Quick Fan Question

[Sirus]

Going with the 6" S&P TD 150 Inline fan 293/218 CFM, as my reflector has 6" flanges.

The cab space is 2x4x6 and the set up will be filter>fan>light>exhaust.

Should I go with this? CAN FILTER 9000 Max CFM: Recirculating
(Scrubbing):
110/400 m³/h
Exhaust:
55/200 m³/h
@ 0.1 sec contact time
Dimensions:
(with pre-filter)·Outside Diameter: 140mm/5.5"
·Height: 600mm/25"
·Total Weight: 5.5kg/12lbs..
·Carbon Weight: 3kg/6.6lbs
Flange:*4"/5"


Or this one?


CAN FILTER 33
Max CFM: 200 cfm (non-recirculating) Min CFM: 100 cfmDimensions:
(with pre-filter)·Outside Diameter: 305mm/12"
·Height: 330mm/13"
·Total Weight: 11.5kg/25.3lbs.
·Carbon Weight: 7.5kg/16.5lbs.
·Carbon Bed Depth: 50mm/2"Max Operating Temp: 176º F / 80ºC Pressure drop
at max CFM:180pa/ .75wg Flange:*4" or 6"

Appericate any input.

 

[Batboy]

That's the cool thing about this site, there are so many people that you're bound to find someone with similar specs.

As luck would have it, I am currently running an S&P TD-150 with a Can 9000. My cab is 3.5x2x4. I go filter--fan--6" cooltube--exhaust.

I just finished an LR#2 and that is one nasty, stinky plant. Unfortunately, I needed supplemental odor protection; the can 9000 could not handle it on its own. MY S&P has a speed controller, so I was able to play around with the fan speed to try to optimize the contact time with the carbon, but I never got it to the point where there was no lingering odor. Now that the LR#2 is gone, the filter is handling the one remaining flowering plant just fine.

I too looked at the Can 33 at first, but it's bulk turned me off. While it's shorter, the difference in diameter is insane and I could not figure out how to work it into my cab. You've got a bigger cab, so that shouldn't be as much of a factor. Another turn off, and potential problem with the Can 33, is the ability of the TD-150 to effectively pull air through. As you may know, while the S&P mixed vent type fan is ideal for noise reduction, it does not have the pulling power of a centrifugal. Consequently, its performance falls apart when the static pressure increases. My biggest concern using the TD-150 with the Can 33 would be the fan's ability to effectively do its job of both cooling the light and venting filtered air.

Having said all that, the fact is that the Can 33 has 10 pounds more charcoal than the 9000. That's 150% more! I am enticed enough that I have already started planning how to fit the Can 33 into my cab for the next round. Like I said, I'm just nervous that the new filter, with its impressive 16.5 pounds of charcoal, will be too much for the fan.

Hopefully others will respond and on a selfish note, I hope that you get the TD-150 with the Can 33 and tell me all about it!

Final note: I think that you should retitle the thread (if you are allowed). This is more of a filter question than a fan question, no? It seems that you are settled on the fan, so the big question here is what filter to get.

 

[qbert]

I hear on the size of this Can 33. Its a beast to fit. I'm working with 2'x3.5'x6'-ish and trying to squeeze that in with a Super Sun 2 and separate air pathways (6" for hood, 8" for filter) is not intuitive (not happy with any arrangement yet).


batboy - the static pressure that the filter presents is a function of the air flow through the filter. Yes the Can 33 has 10 lbs more carbon, but that doesn't equate to more pressure - there's a vastly larger surface area through which air is drawn.

If the TD-150 can pull/push through that 9000, at the same fan speed setting it will likely pull/push more air through the Can 33. At any given total system flow rate the Can 9000 will present more resistance to the flow of air than the Can 33. Don't ya think? Or am I wrong?


I also happen to have the Can 33 and a 2600 along with a td-125, 150, and 200 - so I can do a little testing in the open - but my cab's not built and I'm short on duct and flanges (and time, lol) to try every combination.

