Datacenter ccoling and Airflow discussions

[BillP]

We have been working on datacenter audits especially on airflow at subfloor and woud like to understand easy measures to analayze whether a CRAC units is actually working at a derated capacity or not. This is very crucial for countries like India where majority of the times the service component of CRAC units is least looked after and hence we have seen CRAC units working at derated capacities to the tune of 65% at times!

Just as ane xample we found that the inherent delta T for the CRAC unist at majority of sites where having the following readings:
CRAC (RAT :Return Air temperature): 22 degree C -- 71.6
CRAC (SAT: Supply air temperature): 18 degree C -- 64.4

If we see according to Celsius scale at is hardly 4 degree delta which is not normal and indicate derating of CRAC and ideally we feel it should be atleast 8 degree C.

What do you feel?

[upsguy_apc · Accepted solution]

A delta of 4C is horrible.... I suspect you have no targeted return air ducts and large amounts of supply/return air mixing.