[HN Gopher] Staying cool without refrigerants: Next-generation P...
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Staying cool without refrigerants: Next-generation Peltier cooling
Author : simonebrunozzi
Score : 86 points
Date : 2025-07-20 20:18 UTC (2 hours ago)
(HTM) web link (news.samsung.com)
(TXT) w3m dump (news.samsung.com)
| WarOnPrivacy wrote:
| I used peltier coolers on K6 processors 1M computer years ago.
| They worked great and lasted about as long as the PCs did.
|
| Not long after I bought mine, they disappeared from cooler
| offerings. I've wondered what became of the tech.
| PaulHoule wrote:
| I remember one objection to Peltier coolers in that application
| is that could possibly cool the CPU below the dew point and
| cause water condensation, something a fan can't do.
| rurban wrote:
| For this we calculate the dew point with 2 sensors and react
| accordingly in my temperature controller.
|
| I'd really like to try out these better peltiers, our current
| ones suck. And the fans to remove the heat are huge and loud.
| PaulHoule wrote:
| There are other ways of building refrigerant-free
| refrigerators too
|
| https://en.wikipedia.org/wiki/Magnetocaloric_effect
|
| and
|
| https://en.wikipedia.org/wiki/Elastocaloric_materials
|
| of course they also have the dew point problem, but so do
| ordinary refrigerators and freezers.
| marcusb wrote:
| A friend had a Peltier cooler on a late 90s/early 2000s CPU
| and had the condensation problem. The cooler (or maybe CPU,
| or both; I can't remember which) had an algae-like growth all
| over it.
| duskwuff wrote:
| > I've wondered what became of the tech.
|
| Remember that Peltier coolers don't make heat disappear - they
| just move it from one side of the cooler to the other, and
| produce a lot of additional waste heat in the process. There
| are better ways of transferring heat from a hot IC to a heat
| sink nowadays - like liquid cooling for really high-performance
| systems, or capillary-action heat pipes for more typical needs.
| delusional wrote:
| > There are better ways of transferring heat from a hot IC to
| a heat sink nowadays
|
| Peltiers were always a bad way to move the heat. What they
| offered was the ability to go below ambient, which at the
| time could improve overclocking. Peltiers of course lacked
| the capacity to actually take you there with any decent load,
| but in theory it could.
|
| It never really made much sense for consumers, and once
| consumers realized that, the market went away.
| s0rce wrote:
| They are inefficient and dump a bunch of additional heat into
| the heatsink that you need to get rid of.
| Aurornis wrote:
| Your K6 processor has a TDP somewhere around 20-30W depending
| on the model.
|
| Modern performance CPUs have TDPs in the 100-200W range.
|
| Peltier cooling generates a lot of additional heat. It doesn't
| scale well to the higher loads. That's why you don't see them
| any more.
| rcxdude wrote:
| TDP went up. TECs are extremely inefficient, and have limits on
| how much heat they can pump in a given area anyway. a 10W chip,
| you can maybe get away with, and it might be a meaningful
| improvement compared to the other cooling tech available at the
| time, if you don't mind the power usage. with a 100W chip, you
| have no chance.
|
| (You can see a demo here where LTT try it, and they, after
| dumping 500W into the cooler, can get the CPU to a vaguely
| reasonable temperature, until they actually load it up:
| https://www.youtube.com/watch?v=sWrqyQWfhrs)
| anticensor wrote:
| Did they solve the inefficiency problem of peltiers?
| cosmotic wrote:
| The article says they have made peltiers 75% more efficient
| than existing ones.
| nine_k wrote:
| OK, a typical Peltier device has 3.5% coefficient of
| performance, that is, it produces 35 W of cooling per 1 kW
| consumed.
|
| Fine, let's expect that the new tech doubles the efficiency,
| to 7%. Still, to my mind, pretty wasteful, on par with a
| steam railway engine. A Peltier element is good in cases
| where you can afford a large heat removal device, but need
| precise temperature control and no moving parts. For a home
| fridge, I'll take the sound of the compressor and the
| temperature fluctuations of a 400% efficient compressor-based
| heat pump over a Peltier element any day.
| sunshine-o wrote:
| While Peltier cooling have low efficiency wouldn't it be
| ideal in some cases like:
|
| - energy source is solar, DC already and abundant.
|
| - cold climate so the fridge can contribute to heating the
| room
|
| Anyway good to know those small electric cooler with
| Peltier effect must be consuming a lot electricity.
