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Can somebody help me with the CFM of the Front fan and the rear fan of the Ant miner S9 please? Thanks. 

Didn't notice all the data regarding this already in the S9 thread?

Very new here so do not know exactly where I can find things. I will go and find it now. Thank you Vrobb!!

S9 thread is here: https://bitcointalk.org/index.php?topic=1493601.0
Do a search for CFM in there and I'm sure you'll get more than you wanted!

Thank you very much Vrobb!!

If you are thinking of replacing an Antminer S9 (or S7) fan, there is more to it than just CFM. These miners are pretty "dense" in terms of their heat-sinks inside, and require a fair amount of "pressure" by the fan in order to actually push the air through the miner to the other end. Virtually all fan CFM ratings are in "free air" meaning that they don't encounter obstructions to impede the flow of air. It's easy to find a high CFM fan that fairly quiet, but when paired up to an S9 won't actually push through enough air.

The "static pressure" rating of the S9 fans are pretty high, and that's a significant part of their noise.

Indeed..that's why I use and highly recommend one of these....They are a little loud mind you..
General Electric GE90

And as a result you need to stick with the various Delta "Focused Flow" fan series (FFB or derivatives) or the VERY FEW similar fans from other companies.

 Even though they have comparable CFM ratings, I would NOT put a Delta AFB series fan on any Antminer past the S5.


 Exhaust of the GE90 is a bit hot for miner usage.
 Perhaps a CFM56?

 8-P

Thank you for mentioning this...I had little clue about it. But to tell you more about it...I am not planning on changing the fans to reduce the noise. I was originally planning below:

1) Install 32 antminers on a 8Ft X 2FT X 6 FT rack and
2) Put the racks back to back to create a hot tunnel. Leave 30 inch of distance between the two racks for the hot tunnel.
3) Put drywall on the back of the rack (Question for the experts: Is Drywall a good idea?) so only the hot air will go through the fans in the hot tunnel and hopefully there won't be any hot air leaks
4) Put fans on the top of the hot tunnel to suck out the hot air.
CHALLENGE: Now the issue or more so confusion is how much CFM exhaust should I put for the exhaust? I will have total of 2 racks on one side and 2  racks on the other so total of 4 racks and 128 miners on them in total. So that is the reason why I was asking about the CFM rating so I can figure out the exhaust...Am I even thinking right? I thought that if each exhaust is 250CFM then 250*128= 32000 so I need atleast 35000 CFM. Is there anything like more exhaust then needed? And for the intake I was planning on keeping 30000 to maintain a negative static pressure in the suction i.e. on the exhaust side

Does this design have any teeth to it? Am I even thinking in the right direction? Should I be careful about anything?

P.S. Thanks to everyone who has contributed to the post so far....

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1) Install 32 antminers
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Ok..yeah thats not going to happen
That's when I knew you are way out of your league with more money than brains and just pipe dreaming

Very good! Yes you are thinking right. What you are setting up is called 'hot-aisle/cold-aisle' and is the most common way of controlling and routing airflow in data centers. Ja figuring 250CFM per miner is a good ballpark to base total airflow needed in worst-case incoming air temps. Use multiple fans preferably with speed controls to throttle them as the conditions dictate.

As long as the incoming air temp is around 95F or less they can tolerate very high exhaust side temps of around 120F so as long as enough air is moved to get that heat out you are good.

Hardest part of you plans will be getting the miners themselves as supply is very tight from both Bitmain and Canaan (Avalons).

Mine on Dude!

When doing temp rise calcs keep in mind that every kw of miner power = 3,412.14 BTU of heat.

Thank you very much NotFuzzyWarm...

What about humidity? What aspects of low or high humidity should I be concerned about? I read that ESD i.e. Electro Static Discharge is generated when the humidity is too low. And I am thinking that the humidity will be way too low during the winter if I am sucking out the outside air. Let me know your thoughts everyone.


Thanks to everyone...

