»Energy efficiency« in data processing?Stefan FassbinderDeutsches KupferinstitutAm Bonneshof 5D-40474 DüsseldorfTel.: +49 211 4796-323Fax: +49 211 4796-310sfassbinder@kupferinstitut.destf@eurocopper.orgwww.kupferinstitut.de

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An accidental finding:

Wanted:

The noise free living room PC

Found:

An energy glutton wasting energy for lack of aluminium and copper

4

This brand new PC power supply unit

promises to be 60% less noisy!

at 39.95€

Well, 60% less noiseis at least a statement!

Though not really any more than that …

… as long as the question remains unanswered:

Less than what?

This was not the way

Now what to do?

Loss heat can be

• either blown away

• or avoided!

So a different solution had to be found:

A fanless PSU (at 79.50€) works totally noise free!

How is this reduction in noise level achieved?

By improvement of passive cooling or by reduction of cooling need, say losses?

By improvement of passive cooling and by reduction of losses:

• Substantial enhancement of cooling surface on the aluminium heat sinks

• Substantial enhancement of copper cross sections in the windings of HF converters

But loss reduction holdsthe greater share!

0W

20W

40W

60W

80W

100W

120W

140W

00:00min 05:00min 10:00min

P

t

Starting up a PC withsubsequent idle operation

Original PSU Antec True 380 SP

Fanless PSU FSP ZEN (2009)

How to reduce losses? – Use more material!

Conventional Fanless

420 W 300 W

Still, the actual net power consumption of a common PC (built in 2005, 800 MHz) is:

• 50 W when idling (whereas writing a text or composing an Excel table is idle for a PC!),

• 100 W at peak processor demand (gaming),

while the common power supply unit is very much over-dimensioned!

Therefore the 300 W model can quite conveniently replace a 420 W unit.

If this were not so the copper content would have to be 41% higher rather than just 11%

Power rating 380W 300WWeight 1995g 2223g

Material intensity 5.250g/W 7.410g/WFactor 100% 141%

FSP ZEN with active

PFC, fanless

PC power supply unit comparison

Antec True 380 SP with active

Who else should have an interest in this topic?

This is the reply to a request to the colleagues from www.aluinfo.de sent March 31, 2009:

I‘m still waiting…

Conventional PC power unit, 420W

PC power supply LC4620, S/N: 7J090402Rated power 420W

30.0A 28.0A 14.0A Output

P 3.3V 5.0V 12.0V P P /P N η

4.4W 0.0A 0.0A 0.0A 0.0W 0.0% 0.0%13.5W 0.0A 0.0A 0.0A 0.0W 0.0% 0.0%64.0W 0.0A 0.0A 3.3A 40.1W 9.5% 62.6%71.0W 17.5A 0.0A 0.0A 57.8W 13.8% 81.3%

109.0W 0.0A 0.0A 6.7A 80.2W 19.1% 73.5%148.0W 0.0A 0.0A 9.4A 113.2W 26.9% 76.5%161.0W 0.0A 25.0A 0.0A 125.0W 29.8% 77.6%286.0W 0.0A 0.0A 18.8A 226.0W 53.8% 79.0%307.0W 28.5A 24.0A 0.0A 214.1W 51.0% 69.7%450.0W 28.5A 25.0A 7.0A 303.1W 72.2% 67.3%740.0W PSU failure after ≈2s with <20% overload

Input

Conventional PC power unit, 300W

PC power supply T.I.P. 300 ATXRated power 218W

14.0A 20.0A 6.0A Output

P 3.3V 5.0V 12.0V P P /P N η

0.0W 0.0A 0.0A 0.0A 0.0W 0.0% 0.0%3.1W 0.0A 0.0A 0.0A 0.0W 0.0% 0.0%

21.4W 0.0A 0.0A 0.5A 6.1W 2.8% 28.6%43.3W 0.0A 2.2A 0.9A 21.7W 9.9% 50.0%56.8W 0.0A 0.0A 3.2A 38.9W 17.8% 68.5%70.0W 0.0A 0.0A 4.3A 51.4W 23.5% 73.4%97.0W 0.0A 5.0A 3.4A 66.1W 30.3% 68.1%

122.0W 0.0A 5.0A 5.2A 87.2W 40.0% 71.5%148.0W 5.8A 5.0A 5.2A 106.0W 48.6% 71.6%181.0W 5.8A 9.5A 5.2A 129.0W 59.1% 71.3%226.0W 14.0A 9.5A 5.3A 157.4W 72.1% 69.7%