 

[Batboy]

batboy - the static pressure that the filter presents is a function of the air flow through the filter. Yes the Can 33 has 10 lbs more carbon, but that doesn't equate to more pressure - there's a vastly larger surface area through which air is drawn.

If the TD-150 can pull/push through that 9000, at the same fan speed setting it will likely pull/push more air through the Can 33. At any given total system flow rate the Can 9000 will present more resistance to the flow of air than the Can 33. Don't ya think? Or am I wrong?

Maybe I was thinking of things too simplistically (I was thinking about pulling air through 6 pounds of carbon versus 16.5 pounds). However, with a larger surface area and larger volume of carbon, you will reach a point where the airflow created by the fan isn't sufficient to pull/push through the carbon covering the surface area. This must be true, otherwise you'd be able to use a small fan with a large filter like a Can 50, 66, 100. . . . Logic tells us that's not true.

Thanks to the internet, I can come off as smart by calculating the surface area and volume of the different filters. Interestingly, while the Can 33 obviously has much larger volume into which to place the carbon (1,469.52 vs. 593.65), the surface area through which the air is pulled/pushed is much closer than you would have thought (489.84 Curved Surface Area for the Can 33 versus 431.75 for the 9000). It seems to me based on these numbers that the fan will be pulling air through evenly sized surface areas (only a 13% difference), but through a bed of carbon that is roughly 150% larger. I can't imagine that the fan performance won't take a huge hit.

I also happen to have the Can 33 and a 2600 along with a td-125, 150, and 200 - so I can do a little testing in the open - but my cab's not built and I'm short on duct and flanges (and time, lol) to try every combination.

Well then I think it's obvious that you quit your day job, pick up some duct tape and flanges, purchase some type of meter that can measure airflow, and get on it! I'd love to see how the TD-150 does with the Can 33, and it would be interesting to see how the performance changes when the specs change to the 2600. Get on it!




.

 

[Jnugg]

Time to learn how to do the math folks.....

You need a carbon filter to remove odors,no doubt about it.You also need a certain amount of airflow/cfm's to keep the light and the grow cool and well ventilated.

If you notice,canfilter.com lists maximum airflow/cfm's and minimum airflow/cfm's that each filter can handle.

If setting your filterup in the grow so it is set up as so:

filter > a/c light > fan/exhuast

The you want to pay attention to the recirculating max airflow/cfm as shown in red in the pic below:




Now if you set it up to where you exhuast into the carbon filter then you need to pay attention to the exhuasting max airflow/cfm's as shown in red in the pic below:





Now how do we use this...simple.

You have your fan,an S&P TD-150 which is rated 293cfm @ full speed and 218cfm on low speed...lets say you want to run that fan full speed.

Take the cfm rating of the fan 293cfm and divide by the max airflow/cfms for whatever way you choose to filter.

If recirculating (filter > a/c hood > fan) then take 293cfm and divide it by the filters max airflow for recirculating which happens to be 400cfm.

293/400 = 0.7325

What is this number?It's the amount of static pressure your fan will have to work against.

A TD-150 @ full speed connected to a can 33 carbon filter would result in 0.7325" of static pressure....if we look at the S&P tech chart we would see that the TD-150 @ full speed connected to a Can 33 carbon filter would drop your fans airflow from 293cfm to about 131-150cfm.....hardly enough to keep a light cool let alone also ventilate the grow and keep the grow cool.

With that fan and a Can 33 filter exhuasting into the filter is out of the question.

The can 50 filter set up recirculating ( filter > a/c light > fan) has a max airflow/cfm rating of 840cfm.For exhuasting into the max airflow/cfm is 420cfm.

293/840 = 0.348" static pressure

293/420 = 0.697" static pressure

I'd say go for the can 50.

