Maybe I'm being dumb, but I don't understand what the innovation is here.
I get that they're using liquid coolant at higher than usual temperatures, but why couldn't they do that before? Most of the comparison in the article is for air cooled datacenters but what about other liquid cooled ones?
Surely in all the previous datacenters that have been designed there has been someone doing the math and determining what temperature things need to run at, how much energy it will use, how much heat it all will produce, etc.
I never looked into this, but why would a datacenter consume water for cooling in the first place? Sure, they use some. But just like you fill up the cooling loop in a car, once it is there it just circulates between the heat source and radiators and/or heat exchangers, with perhaps some minimal top off needed (since flexible tubing isn't 100% water proof).
Or are they for some unfathomable reason using evaporative cooling in data centers?
The NASA Ames Research Center Modular Supercomputing Facility is highly efficient, both in terms of electricity and water use. The facility isn't air conditioned. The chips are water cooled, and the inlet water temperature is pretty high I believe - I think it's 90 degrees Fahrenheit.
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.
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.)
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.
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”.
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.
>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.
> In favorable climates, NVIDIA’s 45-degree liquid-cooling architecture ....
What's a favorable climate, apart from, obviously, Greenland? The piece is a little light on details on the correlation between outside temperatures and efficiency & cost. It'd be nice to see even a broad-strokes discussion of that.
The university where i studied uses high temperature cooling since a few years. The weather on Germany ranges to quite high temperatures, but according to the tech stuff they only need active (as in AC) cooling for the higher end of the 30 degrees. The technology is quite fascinating.
Yeah, this is part of the issue to be honest. You'd need outdoor air to be below ~37°C to guarantee 45°C water outlet temperature. In most locations you still need cooling towers or compressors some of the time, so you still have to build all the infrastructure that comes with them; though reducing their use is still great, saving serious amounts of water or energy.
For e.g you might think of the outskirts of London as fairly moderate, but this week it's been hot enough that supplemental cooling would likely have been needed at points. For a data centre here you'd typically design the cooling system to cope with outdoor temps in excess of 40°C, which is not a conservative number anymore.
Also, while Nvidia might be happy with you supplying water at 45°C I suspect you will get better longevity of the hardware at lower temps like say 35°C. GPUs are expensive, and extending longevity may well be 'worth' a bit more water or energy to you.
Weird I was daydreaming about why isn't this done the other day (in the context of desert datacentres running on solar anf battery). Glad to see it is a thing.
Heat exchange is used instead of refrigerating the coolant. Makes sense. How do they manage the indoor climate for the humans working there though? Eventually everything will be at 45C in the building, will it not?
The heat exchange between that fluid and the ambient air isn't infinitely fast, if it's low enough they can just run "normal" A/C at low power for the humans. They just need to keep the heat in the fluid until it reaches… well… whatever heat dump there is. (cf. top-level post)
> Heat exchange is used instead of refrigerating the coolant.
There are some systems that pipe refrigerant around the building, but they’re relatively uncommon (VRF or variable refrigerant flow if you want more details).
Glycol and water is cheaper than refrigerant so there’s usually a chilled water loop that passes thru a heat exchanger that interfaces with a chiller (vapor compression refrigeration) to reject the heat from the chilled water loop.
This eliminates the need for evaporative cooling towers.
On the other hand: the heat has to go somewhere. So… where? Datacenters already create a warm microclimate in their vicinity, is that getting even worse?
This approach appears to directly reduce energy use (that's what the articles says). The heat would still be going into the local environment, but if there is a reduction in energy use, there should be less of it.
Actual heating due to human energy use is not really a big deal except perhaps locally. Climate change is caused by changing how much heat the earth retains from the sun. Maybe if we stopped using fossil fuels and used immense amounts of nuclear power, we would care about the waste heat. But solar and wind power largely redirect energy flows.
It’s kind of like how brine from desalination is not a global problem for the oceans at all — all that matters is diluting it enough that it doesn’t poison the local ecosystem.
The temperature is independent of the actual heat flux. Also - a quick search suggests that at best the data center coolers run at COP of little more than 10. The inverse of that is the amount of heat wasted just on cooling. Having a system not relying on heat pumps would only make it better. A back of the envelope calculation based on PC AIOs suggests they would achieve a COP of 20 or more. A scaled up system would be more efficient than that, if not just for wider tubes.
I feel that the sad reality is that most blogs in the future will be addressed to AI and not humans, it's gonna be quite rare to read directly something as we will have built-in tools within browser and phone and OS and so-on that always rewrite on-demand based on current expertise, wanted tone and so-on. There is a recent study I believe that demonstrated that AIs digest better articles made by AI, which means that it might be just better to let AI write the articles so others AI have a better accuracy in digesting it (and incorporating it in their training data as well).
