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45°C cooling design cuts data center water use to near zero

245 points16 hoursblogs.nvidia.com
amluto14 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.

lrasinen13 hours ago

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.)

uberex8 hours ago

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.

matt-p7 hours ago

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.

superluserdo6 hours ago

>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?

matt-p4 hours ago

In essence you can't really because slower flow rate makes the heat transfer less efficient. You'd be halfing the flow rate in that example.

SkyPuncher2 hours ago

Heat pumps can effectively bring that temp up higher.

The problem is really how much energy is actually available.

shagie7 hours ago

Of old... https://web.archive.org/web/20210115152829/https://www.nrel....

It's got a "heat energy to/from campus" exchange in there.

That's a link in March and the air temperature was 31°F.

https://web.archive.org/web/20210708150410/https://www.nrel.... is later with air temperature of 68°F.

badpun11 hours ago

European cities are doing it already.

ramon15614 hours ago

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

annzabelle4 hours ago

I grew up in Northern Virginia, (of AWS US-East-1, MAE-East, and Equinix fame), where there are more data centers than anywhere else in the world, and I never heard organized opposition to them until the last couple of years. They were mainly viewed as a way for Loudoun County to build their industrial tax base without the downsides of having industrial workers, and allowed them to consistently lower property taxes while having excellent schools. Data centers are unsightly and use electricity and water, but so does literally any kind of industrial facility. They are also pretty quiet, if you exclude the ones using on site gas turbines for electricity.

Property values have consistently gone up in that region for decades, and are up to $6 million an acre if there's enough contiguous land to put another data center on.

Many of the people complaining about datacenters would also complain about literally any kind of development.

juneyi1 hour ago

i'm confused on the humming part, i've driven by them many times and they're just...large, sorta ugly, buildings. but that's really it. i wonder if i walked up to a building i'd hear the humming. quite surprised to learn that they emit a humming that bothers nearby folks

majormajor2 hours ago

The new gen of AI-boom-construction datacenters seem to be substantially different than the ones I used to go when working at companies whose software ran inside them. Those were running air-cooled rack servers, which is a whole different world from these things. The couple of the new gen I've seen have been much larger and much more turbine-happy.

amluto12 hours ago

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.

loeg7 hours ago

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.

+2
TitaRusell6 hours ago
pdoege2 hours ago

When I was building data enters in populated areas there were regulations for noise, visual signature, power usage, and etc. It looks like a lot of these newer sites are in low regulation areas. Which is great for profit margin, and not so great for neighbors.

vablings9 hours ago

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

mixdup8 hours ago

>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

wolvoleo11 hours ago

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

amluto9 hours ago

> 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.

Right. Vibration propagates through solid (and liquid) materials.

But this can all be measured and controlled, and there's nothing special about datacenters. A building that is hundreds of feet away will couple to your pillow much less strongly than a washing machine in your building. And the washing machine often has a wildly unbalanced load and minimal decoupling between itself and the floor, whereas a big fan in a datacenter or other industrial building ought to be balanced and also ought to be installed on decoupling mounts.

If datacenter operators (cough xAI) are being lazy about properly selecting, installing and maintaining equipment, then you can have a problem. Otherwise you have a much smaller problem.

+1
thewebguyd11 hours ago
naasking7 hours ago

> It depends a lot on things like geology and some people are a lot more sensitive.

People said this about high voltage electric lines and wind turbines. Blind tests proved they were imagining things.

SamPatt5 hours ago

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

Nearly 10x more people die from the cold than from the heat.

"...9.43% of global deaths were attributable to non-optimal temperatures, with 8.52% from cold and 0.91% from heat."

https://www.thelancet.com/journals/lanplh/article/PIIS2542-5...

ryan_lane4 hours ago

This study doesn't factor in droughts, floods, crop death (and starvation), and other non-direct effects. It also doesn't consider wet-bulb events, because it's looking at average ambient temperatures.

