Server Closet Cooling - Intake Fan Recommendations?

[Redcoat]

• No, not significant.
• Of course, that Enclosured Area is by no means air tight, i.e. the warm air will cool and descend between the studs, escaping at outlets, wall switches, light fixtures, and surely other crevices I haven't thought of (as well as other ways).

• Create a passive vent to the utility closet from the Server Closet or the Enclosed Area?
• The way, I read your post is to cut a vent from the Server Closet to the Utility Closet and that the fan is worthless in extracting air and the only air "extracted" would be that which convection drives.

Create a passive vent to the utility closet from the enclosed area into which the fan discharges. No it's not airtight but it will clearly have resistance.

Just for fun go here and select your model and its rated capacity of 100 cfm and see how much smooth 4" duct you can put on the 4" outlet...

 

[svtkobra7]

Create a passive vent to the utility closet from the enclosed area into which the fan discharges. No it's not airtight but it will clearly have resistance.

Just for fun go here and select your model and it's rated capacity of 100 cfm and see how much smooth 4" duct you can put on the 4" outlet...

• 10-4 regarding vent.
• You are a fan ninja!
• @100 CFM: "Specified system is not likely to achieve the design flow. Please vary the inputs to identify a compliant system."
• @90 CFM:
• 

The duct length I have in there at the moment is 8" before an elbow.

My initial hesitancy to use a "real" fan: (a) fan is already installed and (b) limited height available above closet ceiling.

I was thinking about it though and I did figure out a way to put a max 12" fan up there:

• If I nudged the HVAC branch over a tad, I could mount to the studs above the door.
• I would probably want to "enclose" that ~41" wide x ~26" deep area directly above the closet ceiling with sheetrock and add Roxul for sound deadening.

So, if:

• you still think a "real" fan is needed (and I'm sure you do if I do);
  
• and, if one can be used that I can't hear outside the closet (with mentioned install conditions);

and, considering:

• continued discussion regarding its inadequacy;
• @tvsjr 's experience;
• and, the consideration that I've put a bit of time into this so I may as well do it right;

and, you want to recommend the following:

• Appropriate fan;
• Thermostat for variable speed;
  
• and, Appropriate vent;

let's consider this done. I don't think you would still recommend the Broan L200L, right?

 

[svtkobra7]

Hopefully my ramblings will benefit you somewhat :)

• I hate the fact that you have had so much trouble, but I loved reading your "rambling" and find it very useful information.
• I'm a bit jealous of your set up, but would suggest you have very good taste in processors, motherboards, and boot drives (I run the same). :)

If I go close the door and seal the room right now, ambient air temperature will increase 20 degrees in about 60-90 seconds.

That is nuts.

At this rate, even with HVAC, a 1-2min power outage can be a Big Problem

I was going to say jokingly that you should put that HVAC on a UPS, but then read your comment about the diesel generator.

Now, what I expect was happening (but never proved through the use of colored smoke/etc.) was that air was flowing from the inlet directly to the exhaust, largely bypassing the pocket of hot air being created behind the servers. I was hoping the box fan would introduce air with enough velocity to push this air out, but apparently not. The path of least resistance would be straight out the exhaust.

• I put colored smoke on my to buy list, as I can see many non-server related use cases that would be fun. It is funny that you mention that, as in lieu of colored smoke, I always attempt to take a large hit from my vaporizor and exhale when I'm attempting to see airflow. That approach is somewhat flawed as expelling the "cloud" induces flow itself. BTW, vape as in nicotine (how I quit smoking years ago) not Mary Jane.
• Fair conjecture here (path of least resistance), but does it work like that? That cool air can't just zip straight to the ceiling displacing less dense air. I'm not really doubting your supposition, as clearly you know your stuff, rather asking for my own understanding.

My potential solution to this (negating the issue of the loss of conditioned air to atmosphere) would be to seal the system in some sort of cabinet. Ensure that the ONLY air in is from the conditioned supply (through the front) and the ONLY air out is through the exhaust vent (through the rear). Assuming you can balance the intake and exhaust fans (variable speed fans would be best here) there should be no static pressure issues to deal with (intake should "push" with the same pressure the exhaust "pulls").

• I reached the conclusion recently, after researching sound deadening, that in order to have optimal thermals and acoustics, outside of a datacenter, servers really need to be in one of these guys. Unfortunately, they are rediculously expensive.
• Make sure CFM in/out is balanced, we wouldn't want an implosion or explosion (joking).

