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Data centers are transitioning from AC to DC

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Re: Data centers are transitioning from AC to DC

#251

Post by KaiserPro »

stego-tech wrote: post #8

I've been hearing this line for over a decade, now. "Immersion cooling will make data centers scale!" "Converting to DC at the perimeter increases density!" Yes, of course both of those things are true, and yes, some data centers do engage in those processes for their unique advantages. The issue is that aside from specialty kit designed for that use (like the AWS Outposts with their DC conversion), the rank-and-file…

Immersion cooling was/is so fucking impractical it is only useful for very specific issues. If you talk to any engineer who worked on CRAY machines that were full of liquid freon, they'll tell how hard it is to do quick swaps of anything.

Its much cheaper, quicker and easier to use cooling blocks with leak proof quick connectors to do liquid cooling. It means you can use normal equipment, and don't need to re-re-enforce the floor.

A lot of "edge" stuff has 12/48v screw terminals, which I suspect is because they are designed to be telco compatible.

For megawatt racks though, I'm still not really sure.

Re: Data centers are transitioning from AC to DC

#252

Post by fuzzfactor »

swed420 wrote: post #213
mjuarez wrote: post #35

Earlier quoted context omitted.

Not to be _that_ guy, but it was technically -48V DC. Honestly, that was pretty surprising to me when I had to work with some telco equipment a couple of decades ago. To this day, I don't think I've encountered anything else that requires negative voltage relative to ground.

> I don't think I've encountered anything else that requires negative voltage relative to ground Automotive collectors can probably still relate to cars from the 1920s-50s having a "positive ground."

With positive ground the traditional more-sacrificial spark plugs lasted longer.

Re: Data centers are transitioning from AC to DC

#253

Post by KaiserPro »

ericd wrote: post #28
adrr wrote: post #23

Our houses should be DC. So wasteful to have all these bricks to change to AC to DC.

Something to consider, and something I got a vivid demonstration of while playing with solar panels, DC arcs aren't self-extinguishing, unlike AC arcs. At one point I stuck a voltage probe in, and the arc stuck with it as I pulled the probe away. It also vaporized the metal tip of the probe. My understanding is that DC breakers are somewhat prone to fires for this reason, too.

> My understanding is that DC breakers are somewhat prone to fires for this reason, too.

I think its that DC breakers are more expensive, so people use AC rated breakers instead. They are both rated for 400v @10 amps, its the same thing right?

It turns out they are not, and most people, even electronics types rarely play with 200v+ of DC.

Re: Data centers are transitioning from AC to DC

#254

Post by margalabargala »

bregma wrote: post #180
manwe150 wrote: post #93

Earlier quoted context omitted.

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?

> but surely someone wanted hot tea faster No one in the USA drinks hat tea. The choices (and it tends to be regionally-based) is sweet or unsweet tea. No need to boil a kettle quickly for that.

What? Plenty of people in the US drink hot tea.

Re: Data centers are transitioning from AC to DC

#255

Post by mauvehaus »

aidenn0 wrote: post #128
jacquesm wrote: post #98

Earlier quoted context omitted.

Well, as you say, it would not be according to code and the insurance company might have something to say about it. It's also single phase but not quite the way you do it in the USA, it would be a neutral and a phase whereas in the USA I think it is 2x110. Finally, it's 50 Hz rather than 60 which would work fine for resistive loads but not so well for inductive ones such as transformers and motors. In all likely not…

> In all likely not worth the trouble. When I moved to Canada I gave away most of my power tools for that reason and when I moved back I had to do that all over again. If you ever have to do it again, you can probably get a transformer rated high enough for power-tools for cheaper than replacing all of your power tools.

The line frequency tends to screw with things with motors too. Moved from the US to Belgium back when compact cassette was a common format for music.

Killed a few tapes with a transformer on a US tape deck before buying a 220V 50Hz unit. No, I don’t remember if the pitch was grossly off, but I’m guessing it wasn’t.

Re: Data centers are transitioning from AC to DC

#256

Post by mauvehaus »

bregma wrote: post #180
manwe150 wrote: post #93

Earlier quoted context omitted.

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?

> but surely someone wanted hot tea faster No one in the USA drinks hat tea. The choices (and it tends to be regionally-based) is sweet or unsweet tea. No need to boil a kettle quickly for that.

> No one in the USA drinks h[o]t tea.

There are dozens of us.

Perplexingly I was traveling in one of the iced tea regions of the country in need of a cup of hot tea, and they had no way to make it. Like, you have a commercial coffee maker and hot cups, the coffee maker has a hot(ish) water tap. All you need is a $4 box of teabags that’ll last until the heat death of the universe. Nope.

Re: Data centers are transitioning from AC to DC

#257

Post by something765478 »

ndsipa_pomu wrote: post #233
Imustaskforhelp wrote: post #194

Earlier quoted context omitted.

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…

Whilst I agree that Keanu is a most excellent human, he was hardly responsible for the concept of the Matrix. In my opinion, Philip K Dick was a major influence (I'm a fan and consider him the prophet of the modern age), though Gibson's Neuromancer was likely a big influence too. (Also, there's the old Doctor Who episode "The Deadly Assassin" which features the Matrix). It always seems to me that the far right are be…

> the far right are bereft of original ideas and always co-opt other pre-existing concepts.

That's not unique to them: Good artists copy; great artists steal.

Re: Data centers are transitioning from AC to DC

#258

Post by pwndByDeath »

bananaflag wrote: post #206
mikkupikku wrote: post #178

Earlier quoted context omitted.

There's a component of modern culture that trains and expects people to be extremely pessimistic about long term human development. It results in situations above, where without any further information people just assume by default that were going to run out of a thing and are on some collision course with not just a disaster, but every single conceivable one. (Gallium is a byproduct of aluminum production. We aren't…

On the other hand, it is possible to run out of a metal when all of it is either somewhere in some device or scattered among landfills (i.e. not concentrated in a place like a mine).

Its concentrated in a place like a landfill that already has access for large vehicles.

Re: Data centers are transitioning from AC to DC

#260

Post by mauvehaus »

scarecrowbob wrote: post #76
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 )

Well, having spent some time operating a 12VDC system last year when I moved into some shacks, I will say that I find it a lot more convenient to run 120VAC. I end up converting stuff anyhow, because all my loads run at different voltages- even though I had my lights, vent fan, and heater fans running on 12V I still ended up having to change voltages for most of the loads I wanted to run, or generate a AC to to charg…

Do you have a website with your system on it? I have an off-grid building I need to add solar to in the next year or so. After I fix the foundation and roof, of course. Naturally I’m exploring options for item 387 on the todo list instead of think about how I’m going to jack the building up.
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