Data Center Uptime Institute Tier Topology

[RonShap]

For those familiar with the Uptime document, I'd appreciate your opinion. The terminology used below is directly from the document and does not always reflect reality.

Data center with a "N" steady generator load of 10MW. Since it is specified as a Tier III topology, there is "N+1" generators (Uptime calls "active capacity components") paralleled to allow for concurrent maintainability to the generators. The utility power path to the equipment (Uptime calls "alternative distribution path") will allow for concurrent maintainability for the generator parallel SWGR (Uptime calls "active distribution path").

Uptime's Data Center Site Infrastructure Tier Standard: Topology "standard" indicates that engine generators for Tier III sites shall have no limitation on consecutive hours of operation when loaded to "N" demand.

http://uptimeinstitute.org/index.php?option=com_docman&task=doc_download&gid=82

Since this is a standby application and the specified generators are standby rated, the ISO 8528 standard indicates "standby power" as Power generation for a limited period under variable load. It can work 200 hours a year under 70% load in average. It is used as standby power supply in case of municipal power failure. It must not be overloaded.

So .... sorry for being long winded, due to the time limitation of the standby rating, if I use 2.5MW generators, do I need six or seven to handle the project? I think it is seven if I use the 70% derating (some manufacturers will rate their's higher than 70% of Standby for unlimited running for the outage, but that si neither here or there for competitive bidding).

Thanks

 

[jghrist]

I would get clarification from the owner. You may be the only bidder making a conservative interpretation of the specifications. Someone will surely bid five 2.5 MW generators to get N+1 for 10 MW of load. If this is acceptable to the owner, it will be difficult to compete with your interpretation.

You could also interprete the requirement for no limitation on consecutive hours of operation to mean you have to have enough generators to run 10 MW continuously for 8760 hours. Meaning you need a whole bunch of generators that can only run 200 hours per year each.

 

[ScottyUK]

At 2.5MW you could likely install prime-rated or baseload generators and use five of them instead of seven standby sets derated to 70% output. The installed cost may not be far apart (savings in civils, switchgear, etc offset against the higher cost of the prime set).

Submit a TQ to the client regarding his requirements, then detail exactly what you are proposing and why. Mis-interpreted specs can sink a bid.


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