This isn't necessarily what the thread is about, but I've got an idea about heating/ventilation that I may be implementing when I start mining in October.

I plan to use two racks side by side (not back to back) to put the miners on. I'll put an insulated tarp on the back of the two racks and cut holes in it for the exhaust fans of the miners (should work better than drywall as BitcoinIntern suggested). From there I'll put two "poles" up vertical to each end of the rack, creating the frame for a small square "room". Then I'll fasten more of the insulated tarps from the pole to one end of the rack on each side, and then a tarp over the top. This should effectively create a small insulated room which you could then place an industrial portable AC in front of which would shoot cold air into the room for the miners to suck up.

It's difficult to picture but imagine a small room with a bunch of holes cut out of the back, and one hole cut out of the front to stick the AC output into. The exhaust of all of the miners can be ventilated out of the room without ever recirculating back into the miners intake, or heating the air up that the miners will be sucking in. I'm thinking that even if the room the miners were in is 100 degrees, with the insulated tarps and an industrial portable AC creating positive air pressure in the makeshift room, the miners should run as if it were only 70 degrees out, which would be extremely cost efficient. Another note, I wouldn't consider the AC and would simply use outside air as intake to the small room, but I live in Florida, so sucking in 90 degree air would be a bad idea. Let me know what you guys think.

Tarps will surely be very easy to work with. But what if the Tarps catch fire due to excessive heat?

You can buy fire retardant insulated tarps but they are very costly. Assuming you never have any part of the miners touching the tarp directly which shouldn't be difficult to do, the tarps shouldn't spontaneously catch fire. Especially if you're going to use the A/C which would keep the inside of the tarps cool. The holes that you cut for the miners exhaust may get hot, but the holes can be wrapped with fire retardant duct tape so the inside layers of the tarp are never exposed to any hot metal.

Dont use tarps. Use foam board insulation to build your hot isle. Tarps have no structural rigidity and will just make a mess of things.

Have you done this as a proof on concept in the past? Creating a hot tunnel has been a proven method. I am not sure if this would really work. You will need a lot of AC's to actually get this going. Just my thought here....I could be wrong...Would want to see what other pro miners think. Thanks.

How about Drywall? Thanks.

Those insulated foam boards are really cheap too, not a bad idea. Instead of using two poles to attach the tarps to, I could just use two more racks on either side. Use the back of them facing the inside to put the foam boards on, use the other side on the outside for storage. I wonder if they would do as good of a job though. I'd also probably still need a tarp for the roof of the structure, I don't think they make foam boards long enough.

I haven't. I would go with your idea because doing a hot/cold isle like you described with exhaust out of the top is really smart, I just don't think it would work nearly as well as my idea with an AC.

It would be far more cheap as I wouldn't have to purchase the AC, but I live in Florida, so I think if I don't make some sort of smaller insulated room within the warehouse (which will probably turn into an oven), no amount of airflow or hot/cool isle is going to keep them cool enough.

 Drywall is almost always FIRE rated, it WILL handle high heat levels if it's properly installed.
 Down side is that it's not very strong structurally - it needs a solid frame and optimally something like plywood to back it for strength, or you risk poking holes in it pretty easily.

 Foam board insulation is NOT generally fire rated (I'm not sure if fire-rated foam board EXISTS), and doesn't handle high heat levels as well.

 Tarps are a bad idea, even if they are hot temp rated - they flap around too much. Tolerable for TEMPORARY situations but I would never use one in any sort of a permanent installation.

I think you guys are in hot moist climates are in for a rude awakening...if you are not more careful.

Tarps.... bad idea
Drywall/gyproc...GOOD idea.... cheap but pain in the ass to cut nice custom holes in ...
Foam insulation..good idea..cheap easy to cut custom holes...BUT high temp fire resistant foam IS expensive...

If you think you need fire resistance chances are your op temps are so hi you miners will be dead in no time anyway..



And you still need to vent the hot aisle outside...that means ANOTHER high volume fan...
Or are you planning to just have the hot aisle exposed to the wind and rain sunshine insects etc...that would be very dumb...

