This question was originally posted on DCIM Support by Valentin Kozlov on 2018-07-23
Now I'm configuring DCO for our customer.
There is centralized cooling solution on site and air distributed to server room via grilles placed under floor and on the walls.
So I decide to model it with Vertical Grilles.
I've place Grilles on the wall, perforated tiles on the floor and set up measured airflow values fot it. It looks cool but I have an issue "Floor tiles imbalance: Measured airflows do not up to floor plenum supply airflow."
And there is message in recommendation tab "There is no perforated tile airflow. Consider adding a CRAC"
What does that mean? Any ideas will be appreciated.
I've tried to play with airflow on wall grilles, but with no luck.
Is there detailed description how our alghoritm works or someone can tell me how to set up such config properly?
This answer was originally posted on DCIM Support by Christopherus Laurentius on 2018-07-25
Try adding an 'imaginary' CRAC (or several to better model the cold air distribution) outside of the wall where your vertical grills are located, similar to below but with vertical grill for hot air return and no ceiling duct:
Also, you may want to leave the vertical grill & perforated floor airflow empty, or at least some of them empty, so DCO can calculate those, based on the CRAC you add , racks etc.
-putting this as comment, to see if anyone else have ideas how to best model this.
This comment was originally posted on DCIM Support by Valentin Kozlov on 2018-07-25
Thanks for your reply!
After series of tests, I've found out that I need to consider raised floor leakage.
So, Supply airflow = Floor tiles airflow + (Floor tiles airflow*Floor leakage).
Drop ceiling leakage is not considered.
I think it's strange that we have no info about how our cooling model works. Because it's important part of capacity planning.
My customer tell me "I know that in row A I have 50 kW electrical power but only 35 kW cooling capacity. How DCO can tell me about that?". And I dont know how to answer...
This comment was originally posted on DCIM Support by Christopherus Laurentius on 2018-07-26
Glad you got that sorted out.
On cooling capacity, the figures in kW is on room level, based on total available CRAC cooling capacity.
Not exactly cooling kW capacity at row/rack, but DCO does provide the breakdown on cooling at rack level using capture index to indicate % cold air (from CRAC) captured by the rack, and % of the rack's hot air captured by CRAC
-leaving this as comment, let's see what others can add here.
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