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Data centers are transitioning from AC to DC

spectrum.ieee.org

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Re: Data centers are transitioning from AC to DC

#221

Post by amelius »

hristov wrote: post #9

It is absolutely stupid to talk about this as edisons revenge. If Tesla had the modern high power transistors needed to get high voltage dc out of the ac produced from a spinning turbine he would be all for high voltage dc too. Tesla understood that high voltage was needed for efficient long range transmission. He also understood that transformers were the inly remotely efficient way to climb up to and down from thes…

But there was an equivalent: a mechanical switch. Or an electromechanical relay. Or a spinning wheel with electrical contacts.

Re: Data centers are transitioning from AC to DC

#222

Post by ghighi7878 »

hristov wrote: post #9

It is absolutely stupid to talk about this as edisons revenge. If Tesla had the modern high power transistors needed to get high voltage dc out of the ac produced from a spinning turbine he would be all for high voltage dc too. Tesla understood that high voltage was needed for efficient long range transmission. He also understood that transformers were the inly remotely efficient way to climb up to and down from thes…

Title is clickbait. Edison is not mentioned anywhere else in article. I am okay with it.

Re: Data centers are transitioning from AC to DC

#223

Post by mschuster91 »

myrmidon wrote: post #217
ta9000 wrote: post #160

Earlier quoted context omitted.

Does that mean when we run out of Ga there are no more LED TVs?

Sidenote: Whenever someone tells you that (vital) reserves of some ressource are going to run out soonish (implying drastic consequences), you should be extremely skeptical: Such predictions have an abysmal historic track record, because we tend to find workarounds both on the supply side (=> previously undiscovered reserves) as well as flexibility on the demand side (using substitutes). This applies historically for…

> Such predictions have an abysmal historic track record, because we tend to find workarounds both on the supply side (=> previously undiscovered reserves) as well as flexibility on the demand side (using substitutes).

That's a classic example of the "preparedness paradox" [1]. When no one raises the alarm in time or it is being ignored, resources can go (effectively) exhausted before alternatives can be found, or countries either need to pay extraordinary amounts of money or go to war outright - this has happened in the past with guano [2], which was used for fertilizer and gunpowder production for well over a century until the Haber-Bosch ammonia process was developed at the start of the 20th century.

And we're actually seeing a repeat of that as well happening right now. Economists and scientists have sounded the alarm for decades that oil and gas are finite resources and that geopolitical tensions may impact everyone... no one gave too much of a fuck because one could always "drill baby drill", and now look where we are - Iran has blasted about 20% of Qatar's LNG capacity alone to pieces and blocked off the Strait of Hormuz, sending oil prices skyrocketing.

[1] https://en.wikipedia.org/wiki/Preparedness_paradox

[2] https://en.wikipedia.org/wiki/Guano

Re: Data centers are transitioning from AC to DC

#224

Post by xoxxala »

manwe150 wrote: post #93
jacquesm wrote: post #53

Earlier quoted context omitted.

Not going to happen. For the same reason that the US never converted to a higher domestic voltage even though there are many practical advantages. The transition from one system to another at the consumer level would be terrible, even if there would be some advantage (and I'm not sure the one you list is even valid, you'd get DC-DC converters instead because your consumers typically use a lower voltage than the house…

I suppose that still begs the question somewhat, since the US does have 240V (2 phase) already driving many appliances. Why hasn’t it ever become standard for luxury kitchens to have a European-style outlet for use with a European kettle? I know the US already has a different 240V plug shape, so it might have to be an unlicensed installation, but surely someone wanted hot tea faster and did that calculus before?

Technology Connections did this with an EV battery charger:

https://youtu.be/INZybkX8tLI

Re: Data centers are transitioning from AC to DC

#225

Post by reylas »

myrmidon wrote: post #217
ta9000 wrote: post #160

Earlier quoted context omitted.

Does that mean when we run out of Ga there are no more LED TVs?

Sidenote: Whenever someone tells you that (vital) reserves of some ressource are going to run out soonish (implying drastic consequences), you should be extremely skeptical: Such predictions have an abysmal historic track record, because we tend to find workarounds both on the supply side (=> previously undiscovered reserves) as well as flexibility on the demand side (using substitutes). This applies historically for…

I always add "cheap" to the sentence. It seems they are always talking about the cheap version of anything. Going to run out of water? Or are we running out of the "cheap" version of water that does not have to be processed?

Re: Data centers are transitioning from AC to DC

#226

Post by giancarlostoro »

Imustaskforhelp wrote: post #194
elar_verole wrote: post #171

Earlier quoted context omitted.

People need heroes. It's like the Keanu Reeves or Musk era, all the ""badass"" stories about this or that soldier / local hero / w/e that are very often overblown and get further and further away from the initial facts every time they resurface. No hate here, just noticing there is a weird visceral need to distill stories to their most essential, good vs evil, and the Tesla v Edison thing embodies this perfectly I th…

Keanu Reeves and Nikola Tesla to a degree as well, are decent figures. Aside from all the cult classics Keanu is part of like john wick and the matrix, even discounting that, he is a good person in it of itself who is genuinely humble and might be one of the best persons within hollywood. What I feel pissed about is that people like Andrew Tate and others like them took the concept of Matrix and the contributions Kea…

Tate is just attention hungry. It’s pretty obvious. If you feed no attention to him, he will go back to where he crawled from.

Re: Data centers are transitioning from AC to DC

#227

Post by pjdesno »

90% of the power in our academic data center goes 13.8kV 3-phase -> 400v 3-phase, and then the machines run directly from one leg to neutral (230v). One transformer step, no UPS losses, and the server power supplies are more efficient at EU voltages.

But what about availability? If you ask most of our users whether they’d prefer 4 9s of availability or 10% more money to spend on CPUs, they choose the CPUs. We asked them.

There are a lot of availability-insensitive workloads in the commercial world, as well, like AI training. What matters in those cases is how much computing you get done by the end of the month, and for a fixed budget a UPS reduces this number.

Re: Data centers are transitioning from AC to DC

#228

Post by gwbas1c »

KnuthIsGod wrote: post #49

Waiting for home DC. It is silly to have AC to DC converters in all of my wall connected electronics ( LED bulbs, home controller, computer equipment etc )

Assuming you live in a "large" western home, it's impractical. Remember, Edison's first power grid operated at 110/220v DC to the home. If there was lower voltage (IE, 12 volts) going from the street to your walls, the line loss would be significant. It only works in RVs and shacks because the wires are short.

Thus, even if you had DC in the walls, it would be 100+ volts, and you'd still have conversion down to the lower voltages that electronics use. If you look at the comments in this thread from people who work in telco, they talk about how voltage enters equipment at -48V and is then further lowered.

Re: Data centers are transitioning from AC to DC

#230

Post by amelius »

bluGill wrote: post #16
otterley wrote: post #7

DC power has been an option for datacenter equipment since I was a young lad racking and stacking hardware. Cisco, Dell, HPE, IBM, and countless others all had DC supply options. Same with PDUs. What’s old is new again. See e.g. https://www.dell.com/support/kbdoc/en-us/000221234/wiring-in...

48vdc was common in phone exchanges. They filled the basement with lead-acid batteries and to could run without the grid for a couple weeks. In turn the phone was 99.999% reliable for decades.

You need thick cables if you want to power a rack with 48V.
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