I don't think this is climate change propaganda, but your application of this study by evoking it in a discussion about climate change feels like it.

arjie6 hours ago

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.

toast05 hours ago

> Honestly, I wish there were more urban datacenters.

There's a lot of them in high rise buildings... but they come with high rise rent.

+1
arjie4 hours ago
xattt13 hours ago

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.

Marsymars4 hours ago

> No one bats an eye when an air conditioner runs.

I find their noise pretty obnoxious. Out of respect for my neighbours, when I get around to installing one, I'll be getting the absolute quietest model available.

dgellow12 hours ago

> No one bats an eye when an air conditioner runs.

In the US

bethekidyouwant6 hours ago

Data centres aren’t loud it’s the gas power generating stations next to them that are loud.

rokkamokka14 hours ago

Couldn't imagine living with the ~55dBA noise literally all the time

skybrian13 hours ago

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

zie7 hours ago

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.

michaelt8 hours ago

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.

stubish6 hours ago

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.

energy1237 hours ago

The humming are the gas turbines which also damages your health.

abc4211 hours ago

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.

joe_mamba8 hours ago

>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.

drnick17 hours ago

> 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.

brailsafe6 hours ago

> Driving is also something (nearly) everyone does and benefits directly from, so negative externalities are easier to accept.

This reads a little too close to driving being an inherently good thing or some sort of objective requirement, but it's only that way in certain urban places because the built environment makes it as arduous as possible to do those things without.

Something that pisses me off about many urban places that don't even otherwise require people to drive, is that many who do use their cars the most often have their neighborhoods protected from the noise they contribute to everywhere else. This whole thing of putting apartments only where there's already the most disgusting car-infested thoroughfares; "sorry, can't have an apartment one street in off the main drag, that's only for bungalows! Don't like it? Get richer. Excuse me while I drive through your bedroom and park for free in front."

ChoGGi7 hours ago

I live nearby a road going down a coulee that dickheads love to speed down in warmer weather at night. I'd trade that for a hum any day.

energy1237 hours ago

More noise categories should be illegal or fined in dense areas, not less

+1
joe_mamba7 hours ago
b5n6 hours ago

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.

tucnak11 hours ago

> 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?

reaperducer7 hours ago

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

You do eat, don't you?

why_at7 hours ago

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.

edit: just saw this:

>Previous liquid-cooled servers were hybrid: GPUs and CPUs got cold plates, but the rest of the system stayed air-cooled, with finned heat sinks designed to shed heat into moving air. In a fully liquid-cooled server, the cooling for these components needed to be completely redesigned to use liquid.

RachelF7 hours ago

The "innovation" is that everything is now attached to a watercooled block.

The rest is marketing: The Cray supercomputer were fluid cooled back in the 1980's, the entire board had an inert liquid flowing across it.

jasonwatkinspdx3 hours ago

When my grandpa retired from Monsanto chemical back in the 90s, I helped him clean out his office and got a tour of a bunch of stuff.

He showed me their Cray, which had its own dedicated computer room, and they set it up with the coolant pump and fountain unit right in the middle in front of a glass wall facing the hallway so everyone could gawk at it.

maxnevermind2 hours ago

> everything is now attached to a watercooled block

Does it increases manufacturing and operational cost of such racks?

frollogaston5 hours ago

The innovation is being able to run the chips at higher temps without ruining them too quickly.

dietr1ch4 hours ago

Haven't AMD CPUs been targeting a 95°C limit for 5+ years already? I'd have guessed servers could do 60°C without degrading a whole lot before switching to more power efficient hardware is available.

frollogaston4 hours ago

95˚C is the core temp, not ambient. My parent comment was probably wrong though, see https://news.ycombinator.com/item?id=48667527

fennec-posix6 hours ago

My partner lamented the same thing... Cray was doing this 40+ years ago

briandw5 hours ago

Cray used Fluorinert, a chlorofluorocarbon. So not exactly a environmentally friendly solution.

trhway5 hours ago

Bad quality of water clogging the pipes integrated onto the PCBs (thus requiring to replace the PCBs) was said to be what were killing those few USSR Elbrus supercomputer installations.

toast05 hours ago

> 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.

