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Comment by Animats | Hacker News Reader

Wonder whatever happened to that. And how they got nitinol to work so well. I've seen nitinol wire, but it's not very efficient. You usually only get a few percent of the heat energy out as mechanical energy.

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Efficiency was what I was wondering. But maybe a few percent efficiency is about the best we can do with relatively small temperature differences? I think radio isotope thermal generators are usually only a few percent efficient.

It'd be interesting to try to propel a ship with the temperature differential between air and water.

RTGs have other issues as well, they need to radiate all heat on the "cold" side into space, so you're between a rock (high hot-cold temperature difference needed) and a hard place (need high cold temperature to radiate) even before you get to thermo-electric generators being inefficient.

iirc the stuff on probes is ~90W of TEM. I know a lot of people say "it's hard to cool stuff in space" but blackbody radiation is a thing. It's all just photons, in the end. the TEM just takes the high energy particles and slows them down enough to be "light" and takes a bit (10%?) of the energy from doing that and uses it to charge batteries. Kind of.

Considering they only talked about applications using low grade heat, I'd say it makes sense iff it's cheap enough, no matter how inefficient because that heat is normally wasted.

So you say!

Meanwhile, nitinol actually works via a quantum property, and is sucking energy out of a sister universe.

You don't care because cheap and free, but they do! Doubly so because it sucks power at the easiest parallel source, which are (in their universe) simple copper wire.

Worse, the power stolen is 1000x of times that received, meaning they have been having significant power losses on long power runs.

This means that they have to setup more local generating power, as long power transfer from hydro dams, and clean central sources won't work.

More coal, natural gas, thanks to you! And global warming is far more advanced there.

But you don't care, eh?

When will people learn.

I remember that episode of Stargate Atlantis

The Gods Themselves (1972) by Issac Asimov was perhaps the original inspiration.

Funny story, the setting of part 2 was so different to part 1 that I mistook the book for a collection of novellas until more than half way through.

Thanks for the reference. For me it was not Stargate but a recent popular Sci-fi book.

It's called the W dimension.

Only if you ignore costs.

Quite an expensive machine to only generate 35W. Consider how much cheaper and more reliable 35W of solar would be (even including an overnight battery).

Comparing a 35W prototype from the 1900s with a modern 35W PV panel isn't very fair though.

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