 

[qbert]

However, with a larger surface area and larger volume of carbon, you will reach a point where the airflow created by the fan isn't sufficient to pull/push through the carbon covering the surface area. This must be true, otherwise you'd be able to use a small fan with a large filter like a Can 50, 66, 100. . . . Logic tells us that's not true.

I agree this is true, but I am suggesting the logic behind why is different.

Yes, fans can get too small for a filter. But I am suggesting this is NOT because of too much static pressure - instead I am suggesting it is from too much contact time with the carbon.


You'll notice on Can-Filters site that the successively larger filters provide linearly larger maximum flow ratings. A doubling of surface area doubles the rated max cfm while maintaining the same static pressure at max cfm.

So, unless we think that these filters present more static pressure as the cfm drops, than the only way a fan can be "too small" is by not moving enough air through the filter.

The minimum ratings on the filter, to the best of my knowledge, are due to air contact times with the carbon - not static pressure. Bigger filters need bigger fans because they are designed to move more air, not because they present more static pressure.


If your TD-150 is pulling/pushing 55 CFM through that Can 9000, it will pull at least 55 CFM through a Can 33. The question is if it will pull the 100 cfm they list as a minimum CFM for the filter.

Thanks to the internet, I can come off as smart ...

lolz, unless its a dig.

It seems to me based on these numbers that the fan will be pulling air through evenly sized surface areas (only a 13% difference), but through a bed of carbon that is roughly 150% larger. I can't imagine that the fan performance won't take a huge hit.

Would you imagine that a fan would take a huge hit when increasing the length of duct by 150%? Would you imagine that a fan would take a huge hit when trying to increase the air flow volume by 100%? Which do you think would be the much larger performance bottleneck?

Well then I think it's obvious that you quit your day job, pick up some duct tape and flanges, purchase some type of meter that can measure airflow, and get on it! I'd love to see how the TD-150 does with the Can 33, and it would be interesting to see how the performance changes when the specs change to the 2600. Get on it!

I know right, all speculation until there's some controlled tests. Its not like I don't want to...

 

[qbert]

The you want to pay attention to the recirculating max airflow/cfm as shown in red in the pic below:




Now if you set it up to where you exhuast into the carbon filter then you need to pay attention to the exhuasting max airflow/cfm's as shown in red in the pic below:

I'd like to discuss this. Frankly, I think most people are interpreting Can-Filters numbers wrong.


I'm actually not sure what usage you are referring to, Jnugg. Most people ite seems when referencing this Can-Filter numbers interpret "recirculating" to mean pulling through a filter and "exhausting" as pushing through a filter.

I think this is entirely incorrect, and that "recirculating" means EXACTLY that - the fan dumps the scrubbed air right back into the same room (I mean, that IS what re-circulating is) and "exhausting" also means exactly that - whether pulling or pushing through the filter - cause lets get real, the filter doesn't give one whit which way the air is going through it - won't affect static pressure in the least. (in before everyone tries to point out how this does matter to the FAN [not filter]). It also explains the different CFM ratings, because when recirculating the air will get processed several times so eliminating all odor in one pass isn't necessary, but when exhausting it is.

293/400 = 0.7325

What is this number?It's the amount of static pressure your fan will have to work against.

uuhhh .. huh?


So, you're going to take two constant numbers - a maximum airflow rating for a fan and a maximum airflow rating for a filter - ratings determined by completely different criteria - divide them, and say that's the static pressure presented by the filter??

Maybe I don't understand half of what I think I do, but isn't static pressure in a system in large part defined by the velocity of fluid through the system? If so, how can you say that the static pressure is simply 0.7325" when that would change when the flow rate changed? My understanding is this: the fan's cfm drops as static pressure increases and also the resistance of static pressure in an airway increases as velocity increases (velocity is proportional to cfm) - there is a point at which the cfm and static pressure reach an equilibrium; this is the steady-state of operation for the whole system.

