommended. So let's look at the formula...
l x w x h = cf / pm = cfm
Length times width times height = cubic footage divided by cycles per minute equals desired cfm of exhaust fan.
We already have the volume, 512 cf so we divide by the number of cycles, for example 3, we get 170 cfm. Keep in mind that this doesn't reflect pulling air through lights or a carbon filter. This formula is simply for air exchange.
When you add the light (approx 350 cfm per 1kw), you can now account for heat exchange as well. So using the same example as above, if you had 2k watts of light (2 1k in an 8'x8') You are looking at a requirement of 870 cf/m, and we haven't factored in duct loss and back pressure yet.
You'll also need to take into consideration the resistance from the charcoal filter/scrubber. In our example, I would use a fan with a cfm rating of about 1100 cfm. Fans that size require 12" ducting, so it maybe ideal to split the requirement and run two exhaust fans, however you'll need two controllers and two scrubbers.
I hope this info was handy.
Cereall
Well-Known Member
Hello
Thank you for pulling all the info... yes 8 foot ceilings so you are dead on there
I have no lights to cool as they are all leds so i am not worried about air cooling anything, just thanks for taking that into consideration. So i am needing it for carbon filter purposes only. So 170 cfm needed... probably lose like 25% suction by going through carbon filter?
so i would need roughly a 227 cfm fan and filter?
Thank you for pulling all the info... yes 8 foot ceilings so you are dead on there
I have no lights to cool as they are all leds so i am not worried about air cooling anything, just thanks for taking that into consideration. So i am needing it for carbon filter purposes only. So 170 cfm needed... probably lose like 25% suction by going through carbon filter?
so i would need roughly a 227 cfm fan and filter?
Serapis
Well-Known Member
I would go with a larger one if you can budget it, and here is why....
If you do decide to introduce any HID lighting, or any other devices that generate btu, regardless of how small, you'll have the power to move the air necessary to prevent heat build up. You can always throttle the fan down with a controller and it won't be as loud as a 227 cfm running full blast. I'd go with a 440 if it were me, just to cover any future additions or needs.
If you do decide to introduce any HID lighting, or any other devices that generate btu, regardless of how small, you'll have the power to move the air necessary to prevent heat build up. You can always throttle the fan down with a controller and it won't be as loud as a 227 cfm running full blast. I'd go with a 440 if it were me, just to cover any future additions or needs.
Cereall
Well-Known Member
Thanks, budget is no issue... im just going all out once and be done
i am growing in 3 tents in 8x8 room... i see your location is in your jardin
maybe you can further help....
i figured it would be easier to air scrub my 1 big room rather than 3 individual tents....
i grow 100% leds after switching from HID so no chance going back there... not knocking them, im just moving to other ventures
SO maybe i can go back with a 10" fan and filter... had 424 CFM before and just throttle it back like you said to reduce vibration? i just got a lot of vibration and noise and that was with the quitest fan i have ever seen and still not happy with it, but hey, cant be total stealth i guess
again, so whats the best fan brand? i was using sunleaves and they seem pretty good, just dont know if there are better
i am growing in 3 tents in 8x8 room... i see your location is in your jardin
maybe you can further help....
i figured it would be easier to air scrub my 1 big room rather than 3 individual tents....
i grow 100% leds after switching from HID so no chance going back there... not knocking them, im just moving to other ventures
SO maybe i can go back with a 10" fan and filter... had 424 CFM before and just throttle it back like you said to reduce vibration? i just got a lot of vibration and noise and that was with the quitest fan i have ever seen and still not happy with it, but hey, cant be total stealth i guess
again, so whats the best fan brand? i was using sunleaves and they seem pretty good, just dont know if there are better
Serapis
Well-Known Member
If you get a quality fan, it will have a balanced blade and a sealed bearing that is lubed for life (don't laugh Stoned Pony). Look for the Vortex name and avoid cheap knock offs.
I'm not sure how it will work with 3 tents and one general exhaust. Exhaust is usually the way to get fresh air drawn into a tent. If you are going to be exhausting the entire room, you will need to duct in supply air for each tent individually.
I'm not sure how it will work with 3 tents and one general exhaust. Exhaust is usually the way to get fresh air drawn into a tent. If you are going to be exhausting the entire room, you will need to duct in supply air for each tent individually.
Serapis
Well-Known Member
I used two 120 Watt LED tri-bands in my closet and temps got up to 95 degrees.... they do produce heat and it will accumulate.
Cereall
Well-Known Member
Thanks smokebros
that is my question... what size fan and filter would be sufficient for the whole room instead of running 3 individual set ups inside each tent
no plans on exhausting the room or adding new fresh air just cleaning the stuff stuck inside to the smell doesnt linger throughout the rest of the house
I have 4 170w actual draw LEDs and they raise ambient temp by about 17* from 60* ambient to 77* which i need to get hotter actually to maximize c02 benefit so leds run pretty dam cool
that is my question... what size fan and filter would be sufficient for the whole room instead of running 3 individual set ups inside each tent
no plans on exhausting the room or adding new fresh air just cleaning the stuff stuck inside to the smell doesnt linger throughout the rest of the house
I have 4 170w actual draw LEDs and they raise ambient temp by about 17* from 60* ambient to 77* which i need to get hotter actually to maximize c02 benefit so leds run pretty dam cool
smokebros
Well-Known Member
ohhh if its a tent just get the inline fan like serapis said, get a carbon filter, and use negative air pressure to bring fresh air into the tent.. wala!
Serapis
Well-Known Member
That would have been wonderful information to provide up front before you drug me into the entire math calculations and shit... 
Good luck, I'm out
Good luck, I'm out
Cereall
Well-Known Member
LOL that was my first post... totally sealed 8x8 room and what size filter/fan i would needThat would have been wonderful information to provide up front before you drug me into the entire math calculations and shit...
Good luck, I'm out
I appreciated all your input on exhaust and pressure but that was not what i was aiming for, just an appropriate sized filter for a totally sealed 512 CFM room or whatever that will be efficient to eliminate my odors
i dont get what part of TOTALLY SEALED that knocked you off with such misconceptions