And you still need to supply the sealed box (Miner house) with LOTS of CLEAN COOL DRY AIR..that will be expensive...

Don't mean to discourage you....just a reminder that operating environment has a HUGE impact on effectiveness and longevity of components.

About filtering the air, mainly just need to keep out bugs, leaves and other floating bits of Nature. Just find some of the threads about the various mines and look at their pics. Most use a wall of filter material. At home could of course use a bunch of furnace filters but best would be getting wide rolls of air filter material and support it on frames. Check McMaster (http://www.mcmaster.com/) or others for it, typically available on rolls up to 48" wide and near dirt-cheap.

If the local humidity permits that can easily be expanded to also become a very large evap cooler system... You already have the sir flow, just add a water drip or spray system along the top of the filters.

edit: If doing evap of course build the filter system to be wet....

Dry air is NOT critical - I've yet to see any miner that wasn't specified to 80% or higher humidity for operating conditions.
Just need to keep the humidity low enough that you don't get condensation at the intake.

 Furnace filters work fine - a common 20" x 20" furnace filter is an almost PERFECT fit for most common "box" fans.

 Dripping on top of those filters = VERY BAD idea, they are PAPER filters they don't handle getting wet like that.
 Might work OK with fiberglass-based filters, but those don't FILTER very well.
 They probably would work as an evap pad, but not nearly as well as a standard Aspen type pad (lots less surface area).

 
 I concede that the MINERS don't really need the good filtering I insist on - it's more about avoiding my own problems with sinus issues, especially with the very very high smoke levels my area has suffered through a lot of this summer.

@QuintLeo: I wish I were a good drawer so I could convey my idea for the tarp usage better, I can see it perfectly in my head but it's very difficult to explain to other people haha. There is a company online that makes custom tarps that are relatively inexpensive that allow you to choose the material they use for insulation. They could be sized perfectly to be attached flush to the back of storage racks that the miners will be sitting on, with holes cut directly where the miners will be sitting for exhausting the heat directly out of the "makeshift insulated room". Using them this way, the tarps wouldn't flap around at all, as they would be secured flush to the back of the racks as an insulation barrier and way to direct airflow from a portable industrial AC (http://movincool.com/portable-air-conditioners/classic-plus-26), that way the entire warehouse space doesn't need to be cooled, just this makeshift insulated room where the intakes for the miners will be.  

@NotFuzzyWarm: As far as intake air goes I won't be worried about using the garage door to suck hot Florida air in, but rather use that for exhausting the heat out. One of these (http://movincool.com/portable-air-conditioners/classic-plus-26) feeding directly into my little "makeshift insulated room" idea seems like it would work well as "intake air", that way the entire warehouse space doesn't need to be cooled, but just this tiny insulated room where the miner intakes are. Then some large drum fans exhausting all of the heat out that the miners produce, which would never be recirculated into their intakes as their exhaust would be fed directly out of the small insulated room via the holes cut into the tarps, attached to the racks.

added edit to ^^ about filters and making them into evap cooling. Again, check McMaster.

Just read your portable cool link. Along that line see those from one of my go-to companies Global Industrial Products (http://www.globalindustrial.com/g/hvac/air-conditioning/commercial-portable-ac/industrial-portable-air-conditioners-1?trackType=3&trackPrimKey=0&trackCatKey=39858&webCatKey=1751&presentType=3) Link should put you in the right area.

