Increasing the Efficiency of UPS Systems – And Proving It! Richard L. Sawyer Director, Critical...

Increasing the Efficiency of UPS Systems – And Proving It!Richard L. SawyerDirector, Critical Facilities AssuranceEYP Mission Critical Facilitieswww.eypmcf.com

Conference nameConference date

The Problem

| 60% of US Energy bill is in buildings.| Energy consumed by data centers more than

doubled between 2000 and 2005 – J. Koomey, Stanford University.

| U.S. Data center electrical bills totaled $2.7 Billion in 2005.

| A single, moderate size server in a data center has the same carbon foot print as a SUV that gets 15 MPG (R.Muirhead, Data Center Journal).

| A single rack with 6 Blade Server units consumes as much power as 3 kitchen electric ranges (24-30Kw)!


Relative Power Densities

0

100

200

300

400

500

Watts/Sq.Ft.

StandardOffice

Building

MainframeData

Center

ModernServerData

Center

SuperData

Centers

Power Density


21st Century Computing – Blade Servers

Power = Up to 6 kW per Blade chassis or 30 kW per rack


Where does the power go?

0%

5%

10%

15%

20%

25%

30%

35%

UPS = 18%

Actual IT Load is 30% of Power Consumed

APC-MGE: Neil Rasmussen


DISTORTION

SPIKE

SWELL

SAG

OUTAGE

Lightning StrikesFaulty SwitchgearStormsHigh WindsFalling TreesTraffic Accidents

Faulty SwitchgearHeavy LoadsPoor Distribution

Poor Distribution

Switching OperationsPoor FiltersFaulty Load Eq.Static ElectricityRF Interference

Harmonics/Electronic LoadsPoor Distribution

FREQUENCYMajor UtilityProblemsFaultyGenerator

INPUT POWERFROM

UTILITY/GENERATOR

UPSOUTPUT POWER

PURPOSES OF UNINTERRUPTIBLE POWER SUPPLY

1.Maintain clean, uninterrupted power during utility events2.Power Conditioning3.Isolation from other electrical loads4.Separately Derived Source of Power


Strategy to Improve UPS Efficiency

| Technology: Make the units more efficient.

| Selection: Size the units more closely to the load.

| Application: Use redundancy only where it is needed.

IBM Blue Gene 1.2 Megawatt

Understanding UPS Inefficiency Factors

No-Load LossesProportional LossesSquare-Law Losses

Paying the price to process power!


EPRI Efficiency Curves for UPS Products


100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%100%90%80%70%60%50%40%30%20%10%0%

UPSEfficiency

Nominal 92% efficiency only applies Nominal 92% efficiency only applies when UPS load is over 70%when UPS load is over 70%

Below 30% loadBelow 30% loadefficiency drops rapidlyefficiency drops rapidly

UPS Load% of full power rating

Typical UPS efficiency curve


UPS

Bypass B

Static

Switch

PDU

Primary Bus A Primary Bus B

UPSUPS UPS UPS UPS

Bypass A

UPS Output 2A UPS Output 2B

13.5 KV

480

13.5 KV

480

Load Bank

Load Bank

Subsystem Bus A Subsystem Bus B

Critical Load Bus A Critical Load Bus B

Static

Switch

PDU

Each side must have capacity to support both critical loads but maintain redundancy.

Total load cannot exceed capacity of 2 UPS Modules.

EFFECTIVE DESIGN LOAD = 33% of total capacity, maximum.

Critical Load

2(N+1) System


Aggregate UPS Power Losses

No-load portion of loss stays constant from full load all the way down to zero load

{

}

No-load loss is present even at no load

Many data centers operate in this rangeoperate in this range

UPS load% of full power rating

100%90%80%70%60%50%40%30%20%10%0%

Power delivered to load

UPS internal power consumption (loss) 93.4%93.4%

93.3%93.3%

93.1%93.1%

92.8%92.8%

92.4%92.4%

91.8%91.8%

90.7%90.7%

88.9%88.9%

85.5%85.5%

76.4%76.4%

0%0%

EFFICIENCY

}

Proportional and square losses


No Load Losses

| Definition: The power consumed by the UPS at 0% load just to keep the UPS operating.

| Sources – Transformers, capacitors, logic systems, fans, communications cards.

| Sometimes referred to as “tare”, “constant”, “fixed”, “shunt” and “parallel” losses.

| Most significant inefficiency: Accounts for up to 40% of UPS losses.


Proportional Losses

| Definition: The power needed to process more power through the UPS.

| Sources – Switching losses, capacitor and inductor impedance, internal resistance

| Proportional losses increase as the output load the UPS support increases.

| Proportional losses are directly related to the topology (internal design) of the UPS.


Square - Law Losses

| Definition: Losses related to the amount of current flowing through the UPS.

| Power is the result of voltage times the current.

| Current does the work, and power is lost as the amount of current flowing increases, by a square factor, hence “square – law losses”.

| Power loss is in the form of heat.

| Square-Law losses are 1% to 4% at higher load levels.


