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Comment by amluto

8 hours ago

This opens up an interesting synergy: district heating. 45C is low but not unworkable for a district heating loop, and a data center might be able to make a nice pitch to a community if the data center offers to provide heat to a district heating system for free. This brings the value to the local community of a nearby datacenter up from near zero to potentially a few million dollars per year.

Summer is still an issue, but fun solutions are possible. With the right geology, I think it’s possible to heat an underground volume in the summer and recapture (some of) that heat in the winter. In many, many climates, annual heating costs are far higher than cooling costs, at least if people aren’t stupid with skylights. [0]

[0] As a back-of-the-envelope heuristic, heating or cooling load due to conduction and air exchange is proportional to the difference between indoor and outdoor temperature. Outdoor temperatures of -10F to 30F are not unusual in the winter and are 40-80F away from an indoor temp of 70F. But outdoor temperatures in these climates rarely exceed 95F and are mostly lower in the summer, so that’s 15-25F of cooling. And heat pumps are more efficient at smaller temperature differences.

Radiative heating is an entirely different story.

Microsoft's already building data centers hooked up to district heating (Espoo and Kirkkonummi, Finland). Heatpumps are amazing.

(Seasonal heat storage is also a thing, Espoo's neighbours have tens of GWh of storage, with a new 90 GWh cavern in the works. Not sure if the systems are interlinked.)

45 is the cool temp so they could send the community a higher temp water to their heat exchanger?

Then 45 or below is sent back on the return.

  • Yes, but the heat will still likely need boosting by about a further 10 degrees either at the source or end user.

    DC inlet is 45°C, outlet is 55°C assuming a 10°C ΔT. By the time that's travelled 500m–1km through pipework you've lost a few degrees, so you're arriving at the HIU at maybe 50–52°C. The home radiator circuit then takes that down by around say 12°C, returning ~38°C. Factor in pipe losses on the return leg and you're back at the data centre with maybe 35°C inlet rather than 45°C — meaning the DC output is now only 45°C rather than 55°C, and the whole system gradually degrades each cycle. You could address this by mixing some hot output back into the return to keep the DC inlet stable at 45°C, but eh.

    • >Factor in pipe losses on the return leg and you're back at the data centre with maybe 35°C inlet rather than 45°C

      Surely having the input fluid being colder is a benefit, not a problem? Just run the fluid more slowly through the system?

Do you live near a datacenter? Property value goes down, constant humming.. the way we heat up the earth right now, i don't think you have to worry about heating

  • I’ve been to datacenters, but not the huuuge ones people seem to talk about in the context of AI. They are noisy inside (due to air cooling, which is largely avoided by the tech in the OP), but they’re entirely unremarkable outside compared to any other commercial or industrial building. Computers are not inherently loud, nor is power conversion.

    Power plants are all over, even in populated areas. They’re not so bad either (except perhaps coal).

    There is no fundamental reason that datacenters need to be especially unpleasant to their neighbors.

    • On-site natural gas turbines at a handful of DCs are genuinely loud. In general I agree that DCs are mostly fine neighbors, but maybe louder power plants aren't.

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    • It's like anything else in this world. Corner cutting and being shitty leads to shitty outcomes

    • >There is no fundamental reason that datacenters need to be especially unpleasant to their neighbors.

      Sure there is, being a good neighbor costs more than being a bad neighbor

    • It depends a lot on things like geology and some people are a lot more sensitive. It is really an issue.

      I don't have any datacenters near me but I can hear some heavy hums from the washing machine 3 floors up when it put my head on my pillow, for some reason it just propagates through the building physically. When I walk around I don't hear it. Datacenter noise can be the same.

      IMO they should be put away from habitation, there's no reason for them to be near there anyway

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  • Do you? I live at 4th and Brannan and there was one just off 3rd and Brannan in San Francisco. It was shut down when hosting.com sold it off but I didn't notice it while walking by then and I don't notice it while walking by now.

    My GPUs at Hurricane Electric in Fremont are also completely unnoticeable outside the building. Inside, when I'm working at the cabinets it's obviously deafening. Outside you wouldn't even know. Realistically, the predominant sounds at my home are from the traffic on the Bay Bridge so it's nice when there's congestion because it's quiet.

    Honestly, I wish there were more urban datacenters. It's getting quite annoying having to make a 1 hr trek to Fremont every time I want to rack a new server.

  • Noise is a design choice and could likely be legislated away. Reject heat is different than heating from greenhouse gas effects that are “heating the planet”.

    No one bats an eye when an air conditioner runs.

  • It sounds like with this liquid cooling, they won’t need the fans?

    • If the outdoor temperature is cool enough (maybe 30C?), you just pipe the liquid outside through a large enough loop or heat exchanger to get it back down to under 45C. Even better if you can put the loop in a lake and dump the heat there (maybe not better from an ecological POV though). The pumps moving all that liquid becomes the noisiest component.

    • They almost certainly need fans on the outside of the building to cool the 55C water back down to 45C. But correct, no fans on the servers themselves or even in the building. Except perhaps for the humans, so they can stand to work inside the building, when needed.

    • Some systems use liquid cooling for the GPU and CPU, but air cooling for the PSU, RAM and SSDs.

      With that said, by the standards of industrial sites data centres are quiet, low traffic and smell free. An industrial area that can’t build a data centre certainly can’t build a steelworks or oil refinery or leather tannery.

  • Coldest month average temperature where I live is around -7C, with peaks of -35C. Climate change is not going to increase that average, more like decrease. Typically, of course, electricity price is the highest during that month too.

    I think we are going to need heating.

  • >Do you live near a datacenter? Property value goes down, constant humming

    I don't live next to one but I'd take constant humming over the constant stop/go traffic noise, honking, squeaky brakes, slamming doors and revving engines I now have on my western side of the apartment, thanks to the unemployment office the city opened on my street not too long ago.

    So how come constant humming is somehow an illegal nuisance, but we've been expected to put up with the much more annoying urban traffic noise for decades just fine?

    My parents apartment have constant humming anyway thanks to the HVAC system on the roof of the nearby supermarket and white/brown noise is far more tolerable and easy to tune out than traffic noises.

    • > we've been expected to put up with the much more annoying urban traffic noise for decades just fine?

      For one, there tends to be little traffic at night when most people want quiet in order to sleep. Driving is also something (nearly) everyone does and benefits directly from, so negative externalities are easier to accept. It is much harder to accept a new source of noise near your home you haven't asked for and don't directly benefit from.

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    • How dare those nasty, dirty, unemployed live their lives under likely desperate circumstance. They are so much worse than corrupt oligarchs pumping and dumping their way into the greed hall of fame.

  • > the way we heat up the earth right now, i don't think you have to worry about heating

    So what, winters would be no more? Snow will disappear, no more ice-men and christmas trees, and subzero conditions in general, too?

    • And no more food. Or at least not enough of it to feed very many people.

      You do eat, don't you?