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

6/24/2026 at 3:34:20 PM

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.

by amluto

6/24/2026 at 4:49:56 PM

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.)

by lrasinen

6/24/2026 at 4:01:47 PM

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

by ramon156

6/24/2026 at 6:17:41 PM

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.

by amluto

6/24/2026 at 6:49:14 PM

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

by wolvoleo

6/24/2026 at 5:05:48 PM

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

by skybrian

6/24/2026 at 4:16:38 PM

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

by rokkamokka

6/24/2026 at 5:14:06 PM

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.

by xattt

6/24/2026 at 5:24:41 PM

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

In the US

by dgellow

6/24/2026 at 6:19:43 PM

> 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?

by tucnak

6/24/2026 at 6:42:46 PM

European cities are doing it already.

by badpun

6/24/2026 at 3:09:13 PM

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?

by qsxfthnkp2322

6/24/2026 at 3:45:32 PM

> 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.

by palmotea

6/24/2026 at 3:11:09 PM

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

by jazzyjackson

6/24/2026 at 3:12:21 PM

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.

by qsxfthnkp2322

6/24/2026 at 4:17:29 PM

>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.

by officeplant

6/24/2026 at 3:20:33 PM

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)

by pixel_popping

6/24/2026 at 5:41:32 PM

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

by t0mpr1c3

6/24/2026 at 4:53:21 PM

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.

by mchusma

6/24/2026 at 5:32:00 PM

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

by dgellow

6/24/2026 at 6:19:14 PM

> 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.

by battery_staple_

6/24/2026 at 6:21:17 PM

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

by asdff

6/24/2026 at 6:50:17 PM

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

by wolvoleo

6/24/2026 at 2:26:12 PM

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?

by nialse

6/24/2026 at 2:52:34 PM

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)

by eqvinox

6/24/2026 at 3:58:57 PM

> 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.

by quickthrowman

6/24/2026 at 2:49:28 PM

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?

by eqvinox

6/24/2026 at 3:16:43 PM

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.

by maxerickson

6/24/2026 at 3:26:51 PM

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.

by RicoElectrico

6/24/2026 at 3:37:49 PM

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.

by amluto

6/24/2026 at 3:59:37 PM

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.

by eqvinox

6/24/2026 at 6:11:18 PM

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.

by amluto

6/24/2026 at 3:38:36 PM

wasn't this announced at gtc in march?

by htrp

6/24/2026 at 2:23:15 PM

[dead]

by transformerash