4 ms·

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.

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.