The same as technical docs for any codebase, humans will not read them anymore, only AIs which then translate it to human on-demand, it's already happening, I've worked recently with many new frameworks/codebases without even opening the doc (not even the Github page) and solely asking the agent to gather info for me about it.
PS: The reason I feel it will be this way is that it will allow to legitimatize mass data collection indirectly, instead of doing telemetry on page and software level, we will just send all the content automatically to some inference providers (probably provided for free by Google, MS and so-on)
This is also the type of thing that makes space based data centers more viable. I was previously more skeptical on the concept but have come around.
I do think ground based centers will have better economics when they can be built though, and this addresses noise and water complaints which are the big 2 regional complaints.
It seems like lots of bottlenecks are getting solved quickly, except for maybe memory.
How does that change the calculus for space datacenters? There is still no reasons or benefits to having them in space. You still have to rely solely on radiative cooling. That doesn’t solve any of the maintenance problems.
Space datacenters is a really dumb and unrealistic idea Musk is talking about to hype his companies, it’s not meant to actually be done. Anything in space is more expensive and way harder to do, for a datacenter there is no benefit. We aren’t lacking places where to have them on earth
Plans for space data centers should be seen with skepticism. However when they are backed by different parties who have stakes in the game, that's more credible. More than HN crowd for sure.
To be precise, heat rejection via radiative cooling scales with the fourth power of the temperature (in K) the radiator operates at, all else constant.
I honestly think musk wants them there because they are hard to reach.
I do really think that if large numbers of jobs are indeed going to be displaced by AI, movements will pop up of people attacking datacenters (and honestly I wouldn't blame them even though it won't really accomplish anything). Having them in space keeps them out of reach of anyone but state actors.
> Anything in space is more expensive and way harder to do, for a datacenter there is no benefit.
If we pick an extremely fast orbit, then relativity means the hardware will age out (slightly) slower, so I'm sure that'll help with the maintenance issue.
It's the wrong way around though. Ideally we want to speed up our current compute ability not slow it down; if it experiences more time than we do then it can do more. Relative-MHz means my slower hardware becomes tangibly fast again.
General Relativity says mass warps space time, so we need to get these datacentres out of the Earth's gravity well. And the Sun's, and the Milky Way's; out into the deepest void of intergalactic space. The good news is that a maintenance callout is still quicker than some of the earth based DC's I've had gear in, but the bad news is that it doesn't get us much of anything at all.
Special Relativity lets us abuse time with speed (something I discovered as a teenager). Going faster than Earth means we experience less time, so we just need to try and slow down comparative to our home base. The earth is orbiting the Sun at ~30km/s, the solar system is orbiting the centre of the Milky Way at ~230km/s and our local group of galaxies is moving relative to the Cosmic Microwave Background at ~600km/s. We can easily get our DataSpaceCentre up to 1,000km/s or more, so we just need to point it relative to all that movement we mentioned above making stationary relative to the universe. It's completely doable, but (as well as far more variable response times to callouts) only gets us an extra second of compute over a human lifetime.
Fundamentally, we're attacking this problem in the wrong direction. Earth's gravity is comparatively minor, and our piddly ~600km/s relative movement is a tiny fraction of the speed of light. We should be filling The Earth with compute, and then decamping humanity into space and travelling at relativistic speeds. Or put the compute in space and move the Earth into the event horizon of a black hole. You can't do the inverse of Interstellar keeping Earth where it is, the maths isn't in our favour. If everyone lived on (a less moist) Miller's Planet, we'd get 7 years of compute every hour. It puts Moore's Law to shame; the relative MHz are obscene.
There's the obvious problem of communications. I'm led to believe there's issues with radio and light, so this probably isn't a job for fibre. Veritasium seemed to imply a battery, switch, lightbulb and a wire stretching around the globe would light instantaneously, so I'm sure we can come up with a new copper Ethernet standard for low latency over solar distances.
Maybe I'm being dumb, but I don't understand what the innovation is here.
I get that they're using liquid coolant at higher than usual temperatures, but why couldn't they do that before? Most of the comparison in the article is for air cooled datacenters but what about other liquid cooled ones?
Surely in all the previous datacenters that have been designed there has been someone doing the math and determining what temperature things need to run at, how much energy it will use, how much heat it all will produce, etc.
I never looked into this, but why would a datacenter consume water for cooling in the first place? Sure, they use some. But just like you fill up the cooling loop in a car, once it is there it just circulates between the heat source and radiators and/or heat exchangers, with perhaps some minimal top off needed (since flexible tubing isn't 100% water proof).
Or are they for some unfathomable reason using evaporative cooling in data centers?
Yes, they are using evaporative cooling.