 

[RugerBaby]

you guys lost me on this one... lmao

 

[RugerBaby]

just let me know which filter is best because Im also waiting on my TD-150

 

[qbert]

Can 50 if you can fit it. Can 33 if you can't. Both should work ok with a TD-150, but the Can 33 will be more of a restriction and cause the fan to work harder (louder). If the 33 won't fit, there is the 9000, but Batboy got limited mileage out of it.

 

[Batboy]

Jnugg and qbert - I carefully read your recent posts last night and could not make sense of them. This morning, with fresh eyes, I tried again. . . still not seeing it.

In the simplest of terms, Jnugg, I do not believe that you calculate static pressure for any particular fan/filter combo by dividing fan CFM by filter max ratings. I am no expert here and have no problem being proven wrong; any chance you could source this formula -- even showing me another thread where this is discussed?

qbert - I tried to stay with you, but it's just not happening. In the end, you recommend a Can 50 as the best pairing for a TD-150. If the pressure drop is close to .75"wg, then the TD-150 will be pulling 131 cfm, which is far less than the Can 50's published min airflow of over 200 cfm. I think that this a bad recommendation - especially when you look at the airflow of the fans that Can recommends be paired with the Can 50, the smallest of which is a high output fan that maxes at almost 400 cfm and doesn't suffer the huge drop that S&P does when presented with resistance. I just don't see the evidence that the Can 50's resistance will not be at a level that drops the fan's cfms below the filter's minimum.

We need an expert in here stat.

 

[qbert]

If the pressure drop is close to .75"wg

Only at max cfm. At a lower cfm the static pressure will be less.

The info on the Can-Filter site confirms this.

If we look at the Can 50 page we can see they state the filtered CFM with a Can Fan 6" HO is 312 CFM.

If we go to the fan page we can look at the table of CFM vs. static pressure and see that the static pressure in this system lies between 0.375" and 0.5". Not 0.75"

You can do the same for the Can Fan 10" HO, with a much higher filtered CFM, and see that the static pressure of the system is much higher - higher than 0.75" in fact (which is sort of contradictory, hmmm...).




I did some more refreshing last night. I am certain: static pressure rises when the air velocity rises. Its not a static value. You can't take a section of duct with a filter on it and say the static pressure of it is X"wg. It matters how much air you are trying to shove through it.


The fan tries to shove more air through, as it does that the ducts, filters, etc. present more resistance (think of how it gets harder and harder for a car to go faster and faster and push through more and more air - same principle). There will be a point where the ability of the fan to push air and the resistance of the ducting to an amount of air flow match up.


If we graphed it, it would be something like this: You hopefully will recognize the line for the fan - that is the standard CFM dropping while the static pressure increases (actual TD-150 #'s), but I've overlaid a made up #'s line that show the general trend a passageway (ducting) makes - the static pressure increases as the cfm increases. The point where they cross is where your system will operate. That's where everything balances and that's how many CFM the whole system would process in this imaginary example.

So, if the Can Fan 6" HO can put 312 CFM through the filter with a static pressure between 0.375" and 0.5", then we know that the TD-150 will pull through less, because its max CFM isn't even 300 CFM.

So, the static pressure with the TD-150 will be less than it is with the Can Fan 6" HO because its trying to move less air through. How much? Who knows, but it doesn't really matter cause less is more. Lets say its 0.5" just for fun. It will be less, because the Can 6" HO isn't even 0.5", but even at 0.5" the TD-150 can pull over 200 CFM.


That is why I say the TD-150 and Can 50 will work just fine together. In fact, I suggest this as the recommended pairing if you can fit the filter.


Making sense yet? I'm not that good at explaining things, but I'm pretty sure I've got it straight.

 

[Batboy]

Good post qbert. I did not consider that the Filtered Air CFM column in the fan recommendations implicitly provides you with the means to calculate the static pressure at which each fan will be operating.

