Friends of the fan leaf, colleagues of the calyx, pilgrims to the pistil... I pose a question to those with experience: Is it possible to reliably and functionally power a small carbon can filter (4" inner, 5" outer, 6" long) with one or two CPU-sized fans? The filter will be placed over the exhaust fan on the inside of the cabinet wall. I'm concerned about creating enough negative pressure to flow the air needed to properly vent a Rubbermaid sized cab (less than 5ft^3). The filter is comprised of a mesh metal pencil cup with a swiss-cheesed 2L soda bottle surrounding it. I have vent filter foam surrounding each layer to keep the carbon in place. Needless to say, I need some active power on this filter. So to the point then: Do you think a single 60mm fan on the exhaust side of the filter would suffice? My 12v power adapter can handle 1000mah, so I can afford to run 2 fans on the filter if need be, as well as a small intake fan on the cabinet. Do you think 2 fans is necessary for my application? Or could it over-flow the filter and cause odor issues? Also, how can I figure the CFM of a fan? Most 60mm fans I've seen have been 12v ~.25a, and the 80mm ones I've seen have been 12v ~.10a. I feel like the 60's are more suited for the load of the filter, since they run at a higher RPM and use more power. Please chime in with any experience you've had with using CPU fans in conjunction with carbon filters, large or small.
After looking around a bit, I've decided I like the deals and selection at surpluscenter.com. So I'm looking hard at their 52 CFM, 92MM 12v fan on the DC fan list. It draws .30 amps, so I can run at least two in addition to what I have now. Since this is for a true mini-grow, there is no need for major CFM. I think PC sized units can do the job, but I know I'll need a well thought out system of fans working together. I just don't see a single fan pulling hard enough to properly flow the air needed through what seems like a pretty restrictive filter. Here's what I've got so far... Option A: running them in tandem as an exhaust-only system. One fan in the wall of the cab, pulling air through the filter on the inside of the box; one fan running just past the cab, probably at the bottom of a labrynth style light trap. Option B: running both fans on either side of the filter, intake and exhaust. First fan on the inside of the cab, acting as an intake for the filter; one fan as an exhaust in the same spot on the cab wall. If I go with B, I may get a smaller 60mm fan for the intake side of the filter, and stick with the 92MM for the exhaust side. Any thoughts?
well the filter will definitely do a good amount of air flow constricting as well as every corner that the air must take drops the air flow a decent % as well. If you are going to go pc fan, I'd recommend getting a larger one. I've never been pleased with the air flow of the 80mm ones. I purchased a new 140mm pc fan that pushes 128 cfm, and am yet to have a good chance to set it up yet, but i am pleased with the power of it. I guess I'm just trying to say, get a fan that would seem like overkill if it's gonna be a pc fan. It will work best to have one fan on each end of the carbon scrubber, one pushing the air in, one taking it out.
Its a static pressure issue... Pc fans were not built to deal with the pressure on the motor (I guess...) from pulling a scrubber through it thus overworking it... But A realy small scrubber for a grow cab the size of those good sized rubbermaid buckets... Im sure it could work...Just need more CFM than 90... NOt much more though.. I've seen small cab scrubbers on ebay that use "pc-looking" fans... Impossible? I think not...
i have a cpu fan to use with my scrubber, except it is pushing the air through the filter, not sucking it through it
You will be pissing against the wind. A computer fan will not be sufficent to pull/push air through a carbon filter. If it did, the filter wouldn't be worth a shit.
Hmmm this complicates things for me as well. Was thinking of using dual 120mm fans for my scrubber, but if impossible will have to go back to looking at an inline fan set up.
i dont know, but my fan is powerful... was testing it before i set it up and it had enough force to push itself around... i do have a smaller carbon filter though
I've seen some pretty wicked fast PC fans, usually on processor heat sinks. I do not think the fans you're speaking of will work though. 60mm is also very small for a PC fan. I have a PC fan in my closet that rips, sounds like a vacuum cleaner on the highest rpm.
I'm going to 'try' to run two (2) 92mm, 50+ CFM fans for the scrubber alone, then another 80mm, .10 amp fan at the end of the exhaust light-proofing for some extra negative pressure. Intakes are three (3) 1" PVC pipes. Have a vertical fan outside the box to move air toward the passive intakes. I currently have the weaker 80mm running filter-free exhaust, and a fairly high-rpm .25 amp 60mm inside the box for circulation, this will all change when I get the new 92mm units, and I'll let you all know! Here's hoping ~100 CFM is enough to get things moving!
I know for sure one 12v computer fans will not have enough torque to push/pull air through enough layers of active carbon effectively to remove odor from the air. I'm eager to find out if 2 or 3 might work.
Most likely going through newegg. Actually looking at this fan now: http://www.newegg.com/Product/Product.aspx?Item=N82E16835185054 Rated at 133cfm. And thinking of trying this controller: http://www.newegg.com/Product/Product.aspx?Item=N82E16811998808 I am curious how hard it would be to wire up the controller? Same thing as the fans and just using a 12v plug in adapter or ??
I am using two of these. http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3478779&CatId=802 Seems like theres alot of skeptics in this thread but if you search around the forums you will see other people used pc fans and it seemed to work. Hopefully it does or I'll be screwed lol. Also it depends on your setup. I have a small box 2.5'Hx2.5'Wx1.5'D. I think it will work for that but not a large box.
Looks like the fans get wired into the controller, then the controller gets power and regulates each fan. Wiring should be pretty simple, just be sure you have room in that adapter for the required amperage. Good luck, keep us posted!
They are easy to wire. Heres a guide http://www.rollitup.org/grow-room-design-setup/48068-diy-wiring-fans.html Heres how to wire two of them in parallel http://forum.grasscity.com/grow-roo...w-connect-your-pc-axial-fans-12v-adapter.html