| bluGill wrote:
| A steam railway engine is a lot better than you would
| think. They were more efficient than diesel engines when
| diesel took over - the diesel engine needs much less human
| labor and so was cheaper overall, but for efficiency steam
| was better. (Note that diesel technology has improved since
| the 1950s, so I don't know how they compare now)
| bluGill wrote:
| They claim 75% better. I doubt this is better than compressors
| in general but they seem to be going for a niche where a high
| power compressor does the high load part but when only a litte
| cooling is needed the compressor is now very inefficient and so
| the peltier is better. Normal fridges just let the temperature
| have a wider swing which is good enough for most needs.
| mort96 wrote:
| > Normal fridges just let the temperature have a wider swing
| which is good enough for most needs.
|
| These wide swings annoy me. You hear that you shouldn't let
| your fridge go above 4degC, because that's dangerous. And you
| obviously don't want your fridge to go below 0degC. But
| finding a setting where the hottest part of the fridge
| doesn't go above 4degC (or even 5degC or 6degC) during the
| hottest part of the cycle and the coldest part of the fridge
| doesn't go near 0degC during the coldest part of the cycle is
| really pretty difficult, in my experience.
| palata wrote:
| > You hear that you shouldn't let your fridge go above
| 4degC
|
| Really? My fridge says 8degC, I think?
| nandomrumber wrote:
| Between 3degC and 5degC is the recommended refrigeration
| temperature
| dijit wrote:
| https://www.which.co.uk/reviews/fridges/article/how-to-
| store...
|
| Christ.
|
| I also run my fridge at 8C, which I think was the default
| setting when I bought it.
|
| Gonna go change that right now.
| userbinator wrote:
| 8 degrees or just 8 on the 1-10 scale that many of them
| use?
|
| (I always remember the recommended fridge temperature as
| 40F, which avoids the confusion.)
| nandomrumber wrote:
| Put a thermometer in a plastic bag (to keep it dry) in a
| jar of water in your fridge, you'll likely find the
| temperature of items inside the fridge much more stable
| than the air temperature.
| javiramos wrote:
| You should buy a fridge with a fan in the cooling chamber.
| My Samsung fridge has a nice fan and associated ducting to
| circulate air and keep temperatures ~uniform.
| mort96 wrote:
| I may consider that the next time I buy a fridge, but the
| reality is that this isn't something I care deeply enough
| about to buy a new fridge over.
| obfuscator wrote:
| Why should that be dangerous? I have never heard that.
|
| I have always had my fridge at 8degC and never had
| something dangerous happen to me. I have never come across
| fridges that were way cooler, apart from fridges of friends
| in Canada and the US. What's the reasoning?
| ethan_smith wrote:
| Traditional Peltier devices operate at ~10% efficiency (COP of
| 0.5-0.7) compared to vapor-compression systems (COP of 2-4),
| but recent advances in thermoelectric materials like bismuth
| telluride alloys and segmented elements have pushed lab
| efficiencies to ~15-20%.
| HPsquared wrote:
| It's clearer to think in terms of "efficiency relative to
| ideal Carnot efficiency".
|
| Compressor systems use twice as much energy as an ideal
| system, while Peltier systems use about 10x as much.
| BearOso wrote:
| AI has literally nothing to do with this. Why do they feel the
| need to sprinkle the phrase everywhere? AI inverter/compressor?
| Come on, have some sense of shame, please.
| savrajsingh wrote:
| Because it works wonders on non-technical people
| rcxdude wrote:
| It's the name of the game, alas. In the area I work in, I've
| seen many companies get many multiples of the investment we've
| gotten because it's "quantum", even though they're trying to do
| the same thing we're doing and doing less well at it.
| throwaway81523 wrote:
| I thought Peltiers can't lower the temperature by more than 40
| degrees F, in practice less than that. This is not cold enough
| for a refrigerator on a warm day.
| szvsw wrote:
| FWIW, in a typical apartment or single-family home,
| refrigeration uses a fraction of the energy that space cooling
| (also via a refrigeration/vapor compression cycle) requires on
| a warm day (and probably year round too unless in very mild
| climates). The psychrometric chart path is different so there
| are of course differences in the amount of energy required for
| the sensible and latent components, but the real difference is
| just the volume of air that needs to be dealt with.
|
| My point being that at least from an energy and carbon
| perspective, lowering the space cooling demand via more
| effective building envelopes or increasing the space cooling
| supply efficiency - eg via membrane or dessicant
| dehumidification, better heat pumps etc) is far more impactful
| on a macro scale than better refrigeration.
|
| Granted refrigeration in a warehouse eg is really also space
| cooling, but I'm just making the distinction between the
| dT=0-25F context and the dT>25F context. If I could only choose
| one technology to arrive at scale to improve the efficiency, it
| would be for the former context.
| closewith wrote:
| Definitely not the volume of air. The thermal mass of air is
| tiny.