It seemed like a pretty big deal ~ 2011 when big companies were running their (air cooled) datacenters closer to 95F (35C) vs the traditional 72F (22C). So jumping up a little more is maybe not super exciting, but it's still innovation.

mistercow4 hours ago

And I think the answer to the "doing the math" question is, until you've actually collected the data, "what math?" Until someone actually puts a bunch of six-figure value hardware through its paces, pushes the previous limits, and sees what that does to its lifespan, there's nothing to meaningfully calculate.

gleenn5 hours ago

And the fact that their system doesn't dump water. I think that is actually perhaps the bigger deal. Datacenters have been getting a lot of heat (pun intended) for using significant fresh water at the expense of local municipalities.

frollogaston5 hours ago

Closed-loop water cooling chips is nothing new. There are two separate water systems that often get conflated*. The loop warms up the water, which is recycled but first needs to be cooled externally somehow. Normally they use evaporative cooling towers that do use water, or chillers that don't use water but use more energy. But they're claiming they can get that water loop so much hotter than the outdoor environment that active cooling isn't needed. They attribute this to improving the chip-to-water interaction.

Even air-cooled datacenters work somewhat the same way, but instead of water to chips, it's air. The air goes into hot aisles then exchanges heat with water, after which, see above.

* Other datacenter marketing materials talk about how they have a "closed loop system that uses no water" and they do still use water in the evap towers. I was half expecting this article to be that again, glad it wasn't.

+1
XorNot5 hours ago
loeg7 hours ago

You have to design your hardware to tolerate being run in consistently hotter conditions. There's a tradeoff between cooling cost and failure rate / capex.

frollogaston5 hours ago

Doesn't look like they made the hardware more tolerant of temperature, rather they made it remove waste heat more quickly.

"NVIDIA’s thermal engineering team reworked how those components handle heat, designing cooling loops that simplify how liquid is routed to multiple high-power chips on the board using a single inlet and outlet, resulting in a cleaner tray-level cooling architecture"

AlotOfReading5 hours ago

Nvidia's automotive and aerospace variants get ratings up to 85C, for comparison.

taneq5 hours ago

Don’t their consumer GPUs run at 85C core temp? Maybe not for as long though.

frollogaston5 hours ago

Core temp though. Ambient temp is a different story, and also depends on air vs water. In fact the article suggests the difference is getting the water more directly onto the chips, no mention of running at a higher core temp.

NekkoDroid5 hours ago

AMD CPUs basically all boost up to 90°C as a relatively normal operating temperature as long as the power (and some other factors) allow it to. I assume AMDs and NVs GPUs do to, but I play mostly CPU bound games so I see mine just sitting at ~60°C under load.

AlotOfReading4 hours ago

Temperature ratings are the allowed ambient temperature. The actual silicon will inevitably operate somewhat higher, because coolers are just moving heat down a temperature gradient.

sheepscreek4 hours ago

Speculating here - “effectively” cooling the CPU and GPU materially using this technique at datacenter scale may have never been done. Those things than run hot, easily crossing 100C. So the loop is doing a lot of work to keep them stable at 55C.

The innovation may be in the speed or volume flow of the coolant through different parts of the data centre to regulate the temperature. And of course, redesigning every component to be compatible with this fan-less design.

I think it’s only possibly because NVIDIA is much more vertically integrated than ever before.

joe_the_user2 hours ago

There's never been a reason a sealed water-cooled system ever had to use vast amounts of water. But State Of The Art wound up being using and expelling the water. It seems like data centers operate like other industrial enterprises - locate in the city/county/state that gives you carte blanche, do whatever is convenient, get used to the idea that this the only way things can be done.

