39
TOTALCOSTOFOWNERSHIP
EVALUATIONFORDATACENTERS
UsingMulti-ModeUninterruptiblePowerSupply (UPS)Systems
There isn’tadatacentermanagerwho
isn’tworriedaboutbalancing the
enormousenergyconsumptionand
costsof runningadatacenterwith the
rightmixofenergyefficiencyand
reliability.
Someestimatesproject thatdata
centersconsume two to twoandahalf
percentofall theelectricitygenerated
in theUnitedStates
(1)
. Manydatacenter
energyconservationeffortsbeginwith
someof the larger information
technology (IT)systemssuchasservers
and relatedequipment thatuseup to
55percentofadatacenter’senergy,
followedby30percentconsumedby
coolingsystems tokeep the facility
operational
(2)
. Next in lineare
uninterruptiblepower supply (UPS)
systems thatcanconsumeup to 12
percentofa typicaldatacenter’s
energy through theenergyandheat
lost related toalternatingcurrent (AC)
todirectcurrent (DC)power
conversion.
On theother sideof theenergy
consumptionequationareenergy
qualityand reliability. Aside from the
costofutility-providedenergy, data
centermanagersareequallyconcerned
with the reliabilityandqualityof that
power. Forexample, serversandother
ITequipmentcanbeverysensitive to
fluctuationsor inconsistencies in the
qualityof theelectricalpowerprovided
byautility. Evenabriefpoweranomaly
lastinga fewmilliseconds (ms)can
forceaserver toshutdownandbegina
lengthy rebootcycle. Thatdowntime
literallyshutsdowncritical enterprises:
hospitalscan’tadmitpatients; credit
cardcompaniescan’tprocess
payments; orairlinescan take
reservations.
Further, anyequipmentdowntime
causedbyadisturbance inpower
qualitycanbequitecostly for thedata
centerand theenterpriseasawhole
due to lossofdataaccess, service level
agreements (SLAs)penaltypayments
tocustomers, and reduction incapacity.
Frequent server shutdownsmayalso
affect theoperating lifeof the IT
equipment.
UPSPowerConversionTechnology -
DoubleConversionMode&EcoMode
Tomitigate theseconcernsand risks,
thepowerusedatdatacenters is
routed throughaUPSsystemwhich
providesback-uppowerduringa
completepoweroutageandalso
monitorspowerquality foranomalies
suchasblackouts, brownouts, surges,
sags, transientsandshortcircuits. This
process involves theutilitypowerbeing
converted twice: first fromAC toDC to
chargeaUPSsystem’senergystorage
back-upsystem. TheUPS then re-
converts theelectricityback toAC,
providing regulated& filteredpower to
the ITequipment in thedatacenter.
Thisso-calleddoubleconversionmode
enables theUPS tocloselyanalyze the
qualityof thepower from theutilityand
headoffanypoweranomaly
disturbancesbefore they reachdata
centerequipment. Unfortunately,
powerefficiency isoften thepricepaid
forprotection.DoubleconversionUPS
systemshavea typicalpowerefficiency
rating in the rangeof92 to94percent.
Asa result, doubleconversionUPS
systemsplaceasteep tollonyearly
datacenterenergyoperatingbudgets.
Thenextgenerationofenergy-efficient
UPSpowerconversion technologies,
referred toasmulti-mode, offera
differentpowerprotection-to-
efficiencycalculation. Itprovides the
userwith twomodes—double
conversionandecomode,with theuser
selectingwhichmode theypreferas
thedefaultmode. Thesenew
generationofUPS technologies,
includingGE’sTLESeriesorSGSeries
UPSSystemswitheBoost* technology,
switch in less than2ms, asneeded,
between premiumefficiencymode
byRayPrince
