7 ms·
Electrocaloric material makes refrigerant-free solid-state fridge scalable
- vlovich123 3y agoThis is just more efficient Peltier coolers right? Or is this some other effect?
- calamari4065 3y agoIt's a different effect: https://en.m.wikipedia.org/wiki/Electrocaloric_effect https://en.m.wikipedia.org/wiki/Electrocaloric_effect
- addaon 3y agoPeltier 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 3y agoNow 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 https://news.ycombinator.com/item?id=38259991
- westurner 3y agoPerhaps a black hole could do some of the Heat phase, at least. From https://news.ycombinator.com/item?id=38450636 https://news.ycombinator.com/item?id=38450636 : "Using black holes as rechargeable batteries and nuclear reactors" (2023) https://arxiv.org/abs/2210.10587 https://arxiv.org/abs/2210.10587
- araes 3y agoThank you. That's a clear description. I read through that whole article and still was not sure why it was not a Peltier cooler with oil flowing around.
- londons_explore 3y agoI 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 3y agoIt 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 3y agoThis had me thinking of "Tech Ingredients" on diy solid state refrigerator. https://www.youtube.com/watch?v=YWUhwmmZa7A https://www.youtube.com/watch?v=YWUhwmmZa7A
- Animats 3y agoIs this the same one as last week?
- westurner 3y agohttps://news.ycombinator.com/item?id=38359089 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 https://www.science.org/doi/10.1126/science.adi5477 > Electrocaloric effect: https://en.wikipedia.org/wiki/Electrocaloric_effect https://en.wikipedia.org/wiki/Electrocaloric_effect
- londons_explore 3y agoNot 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 3y ago> 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 3y ago> 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_ 3y ago> 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 3y agoNot 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 3y agoWith elements though it really depends how much you need.
- logtempo 3y agoIt's scalable from an industrial point of view, but it's not from a commercial/regulation perspective.
- OscarCunningham 3y agoI 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 3y ago> SSDs dies faster than spinning disks. That's so wrong it's hilarious.
- adrian_b 3y agoWhich 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 3y agoDefine "dying" because I prefer my SSD staying in read only mode than my HDD becoming unreadable overnight.
- lupusreal 3y ago[dead]
- imtringued 3y agoYour SSD controller gets corrupted and you can't read the data anymore.
- Kuinox 3y agoHDD also have a controller.
- deleted 3y ago[deleted]
- spatialwarrior 3y agoWould 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 3y agoThe 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 https://en.m.wikipedia.org/wiki/Thermoelectric_effect
- logtempo 3y agoThere 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 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 3y agoTo 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 3y agoI'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 3y agoI 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 3y agoUsually 1.6
- thrawa8387336 3y agoWe could use ammonia or co2.
- deleted 3y ago[deleted]
- hilbert42 3y agoCapacitors are known to add distortion to signals that pass through them, especially those that use a high-k dielectric such as the ceramic type. It's why capacitor selection in ultra low distortion audio amplifiers is an important consideration. Leaving capacitive effects aside and concentrating on secondary effects, it's been my understanding until now the electric field in a bulk dielectric is never 100% in sync with the applied signal as the field itself physically distorts the dielectric, as such nonlineararities are introduced into the signal as it's transferred across the capacitor and that they vary to some degree with the signal's (field's) frequency and amplitude. Nevertheless, it's never been very clear to me what happens at the molecular level that contributes to this nonlineararity. Essentially, losses in capacitors are due to I²R in its electrodes, bulk resistive leakage within the dielectric as well as resistive impurities in the dielectric and that signal distortion is principally due to the intrinsic nature of the dielectric itself. That is, signal distortion is caused by the action of the field on the dielectric which physically distorts it, and although this action is essentially elastic the effective energy through the capacitor is never a 100% truly accurate analog of the applied signal in that group delay and related effects are introduced, and these contribute distortion (that is, energy essentially remains the same but the signal is changed albeit to a minuscule extent). This new work seems to indicate there are additional reasons for why capacitors contribute distortion to signals. After reading this article it's occurred to me to question how much heat is actually generated within the dielectric by, say, nonelastic strain or deformation of its crystal structure (through molecular movement, phonon coupling losses and or whatever). Heat generated through actual dielectric deformation is energy and by conservation of energy it has to come from the input signal. Signal distortion will then occur by virtue of some energy changing into heat which then becomes subject to thermal inertia. In effect, energy through the capacitor can be lost and if reabsorbed [by adiabatic process?] into the dielectric’s field then the transferred signal will not precisely mirror the input, thus additional distortion is incurred. Moreover, I'd then contend that distortion harmonics introduced into the signal by the dielectric and its related processes are not only likely to be complex but also frequency and amplitude dependent, and would only be predictable with a full understanding of both the dielectric's electrical properties and the heat flow within and around the dielectric. This mechanism may also account for why high-k ceramic capacitors are more lossy at higher frequencies (it also seems the only true distortionless capacitor would be the vacuum type where ε₀ is the effective 'dielectric'). I'd appreciate it if someone with a better understanding of these issues could enlighten me.