Note I will check filtering mentioned here we need some  as  we get bugs in the gear at times. ;D
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3 layer system and a rack for the gear


this is the rack I have 2 side by side

https://www.target.com/p/adjustable-3-tier-wide-wire-shelving-chrome-room-essentials-153/-/A-17136152?lnk=rec|slp|search_bought|slp|17136152|5




first layer is used in car engine components.  it wraps around the racks and directs air to a pair of gable fans

https://www.amazon.com/Car-Insulation-Deadener-Automotive-Lightweight/dp/B016QUS1YE/ref=sr_1_1?


second layer light duty  reflects heat
https://www.amazon.com/Reflectix-BP48050-48-Inch-Bubble-Pack-Insulation/dp/B0002YPIOW/ref=sr_1_fkmr0_2?

third layer

reflects heat and in our case prevent roof leaks

https://www.amazon.com/Heavy-Duty-Silver-Tarp-12X20/dp/B0009Q39CQ/ref=sr_1_8?s=hi&ie=UTF8&qid=1504830877



https://images-na.ssl-images-amazon.com/images/I/81p%2BpquA0ZL._AC_UL115_.jpg

https://images-na.ssl-images-amazon.com/images/I/41P%2B61BJXSL._AC_UL115_.jpg


https://images-na.ssl-images-amazon.com/images/I/617E-CqfF5L._AC_UL115_.jpg



finished product  we can do 13 kwatts with this set up.   I spent  90 + 90 + 30 = 210

  I needed a 20 foot car insulation piece  to wrap around  the 2 racks   6+6+3+3 = 18 ft  fully wrapping the two racks


we have 4 avalon 721/741  4400 watts  we have 4 s-9's 5000 watts 9400 watts 24/7/365


all three layers of insulation  the rack acts as a structure for the car insulation  this makes the loft 10 f lower  then outside temp 100f outside 90 f under the loft and three layers.

https://i.imgur.com/T0PeB5t.jpg


only the car insulation  if 100f  summer temp that loft was 105f

https://i.imgur.com/dZLTmCj.jpg

two fans from home depot

https://i.imgur.com/5em72rF.jpg

Was browsing through stuff and found this...Scary...

http://gizmodo.com/a-huge-fire-took-out-a-bitcoin-mining-operation-1655981855

I remember when that happened... never skimp out on your electrician, lol.

Could it not be a option, to open the miner. So its naked, and put som 120mm fans above it? Yes then you couldn't exhaust the air so easy.

That would void the warranty.

Not to mention would not cool the miner very well at all.... High power in small package = forced air cooling. Period.
Even if opened and the boards splayed out you still need a lot of airflow moving over the heatsinks. Use enough 120mm fans and sure, it is doable but a pretty pointless exercise in my book.

I've been also researching the cooling requirements and airflow management for my soon to arrive Antminers.  I've run across a resource that may be helpful.  It's from APC Electric which is, according to their website, the "industry-standard for reliable power and physical IT infrastructure."  

It's a whitepaper on calculating the total cooling requirements for a data center.

http://www.apc.com/us/en/support/resources-tools/white-papers/calculating-total-cooling-requirements-for-data-centers.jsp (http://www.apc.com/us/en/support/resources-tools/white-papers/calculating-total-cooling-requirements-for-data-centers.jsp)

The other resource is from a company called Upsite Technologies which is all about optimizing data center cooling.

https://youtu.be/sWinOiYqPSE (https://youtu.be/sWinOiYqPSE)

You are effectively building a very small data center and you don't have to reinvent the wheel to implement best practices to your own "mini-center".  Obviously you won't spend the kind of money big companies do but you can still take the principles of efficient energy use, airflow management and cooling techniques and creatively fit them to your needs.  Good luck and keep us posted !

APC makes some good gear - they are my VERY long time "go to" supplier for UPS systems - but that whitepaper ASSUMES the use of standard air conditioning, which is an expensive BAD choice for most miners in most of the world.

 It would be better to reference the Yahoo "Chicken Coop" data center design, which is specifically designed for low cost - or take a good look at the Gigabyte "mining shed" design and all of the other "large farm" flow-through air setups, as miners tend to handle warm temps a little better than most traditional server designs.

 Oddly enough, I had a tentative design I'd thought out and done some planning on 2-3 years BEFORE I heard of the Yahoo design - that ended up being somewhat similar but will handle open-rig miners (the Yahoo design DEPENDS on being used with rack-mount cases).