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DC Power Poised To Bring Savings To Datacenters
snydeq writes "InfoWorld's Logan Harbaugh follows up his '10 IT Power-Saving Myths Debunked' to argue in favor of using DC power in the datacenter. The practice — viewed as a somewhat crackpot means for reducing wasteful conversions in the datacenter just a few short years ago — has gained traction to the point where server vendors such as HP, IBM, and Sun are making DC power supplies available in their server wares. Meanwhile, Panduit and other companies are working to bring down another barrier for DC to the datacenter: a standardized 400-VDC connector and cabling solution. And with GE working to list 600-VDC circuit breakers with the Underwriters Labs, DC's promise of reduced conversion waste could soon be commonly realized."
Suggestion for the DC power supply designers: have a heart and build GFCI into the spec.
I don't run a datacenter, but I sure would like to get rid of the power bricks that all small electronic appliances seem to come with these days!
"[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz
Though there are more transmission losses with DC than with AC
There aren't, at the same voltage. In fact AC loses slightly more at a given voltage, up to a lot more for really long wires.
Finally! A year of moderation! Ready for 2019?
One can't help but reflect upon these two and their stubborn support of DC and AC respectively. Edison created a circus atmosphere demonstrating the dangers of AC. He electrocuted dogs & other animals and even participated in the design of the electric chair to prove his point.
Edison's financial ambition was part of the problem, and his inability to understand AC, but mostly it seems to have been an emotional attachment to DC.
Let's hope that in our time emotion and personal gain have no part in such decisions.
...omphaloskepsis often...
Another pro:
A UPS would consist of nothing more than a battery charger and 48V battery.
Have gnu, will travel.
However, in these links there was no reference to this at all.
I don't think there is any truth to this.
Telcos have been doing it at -48VDC for ages. I'm not so sure -400VDC is a good thing. DC voltage doesn't let go, if you grab a wire by accident you'll be toast
-48VDC is safe, -400VDC is scary
I saw some cool DC gear a couple weeks ago at the Henry Ford Museum, the original DC power plant from NY and a huge 4MW DC generator which was one of nine installed at the Highland Park Ford plant in 1913.
As far as using DC in the datacenter, my calculations show it just doesn't pay, one or two percent more efficient power use does not justify the large premium DC parts demand today. Part of this is economies of scale and part is market segmentation, DC has historically been used for carrier grade equipment which equipment manufacturers have been able to demand a premium for.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Only half of his nose... your server draws a certain number of watts, if you are feeding it 240VAC, it will take 1/2 as many amps as 120VAC (assuming equal efficiency at both voltages, I believe 240VAC-DC conversions are typically marginally more efficient than 120VAC-DC)
P=I^2*R, power loss in your building wiring is based on the resistance of the wiring multiplied by current squared, so dropping current by half will drop your wiring related losses by a factor of 4. Since wiring power loss isn't much of a big deal, a better way you can capitalize on this advantage is by safely dropping your wire diameter by half (to 0.25x cross section) for the same heat/fire potential.
Of course, your boss will fire you when he plugs in a 120VAC coffee pot and it explodes in his face.
The times, they are a changin'
Seriously, after 100 years you might expect technology to switch a few things up.
This is nice, but I see it as interim until we can produce superconducting puddles at room temperature.
AC transmission lines operating at high voltages not only have resistive (I^2R) losses, but they also have to deal with capacitance between phases and corona discharge, both of which cause additional losses. AC is used because it is easily transformed, but for long distance high voltage transmission, high voltage DC is more efficient. Using DC also frees you of having to synchronize the phases between different grids.
Of course, your boss will fire you when he plugs in a 120VAC coffee pot and it explodes in his face.
Then you should wire in different plugs, and power cables. Use european style round-pin connectors, you won't plug any 120VAC equipment in there by accident.
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
Of course, your boss will fire you when he plugs in a 120VAC coffee pot and it explodes in his face.
Yeah, but you don't take a coffee pot into the datacenter.
Come to think of it, you don't take the boss into the datacenter either...