Shut-off – no more measurements possible

Input

PC power supply Antec True 380 SPRated power 380W

28.0A 35.0A 18.0A Output

P 3.3V 5.0V 12.0V P P /P N η

0.0W 0.0A 0.0A 0.0A 0.0W 0.0% 0.0%4.4W 0.0A 0.0A 0.0A 0.0W 0.0% 0.0%

28.3W 2.2A 0.0A 0.0A 7.1W 1.9% 25.1%64.8W 2.5A 0.0A 0.9A 19.1W 5.0% 29.4%90.0W 2.5A 4.0A 0.9A 39.1W 10.3% 43.4%

109.0W 6.1A 4.4A 0.9A 53.3W 14.0% 48.9%148.0W 6.1A 4.6A 3.3A 82.6W 21.7% 55.8%174.0W 5.6A 9.3A 3.3A 105.0W 27.6% 60.3%282.0W 27.0A 9.3A 3.4A 176.2W 46.4% 62.5%381.0W 27.0A 17.0A 6.7A 254.5W 67.0% 66.8%463.0W 27.0A 17.0A 12.9A 328.9W 86.6% 71.0%561.0W 27.0A 17.0A 19.0A 402.1W 105.8% 71.7%

Input

Conventional PC power unit, 380W

Fanless PC power unit, 300W

Rated efficiency:

89% (at full load)

How high is the »efficiency« of a PC?Much higher than earlier, anyway!

Ancient XT: Latest model:

f = 4,7 MHz f = 4,7 GHz

Pel ≈ 40 W Pel <<400 W

This looks like an efficiency improvement by far more than a factor of 100! With similar values for

• storage units,

• hard disks,

• graphic adaptors

you end up with improvement factors around 106!

Where will the journey still take us?A limit will be reached only when for one data bit only more one electron needs to be moved.

So long, however, it‘s still 10,000 to 100,000 electrons that need to be employed for the smallest occurring »elementary process« in data processing.

So the theoretical potential• with miniaturisation,• with acceleration of procedures,• with reduction of energy demand

still lies somewhere near a factor of 104 … 105!

Hence the major partof the job is done

• The first computer »Zuse Z1« had the dimensions of an electrical locomotive…

• …along with its power consumption…

• …and this with the performance of a credit card sized pocket calculator which you get as a giveaway nowadays and which is supplied from 2 cm² of solar cells or with a button cell battery for no less than a year!

But progress with processors is continuing:

PC built upgraded2005 2011

Processor 2.6 GHz, 2*2.7 GHz,

RAM 512 MB, 4 GB, 400 MHz 1.6 GHz

Idle power 59 W 45 W

measured with the same fanless PSU

Only what‘s the use of it allif you do anything you canthink of in order to e. g. implement all available efficiency techniques in a modern diesel engine and then add a gearbox with 30% of losses?

Nobody would do that in a car –in a PC it‘s the usual approach!

For the PSU is sort of a»gearbox for electricity«.

The noiseless operation comes for free!

The saved losses pay back for the price premium within 3 years. The global savings potential in 1 bn PCs would be 100 TWh/a!

Morals: I am a fan of the fanless design!

Calculation of power consumption costs for a PC (built in 2005)before and after replacing the conventional PSU with a fanless one

Conventional PSU with fan Fanless PSU ErsparnisOutput values P S Q LF cosφ P S Q LF cosφ

Full load 100h/a 135.5W 138.9VA 51.4var 0.975 0.977 113.0W 123.2VA 67.0var 0.890 0.940No load 3000h/a 82.0W 87.1VA 29.3var 0.939 0.945 59.2W 70.5VA 38.1var 0.843 0.886»off« 5660h/a 6.3W 24.5VA 23.6var 0.256 0.307 2.0W 24.1VA 24.0var 0.080 0.112

PSU 39.95 € 79.50 €Power 14.0c/kWh

Consumption 294.91kWh/a 200.36kWh/aElectricity costs 41.29€/a 28.05€/aPayback time 2.99a

Price

Then why do portable PCs provide the same computing performance with that much less electricity?

This notebook PCis equipped with an integrated 55 Wh battery and an additional 95 Wh battery and runs for about13 hours on these, corresponding to12 W net DC power requirement!

Metering conditions:

• WLAN off,

• no UMTS device,

• no »action games«,

• moderate screen brightness.

Whereas it is remarkable with the laptop PC

• that the screen is already included

• and the whole PC uses less power …

… than a desktop flat screen uses for itself alone!

So in the end there is one question remaining open:

Why can this technique not be built into a desktop PC?

Energy is still way too cheap.

The availability of electricity from the accumulator is a reason to save energy – the electricity price obviously is not.