It still seems counterintuitive that a relatively weak fan (when it comes to resistance) like the S&P will perform better when paired with a larger filter and a charcoal bed depth 1/2 inch deeper, but I now see how you are interpreting the numbers and I agree, at least in theory, with your conclusion.

 

[qbert]

yeah - this was the thread that goes over the operating point principal: http://www.icmag.com/ic/showthread.php?t=112862

imho, the S&P's require a bit more careful planning than a centrifugal. If they are operated in their sweet spot they move plenty of air reasonably quietly. But when the restriction gets too high, the performance falls off very, very fast - and this tipping point of restriction is easy to hit. The centrifugals maintain a slowly and linearly decreasing CFM into static pressures that are so high we would almost have to purposefully create them.

With the S&P, I can quite literally feel this resistance point on the S&P's as I cover the intake with my hand. As my hand gets closer and closer its like: good, good, good, good, bam - loud as fk and no air movement anymore.

 

[Jnugg]

Ok qbert....you just replied about the Can 50 filter and the Can 6" HO.......so tell me how the math doesn't work again please?


Can Filters page on the Can 50 filter says the airflow of the Can 50 hooked to the Can 6" HO (without ducting,air-cooled hoods,bends in ducting) wouls be 312cfm.

392/840 = 0.46" static pressure/wg.

So if we look at the can fan spec page:



It shows the different airflows at different static pressure levels.If you notice the static pressures listed for the Can 6" HO goes from 0",.125",0.25",0.375",0.5",0.75",1.0",1.25",1.5"

So the static pressure falls between 0.375" and 0.5" wg.There fore the airflow would be between 301 and 324cfm....312cfm...so how does the math not work out correctly qbert?!

Now once you slap some ducting in between the filter and fan and onto an air-cooled light (or two),throw some bends into that ducting....then that math wouldn't make sense.

It may not be exact but I believe it to be damn close.


Soooo.....anybody willing to take part in a little experiment?!

 

[qbert]

Well JNugg, I'll be damned, that does work out pretty close for every combo of can fan & filter I tried.

But I still don't see any logical reason why it would. Other than the fact that it happens to come out right, there's no reasoning why.

Out of curiosity, would you expect the same calculation to work to match, say a Dayton blower and a Phresh filter?

There must be more to how they determine the maximum CFM rating that allows us to draw this conclusion. Without a logical reasoning - a proof - this is just a serendipitous coincidence imo.


Thought: What if we replaced the filter with, say, a length of duct. How would we rate the length of duct for a maximum CFM so that we could perform a similar calculation with the fan's 0 SP CFM and the duct's maximum CFM to determine the actual SP seen by the fan in operation, and therefore the actual CFM of the system. blah, blah, blah, mental masturbation.


But I'm sticking with that's a random unexplained equation that just happens to work for this subset of data and isn't actually true until a why is figured. Nothing personal, I'm just a sucker for knowing why.

 

[Jnugg]

I am no mathematician,in fact math was my worst subject back in school.I have thought of taking HVAC courses offered at my local technical school but want to get into and finish a course based on a proffesion I would like/enjoy doing like possibly Culinary Arts....crawling around in other peoples hot,spider infested attics is not something I can view as enjoyable.

Do I think that math would work with a dayton.....hell no!A dayton is a blower and they don't handle static pressures well at all.Also Dayton and may other manufacturers don't give us a spec. chart stating the airflow/cfm's at different static pressures.

If we look at the Can Fan spec. chart and then the S&P Mixed Vent spec. chart we see that the specs. and measurements are pretty close:

6" HO = 392cfm
6" TD-150 = 293cfm

That's a 100cfm difference between the two fans.

Now take a look at the 0" static pressure rating of the Can Fan 6" HO and the 0" static pressure rating of the S&P Mixed Vent 6" TD-150.

Now take a look at the 0.125" static pressure ratings for both fans.The 6" HO is rated 392cfm 0" static pressure and 371cfm @ 0.125" static pressure.The 6" TD-150 is rated 293cfm @ 0" static pressure and 273cfm @ 0.125" static pressure.

