[HN Gopher] Electrocaloric material makes refrigerant-free solid...
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Electrocaloric material makes refrigerant-free solid-state fridge
scalable
Author : westurner
Score : 136 points
Date : 2023-12-02 03:41 UTC (19 hours ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| vlovich123 wrote:
| This is just more efficient Peltier coolers right? Or is this
| some other effect?
| calamari4065 wrote:
| It's a different effect:
| https://en.m.wikipedia.org/wiki/Electrocaloric_effect
| addaon wrote:
| Peltier effect generates spatially-separated hot and cold
| sides. Electrocaloric effect generates temporally-separated hot
| and cold periods. The Peltier effect is simpler to harness into
| a refrigeration unit (put the cold stuff on the cold side,
| dissipate heat from the hot side), but has lower potential
| efficiency.
| mitthrowaway2 wrote:
| Now we just need to combine it with thermal transistors* on
| the front and back sides to gate and pump the heat in one
| direction. Conduct -> Cool -> Insulate -> Heat -> Conduct ->
| Cool... (while doing the opposite on the heat-sinking side,
| of course)
|
| (*from 3 weeks ago on HN)
| https://news.ycombinator.com/item?id=38259991
| westurner wrote:
| Perhaps a black hole could do some of the Heat phase, at
| least. From https://news.ycombinator.com/item?id=38450636 :
|
| "Using black holes as rechargeable batteries and nuclear
| reactors" (2023) https://arxiv.org/abs/2210.10587
| londons_explore wrote:
| I think the article is carefully written to imply that this
| tech is more efficient than peltier coolers, while not actually
| making such a claim.
| marcosdumay wrote:
| It is potentially more efficient. But the thing on the
| article is on the "make it work" phase, and doesn't work in
| any way even resembling "well".
| ugh123 wrote:
| This had me thinking of "Tech Ingredients" on diy solid state
| refrigerator. https://www.youtube.com/watch?v=YWUhwmmZa7A
| Animats wrote:
| Is this the same one as last week?
| westurner wrote:
| https://news.ycombinator.com/item?id=38359089 :
|
| > _" High cooling performance in a double-loop electrocaloric
| heat pump" (2023)
| https://www.science.org/doi/10.1126/science.adi5477 _
|
| > _Electrocaloric
| effect:https://en.wikipedia.org/wiki/Electrocaloric_effect _
| londons_explore wrote:
| Not one of the figure in the article is relevant to judging the
| future success of this technology...
|
| Temperature delta can be increased by just putting devices in
| series. Cooling wattage can be increased by putting devices in
| parallel
|
| Cooling wattage per electrical watt with a given delta-T is the
| figure that matters (effectively efficiency).
| semi-extrinsic wrote:
| > Temperature delta can be increased by just putting devices in
| series.
|
| Yes, but depending on efficiency this can scale quite horribly.
| Multi-stage Peltier coolers, for example, used to be absolutely
| horrible in yhis regard - a two stage device would need to
| dissipate 100W at the high temperature side to provide just 1W
| at the cold side. (I remember doing the math for a project
| around 2016, don't know how much better it is these days.)
| ozyschmozy wrote:
| > A syringe pump pushes the silicone oil one way through the
| stack
|
| This is better than the refrigerant cycle we're using now, sure,
| but I don't see how this is "solid state"
|
| > "We can scale it because those elements we are using are
| already commercialized for other purposes."
|
| > For one thing, none of the present ceramics' key elements are
| appealing for mass production. Lead is toxic; scandium is
| prohibitively expensive; tantalum is a conflict material in
| Central Africa and, Defay says, best avoided.
|
| So it's not available with the current materials they need?
| Terr_ wrote:
| > but I don't see how this is "solid state"
|
| I think the idea is that there are actually _two_ jobs going
| on, and one of them has been solid-state-ified: (1) cycling
| something between hot and cold and (2) ensuring emit-heat-to-
| environment happens separately from the absorb-heat-from-
| contents part.