But, with all that said, I'm just going to drop a 1-ton low-ambient ductless mini-split AC in and call it a day. Eventually, I'll add a sufficiently large diesel generator to run the whole house.

• So awesome that you can do this. I think you should take it a step further and build a datacenter in a bomb shelter in the back yard. I look forward to eventually moving and buying a single family detached home for future datacenter conversion (seriously - there is only so much you can do with a condo, generally and on this topic).
  
• I didn't realize that these could be had for a reasonable price. I was looking (briefly) and found some under $600.

 

[tvsjr]

I was going to say jokingly that you should put that HVAC on a UPS, but then read your comment about the diesel generator.

Yep, not done yet, but it's in the plans. The panels are set up for it. I've got 2x320A panels, so it's going to take a fair amount of ATS and generator. We also don't have natural gas in this area (nor do I want to depend on the NG pumps working) so I'll be going diesel with a few hundred gallon tank. With a hush kit, it shouldn't be too noisy.

I put colored smoke on my to buy list, as I can see many non-server related use cases that would be fun. It is funny that you mention that, as in lieu of colored smoke, I always attempt to take a large hit from my vaporizor and exhale when I'm attempting to see airflow. That approach is somewhat flawed as expelling the "cloud" induces flow itself. BTW, vape as in nicotine (how I quit smoking years ago) not Mary Jane.

UGH. You've got no idea what nicotine does to sensitive electronics, fans, etc. over time. It's bad. Not to mention what the formaldehyde does to your lungs.

Fair conjecture here (path of least resistance), but does it work like that? That cool air can't just zip straight to the ceiling displacing less dense air. I'm not really doubting your supposition, as clearly you know your stuff, rather asking for my own understanding.

I think it can, since there's an exhaust fan running. The hot air is (instantaneously) not much warmer than ambient, so there should be minimal difference. It's the reingestion of that hot air back into the servers, heating it further in a nearly closed loop, that causes the heating/thermal runaway.

I reached the conclusion recently, after researching sound deadening, that in order to have optimal thermals and acoustics, outside of a datacenter, servers really need to be in one of these guys. Unfortunately, they are rediculously expensive. Make sure CFM in/out is balanced, we wouldn't want an implosion or explosion (joking).

Yep, although cabinets aren't intended to be thermal or acoustic management devices. When we remodeled the house, that closet got rock wool insulation in the walls and the floor (two story house). I'm going to add a solid core door when I do the HVAC, and some MLV on the walls. Done properly, and with the servers nice and cool and set to low speed on the fans, it should be barely perceptible. The closet is in the center of the house, directly above the entryway, near the master, and on the hallway to her office/sewing room. As you can understand, the WAF (Wife Acceptance Factor) is critical.

• So awesome that you can do this. I think you should take it a step further and build a datacenter in a bomb shelter in the back yard. I look forward to eventually moving and buying a single family detached home for future datacenter conversion (seriously - there is only so much you can do with a condo, generally and on this topic).
  
• I didn't realize that these could be had for a reasonable price. I was looking (briefly) and found some under $600.

I know a guy that has a SCIF in a shipping container in his back yard (he does "things" for "people"). So that's pretty close.
As far as the AC, it's more like $2K. This isn't a spot cooler. It consists of a condensing unit outside and an interior unit... but rather than having a separate air handler, it's all integrated in the inside unit. Also important to have a unit that's "low ambient"... basically, designed to run in low outside temperatures without freezing up. These units can go down to -18F, which, in Texas, is plenty sufficient. Obviously, even in the depths of our winter, the servers will still be producing heat and need to be cooled. These units are also inverters, so rather than being on or off like most home ACs (or maybe two-speed), they can dynamically adjust their fan and cooling to meet the need. So they basically run all the time, but at a very reduced power level.

I wish I could figure out an easy and quiet way to reuse that heat... in the winter months, I could dump that in the house and likely not need much heat at all. But, short of a big blower that would create lots of unacceptable noise, I can't find a good way to do it.

 

[svtkobra7]

UGH. You've got no idea what nicotine does to sensitive electronics, fans, etc. over time. It's bad. Not to mention what the formaldehyde does to your lungs.

