If it can extract useful work from merely warm water, it would seem like the ideal thing to maximise the overall thermal efficiency of a large power plant.
material fatigue. basically the nitinol springs/belts/strips eventually breaks.
so it's a high maintenance low-efficiency (hard to scale) system compared to regular steam turbines.
... though of course the latter is in development for ~250 years, so it has a bit of a head start.
so it seems like very much part of modern materials science. (and I'd guess bimetals are standard in many heat-related engineering applications, nitinol is just special because of how fast it changes shape, and because it's an alloy not 2 pieces of metal stuck together.)
https://en.wikipedia.org/wiki/Nickel_titanium#Biocompatible_...
This device seems more useful for generating mechanical motion at the point of use, rather than generating electrical power. I'm envisioning solar and hydro-powered pumping systems that operate in remote environments, like the third engineer interviewed in the video. He proposed that the engine could be used to pump water solely due to the temperature difference between the pumped fluid and the air.
Another interesting thing would be to run the system in reverse to turn mechanical energy into a hot and cold fluid. I haven't thought it through deeply, but it seems superficially similar to elastic band refrigerators[0,1].
[0] https://www.science.org/doi/10.1126/science.aax6182 [1] https://www.science.org/content/article/fridge-made-rubber-b...
And the efficiency of the Carnot engine is 1-T_cold/T_hot, both temperatures expresssed in Kelvin. Room temperature water is 300K (that's by convention, this translates in 27 C or 80 F). Let's say warm water is at 333K (that's more like scalding hot, at 60 C or 140 F). The Carnot engine efficiency is then going to be 1 - 300/333 = 10%.
So, not engine can exceed 10% efficiency when using scalding hot water, for merely warm water it's probably going to be 5% or less.
[1] https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#C...
My theory here is that running all the stems, stalks, and roots that you don't use from stuff like annual food crops through a wood chipper or something should macerate the cell walls enough to allow the yeast to feast, at least.