Power Loss Component Graph

No Load

Electrical Loss in kW(Waste due to inefficiency)

Equipment Loading

Full Load

50% 10% 30% 90% 70%

NO-LOADNO-LOAD loss

PROPORTIONALPROPORTIONAL loss

SQUARE-LAW SQUARE-LAW loss


0kW

10kW

Equipment Loading

UPS A TOTAL LOSS

UPS B TOTAL LOSS

Example: Two different 100kW UPSs with 92% nameplate (full-load) efficiency

50%

UPS A No-load loss

UPS B No-load loss

UPS B has higher proportional loss (steeper line) but lower no-load loss

10% 30% 90% 70%

Loading where most data centers operate

Electrical Loss

(Waste due to inefficiency)

Two devices with same nameplate efficiency can have significantly different losses in actual operating range, due to the particular characteristics of their PROPORTIONAL and NO-LOAD losses

No Load

Full Load

Same nameplate efficiency (full-load loss)

But different performance at actual operating load


0kW

10kW

Equipment Loading

UPS A TOTAL LOSS

UPS B TOTAL LOSS

Example: Two 100kW UPSs with same 92% nameplate (full-load) efficiency

50%

UPS A No-load loss

UPS B No-load loss

UPS B has higher proportional loss (steeper line) but lower no-load loss

10% 30% 90% 70%


Electrical Loss


No Load

Full Load

One device can even have WORSE nameplate efficiency than another, yet have lower loss in actual operating range, if it has a low NO-LOAD loss

UPS AA has better nameplate efficiency (lower full-load loss)

But UPS BB performs better at actual operating load

AB

Improving Efficiency

TechnologySelection

Application


Total loss before improvement

Total loss after improvement


0kW

10kW

Electrical Loss


Equipment Loading

Effect of lowering NO-LOAD LOSSNO-LOAD LOSS

OriginalNo-load loss

Lowered No-load loss

Example: 100kW UPS with 92% full-load efficiency

Electric bill savings

But waste is roughly cut in half in actual operating range

50% 10% 30% 90% 70%

Nameplateefficiency goes from

92% to 94.5%

Same improvement in nameplate efficiency

No Load

Full Load

Improving Efficiency – Fixing No-Load Loss



0kW

10kW

Electrical Loss


Equipment Loading

Effect of lowering PROPORTIONAL LOSSPROPORTIONAL LOSS Example: 100kW UPS with 92% full-load efficiency

Electric bill savings

Waste is reduced by 10-20% in actual operating range

50% 10% 30% 90% 70%

Nameplateefficiency goes from

92% to 94.5%

Total loss before improvement

Total loss after improvement

(UnchangedNo-load loss)

No Load

Full Load

Improving Efficiency – Fixing Proportional Loss


Application Efficiency – Zoned Redundancy

M

M

CRAC CRAC CRAC CRAC

pdu

UPS

ColdAisle

pdu

UPS

HotAisle

pdu

UPS

pdu

UPS

FIRE

SECUR

HEATREJECT

HEATREJECT

EPO

SYSTEMMONITOR

WEBLINK

Site Availability – 99.995%

$2,000+ per square foot

HotAisle

ColdAisle

ColdAisle

CRACUPS

Battery

Central UPS for one “N” side,

scalable, modular system

Rack Based UPS Systems as needed for 2N redundancy

Commissioning UPS Systems

AvailabilityThe Cost of Downtime

The Value of Commssioning


Data Center Tier Ratings

Tier 1

No Generator

Basic UPS for IDF Room,

non-redundant

Single Utility or on Radial line from Loop

99.671% *

Tier 2

Generator

N+1 UPS with redundant components

Single Utility Feeders, N+1 Mechanical

System

99.741%

Tier 3- Concurrently Maintainable

N+1 Generator System

N+1 UPS with redundant components

One Active, One Passive, Utility Source, N+1

Mechanical System

99.982%

Tier 4- Fault Tolerant

2N Generator System

2N UPS Systems

Dual Active Utility Feeders, 2N

Mechanical System, compartmentalization

99.995%

* The Uptime Institute


Maximizing Availability

Availability =Total Time - Downtime

Total Time

• The only variable is Downtime

• Downtime sources: Equipment Failures, Human Error, External Causes, Maintenance

Cost of Downtime drives the Value of CFA!


What does Downtime Cost?


Infant Mortality Period End-of- Life Period

Fai

lure

Rat

e

Time (Data Center Life Span)

The Reliability Curve for equipment (IEEE)

“The Bathtub Curve”

High Probability of Downtime


Infant Mortality Period End-of- Life Period

Fai

lure

s

Time

The Value of Commissioning

Minimize


Commissioning UPS Systems

| Verify the full load performance of each module using load banks – typical burn in is 4 hours at rated KW load (hint: infrared inspections of all connections).

| Measure and verify the efficiency in the full operating range at 5%, 10%, 15%, 20%, 25%..........

| Verify system redundancy under design load levels.

| Verify failure modes (under-voltage transfers, bypass transfers, over load shutdown).

| Verify isolation modes for concurrent maintenance.

Assuring you get the reliability and efficiency you pay for!

Questions?

Richard L. [email protected]

Increasing the Efficiency of UPS Systems – And Proving It! Richard L. Sawyer Director, Critical...

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