|
| In a regular refrigerator, refrigerant is pumped around doing
| both things at once, however we could imagine a system where
| there's two loops with a heat-exchanger: One small liquid+gas
| loop for refrigerant, and another silicone-oil loop.
| Karliss wrote:
| Not sure if that was intention, but fridge system can be split
| into two parts producing temperature change, and moving the
| heat. In a typical compressor fridge the gas does both, change
| the temperature by expanding/ compressing and move the heat by
| pumping it around. I guess the electrocaloric effect does the
| first half in solid state. With oil being pumped doing second
| half in a non solid state way. Isn't system capable of moving
| heat automatically a fridge? No- you can have a heat mover
| which is capable to only move heat from hot to cold like a
| water cooler in a PC.
| slashdev wrote:
| With elements though it really depends how much you need.
| logtempo wrote:
| It's scalable from an industrial point of view, but it's not
| from a commercial/regulation perspective.
| scythe wrote:
| Heat exchangers are almost never solid-state. Convection is
| just way better. But the cooling element is solid-state.
| OscarCunningham wrote:
| I wonder what the lifespan of these refrigerators would be. You
| might think that solid state devices would have longer lifespans,
| because there's no mechanical wear. But in fact SSDs die faster
| than spinning disks. Batteries swell and electrodes corrode. It
| seems like solid state electronics actually tend to be short-
| lived.
| Kuinox wrote:
| > SSDs dies faster than spinning disks.
|
| That's so wrong it's hilarious.
| adrian_b wrote:
| Which of SSDs or HDDs die faster depends strongly on their
| workload.
|
| For a write-intensive workload, SSDs certainly die much
| faster than HDDs.
|
| Otherwise, HDDs die faster, but modern SSDs die much faster
| than flash memories made with old technologies, which can
| have a lifetime of 10 to 20 years, while few SSDs can be
| expected to have a lifetime much longer than 5 years.
| Kuinox wrote:
| Define "dying" because I prefer my SSD staying in read only
| mode than my HDD becoming unreadable overnight.
| imtringued wrote:
| Your SSD controller gets corrupted and you can't read the
| data anymore.
| toast0 wrote:
| All but one of the many SSDs I've worked with that failed
| did so by refusing to respond to any commands from that
| point forward. The other one was actually probably ok,
| but did a big reallocation and performance was trash
| during the process, so we replaced it.
|
| Some of my hard drives that failed when that way, sudden
| unexpected disappearance from the bus, but most of them
| provided signs of upcoming disaster, which could likely
| have been averted if the signs were considered in a
| timely way.
|
| The failure rate of the SSDs was much lower than the
| HDDs, but the means of failure was more troublesome.
| Out_of_Characte wrote:
| It depends on your definition of 'solid state'
|
| hard drives store bits magnetically , ssd's store bits
| electrically. You could call both solid state if the SSD wasn't
| specifically named due to its close relation to dram and cache
| lines that need active power. I would also consider hard drives
| more solid than ssd's if you tested for how long each could
| resist entrophy if there was no source of low entrophy.
| velcrovan wrote:
| uh...no, "solid state" doesn't have competing popular
| definitions. Solid state means the state can be read or
| written without moving parts or gaseous components. SSDs have
| this property, hard drives clearly do not.
| parineum wrote:
| > Solid state means the state can be read or written
| without moving parts
|
| Ahh so the data on this cooler can be read without moving
| parts, interesting.
|
| OP was talking about the definition of solid state in a
| broader sense. In that broader definition (useful outside
| of computer hardware) "solid state" could refer to the
| parts that don't require constant power to maintain state.
|
| OP was demonstrating how the term could be reasonably used
| to mean different things in different ways meaning that
| "solid state" is not a very useful term in it's own, it
| needs context to be meaningful.
| lupusreal wrote:
| If it's got a motor spinning something as an essential
| part of its operation, it's not solid state in any
| conceivable sense.
| velcrovan wrote:
| > Ahh so the data on this cooler can be read without
| moving parts, interesting.
|
| I never said data, I said state. If you're getting hung
| up where I said "written" just think "changed" instead.
|
| > In that broader definition (useful outside of computer
| hardware) "solid state" could refer to the parts that
| don't require constant power to maintain state.
