Koi

Ever wondered about how to get a carbon scrubber that will do it's job, no more...no less? I did some searching on the web and found this, a lot of time was put into this, thankyou to those who put all of this information together in a simple/useful manner! I am just copy and pasting this. Hope it is useful I have tried to preserve the the excellent formating of the original post. A link to the original will be at the bottom of the page.
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I will be using a 38"'Wx28"Dx42"H cab equipped with a 250 watt light and an additional 50 watts of equipment as an example. I will be rounding where appropriate, I may round up even if the numerical value is below 5. I will also make note of when I have done so.

Now, with that out of the way...

Let us begin!

1.) Convert all inches into feet
2.) Find the volume, feet cubed, of your cab.
3.) Find for Exchange CFM rate. We want to echange the volume of the cab 4 to 5 times a minute. I will use the value of 5.
4.) Find for Additional Electrical Cooling CFM rate. Add all the watts of all equipment inside the cab.
5.) Add the two CFM rates to get Total CFM
6.) Find the CFH (Cubic Feet per Hour) from the Total CFM rate.
7.) Find for the amount of carbon needed for the filter.
8.) Divide the amount (in grams) of total carbon by the length to yield the radius quotient. This is done with 2.6cm thickness as a constant.

This one is a bit tricky. You could yield a perfect sqaure of the number and this will net you a very square looking can filter. (diameter and length will be equal) The best way is to play it by ear and round. In all of the examples above the amount of carbon was rounded to the nearest thousand. It's probably safer and more accurate to round to the nearest five-hundred, but whichever you want to do will still give you roughly the same size can filter.

Another method is to subtract (in cm) the desired length of your carbon scrubber. For example; if you know you want your carbon scrubber to only be 1 ft long then convert 12 inches into cm and then divide from the total amount of activated carbon. The formula to convert inches to centimeters is inches × 2.54. You can also earch online, there are dozens of converters and google even has a built in one. But for the sake of example; (12in × 2.54 = 30.48; 4523.04 ÷ 30.48 = 148.393 and change; so, the length of the can filter will be 30.48cm and the quotient is then carried over to find for the radius) Remember to set aside the number you divide the amount of carbon by, this your length. (A ÷ B = C you want to set aside B, this is your length)

One more thing, when simplifying the value and finding the ideal square, take the smaller number out and use that for your length(cm). The larger number should be used for the outer surface. Otherwise you wind up with a [i/]very[/i] round and short carbon scrubber. You'll understand in a minute.

9.) Find for the desired radius.

Okay, hope you're still with me. Now that we have divided by the length we need to find the radius. We will use the product we got from dividing the total surface area of carbon by the desired length for this formula. If you are at all confused, I will put a condensed example (numbers and abbreviations only) of the formula towards the end of this article.
There, 5.3674...cm is your radius. Multiply by 2 to yield the diameter

Radius is the distance from the center of a cirle to the edge.
Diameter is the distance from one edge of a circle to the other edge, passing through the center.

So... now we take the following numbers and apply them to what we need for the carbon scrubber.

Okay, quick rundown... you ready? Let's go!
Additional formulas:
28 grams in an ounce.
16 ounces in a pound.
Centimeters to inches: cm x 0.39
Inches to centimeters: in x 2.54
Diameter: Radius x 2
Inches to feet: in ÷ 12
Surface area of a cylinder: (pi × R2)H * R=radius H=length

Okay, that's it. Kind of long, but very valuable. Note that these numbers are ideals and are meant to create a carbon scrubber that will remove 100% odor and last up to a year or so in use. These measurements are based on professional carbon scrubbers. I compared what kind of canfilter for my grow space (32"x16"x36") I would need and then did this equation. the equation was dead on. You can scale the size down some if you wish.

Just remember that if you scale it down that means you will have to change the carbon more often. Another thing is that sometimes you do not need to change the carbon. Simply taking the filter out and rolling the carbon around to expose unused pores will work.

I in no way take credit for the conception nor orignation of this formula. As to my fullest knowledge, this formula was concieved by 11leafedleaf. All thread posts were copied and pasted from Overgrow.com google caches which I used to reconstruct 11leafedleaf's formula. If 11leafedleaf or any others quoted in this article wish their posts to be removed, PM me or post in this thread and I will comply to your wishes.

Once again, this formula is not my own conception. It was merely reconstructed by me through posts on Overgrow.com All credit for the oprgination and conception of this formula should be given and attributed to 11leafedleaf.

Original

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dedicated

are you bombsquadron65 from planetganja? either way that's a great article!

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dedicated

by the way, does a 6-4" reducer affect performance that much if the filter is 4" diameter and the fan is a 6"? i'd like to make the carbon scrubber 6" diameter as opposed to 4" but have'nt sat down and actually tried to figure out all the formulas to get em right for a 6" diam. scrubber. you guys think it would make that much of a difference if i just made one with a 6" diam by 2ft long and just compensate for the remainder of the activated carbon needed?

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Shocker

Right on for posting your find I've spent many many hours trying to figure this 1 out, now I know

Batting1000

You know, by the time ur done trying to read this, understand it, and apply it to your own room; I just went to the grow store and got a can fan and filter, hooked it up, eliminated my smell and ate dinner.

dedicated

yeah but you can build your own with professional quality for way cheaper with this knowledge. plus some people would rather do it themselves it gives them a a grow setup that they can say HEY i built all this from scratch all by myself with half the amount of money you spent on yours and it's professional quality. plus you dont have to spend $130-250 (for a can33-66) every year. to each theyre own though

hence the 4th paragraph from last ("These measurements are based on professional carbon scrubbers.")

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Seltzer

Holy crap. 4-5 air changes per minute is a lot of air. If you put that into a room, it would be like having a wind tunnel in there.

There's some interesting work here but I'd challenge some of the basic assumptions

Oh, and he didn't carry the 2.

Koi

It's an interesting read for sure "Sometimes" I like to learn why things are the way they are....leads to a more effective how!

I agree that the math is not for everyone! Myself included. I think I left out that this is intended for a miro/stealth "cab" application. Scrubbers for rooms with this equation would get HUGE in a short amount of time.

I modeled my diy scrubber from this and it came out to exactly what I had eyeballed early on... Best advice...go with your gut!

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"I don't listen to music to get away, I listen to get awake. The key to be alive."

CarbonBubblegum

Holy fuck! I didn't understand any of that.
Is there a shorter version?

Andrew024

I take it a carbon scrubber is an odor eliminator

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