|
| The difference is in the thermal mass of the building and the
| surface area exposed to the sun.
| rcxdude wrote:
| Also the area that needs insulating, and in the extremes
| the amount of air that needs to be exchanged with the
| outside to make the house livable, and the heat generated
| by the people living in it (stick a 100W lightbulb in a
| fridge and see how cold it can get).
|
| The insulation is actually solvable, and for heating can
| basically remove the power requirements: a house heated and
| using heat exchange on air leaving vs entering can be
| heated a lot just by having people inside it, let alone the
| other energy they use for other purposes. It's just more
| expensive to build this way, and with cheap energy it can a
| long time to pay back. Cooling you can't push down past the
| heat generated inside the house divided by the COP of your
| cooler, though.
| numpad0 wrote:
| There are no inherent max temperature deltas for Peltiers, just
| coefficient of performance, or watts moved per watts wasted, is
| atrociously low compared to just about everything else.
| wtallis wrote:
| Peltier coolers have non-zero thermal conductivity and are
| pretty thin. At some point, heat leakage from the hot side to
| the cool side catches up to the rate of heat removal the
| cooler is capable of. What that point is will vary between
| devices, so there's no single or fundamental limit.
| rcxdude wrote:
| You can also stack them, but you need ever-increasing areas
| of TEC and corresponding power consumption. I think a
| triple-stack is sometimes practical if you want to get
| something to well below ambient and it doesn't really
| generate much heat itself (and you don't really want to use
| a traditional cooler due to size or vibration or something
| similar)
| dartharva wrote:
| But why? Cooling has been a solved problem for literally over a
| century. No Peltier cooler will ever even come close to normal
| refrigerant-based coolers in efficiency, both in cost and power
| consumed.
| toast0 wrote:
| Peltier coolers can do precision better than a compressor. The
| also work at small sizes/small loads, where a compressor
| generally needs to be a certain minimum size to be feasible.
|
| Do you need those things in a home refrigerator? I suspect not.
| But it might be handy for lab refrigerators.
| Tistron wrote:
| What I want is a silent refrigerator, will this bring that?
| _pray_
| userbinator wrote:
| Absorption refrigerators have been around for approximately a
| century, are silent, and a little more efficient than peltiers.
| bob1029 wrote:
| I've been thinking about what it would look like to convert my
| GE fridge into a minisplit (i.e., move the compressor,
| condensing coil & fan outside).
|
| You can buy R600a on Amazon right now. One $60 can will charge
| the system ~5 times.
| toomuchtodo wrote:
| https://patents.google.com/patent/US20120192586A1/en
|
| (abandoned)
| theluketaylor wrote:
| With home HVAC, fridges, water heaters, and dryers all using
| now able to use of dependent on heat pumps I wonder how long
| it be before we see modular appliances that connect to
| coolant lines where the temperature differential is supplied
| by a central high efficiency heat pump.
|
| Cars already have heat scavenging that can move heat from
| where it's being created through losses to places where it's
| valuable, like the cabin or battery pre-heating. Especially
| in cold climates it feels like homes should be next.
| userbinator wrote:
| It's worth noting that the very earliest electric
| refrigerators had a separate condensing unit outside; see
| this interesting 1920s Frigidaire training video for an
| example of what that was like:
| https://www.youtube.com/watch?v=W-t7DqOAMME
|
| There were also centralised systems for apartments where one
| condensing unit supplied many evaporators in the refrigerator
| in each suite.
| NuclearPM wrote:
| Why?
| iLoveOncall wrote:
| Not OP but it's a massive nuisance if you live in a studio.
| People don't realize how noisy a fridge is until there's one
| in the room that they sleep in.
| storus wrote:
| Just today I ordered a 32dB Liebherr; the previous one had
| 35dB and could be heard all around the studio (I measured
| the noise using a dedicated sound meter).
| tormeh wrote:
| Skill issue on the manufacturer's part. I live in a studio
| and never hear the fridge. This is part of a fitted
| kitchen, though, but I doubt the panel hiding the fridge
| makes that big of a difference.
| majormajor wrote:
| New appliances are far better than old ones here.
| Especially old ones that (I assume) haven't been maintained
| and so are working far harder than they used to. I've lived
| in places with old ones that were fine and old ones that
| were awful, both. I've had much more consistently good
| results in places with newer ones.
| esseph wrote:
| You can hear your refrigerator???
| bob1029 wrote:
| The latest wave of appliances is really fucking loud for some
| reason.
|
| I think they're using different kinds of motor windings,
| bearings, insulation, etc. it's not related to the
| refrigerant or other system parameters. I've had older r600a
| fridges that were dead silent compared to anything sitting in
| a Best Buy showroom right now.
