Precision AC for IT Server

[tejalr]

I'd like your views about dual fluid Vs. single fluid system
Your views and experience about CW and DX precision system
What temparature levels are maintained at IT server room, IT comm/EPABX room, IT network / DLC room, IPG demo, ESG demo (if available) and any other labs and also mention if the RH levels are corrected if so what is the range being maintained
What is the SF/TR accomplished in your buildings as you remember
Your views about Emerson, Scultz, ABB and other brands
What are the key 3 to 5 parameters in your opinion to be evaluated / addressed

 

[danmsnyder]

I don't have any info on Precision Systems, but I would go with the dual fluid if that means 2 cooiling loops, for redundancy.
I would also recommend 100% redundancy for the critical areas, which the IT department would say is everywhere. Each unit sized for 100% of the load. We maintain a temperature around 70 deg F and about 50% rh, the specs are on every component in the computer network.
Cool Air, Liebert, and APC have good systems. Emerson has a good reputation.

Key concerns:
1.Temperature control
2.Reliability
3.Humidity control
4.Ease of repair (quickness)
5. Internal redundancy, i.e. two compressors for DX units with dual loops, 2 belts on the supply fan, 2 or more fans on condenser section.
Also try not to locate over any critical equipment, if ceiling mounted, if they are, specify drip pans under every unit.
Humidity control can be difficult since the only way most units dehumidify is throught cooling and then reheating air. In the summer you may have 65 deg F and 55% rh.

Remember to bring in fresh air from your main system.

I don't know what SF/TR means, please clarify.
Also if you are installing units to run off of your chilled water loop you may want to install 1 dx unit as a back up if you lose chiller, pumps, ect.
They will probably want the units on backup emergency generator.
Good luck

 

[5501463]

Dual sytem is good in areas where the ambient temperatures go very high whereby the cooling effeciency is considerably affected, like middle east. Such times the CW precision system can be put into operation and other times DX can be used. Also the system can be used as a back up in case of emergency. Why this is called a Precision because it takes care of the sensible heat generated in these areas. the temperature maintained in these area is 20 degree C and humidity rh50%. I suggest you go for Stulz Precision A/C from Germany or Uniflair from Italy.
What is this SF/TR you are refering to?
Goodluck