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• Warl0k3@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

  That’s the most common proposal for MHD generators - once it goes thru the MHD proper you use the waste heat to drive a conventional powerplant. Unfortunately MHD requires the production of plasma to be effective, and plasma just does not like to exist, so the engineering practicalities make it… unlikely to ever be even remotely viable outside of incredibly niche applications (non-plasma MHD has been studied, and I believe there are even some human trials, to power implants in the body like pacemakers)

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  • RampantParanoia2365@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    Jesus Christ, I imagined some kind of Matrix scenario when you said human trials.

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    • Warl0k3@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      Worry not, the implanted power systems I know of generate at peak a few nanowatts of energy. Enough to tricklecharge a device or run some very very very efficient digital hardware, but no way you’re harvesting that power for anything useful. It’d be far more practical just to have the humans chained to bicycle generators…

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    • T156@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      The oil crisis isn’t quite that bad yet.

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  • HeyThisIsntTheYMCA@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    ooo, i’m trying to keep up on Deep Brain Stimulation research (i want one for reasons. they aren’t doing what i want yet, but in about 5 years they should be there) and that sounds like related research

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    • Warl0k3@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

      I’ll admit I’ve been out of the field for a couple years so my information is going to be outdated, but I believe the issue with using MHD for continuous stimulation is that it generates tiny amounts of power - enough to trickle-charge a pacemaker, but not enough to keep tickling the brainstem with the frequency needed in DBS.

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      • HeyThisIsntTheYMCA@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

        huh, so you wouldn’t have to plug in and recharge your pace?

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• FuglyDuck@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

  Well, not an engineer myself, either, but generally speaking that would greatly increase the systems complexity, which generally increases maintenance costs, down time, and the initial cost of the system.

  You might be able to eke out a bit more power, but there’s more to the decision than total output and how efficient it is.

  What I would imagine were a fusion-powered MHD being useful would be as a front end to fusion-based plasma propulsion. (Basically something like the VSIMR, Hall effect or whatever plasma thruster, where the fusion reaction generates both some power to create the thrust and its exhaust plasma is also the reaction mass.(I mentioned I’m not an engineer… right? Just an incorrigible nerd who likes sci-fi.)

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  • GreenCrunch@piefed.blahaj.zone ⁨3⁩ ⁨weeks⁩ ago

    There’s a few things (I am an engineer, though not nuclear): 1) Efficiencies don’t necessarily stack like that. For boiling water you’re dependent on kinetic energy as heat. I’m not familiar with running plasma through magnetic fields for power generation, but if you lose thermal energy, your overall efficiency may be worse. 2) In power generation, reliability is obviously extremely important, and the nuclear industry is highly risk-averse. So doing something in a known, tested way is preferable. Any downtime is extremely expensive if things break, since it may be gigawatts of power you’re not selling. 3) Big magnets and handling highly energetic plasma are both really expensive. Steam turbines and generators have existing supply chains since we use them everywhere. I think cost is a big part, since the people building power plants want to make their money back sooner, so may not want to pay millions to billions more for a few percent efficiency gain.

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