5 ms·

Did they solve the inefficiency problem of peltiers?

by anticensor 1y ago

cosmotic 1y ago
The article says they have made peltiers 75% more efficient than existing ones.
- nine_k 1y ago
  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 1y ago
    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.
    - jfengel 1y ago
      A common use case: coolers. You don't want a whole compressor, but you do want to keep your hot dogs safe and your beer drinkable. It's not very efficient but it's enough for short periods.
      - AngryData 1y ago
        There are mini-compressor based coolers available now if you look for them. They cost a little bit more, and obviously have more weight than a peltier, but I think are worth it if a bag of ice isn't viable by itself because they will run for way longer than a peltier setup.
    - Auracle 1y ago
      I considered putting some in our under-sink reverse osmosis tank, to cool the water. Couldn’t come up with a way to exhaust the heat well enough to even look at how much electricity it would have cost me though - probably too much to make it worth it.
  - bluGill 1y ago
    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)
  - mousethatroared 1y ago
    "that is, it produces 35 W of cooling per 1 kW consumed." No, they don't. First, without defining a delta T, efficiency is meaningless (unless its a Carnot cycle). Second, the efficiency is (depending on op. point) higher than 100%. See [1]. You can pump 20 W of thermal power with 2 A @ 4 V = 8 W 20 W of cooling for 8 W of work, or an efficiency of > 200%. This is common to all refrigeration cycles, and frankly for a puny 10C, it sucks. [1] https://www.datasheethub.com/wp-content/uploads/2022/10/datasheet-24.pdf https://www.datasheethub.com/wp-content/uploads/2022/10/data...
    - nine_k 1y ago
      Oh, indeed I was wrong; COP of Peltier elements is much higher than I had gleaned from online charts, not the order of 0.03 (3%) but can easily reach values above 1.0 (100%) and be e.g. 0.5 (50%) at ΔT = 30C, enough for a home fridge. Still a bit far from compressor-based designs, but not negligible, and almost doubling the efficiency is indeed a serious advance.
  - stephen_g 1y ago
    That is wrong, COP is expressed as a ratio, not a percentage (efficiency is expressed as a percentage, which is COP * 100). And as others have said, both efficiency and COP are dependent on ΔT both in refrigeration and thermoelectric cooling.
bluGill 1y ago
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 1y ago
  > 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 4°C, because that's dangerous. And you obviously don't want your fridge to go below 0°C. But finding a setting where the hottest part of the fridge doesn't go above 4°C (or even 5°C or 6°C) during the hottest part of the cycle and the coldest part of the fridge doesn't go near 0°C during the coldest part of the cycle is really pretty difficult, in my experience.
  - palata 1y ago
    > You hear that you shouldn't let your fridge go above 4°C Really? My fridge says 8°C, I think?
    - nandomrumber 1y ago
      Between 3°C and 5°C is the recommended refrigeration temperature
      - dijit 1y ago
        https://www.which.co.uk/reviews/fridges/article/how-to-store-food-safely-in-the-fridge-a05PO7F3s4m3 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 1y ago
      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.)
ethan_smith 1y ago
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 1y ago
  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.
est 1y ago
> In the Bespoke AI Hybrid Refrigerator Samsung launched in 2024, the compressor operates under normal conditions such as routine storage and retrieval, while the Peltier device activates alongside the compressor during high-load situations — like when storing large amounts of groceries or placing hot food inside — thereby enhancing both cooling performance and energy efficiency I'd choose a fridge with a larger compressor.
- baby_souffle 1y ago
  Larger compressor would probably mean short cycling though. That has its own downsides.

Did they solve the inefficiency problem of peltiers?

cosmotic 1y ago

The article says they have made peltiers 75% more efficient than existing ones.

nine_k 1y ago
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 1y ago
  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.
  - jfengel 1y ago
    A common use case: coolers. You don't want a whole compressor, but you do want to keep your hot dogs safe and your beer drinkable. It's not very efficient but it's enough for short periods.
    - AngryData 1y ago
      There are mini-compressor based coolers available now if you look for them. They cost a little bit more, and obviously have more weight than a peltier, but I think are worth it if a bag of ice isn't viable by itself because they will run for way longer than a peltier setup.
  - Auracle 1y ago
    I considered putting some in our under-sink reverse osmosis tank, to cool the water. Couldn’t come up with a way to exhaust the heat well enough to even look at how much electricity it would have cost me though - probably too much to make it worth it.
- bluGill 1y ago
  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)
- mousethatroared 1y ago
  "that is, it produces 35 W of cooling per 1 kW consumed." No, they don't. First, without defining a delta T, efficiency is meaningless (unless its a Carnot cycle). Second, the efficiency is (depending on op. point) higher than 100%. See [1]. You can pump 20 W of thermal power with 2 A @ 4 V = 8 W 20 W of cooling for 8 W of work, or an efficiency of > 200%. This is common to all refrigeration cycles, and frankly for a puny 10C, it sucks. [1] https://www.datasheethub.com/wp-content/uploads/2022/10/datasheet-24.pdf https://www.datasheethub.com/wp-content/uploads/2022/10/data...
  - nine_k 1y ago
    Oh, indeed I was wrong; COP of Peltier elements is much higher than I had gleaned from online charts, not the order of 0.03 (3%) but can easily reach values above 1.0 (100%) and be e.g. 0.5 (50%) at ΔT = 30C, enough for a home fridge. Still a bit far from compressor-based designs, but not negligible, and almost doubling the efficiency is indeed a serious advance.
- stephen_g 1y ago
  That is wrong, COP is expressed as a ratio, not a percentage (efficiency is expressed as a percentage, which is COP * 100). And as others have said, both efficiency and COP are dependent on ΔT both in refrigeration and thermoelectric cooling.

bluGill 1y ago

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 1y ago
> 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 4°C, because that's dangerous. And you obviously don't want your fridge to go below 0°C. But finding a setting where the hottest part of the fridge doesn't go above 4°C (or even 5°C or 6°C) during the hottest part of the cycle and the coldest part of the fridge doesn't go near 0°C during the coldest part of the cycle is really pretty difficult, in my experience.
- palata 1y ago
  > You hear that you shouldn't let your fridge go above 4°C Really? My fridge says 8°C, I think?
  - nandomrumber 1y ago
    Between 3°C and 5°C is the recommended refrigeration temperature
    - dijit 1y ago
      https://www.which.co.uk/reviews/fridges/article/how-to-store-food-safely-in-the-fridge-a05PO7F3s4m3 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 1y ago
    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.)

ethan_smith 1y ago

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 1y ago
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.

est 1y ago

> In the Bespoke AI Hybrid Refrigerator Samsung launched in 2024, the compressor operates under normal conditions such as routine storage and retrieval, while the Peltier device activates alongside the compressor during high-load situations — like when storing large amounts of groceries or placing hot food inside — thereby enhancing both cooling performance and energy efficiency I'd choose a fridge with a larger compressor.

baby_souffle 1y ago
Larger compressor would probably mean short cycling though. That has its own downsides.