• I know I know ... the fiance has made me start tapering the mg/L down. Vaping is the lesser of two evils by far (when compared to smoking).
• I'd imagine formaldehyde is good for your lungs in that it preserves them? Seriously though, the studies I've read suggest it is only produced at a high voltage (and the threshold I saw, I stay well below).
• The nicotine is bad for electronics or smoke from cigarettes? A puff of vape in a cloud should only contain the tiniest amount of nicotine. Further, it isn't as if I go around vaping into all of my electronic devices. ;)

MLV ... WAF

• Alright, nice a man who knows what mass loaded vinyl is ... let's chat.
• What do you think of wrapping my SC836 in it? Obviously I would need to work around the rails, front, and rear, but I'm not looking to soundproof, only pick up a few dB. I considered adding another layer of rock (and researched all of the techniques for sound abatement), but with that door intake there, the law of diminishing returns has probably already kicked in as to further reducing the sound at the room level, and I have started to think about attacking the source. Every vent on the chassis is already sealed, so aside from marginal cooling provided to the server by radiation, I don't think this effects its ability to stay cool. A good bit of air is moving in and out and that should be doing 99% of the cooling, not radiation from the chassis.
  
• Even though I will be using a gap under the door for air intake, do you think if I were to go solid core I drop a few dBs? I know that airflow / sound sit in juxtaposition.
  
• Regarding WAF, I was thinking earlier you must have the coolest wife in the world with her "allowing" a datacenter.

I know a guy that has a SCIF in a shipping container in his back yard (he does "things" for "people").

• I had to google SCIF ... now I'm damn curious.
• Texas, eh? I spent a year out there ... And you are worried about NG? You are swimming in it. Point noted about not relying on infra of course.
• Integrate water cooling into your whole house, so you could primarily cool the servers, but then reuse the heat in the winter. That would be a project.

 

[Redcoat]

• 10-4 regarding vent.
• You are a fan ninja!
• @100 CFM: "Specified system is not likely to achieve the design flow. Please vary the inputs to identify a compliant system."
• @90 CFM:
• View attachment 19435

The duct length I have in there at the moment is 8" before an elbow.

My initial hesitancy to use a "real" fan: (a) fan is already installed and (b) limited height available above closet ceiling.

I was thinking about it though and I did figure out a way to put a max 12" fan up there:

• If I nudged the HVAC branch over a tad, I could mount to the studs above the door.
• I would probably want to "enclose" that ~41" wide x ~26" deep area directly above the closet ceiling with sheetrock and add Roxul for sound deadening.

So, if:

• you still think a "real" fan is needed (and I'm sure you do if I do);
  
• and, if one can be used that I can't hear outside the closet (with mentioned install conditions);

and, considering:

• continued discussion regarding its inadequacy;
• @tvsjr 's experience;
• and, the consideration that I've put a bit of time into this so I may as well do it right;

and, you want to recommend the following:

• Appropriate fan;
• Thermostat for variable speed;
  
• and, Appropriate vent;

let's consider this done. I don't think you would still recommend the Broan L200L, right?

No, thanks - I don't want to make those detailed recommendations based on the dialog capability here.

While I enjoyed the basis and originality of the exercise where you investigated and reported on the cooling examination you made on your server, I guess I've become disenchanted that the diligence and self-sufficiency that you seem to have deployed there have deserted you here. Despite the mass of comment, experience-based advice, analysis and re-analysis based upon seemingly unfolding design decisions, and my displays of personal bias and prejudice (and maybe those of others) that you have received, all giving you a panoply of choices and considerations, you seem to be unwilling to make decisions and embark on a trial and error process that will get you to a comfortable place.

@MatthewSteinhoff gave you the best set of advice I have seen in this thread - I'd go with his horizontal mount solution, bracketed appropriately (surely even "shelf brackets" would do?). He and @BigDave talked to you about ventilation options. I tried to clue you in on considerations on fans, fan selection, fan system performance aspects, and a bit on fluid flow and the associated physical laws. I think we're all here to teach you to fish.

In the end it's on you to make some decisions and live with them.

Oh, the L200L - I looked for that as a continuous duty rated unit equivalent to the non-continuous duty rated unit you installed that you earlier indicated was performing adequately:

hrm ... I may not have much of a problem to solve ...

She has been suffocating in the closet with the door closed and no intake for the past hour. Regarding HDD temps, of those 60 minutes, only 4 were spent above 40C @ 41C and then the full speed fan profile kicks in to knock them back down. Ambient outside the closet is ~80F. Ref fan script log below (from 6:47 - 7:05 I was running a stress test in a 32 core VM I spun up, not that should drive up HDD temps, but def ambient in the closet).

