Question about proper rack airflow

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amrogers3

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Hopefully, this is the correct spot for this question....I am planning on mounting a Cisco 24 port PoE switch. 350X-24MP. Looks like it will generate a bit of heat.
  • power comsumption is 468W and dissipation is 1607 BTU/hr
Going to mount a rack to the wall in a closet that is about 6' wide x3' depth x10' height. The rack is roughly 30" wide and closet is 36" across which will only give the rack about 3" on each side and 2" from the ceiling.

Is this space too tight to get proper airflow?

It's this rack: https://www.tripplite.com/smartrack...osure-cabinet-wide-acrylic-window~srw9udpgvrt

Diagram of install:

9dxHJQW.png
 
The recommended distances are usually in the products owners manual, but since this is an enclosed rack, the bigger problem is if there is enough fans on the rack to remove the heat and feed in fresh air.
 
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SamirD said:
The recommended distances are usually in the products owners manual, but since this is an enclosed rack, the bigger problem is if there is enough fans on the rack to remove the heat and feed in fresh air.
Click to expand...

Manual isn't very specific on distances:
Code: 
Leave adequate space at the front and rear of the enclosure for proper ventilation. Do not block, cover or insert objects into the external ventilation openings of the enclosure.

Should the fans be pointed in or out?
 
amrogers3 said:
Manual isn't very specific on distances:
Code: 
Leave adequate space at the front and rear of the enclosure for proper ventilation. Do not block, cover or insert objects into the external ventilation openings of the enclosure.

Should the fans be pointed in or out?
Click to expand...
Fans work best blowing at. The direction depends on which side of your gear the fans are.
 
amrogers3 said:
Manual isn't very specific on distances:
Code: 
Leave adequate space at the front and rear of the enclosure for proper ventilation. Do not block, cover or insert objects into the external ventilation openings of the enclosure.

Should the fans be pointed in or out?
Click to expand...
Wow, usually they're more specific than that. In your diagram, you have directions for what looks like airflow--is this what the stock fans do? If so, where does that air vent out of the unit?
 

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amrogers3 said:
If I understand your question, you asking how the air vents out? Picture would probably explain better.

https://www.tripplite.com/smartrack...osure-cabinet-wide-acrylic-window~srw9udpgvrt
it's got fan placements on top, bottom, and sides.
View attachment 413657
Click to expand...
You know, now that I re-read your question and look at the diagram, it makes a little more sense.

So I think your bigger problem will be--will the closet door be opened or closed? Because if it's closed, and there isn't any type of cool air source in that closet (ac vent), you basically have a self-heating system in that closet with no place for the warm air to go.

Now, that being said, if you're not worried about fan noise, power usage and the like, I've seen enterprise level equipment run in 100F for years with fan screaming.
 
Where is your cool air source and in what direction do the devices that will be mounted in the rack move air? Ideally you want to match the cabinet airflow with the equipment airflow. If you can't do that then cabinet airflow should be bottom to top so that physics is providing an assist. If you have any equipment with intakes on the side the arrangement in your diagram is very much not ideal. You should avoid pulling cool air away from the intakes of equipment.
 
Nicklebon said:
Where is your cool air source and in what direction do the devices that will be mounted in the rack move air?
Click to expand...

There is no cool air source, just ambient air in a closet 6' x 3' x 10'.
I dont have the unit yet, it should arrive Friday, but looking at pictures it looks like it has fans on the left side and vented grill on the right. Looks like may house 5 fans on left side.
SG350X-24MP-K9-NA_2048x.jpg


Not sure if it is sucking air in or blowing it out.

The rack is capable of mounting fans on the side as well as top and bottom mounts. Would airflow be right to left and bottom to top in this case? Im afraid of creating a heating loop by dragging warm air back in the case.

srw9udpgvrt-other01-2xl.jpg
 
amrogers3 said:
There is no cool air source, just ambient air in a closet 6' x 3' x 10'.
Click to expand...

Well as Samir says earlier in the thread if there is no air exchange, or very little, eventually your closet will reach equilibrium at or near the inside of the switch temps. You need to have somewhere for the hot air to go and be replaced with fresh air. As for flow direction Cisco is pretty notorious about right to left on non-NEBS equipment. So ideally your right side fans should blow "fresh/cooler" air into the case while the left side pulls the hot air out. As for heating loops ... I could tell you about a stupidly expensive, >$1.5M, chassis based firewall cluster solution that was racked by idiots. The chassis were placed side by side in adjacent racks pulling air right to left. The left chassis would overheat and shut down after about 45min.
 
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