Posted by mcswell 6/30/2025
https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine
it should be pointed out that thermoelectric cooling that was able to outperform mechanical pumps, would still be mostly useless for on device cooling as it cant move heat any distance, with it's own heat stuck in the same box or package, making design pivot around that limitation.
>system-level coefficient-of-performance is ~15 for temperature differentials of 1.3 °C.
There's a long way to go. As far as I know, the leader in condensed-phase refrigeration cycles is still the sodium iodide ionocaloric method, which blew past all of the competing methods (magnetocaloric, elastocaloric, thermoelectric) when it was announced in 2022:
https://www.science.org/doi/10.1126/science.ade1696
...but the temperature drop of 25 C is just barely practical for air conditioning in warm (but not desert) climates.
No, they turn a temperature gradient into electricity. If one side is heated and the other cooled, you can get current flow on the two leads. And as with many electrical devices, it can also be run in reverse: if you put a voltage across the leads then one side will get hot and the other side will get cold.