So a multitude of communities rebelling and complaints about environmental damage fell on deaf ears but a technical spec might be paid attention to.

voxelghost2 hours ago

Ai slop from Nvidia, who would have thunk.

taneq5 hours ago

Is this not how it was already done? Huh.

kayo_202110309 hours ago

> 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.

notrealyme1238 hours ago

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...

kayo_202110308 hours ago

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 :-)

mattmanser8 hours ago

Speaking from a UK perspective global warming is now noticeable, hot days are hotter and there's more likely to be a heat wave, and that's changed in the last decade.

I assume Germany is the same, many years ago really is different to today.

kayo_202110308 hours ago

For sure. Everywhere. Even observationally, we just all know it's hotter, or wetter, or colder - it's all way more extreme in all dimensions.

matt-p8 hours ago

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. In practice you are also likely to have air cooled systems that sit 'beside' the AI compute like storage severs, any extra CPU compute and network switches. So you are likely to need a separate room and cooling system for that. Great progress though.

frollogaston5 hours ago

So they only have to actively cool when it's above 98˚F outside, that's still way better than what they do now

matt-p4 hours ago

Definitely!

metabagel8 hours ago

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...

sabareesh7 hours ago

I am pretty much doing the same but running the coolant at 40 deg C instead of 45 as my pumps are rated for 45 C max temp. Here is bit more about my setup https://sabareesh.com/posts/blackwell-waterblock/

prng20215 hours ago

“That unlocks something beyond energy savings: the possibility of eliminating water consumption entirely.”

They’ve made this claim numerous times in the article and I really don’t understand it. The building has tons of water being recirculated through it. That water came from somewhere in the surrounding natural world. How is that 0 water consumption?

dgacmu3 hours ago

As someone else noted - it's effectively zero compared to the water evaporated in evaporative chillers.

But it's still misleading. The major source of water use in datacenters, by _far_, is the water used in power generation. This improves PUE, which reduces power draw, but the savings are almost certainly under about 20% given that many modern datacenters already operate at a PUE of under 1.2. So if you're running on coal or gas, you're still consuming quite a bit of water indirectly.

Now that said again - the water consumption part of this equation is generally overhyped. The power draw is the problem, as are the really bad temporary hacks to the power problem (e.g., what x.ai is doing with "temporary" gas turbines).

vkou5 hours ago

After filling the tanks once, subsequent draw would be zero. Most data centers currently use evaporative cooling - where they pull tons of water in, and then... Let it evaporate.

Imagine a residential building that reclaims and reprocesses and purifies 100% of all the water it uses. This would be dramatically more difficult and better than the status quo, and would be called 'net zero' by any sensible accounting method.

---

Obviously, evaporative cooling is net-zero water use when accounted across the entire globe (the water falls as rain, somewhere, eventually), but it is net-negative for a local community.

t0mpr1c312 hours ago

with efficient heat exchange you could get the coolant up to mash temperature (65C) and run a combined data center/brewery

dialogbox6 hours ago

>Previous liquid-cooled servers were hybrid: GPUs and CPUs got cold plates, but the rest of the system stayed air-cooled, with finned heat sinks designed to shed heat into moving air. In a fully liquid-cooled server, the cooling for these components needed to be completely redesigned to use liquid.

Does that mean the whole server board is running in liquid? If true, how do they do maintenance? Replacing parts must be extremely difficult.

pwg4 hours ago

The article implied (but did not seem to ever state) that they simply added liquid cooled cold plates to all the other components that were previously air cooled.

But it did not sound like they were describing a Cray 2 style liquid immersion cooling system.

mips_avatar3 hours ago

My GPUs at home produce 60°C water. I just wish I had a good use for them.

VorpalWay7 hours ago

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?

loeg7 hours ago

Evaporative cooling consumes less expensive electricity than air conditioning. Electricity is much more expensive than water (for the same cooling load) in most places DCs are located.

rnxrx7 hours ago

It’s usually open loop - closed loop, so closed loop goes through CRACs or liquid cooled equipment manifolds. That heated water circulates through an heat exchanger on the roof that uses open loop cooling to shed the heat to the surrounding environment.

bozhark7 hours ago

How inefficient

cl0ckt0wer7 hours ago

Way more efficient, that's why they do it. Evaporating water carries an enormous amount of energy.

quickthrowman7 hours ago

It uses almost half as much electricity, it’s way more efficient than air cooled chillers by themselves.