| userbinator wrote:
| Likely high speed compressors --- the oldest hermetic
| systems used an induction motor running at 1800 RPM, then
| later they went to 3600 RPM, and now they're running on a
| VFD that possibly goes much faster. By making it pump
| faster, they can use a smaller compressor and reduce costs,
| at the expense of longevity and noise.
| madaxe_again wrote:
| They use lighter lubricant oils than were historically
| used, which allows more vibration. It's also why
| compressors burn out far more quickly than they used to.
| dayjah wrote:
| I worked on a scientific instrument a while ago, it had a Peltier
| heater on it to raise the sample to 60c from whatever residual
| environment temp was (approx. 20c in a lab). It was pretty
| amazing to see my old overclocking cooling solution come back
| around and be used in my professional career some 20+ years later
| madaxe_again wrote:
| And they couldn't use a 100% efficient resistive element
| because...?
| rcxdude wrote:
| The TEC is more than 100% 'efficient' - you get more heat out
| than power you put in. Though I would guess it's mainly there
| to get heat control that can span above, around, and slightly
| below ambient.
| fghorow wrote:
| For those worried about tiny COPs from these gizmos, trawling
| through the actual paper -- as well as the PR from JHU APL -- in
| this HN post [1] shows claims of COPs of ~15 for Delta Ts of
| 1.3degC.
|
| A compressor based cooler gets a COP of about 4 in the real
| world. I'm pretty sure this is an apples to oranges comparison to
| an expert (I am not one of those) but a factor of 3+ increase in
| COP is fairly noteworthy -- if it holds up.
|
| [1] https://news.ycombinator.com/item?id=44424087
| moffkalast wrote:
| 15 is absurd, regular peltiers get like 1.05 at most don't
| they? That's like inventing the warp drive but for cooling.
| 1oooqooq wrote:
| lol yeah they did not. it's right on the abstract.
|
| > is ~15 for temperature differentials of 1.3 degC.
| rcxdude wrote:
| You can get a COP of ~3-4 out of regular TECs, but only at
| pretty low temperature differences. That's the killer,
| fundamentally the TEC material itself is thermally conductive
| and heat really wants to flow back the other way, so no
| matter how well it moves the heat, it winds up fighting
| against the heat load generated by itself. A refrigerant
| based heat pump works much better because the heat basically
| only moves in the direction the refrigerant itself is moving.
| userbinator wrote:
| _Delta Ts of 1.3degC._
|
| Might as well not use a refrigerator if your ambient
| temperature is that low.
| HPsquared wrote:
| What about a DT of say 20degC? I'd reckon most refrigerators
| and air conditioners are around there (temp difference of
| refrigerant between evaporator and condenser).
|
| Stacking a bunch of these Peltiers to give more temperature
| difference would give a pretty low CoP. Say, for a 13degC
| temperature difference you'd have to stack 10 of them and use
| 10x the power. It's even worse actually as the hotter ones have
| to also pump the waste heat from the cooler ones.
| MobiusHorizons wrote:
| I believe the "apples to oranges" is the temperature gradient.
| AC units would routinely manage 15-20c and are rated for more
| than that. And some freezers manage up to 50c. The greater the
| gradient the worse the efficiency in general.
| madaxe_again wrote:
| The delta of 1.3C is critical there - peltier cooling drops
| precipitously in efficiency as the delta increases, and
| struggles to hit a COP of even 1 in _real world_ scenarios.
| Their figure works out at about 6.5% Carnot efficiency, whereas
| a normal heat pump is usually nearer 45% over a much broader
| range of temperatures, as you can separate the hot and cold
| sides completely. Not so with a peltier wafer.
|
| What they've done here is add a point of failure, use
| additional materials as well as a traditional heat pump, and
| called it "AI" and "eco friendly".
|
| Never have I seen more prime VC bait.
| iLoveOncall wrote:
| The most impressive thing about this article is that they somehow
| managed to shoehorn AI in a fridge.
| 1oooqooq wrote:
| AI compressor.
|
| It's full on clown world.
| TealMyEal wrote:
| What's even AI about it?
| koakuma-chan wrote:
| Much like a hybrid vehicle, this system intelligently
| switches between the two cooling methods depending on what
| best suits the situation.
| 42lux wrote:
| Killed an AMD K6 with my diy peltier cooler when I was 14 good
| times.
| dawnerd wrote:
| A lot of people consider them gimmicks but the newer gen neck
| "air conditioners" do actually cool the air and exhaust the hot
| air so the peltier works. Would love to see it improved for more
| cooling capacity (and more airflow).
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