The NASA Ames Research Center Modular Supercomputing Facility is highly efficient, both in terms of electricity and water use. The facility isn't air conditioned. The chips are water cooled, and the inlet water temperature is pretty high I believe - I think it's 90 degrees Fahrenheit.
https://www.nasa.gov/centers-and-facilities/ames/doing-more-...
https://www.nas.nasa.gov/assets/nas/pdf/ModularSupercomputin...
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.
European cities are doing it already.
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.
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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.
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It sounds like with this liquid cooling, they won’t need the fans?
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Couldn't imagine living with the ~55dBA noise literally all the time
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.
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> 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?
> In favorable climates, NVIDIA’s 45-degree liquid-cooling architecture ....
What's a favorable climate, apart from, obviously, Greenland? The piece is a little light on details on the correlation between outside temperatures and efficiency & cost. It'd be nice to see even a broad-strokes discussion of that.
The university where i studied uses high temperature cooling since a few years. The weather on Germany ranges to quite high temperatures, but according to the tech stuff they only need active (as in AC) cooling for the higher end of the 30 degrees. The technology is quite fascinating.
https://www.kit.edu/kit/english/pi_2024_038_kit-supercompute...
I lived in Munich many years ago, but if the temperature ever went to the high thirties for more than a day we'd expect the end of the world :-)
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Yeah, this is part of the issue to be honest. You'd need outdoor air to be below ~37°C to guarantee 45°C water outlet temperature. In most locations you still need cooling towers or compressors some of the time, so you still have to build all the infrastructure that comes with them; though reducing their use is still great, saving serious amounts of water or energy.
For e.g you might think of the outskirts of London as fairly moderate, but this week it's been hot enough that supplemental cooling would likely have been needed at points. For a data centre here you'd typically design the cooling system to cope with outdoor temps in excess of 40°C, which is not a conservative number anymore.
Also, while Nvidia might be happy with you supplying water at 45°C I suspect you will get better longevity of the hardware at lower temps like say 35°C. GPUs are expensive, and extending longevity may well be 'worth' a bit more water or energy to you.
Weird I was daydreaming about why isn't this done the other day (in the context of desert datacentres running on solar anf battery). Glad to see it is a thing.
with efficient heat exchange you could get the coolant up to mash temperature (65C) and run a combined data center/brewery
Heat exchange is used instead of refrigerating the coolant. Makes sense. How do they manage the indoor climate for the humans working there though? Eventually everything will be at 45C in the building, will it not?
The heat exchange between that fluid and the ambient air isn't infinitely fast, if it's low enough they can just run "normal" A/C at low power for the humans. They just need to keep the heat in the fluid until it reaches… well… whatever heat dump there is. (cf. top-level post)
> Heat exchange is used instead of refrigerating the coolant.
There are some systems that pipe refrigerant around the building, but they’re relatively uncommon (VRF or variable refrigerant flow if you want more details).
Glycol and water is cheaper than refrigerant so there’s usually a chilled water loop that passes thru a heat exchanger that interfaces with a chiller (vapor compression refrigeration) to reject the heat from the chilled water loop.
This eliminates the need for evaporative cooling towers.
On one hand: great!
On the other hand: the heat has to go somewhere. So… where? Datacenters already create a warm microclimate in their vicinity, is that getting even worse?
This approach appears to directly reduce energy use (that's what the articles says). The heat would still be going into the local environment, but if there is a reduction in energy use, there should be less of it.
Actual heating due to human energy use is not really a big deal except perhaps locally. Climate change is caused by changing how much heat the earth retains from the sun. Maybe if we stopped using fossil fuels and used immense amounts of nuclear power, we would care about the waste heat. But solar and wind power largely redirect energy flows.
It’s kind of like how brine from desalination is not a global problem for the oceans at all — all that matters is diluting it enough that it doesn’t poison the local ecosystem.
I was specifically talking about the local microclimate. cf. https://edition.cnn.com/2026/03/30/climate/data-centers-are-...
It's not clear to me what changes are happening here. The siblings to your post seem to be indicating an overall improvement.
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The temperature is independent of the actual heat flux. Also - a quick search suggests that at best the data center coolers run at COP of little more than 10. The inverse of that is the amount of heat wasted just on cooling. Having a system not relying on heat pumps would only make it better. A back of the envelope calculation based on PC AIOs suggests they would achieve a COP of 20 or more. A scaled up system would be more efficient than that, if not just for wider tubes.
This is what PC heat sinks uses. Someone could have thought of that
wasn't this announced at gtc in march?
Claude write good.
Nvidia has so much money and they can’t afford to pay a human for a day of their time to write a blog post?
> Claude write good.
> Nvidia has so much money and they can’t afford to pay a human for a day of their time to write a blog post?
The shareholders desperately need that money.
Their valuation is based on their software stacks’s ability to displace human labor, this is just them eating their dogfood.
Oh I understand funny money
We are all fucked.