East of the 100 degree W line of longitude, there is more than enough water to use evaporative cooling if needed.

derac7 hours ago

the unfathomable reason is that it is significantly more energy efficient.

bozhark7 hours ago

Then it’s not being measured adequately.

The loss of material must be included

If water is evaporated or spent out of the system.. it is not more efficient

danstiner7 hours ago

It is more efficient, in terms of cost the datacenter owner pays per unit of heat extracted. Water is cheap in places this is being done, relative to amount of heat vaporization can carry off.

You can certainly argue DCs should pay more for water than other uses, but who gets to decide what is a good vs bad use of water? Pricing in externalities is tricky, and water usage rights are especially complicated. I don't know what a good&fair solution is.

hiddencost7 hours ago

Companies will never price in externalities unless they are forced to.

Groxx7 hours ago

(ab)using fresh water in vast quantities is cheaper.

currently.

and also more energy efficient, because evaporating water away takes a lot of energy with it. you have to raise radiators to a higher temperature to keep up with that, or have much more surface area.

loeg7 hours ago

There's just a lot of fresh water almost anywhere you'd want to site a DC. In places where water is more expensive, obviously it doesn't make sense.

dsp7 hours ago

It’s very efficient. The net electrical energy saved using the latent heat of water is 30 to 100+ times greater than the energy required to desalinate or wastewater recycle the same volume of water.

danielheath6 hours ago

At the scale DCs are operating at, losses from flexible tubing are not negligible either.

1gw of power converts approx 400 liters of cold water into steam _per second_.

1e1a7 hours ago

Yes, they are using evaporative cooling.

bozhark7 hours ago

But you can do that in a closed system and recapture the water

quickthrowman7 hours ago

You cannot have evaporative cooling without evaporating some water into the atmosphere.

A closed circuit cooling tower still has water spraying onto the closed loop process water heat exchanger coil and mixing with atmospheric air to evaporate and cool the process water indirectly instead of evaporating and recirculating the process water that doesn’t evaporate directly like in an open-loop cooling tower.

I suppose you could condense the evaporated water somehow by using a chilled umbrella or some other ridiculous contraption above the cooling tower, but why would you do that?

FWIW I sell and run commercial electrical work, primarily to mechanical contractors who are installing boilers, chillers, cooling towers, and pumps. I spend my professional life immersed in this type of equipment.

Brian_K_White5 hours ago

That is called a heat pipe and doesn't get you anything. It's exactly the same as a closed plain water loop with no phase-change involved.

2OEH8eoCRo06 hours ago

Evaporative cooling is practically a cooling cheat code. Why unfathomable? What's more efficient?

danans5 hours ago

Not more efficient at heat dissipation, but radiative cooling panels can achieve sub-ambient dissipation in conditions (like high humidity) that evaporative cooling performance declines in, and with no water consumption.

https://www.sciencedirect.com/science/article/abs/pii/S13594...

nialse15 hours ago

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?

eqvinox15 hours ago

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)

quickthrowman14 hours ago

> 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.

uberex8 hours ago

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.

eqvinox15 hours ago

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?

maxerickson15 hours ago

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.

amluto14 hours ago

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.

eqvinox14 hours ago

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.

lkbm4 hours ago

This is kinda debunked / obviously false. It's almost entirely a land use issue: a building will create a heat island. Data centers aren't using enough energy to make a significant difference.

More on it at [0], but it doesn't take anything beyond a basic energy calculation to know that 1GW of energy is not going to have a significant effect "6.2 miles away".

[0] https://andymasley.com/writing/data-centers-heat-exhaust-is-...

amluto12 hours ago

Indeed. If the datacenter uses less total power, it produces less waste heat.

If you manage to use the waste heat to avoid generating heat somewhere else (that the article calls heat recovery) then there’s a further reduction in total heat output.