|
| This particular "broader definition" is not used in any
| domain, nor is it at all useful.
|
| Nor was OP talking about any domain outside of computer
| hardware. They were talking specifically about hard
| drives and SSDs.
|
| > OP was demonstrating how the term could be reasonably
| used to mean different things in different ways meaning
| that "solid state" is not a very useful term in it's own,
| it needs context to be meaningful.
|
| They were demonstrating that if you make up definitions
| arbitrarily then nothing means anything. Regardless,
| "solid state" is a well-understood term with a specific
| widely understood meaning in the domain we're all
| obviously discussing.
| svnt wrote:
| > "solid state" could refer to parts that don't require
| constant power to maintain state
|
| there is already a perfect term for that:
|
| nonvolatile
|
| non*vol*a*tile [nan'val@dl] ADJECTIVE not volatile.
|
| computing (of a computer's memory) retaining data even if
| there is a break in the power supply
| spatialwarrior wrote:
| Would it theoretically be possible to create a nano-scale (or
| pico-scale?) electric generator that converts heat (atomic or
| molecular motion) into electric current?
|
| It sounds too good to be true to have a refrigerator that
| generates energy, but I lack the education in quantum physics to
| understand why it would be unreasonable or impossible.
| jayknight wrote:
| The Thermoelectric effect can produce electric current from a
| temperature difference (i.e. potential), but heat by itself
| can't do any work unless it has something colder to heat up.
| Refrigerators just do the inverse, they use an electrical
| potential to create a difference of temperature between the
| outside and inside of a box.
|
| https://en.m.wikipedia.org/wiki/Thermoelectric_effect
| logtempo wrote:
| There are very small batteries that use the changes in its
| environments, but it use in general vibration, or light, or
| sugar (see https://en.wikipedia.org/wiki/Sugar_battery). But
| the power is very small, used for very low power devices. One
| could think to use the sun cycle (become a little bit warm,
| then a little bit colder during the night), but at this point
| solar panel do the trick.
| calamari4065 wrote:
| To extract work, you need to move energy across a gradient. You
| can only generate electricity by moving heat from an area of
| high thermal energy to low thermal energy.
|
| The peltier or Seebeck effect does just this. By heating one
| side of the element and cooling the other, you get a small
| amount of electricity. It's impractical and very inefficient,
| though.
|
| Because you must cool one side, you have to have some sort of
| system to remove heat as quickly as you put it in. Active
| cooling with a fan requires too much energy, so you're left
| with passive cooling. As well, the amount of power you get goes
| down as the cold side gets hotter.
|
| There are plenty of good uses, though. Old gas water heaters
| actually used an electronic circuit to control the gas. A
| thermocouple is placed above the pilot light and creates enough
| energy to trigger the solenoid valve. Many types of temperature
| sensors work in the same way.
| blincoln wrote:
| I'm not finding a great ELI5 of the electrocaloric or
| magnetocaloric effects. Specifically, the IEEE article doesn't
| explain how shuffling the generated heat away from the
| electrocaloric material results in a net cooling effect. If one
| tried that with a thermoelectric element, it wouldn't work,
| because when it was shut off, it would just cool down to ambient
| temperature.
|
| Is it correct to say that they're analogous to gases changing
| temperature as the pressure of the gas changes? i.e. not a
| continuous generation of temperature change, but a one-shot
| change between two temperatures that's dependent on the outside
| force (pressure/electrical/magnetic/etc.) and some inherent
| capacity of the medium? That feels like the only way one could
| take away the resulting heat, remove the outside force, and have
| the element end up cooling down to a lower temperature than it
| started out, but I am not a physicist.
| gandalfian wrote:
| I always wonder what the COP efficiency of my fridge is. I mean a
| minisplit AC is about 3 to 1. A fridge is basically a small
| version of the same heat pump. So you would think solid state
| might actually be less efficient, though quieter and more
| reliable.
| coryrc wrote:
| Usually 1.6
| thrawa8387336 wrote:
| We could use ammonia or co2.
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