And it’s sad because Jensen seems like one of the rare good CEOs when I listen to him speak.
But even Dario says he doesn’t let Claude actually write his blog.
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I feel that the sad reality is that most blogs in the future will be addressed to AI and not humans, it's gonna be quite rare to read directly something as we will have built-in tools within browser and phone and OS and so-on that always rewrite on-demand based on current expertise, wanted tone and so-on. There is a recent study I believe that demonstrated that AIs digest better articles made by AI, which means that it might be just better to let AI write the articles so others AI have a better accuracy in digesting it (and incorporating it in their training data as well).
The same as technical docs for any codebase, humans will not read them anymore, only AIs which then translate it to human on-demand, it's already happening, I've worked recently with many new frameworks/codebases without even opening the doc (not even the Github page) and solely asking the agent to gather info for me about it.
PS: The reason I feel it will be this way is that it will allow to legitimatize mass data collection indirectly, instead of doing telemetry on page and software level, we will just send all the content automatically to some inference providers (probably provided for free by Google, MS and so-on)
[dead]
This is also the type of thing that makes space based data centers more viable. I was previously more skeptical on the concept but have come around.
I do think ground based centers will have better economics when they can be built though, and this addresses noise and water complaints which are the big 2 regional complaints.
It seems like lots of bottlenecks are getting solved quickly, except for maybe memory.
How does that change the calculus for space datacenters? There is still no reasons or benefits to having them in space. You still have to rely solely on radiative cooling. That doesn’t solve any of the maintenance problems. Space datacenters is a really dumb and unrealistic idea Musk is talking about to hype his companies, it’s not meant to actually be done. Anything in space is more expensive and way harder to do, for a datacenter there is no benefit. We aren’t lacking places where to have them on earth
What do you think of China, also dumb, or just blindly FOMO?
https://spacenews.com/china-backs-orbital-data-center-startu...
https://www.reuters.com/science/china-vows-develop-space-tou...
Plans for space data centers should be seen with skepticism. However when they are backed by different parties who have stakes in the game, that's more credible. More than HN crowd for sure.
> How does that change the calculus
To be precise, heat rejection via radiative cooling scales with the fourth power of the temperature (in K) the radiator operates at, all else constant.
I honestly think musk wants them there because they are hard to reach.
I do really think that if large numbers of jobs are indeed going to be displaced by AI, movements will pop up of people attacking datacenters (and honestly I wouldn't blame them even though it won't really accomplish anything). Having them in space keeps them out of reach of anyone but state actors.
Starlink is already a space based datacenter. No one is up there maintaining it.
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> Anything in space is more expensive and way harder to do, for a datacenter there is no benefit.
If we pick an extremely fast orbit, then relativity means the hardware will age out (slightly) slower, so I'm sure that'll help with the maintenance issue.
It's the wrong way around though. Ideally we want to speed up our current compute ability not slow it down; if it experiences more time than we do then it can do more. Relative-MHz means my slower hardware becomes tangibly fast again.
General Relativity says mass warps space time, so we need to get these datacentres out of the Earth's gravity well. And the Sun's, and the Milky Way's; out into the deepest void of intergalactic space. The good news is that a maintenance callout is still quicker than some of the earth based DC's I've had gear in, but the bad news is that it doesn't get us much of anything at all.
Special Relativity lets us abuse time with speed (something I discovered as a teenager). Going faster than Earth means we experience less time, so we just need to try and slow down comparative to our home base. The earth is orbiting the Sun at ~30km/s, the solar system is orbiting the centre of the Milky Way at ~230km/s and our local group of galaxies is moving relative to the Cosmic Microwave Background at ~600km/s. We can easily get our DataSpaceCentre up to 1,000km/s or more, so we just need to point it relative to all that movement we mentioned above making stationary relative to the universe. It's completely doable, but (as well as far more variable response times to callouts) only gets us an extra second of compute over a human lifetime.
Fundamentally, we're attacking this problem in the wrong direction. Earth's gravity is comparatively minor, and our piddly ~600km/s relative movement is a tiny fraction of the speed of light. We should be filling The Earth with compute, and then decamping humanity into space and travelling at relativistic speeds. Or put the compute in space and move the Earth into the event horizon of a black hole. You can't do the inverse of Interstellar keeping Earth where it is, the maths isn't in our favour. If everyone lived on (a less moist) Miller's Planet, we'd get 7 years of compute every hour. It puts Moore's Law to shame; the relative MHz are obscene.
There's the obvious problem of communications. I'm led to believe there's issues with radio and light, so this probably isn't a job for fibre. Veritasium seemed to imply a battery, switch, lightbulb and a wire stretching around the globe would light instantaneously, so I'm sure we can come up with a new copper Ethernet standard for low latency over solar distances.
Invest early, we're going straight past the moon!
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