Heat gain from a Catalyst 9200-48P switch

[DavidHemmings7544]

I'm in the process of designing a cooling system for an IT room housing a number of Catalyst 9200-48P switches, and I'm trying to understand what the heat load within the room will be. The unit has a 1000w power supply, and can supply a maximum of 740w to PoE devices. The PoE devices will be outside the IT room dispersed around the building. I need to size the cooling system to meet the maximum possible load for these units, but also need to be careful to not hugely oversize it.

My interpretation of the maximum cooling load that the room system is likely to see is that it would be the rating of the power supply minus the PoE capacity, with a small allowance for heat from PoE cabling. The datasheet for the switch lists a heat gain of 1000w, but I'm thinking this is the total dispersed around the building and not actually the gain at the switch itself. If I just size the cooling based on this 1kW figure, it seems likely on this basis that the system will significantly oversized.

is there any Cisco guidance on this? The datasheet doesn't seem that helpful!

[Seb Rupik]

Hi there,

The hardware install guide gives the BTU values ("total output BTU") for the power supplies. You should use these to base your HVAC requirements on.

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9200/hardware/install/b-c9200-hig/b-c9200l-hig_appendix_0100.html#reference_mh1_gdw_mfb

cheers,

Seb.

[DavidHemmings7544]

Thanks Seb. 

The 3412BTU/h figure is the same as the power supply rating for the switch (1kW); however, 740w of this 1000w is being supplied to PoE equipment outside the room I'm looking at. If I size the cooling in the space based on 1kW for each switch, am I not going to be over sizing the equipment?

Thanks

David

[abiryuko]

Hello!

I'd recommend you using Cisco Power Calculator https://cpc.cloudapps.cisco.com/cpc/ It's providing more accurate data, taking in consideration the number and Wattage of connected PoE devices.