Can Fan 6" HO: 392 - 371 = 21cfm lost
S&P 6" TD-150: 293 - 273 = 20cfm lost

We can keep doing this math to see how similar the fans are when it comes to dealing with static pressures....

We'll look at the 6" HO's airflow at 0.125" and 0.25" static pressure and the TD-150's airflow at 0.125" static pressure @ 0.125" and 0.25" static pressure.

Can Fan 6" HO: 371cfm @ 0.125" sp and 348cfm @ 0.25" sp
TD-150: 273cfm @ 0.125" sp and 250cfm @ 0.25" sp

Can Fan 6" HO: 371 - 348 = 23cfm lost
TD-150: 273 - 250 = 23cfm lost



Lets keep going shall we.....

The 6" HO is rated 348cfm @ 0.25" static pressure and 324cfm @ 0.375" static pressure.The TD-150 is rated 250cfm @ 0.25" static pressure and 227cfm @ 0.375" static pressure.

Can Fan 6" HO: 348 - 324 = 24cfm loss
TD-150: 250 - 227 = 23cfm loss


And going....

The 6" HO is rated 324cfm @ 0.375" static pressure and 301cfm @ 0.5" static pressure.The TD-150 is rated 227cfm @ 0.375" static pressure and 206cfm @ 0.5" static pressure.

Can Fan 6" HO: 324 - 301 = 23cfm loss
TD-150: 227 - 206 = 21cfm loss


Still pretty damn comparable to me as far as handling static pressures go.So I would say yes when matching an inline centrifugal (vortex,can fan,eco plus,elicent) or an S&P or Max Fan mixed vent fan to a can filter (or DIY filter of same/similar design) that that math makes sense...for a dayton or any other blower or an axial fan you might want to contact the company to see if they can tell you what the airflow/cfm ratings are at different static pressure levels.


As far as ducts and static pressure.I just looked for it and could not find it but at one time on Can Filters website they stated 0.75" was the equivalent of a filter attached to a straight run of 25' of ducting (no bends or a/c hoods etc.).Was it smooth insulated ducting or rigid ducting...who knows?!

They also stated that 0.5" static pressure is about the equivalent of matching an inline centrifugal with it's proper filter (no ducting,just fan and filter).

 

[qbert]

Dayton was a bad example.

Meant it more like Brand X centrifugal and Brand Y filter. If it works for Can Fans and Can Filters, and S&P Fans and Can filters, it should work for vortex or ecoplus or whoever else is making centrifugals (or mix-vents for that matter) and anyone's carbon filter. Not everyone gives as many stats as Can does though.


I just noticed something else that doesn't quite jive. Most of Can's filters say the pressure drop at max CFM is 0.75", but using your equation results in a whole lot of fan/filter combo's having more than 0.75" sp. Like the Can 50 & Max 10, at over 1". Not sure what to make of that exactly.

While I understand mathematics and most physics somewhat well (I think/hope, lolz), the fluid dynamics physics was always a little fuzzy for me. Not quite sure I fully grasp pressure differences in a system like this.

 

[eyes]

Thinking of getting that same fan.Had a can 2600(duals ) on an s and p 4inch and those cans couldnt keep up>Anyhow,moving up to the same fan 6inch,and going with the 6 inch carbonaire(500 cfm).

 

[qbert]

Thinking of getting that same fan.Had a can 2600(duals ) on an s and p 4inch and those cans couldnt keep up>Anyhow,moving up to the same fan 6inch,and going with the 6 inch carbonaire(500 cfm).

dual 2600's on a 4" S&P and it was too much flow? air was still stinky? damn. That doesn't bode well for the 2600 & 5" S&P I was planning to use for some pl-l scrog goodness. I knew that filter was too small, but they required palleting a 9000 to ship it for some weird reason. :-/