Airflow needed to keep server room cool? 2

[dalchri]

I have a closet that will house the servers for our company. I would like to keep the closet cool using the air from the office and would like to know what kind of a fan I'll need.


Room size: 5ft x 13ft x 8ft(if that matters)

Heat generated by equipment P = I x V = 15A x 120V ~ 2000W (6 computers, 2 UPS’s, 8 network switches)

Input air temperature: 75ºF (average summertime office temperature)

Desired maximum room temperature: 90ºF

What CFM airflow is needed?

Just looking for a rough estimate. Thanks for your help!

 

[MintJulep]

BTU = 1.04 x CFM x (90 - 75)

Convert your heat generation from watts to BTU. Any monitors?

Don't forget that the air has to be able to leave the room.

 

[friartuck]

Good old Q=mc DT

Q=2kW
m=mass flow rate kg/sec
C=SHC specific heat capacity 1.01kJ/kGK
DT=temp differential (90-75=15F or about 8C)

mass flow of air = 2/1.01x8 = 0.247kg/sec (approx due to temp round up)

Density = mass/vol vol = mass/density

so 0.247/1.205=0.20m3/sec

200 litres/sec of air

a simple wall fan like a 12" Vent Axia would do it but as mintjulep says, what goes in must come out, so you will also need an air relief grille or another fan.




Friar Tuck of Sherwood

 

[dalchri]

Its nice to have a consistency check. It occurred to me that the air conditioner that is in the current room is 7200 BTU so that capacity is what I'm matching.

mintjulep's formula yields ~500 cfm which is consistent with your result.

Thanks for the help!