We have a small mini rack which houses an X-Serve, Raid and Router. We added some more high performance fan units but still find that it gets quite hot in there and have recently been having to keep the door open.

Can anyone recommend some kind of cooler device which can be installed in here?

The rack sits in our studio so it can't be too noisy. The back door is also solid, so it can not vent out there. The top of the unit has two fan holes, this could be used for the venting.

UPDATE: This is a link to the rack in question. http://www.startech.com/item/2636CABINET-DuraRak-Professional-15U-Enclosed-Cabinet-with-Plexiglass-Front-Door.aspx


7 Answers 7


What kind of rack has solid front and back doors? Seems like a design flaw. Up above you say that the rack is 3 inches tall, do you mean 3 feet? Can we get pictures of this setup to get a better idea of what we are talking about?

  • Oops, yes it's 3 feet tall. Let me see about picture.
    – Louis W
    Oct 9, 2009 at 22:15
  • This is the box. startech.com/item/…
    – Louis W
    Oct 9, 2009 at 22:17
  • Just realized there is a vent panel in the back, never saw it back there... Seems like we could just add more fans in there.
    – Louis W
    Oct 9, 2009 at 22:34
  • 1
    Stop adding fans. The problem is bigger than just nailing as many fans as possible to the unit. I have a mental image of a Frakenstein rack with fans poking out of every available orifice.
    – Izzy
    Oct 9, 2009 at 23:52
  • Is there any way you can send that thing back? That design is insane... I can't imagine that ever moving enough air... and that price for a 15 U rack is not good. This would be much better for you... dell.com/us/en/business/servers/server-poweredge-2420/… This is a square-hole 46cm (18") rack. I don't know if Xserves utilize rails for square hole racks or not, but in any event, you can buy a tin of cage nuts to allow mounting of rails & hardware that require screw holes.
    – Adam C
    Oct 12, 2009 at 23:48

The top of what unit has holes? The cabinet? That's insufficient, really.

If you can't vent, you can't cool. That heat has to go somewhere. You can't get rid of the thermal energy, you can only move it. If your only vent is outside the cabinet, then you're effectively just using your office's air as a really inefficient thermal heatsink and your building's A/C to cool the computers.

If you do have somewhere you can vent the heat to, though, there are "portable" or "spot" air conditioners. (MovinCool is a manufacturer that I'm familiar with.) Effectively, they're like window-mounted air conditioners, except they're mounted in a chassis with wheels, and the heat venting is usually through a hose, like a dryer hose.

However, air conditioners are dehumidifiers. It will "generate" water, which you'll have to find a way to dispose of. Most units have removable tanks that allow you to take the water and pour it down a drain somewhere. Some have automated pumps, but you still have to provide a drain. Or carpet you don't mind being wet all the time.

  • The rack is about 3 inches high, glass front door, solid back door, 2 fans on the top. These were replaced for high performance ones but not sufficient. We have taken to keeping both the back and front door open to try to get more air moving in there.
    – Louis W
    Oct 9, 2009 at 21:54
  • "I think that the problem may have been that there was a rackmount cabinet in the studio that was in danger of being crushed by a dwarf."
    – wfaulk
    Oct 9, 2009 at 22:39

CoolCube 10 - rackmountable AC unit. We have a bunch of them and they're decent units.

  • Okay, that's cool. No pun intended.
    – wfaulk
    Oct 9, 2009 at 21:50

Sounds like a bigger problem than just cooling the rack... ideally, you should move the rack to somewhere where noise isn't such a problem.

Also, between an Xserve and a RAID, they should really be in a rack that's open (fully vented/mesh front and rear doors) if they're not cooled with forced air.


From your question I come uiup with the following conclusions:

  1. The rack appears inappropriate for servers use. It was possibly intended more as a switch/hub rack.
  2. The rack is inappropriately located. It shouldn't matter if it's a bit loud.
  3. The fan units may possibly not be optimally located within the rack or the airflow pattern is not or cannot be suitable.

The first two items you'll need to deal with yourself. As for the third item, look at how the air will flow. Can that be improved? Does the rack provide for an adequate amount of air both entering and leaving the rack? Should you throw it away and get something more suited to your needs?


There is also the (currently unpopular) idea of just running things hot. Check your system's documentation for descriptions of the temperature range it will tolerate. For example, Dell has confirmed that their systems are warranted to perform at a 32 degrees Celsius (90 degrees Fahrenheit) inlet temperature.

James Hamilton's blog touches on this idea periodically from an environmental (green/sustainability) standpoint -- here is an example which refers to Dell specifically.

There are downsides. Failures will be at a slightly higher rate, and individual system noise will probably be higher due to increased fan velocities. And your tolerance for a heat rise is much less, meaning you have to act faster if things start to get unexpectedly warm.

But it is an option.

Now I've never done this myself, I'm still attached to my A/C -- but I'm thinking about it for future deployments.


Confirm that you actually have a problem first...

ASHRAE (the professional society for HVAC) performed several studies in cooperation with several major IT vendors and determined that around 85 degrees F, measured two inches from the server air intake is recommended, and peak temps can go well beyond that.

The temperature behind the rack is irrelevant.

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