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Joined 3 years ago
Cake day: July 5th, 2023
  • egerlach@lemmy.catoTechnology@lemmy.world•Data centers raise nearby temperatures by up to 4 degrees in PhoenixEnglish
    2·
    3 days ago

    (TL;DR: It would take >10,000 of the satellites described in the video just to move the two data centres studied in this paper to space)

    I remember that video (been watching Scott Manley on-and-off since his KSP Interstellar series)

    He’s right that you can cool 20kW just fine and I agree that 100kW is still very doable with today’s engineering. Let’s assume that a MW is also within reason, though I think we’re starting to stretch practicality there, as we’re now talking about about 2500m2 of radiator if I’m remembering right. That would be 25 radiator groups, each one 5 times the size of an ISS group. I bet we could manage that with a few years of development.

    The two datacenters that were studied in the linked article were 36MW and 169MW. So just to replace those two you would need 200 of those pushing-the-boundaries-of-human-ability satellites. Or, if you look at the Starlink-sized satellites that Scott Manley was referencing, you’d need OVER 10,000. And that’s just two data centres in one state in one country in the world.

    I don’t think its “impossible”, or that “it can’t be cooled”. I think that focusing on the possibility of space data centres takes attention away from the harm that terrestrial data centres are causing today. “It’s okay if we build these on Earth right now, because we’ll move them into space later”? There’s nothing as permanent as a temporary solution.

    Let’s force these companies to go to space by charging them exorbitant amounts of money to build terrestrial data centres to compensate for the effects that they have here. What would it cost to cool the areas around those data centres back down again? 100 million? A billion?

    (And BTW, I’m a software engineer that’s been working in the AI space since 2018, before LLMs went crazy. I’m optimistic about AI in general. I’m pessimistic about companies that are clearly dumping externalities out into the general public.)

  • egerlach@lemmy.catoTechnology@lemmy.world•Data centers raise nearby temperatures by up to 4 degrees in PhoenixEnglish
    2·
    3 days ago

    The issue with space-based data centres is dissipating that heat, though. The ISS radiators can dissipate less than 100kW and they are the largest in space today, IIRC. Current land-based data centres already generate 100s of MW of heat. US Datacentres alone already consume multiple TWh of electricity/year.

    I’m all for space-based data centres. But I don’t believe anyone who says they’re coming soon. One small space data centre would be 10 ISSs—the largest space architecture project to date.

    I think what people who are pooh-poohing on space data centres are concerned about isn’t the literal heat issue, but that it serves the same purpose as the “Hyperloop”: not a real practicality, but serves to focus lawmakers attention in a direction that ignores a practical issue (with Hyperloop it was away from California HSR, which now has its own problems, but at least it was feasible)

  • egerlach@lemmy.catoTechnology@lemmy.world•Data centers raise nearby temperatures by up to 4 degrees in PhoenixEnglish
    9·
    4 days ago

    The primary issue is that there’s a limit to how much energy you can get out based on the difference in temperature between the cold fluid (liquid or gas) and the hot fluid. With data centres it’s maybe 20°C? Based on that assumption and the Carnot Theorem you get a maximum work extraction efficiency of about 6-7%.

    Unfortunately, in the data centres they obey the laws of thermodynamics.

    It would work better in places that get colder, but unfortunately places like that don’t tend to have as much available electricity (or infrastructure).

    An aside:

    We are starting to run up against fundamental laws of how much energy is required to do a certain amount of computation. i.e. In order to do a computation that moves a system from a state X to another state Y, there is a minimum amount of entropy change. That entropy change requires a certain amount of energy based on thermodynamics, known as the Landauer Limit.

    We were already only about a billion times less efficient than the limit in 2012. I would wager we’ve improved computation per watt by 1-2 orders of magnitude since then. Which means we might only be 107 or so off of the limit. That sounds like a lot, but when you think about how fast we’re improving…