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 (although non-plasma MHD has been studied, and I believe there are even some human trials, to power implants in the body like pacemakers and I remember reading about nervous-interface devices in mice that used arterial MHD on to generate the microcurrent needed)
Worry not, the implanted power systems I know of generate at peak a few nanowatts. Enough to tricklecharge an extremely low power device or run some very very very efficient digital hardware, but no way you’re harvesting that power for anything more useful. It’d be far more practical just to have the humans chained to bicycle generators…
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
I’ll admit I’ve been out of the field for a couple years so my information is going to be outdated, but I believe the issue with using MHD for continuous stimulation is that it generates tiny amounts of power - enough to trickle-charge a pacemaker, but not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. Hopefully there have been/will be improvements to the tech that I am unaware of!
I think the idea was to provide a redundant method of charging in case you’re unable or forget to recharge it externally. But ideally yes, it would be entirely internally powered so you wouldn’t be tethered to the grid.
edit:
A more promising approach is this which is, somewhat unglamorously, just a small turbine implanted into the heart that is spun by bloodflow. oh, no, this is a different study than the one I was thinking of! This uses a flexible generator that generates power from the deformation of the Vena Cava. Fascinating, I’ll have to dig thru it.
now that is a novel use of piezoelectricity. whoever thought of that needs many sloppy kisses from many cats
personally i think they just need to design for the battery run at 80% capacity and let it wear down. although i can see why they might need to periodically replace a foreign object implanted in the body. i had to get all the titanium plates and screws removed eventually because ow.
Yeah. Unfortunately even rechargeable pacemakers are extremely rare - almost all of them just expect that you’ll have to replace the battery every several years (I think the average is 5?), which in the long run isn’t terrible but still. Rechargeable batteries self-discharge far too much and as a result require quite frequent recharging so are far from ideal for implantation, although not having to undergo regular surgery to replace the battery is obviously a highly desirable outcome. The idea with internal power generation is to bridge the gap between the two and allow a person to go for far longer without the need for invasive surgery (there’s a whole sidebar here about rechargeable battery chemistry not being ideal for implantation) but without the drawbacks inherent to rechargeable batteries.
our experience was 7, but that was probably more because it was powering a DBS and not an actual pacemaker (i’m guessing lower charge draw over longer period of time) and it was time to implant a probe on the other side of the brain.
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 (although non-plasma MHD has been studied, and I believe there are even some human trials, to power implants in the body like pacemakers and I remember reading about nervous-interface devices in mice that used arterial MHD on to generate the microcurrent needed)
Jesus Christ, I imagined some kind of Matrix scenario when you said human trials.
Worry not, the implanted power systems I know of generate at peak a few nanowatts. Enough to tricklecharge an extremely low power device or run some very very very efficient digital hardware, but no way you’re harvesting that power for anything more useful. It’d be far more practical just to have the humans chained to bicycle generators…
The oil crisis isn’t quite that bad yet.
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
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. Hopefully there have been/will be improvements to the tech that I am unaware of!
huh, so you wouldn’t have to plug in and recharge your pace?
I think the idea was to provide a redundant method of charging in case you’re unable or forget to recharge it externally. But ideally yes, it would be entirely internally powered so you wouldn’t be tethered to the grid.
edit:
A more promising approach is this which is,
somewhat unglamorously, just a small turbine implanted into the heart that is spun by bloodflow.oh, no, this is a different study than the one I was thinking of! This uses a flexible generator that generates power from the deformation of the Vena Cava. Fascinating, I’ll have to dig thru it.now that is a novel use of piezoelectricity. whoever thought of that needs many sloppy kisses from many cats
personally i think they just need to design for the battery run at 80% capacity and let it wear down. although i can see why they might need to periodically replace a foreign object implanted in the body. i had to get all the titanium plates and screws removed eventually because ow.
Yeah. Unfortunately even rechargeable pacemakers are extremely rare - almost all of them just expect that you’ll have to replace the battery every several years (I think the average is 5?), which in the long run isn’t terrible but still. Rechargeable batteries self-discharge far too much and as a result require quite frequent recharging so are far from ideal for implantation, although not having to undergo regular surgery to replace the battery is obviously a highly desirable outcome. The idea with internal power generation is to bridge the gap between the two and allow a person to go for far longer without the need for invasive surgery (there’s a whole sidebar here about rechargeable battery chemistry not being ideal for implantation) but without the drawbacks inherent to rechargeable batteries.
our experience was 7, but that was probably more because it was powering a DBS and not an actual pacemaker (i’m guessing lower charge draw over longer period of time) and it was time to implant a probe on the other side of the brain.