When I say no intake, I mean no intake. I covered the closet floor with cardboard and taped it down cleanly with painter's tape (to protect the hardwood) so that takes up ~1/8" of the gap between the door and the floor. On one end of the door their is less than 1/8" of a gap and on the other no gap. I can feel the suction when I put my face at the floor. This is with no ceiling installed.

So, what does this look like with a ceiling installed (and even that crap fan I bought on) and the cardboard removed to allow here to breathe (without a separate air intake or maybe a tad of that door shaved to allow more air).

Code:

Jul 07 17 18:34:00 | Tmin,avg,max = 35,36,39°C | FAN MODE: [04]HEAVY I/O CHANGED TO [00]STANDARD
Jul 07 17 18:36:00 | Tmin,avg,max = 35,37,39°C | FAN MODE: [00]STANDARD NOT CHANGED
Jul 07 17 18:37:00 | Tmin,avg,max = 35,37,39°C | FAN MODE: [00]STANDARD NOT CHANGED
Jul 07 17 18:38:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [00]STANDARD CHANGED TO [04]HEAVY I/O
Jul 07 17 18:39:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:40:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:41:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:42:00 | Tmin,avg,max = 36,37,39°C | FAN MODE: [04]HEAVY I/O CHANGED TO [00]STANDARD
Jul 07 17 18:43:00 | Tmin,avg,max = 36,37,39°C | FAN MODE: [00]STANDARD NOT CHANGED
Jul 07 17 18:44:00 | Tmin,avg,max = 35,37,39°C | FAN MODE: [00]STANDARD NOT CHANGED
Jul 07 17 18:45:00 | Tmin,avg,max = 36,37,39°C | FAN MODE: [00]STANDARD NOT CHANGED
Jul 07 17 18:46:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [00]STANDARD CHANGED TO [04]HEAVY I/O
Jul 07 17 18:47:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:48:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:49:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:50:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:51:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:52:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:53:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:54:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:55:00 | Tmin,avg,max = 36,38,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:56:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:57:00 | Tmin,avg,max = 35,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:58:00 | Tmin,avg,max = 35,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 18:59:00 | Tmin,avg,max = 35,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 19:00:00 | Tmin,avg,max = 35,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 19:01:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 19:02:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 19:03:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 19:04:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED
Jul 07 17 19:05:00 | Tmin,avg,max = 36,37,40°C | FAN MODE: [04]HEAVY I/O NOT CHANGED

 

[tvsjr]

• Alright, nice a man who knows what mass loaded vinyl is ... let's chat.
• What do you think of wrapping my SC836 in it? Obviously I would need to work around the rails, front, and rear, but I'm not looking to soundproof, only pick up a few dB. I considered adding another layer of rock (and researched all of the techniques for sound abatement), but with that door intake there, the law of diminishing returns has probably already kicked in as to further reducing the sound at the room level, and I have started to think about attacking the source. Every vent on the chassis is already sealed, so aside from marginal cooling provided to the server by radiation, I don't think this effects its ability to stay cool. A good bit of air is moving in and out and that should be doing 99% of the cooling, not radiation from the chassis.

Your noise is coming from the intake and exhaust fans which, by definition, are open to the outside world. I give this a "meh".

• Even though I will be using a gap under the door for air intake, do you think if I were to go solid core I drop a few dBs? I know that airflow / sound sit in juxtaposition.
  
• Regarding WAF, I was thinking earlier you must have the coolest wife in the world with her "allowing" a datacenter.

Only you can determine that. As far as the wife, she got a 700sqft office/sewing room complete with an 8x8 walk-in closet and a full bathroom. I got a 250sqft office with a reach-in closet and a 32sqft hall closet for my nerd toys. She wins.

• I had to google SCIF ... now I'm damn curious.
• Texas, eh? I spent a year out there ... And you are worried about NG? You are swimming in it. Point noted about not relying on infra of course.
• Integrate water cooling into your whole house, so you could primarily cool the servers, but then reuse the heat in the winter. That would be a project.

Ha, curiosity killed the cat. And yes, I'm not worried about NG supply, but about the infrastructure to deliver it to me. There are many tanks of diesel sitting around... even if the zombie apocalypse happens, a simple transfer pump can pull fuel out of tanks.