RicoElectrico14 hours ago

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.

blondie9x3 hours ago

In a way does this study try to detract from the public backlash against datacenters?

Look at the author of the blog.

https://blogs.nvidia.com/blog/author/joshparker/

Is this NVIDIA lawyer trying to influence the public perception of datacenter for his company?

sourcegrift3 hours ago

I'm worried about the carbon footprint and other impacts of the higher temperature

fwipsy5 hours ago

My understanding is that datacenter water consumption is not really that big of a deal compared to other industries, and it's mostly inflated by people who are looking for a reason to criticize AI/datacenters. If Nvidia is hoping to placate those people, I predict it will not work.

emsign6 hours ago

Greenwashing, that's all. This is not going to be the standard it's just a light house project to calm some nerves to keep on going.

briandw5 hours ago

It's a response to the FUD that is water usage in data centers. Data centers don't use a meaningful amount of water when compared to just about any other industrial application, or many recreational ones. Data centers used about 66 billion liters 2023. source: https://escholarship.org/uc/item/32d6m0d1 Golf courses used 2 trillion liters in 2020. We won't even bring up almond production.

emsign4 hours ago

The issue is though data centers are being built in areas with scarce water resources and they get prioritized. They still use a lot of water.

htrp14 hours ago

wasn't this announced at gtc in march?

m3kw99 hours ago

This is what PC heat sinks uses. Someone could have thought of that

qsxfthnkp232215 hours ago

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?

palmotea14 hours ago

> 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.

jazzyjackson15 hours ago

Their valuation is based on their software stacks’s ability to displace human labor, this is just them eating their dogfood.

qsxfthnkp232215 hours ago

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.

officeplant14 hours ago

>And it’s sad because Jensen seems like one of the rare good CEOs when I listen to him speak.

Have we been listening to the same person speak for the last few years? Jensen rarely even sounds sane anymore.

pixel_popping14 hours ago

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)

Animats7 hours ago

We're there. The recent HN article about the Fender Stratocaster had some content from a Fender press release, which was regurgitating text from a legal aggregation site. It was, overall, bad coverage of the area of copyright on decorative but useful objects.[1]

Watch for cases where content has been through two layers of LLMs. It's not good.

[1] https://news.ycombinator.com/item?id=48665916

mv_d5339e315 hours ago

[dead]

transformerash15 hours ago

[dead]

mchusma13 hours ago

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.

dgellow12 hours ago

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

signatoremo7 hours ago

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.

frollogaston5 hours ago

I would comfortably bet at least $1000 that this is bs, and it would be more money than China has put in so far. They've got a "vow."

To answer your first question, yes. Even if they were US companies. Remember when each Big Tech player was claiming to build their own blockchain, except centralized which was a contradiction.

msla7 hours ago

OK, here's my problems with space data centers. How many of them has China solved?

1. Space is terrible for heat regulation. It's a perfect insulator for everything except radiative cooling, which is the least efficient. Hot things stay hot.

2. Space is full of radiation. Everything has to be radiation hardened, which makes it heavier, more expensive, and, yes, more difficult to cool.

3. Space is far away. Well, farther than a data center on Earth can be. I know China hasn't solved the speed of light.

We put up with it with satellites because it still has some advantages over trying to run cables literally everywhere, but we do, in fact, still use cables laid on the bottoms of the oceans.

So, is physics wrong, or is a country known for making dumb decisions some times making a dumb decision?

wolvoleo11 hours ago

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.

battery_staple_11 hours ago

> 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.

asdff11 hours ago

Starlink is already a space based datacenter. No one is up there maintaining it.

wolvoleo11 hours ago

It's not, it's more like a space based network, the processing and storage is minimal.

+2
asdff11 hours ago
BuildTheRobots10 hours ago

> 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!

dgellow9 hours ago

You’re surprisingly good at this, ngl

frollogaston5 hours ago

This relies on transferring heat to the outdoor air. Can't do that in space.