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Comment by 0_____0 | Hacker News Reader

This is a heat pipe. A technology from the 60s. Your laptop almost certainly has heat pipes in it. They usually use alcohol rather than water as the phase change material though. The (relatively) novel thing is that it's packaged small enough to be in a phone. I suspect the only reason it hasn't been used in handhelds more is because the TDP of mobile processors wasn't high enough to warrant it.

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Vapor chambers and heat pipes use some of the same physics concepts, but a vapor chamber is significantly more effective for spreading heat across a large area. They’re also harder to manufacture and more complex.

Have you ever seen a CPU or GPU heat sink that has 5-6 heat pipes in parallel because they need to spread the head over a larger area? A vapor chamber is an upgrade over heat pipes in applications that aren’t moving heat from a point to a line.

Don’t be so dismissive. This is actually cool.

Perhaps it's just that in retrospect, it seems a relatively small jump from heat pumps to vapor chambers.

Do you know if the vapor chambers operate at reduced internal atmospheric pressure? Unless I'm missing something, in order to get the liquid-gas phase boundary to a useful temperature, you'd have to bring the pressure down to, idk, 10kPa (boiling point of water is ~50C)? That would complicate manufacturing for sure, and also means that any leaks are catastrophic for your thermal solution.

Also I would be remiss if I did not note that the refrigerant designation of water is R-718.

> Do you know if the vapor chambers operate at reduced internal atmospheric pressure?

Indeed they do. A random search found this company that manufactures vapor chambers and they have a short discussion: https://radianheatsinks.com/vapor-chamber-heatsink/

On one side it’s cool. On the other, it’s a hot chip.

Heat pipes are one dimensional (a pipe), vapor chambers are two dimensional (a square chamber). Most vapor chambers I've seen on GPUs have the chamber attached to lots of small heat pipes on the side though (they even note this in article, in case you feel like reading it).

That said, I assume the main technical breakthrough here is in manufacturing, producing tiny chambers consistently in enough volume for iphones.

Any passive phase change thermal solution is doing the same thing - take thermal energy from one place, and distribute it for dissipation. My point is that the geometric configuration isn't that important, it's doing the same work the same way. Not really worth arguing about, I just suspect that the branding people love that they had a new buzzword in "vapor chamber" to bandy about.

I liked this article from 10 years ago that actually goes into detail about how Fujitsu actually constructed a super-thin heat pipe (really just a very long vapor chamber) https://spectrum.ieee.org/superslim-liquid-loop-will-keep-fu...

"Vapor chamber" isn't a new buzzword. It's been the name for flat plate heat pipes since the 1970s.

https://ntrs.nasa.gov/api/citations/19770025469/downloads/19...

This thread reminds me of a friend that was dismissive of anything Apple does. “They didn’t invent it”, “they rebranded someone else’s invention”, “maybe they invented it but all those features are just marketing”.

No, he has never used owned or used an Apple product. Not worth his time.

I think your friend spoke a kernel of truth while misunderstanding what Apple do well. It's pretty rare that they come out with something that hasn't been done at small scale previously, but they have insane scale (100s of millions of iPhones sold per model), and a well-developed ability to take cutting edge techniques, as well as some tech that is in development but not ready for prime time, and integrate it and release it in products a year before anyone else can tool up to compete.

Also on some Android gaming phones since 2018. Regular heat pipes on phones dates back to at least 2013.

As I understand it, it’s more than that: there are small “inverted pyramids” that cause the water to condense more rapidly, to extract even more heat from the system.

https://youtu.be/qAZ-q3KmDHM?si=pb08RMHEAA4o94xF

texture etc to promote condensation and to wick (without a rope) condensed liquid back to the hot point are also used in heat pipes.

I agree with the other commenters that "vapor chamber" is a kind of heat pipe, since "heat pipe" doesn't really impose constant radii by definition.

>The (relatively) novel thing is that it's packaged small enough to be in a phone

Android/other phones have had heat pipes/vapour chambers for a long time now. I'm not sure why anybody calls this novel or new even when applied to mobile devices.

Moar Apple effect, I guess.

Vapor chambers are in laptops already. Mostly gaming laptops, because they need help getting the heat away from GPUs.

The miniaturisation of vapor chambers is cool, though. Not new (phones have been coming out with those for years), but it's not "just" another heatpipe.

I think that the fact that more and more phones producing so much heat that they need vapor chambers is also something worth writing about.

That said, most news media seems to have drunk the Apple kool aid because they all rave about the vapor chamber for some reason. I guess iPhone media is just a few years behind the curve.

It's a little bit older than just the 60s..

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