New cells may be good for the hot side of space stations and space telescopes

[darthgently]

 

Though I'm not sure about the "white hot" requirement, but reflectors and lenses could be used...

Researchers Develop Highly Efficient Heat Engine

The newly-developed heat engine is a thermophotovoltaic cell that captures high-energy photons from a white-hot heat source and converts them into electricity with over 40% efficiency — a performance better than that of traditional steam turbines.

http://www.sci-news.com/physics/thermophotovoltaic-cell-10714.html

Edited April 17, 2022 by darthgently

[Nuke]

i guess rtgs just got a whole lot more efficient. i can see a move from pv panels to solar thermal. say using a thin film of mylar rather than heavier solar cells, pointing at a condensed array of these. it stands to scale up better with distance from the sun simply by scaling up your reflectors and using the same collector you would closer to the sun. 

[darthgently]

7 minutes ago, Nuke said:

i guess rtgs just got a whole lot more efficient. i can see a move from pv panels to solar thermal. say using a thin film of mylar rather than heavier solar cells, pointing at a condensed array of these. it stands to scale up better with distance from the sun simply by scaling up your reflectors and using the same collector you would closer to the sun. 

I hadn't thought of the RTG implications, but is it a good idea to have them cooking white hot?  But if the heat from an RTG could be focused in much the same way solar could be, yes.  Much more efficient than thermocouples at 5% to 8% (?)

Edited April 17, 2022 by darthgently

[Nuke]

49 minutes ago, darthgently said:

I hadn't thought of the RTG implications, but is it a good idea to have them cooking white hot?  But if the heat from an RTG could be focused in much the same way solar could be, yes.  Much more efficient than thermocouples at 5% to 8% (?)

you might need to give them some active components to condence their heat into a smaller area and then heat up a non-nuclear material. but that loop will probibly cost some efficiency. i believe you can also use white phosphorous to convert radiation into heat and light. but that stuff is dangerous and wants to explode under even ideal conditions. there might be a middle ground between an rtg and a nuclear reactor that one could explore. solid state nuclear reactor sounds like a nice technology to have. perhaps have a magnetically contained fission core surrounded by tpvs (now i need to go look up the magnetic properties of fissionables). 

Edited April 17, 2022 by Nuke

[StrandedonEarth]

IIRC the plan for modern RTGs is to use Stirling cycle engines, which I’m unsure about because it involves moving parts which I just don’t see lasting forever. But IRPV may help the efficiency of conventional RTGS, and I don’t think they need to be white hot…

[darthgently]

10 hours ago, StrandedonEarth said:

But IRPV may help the efficiency of conventional RTGS, and I don’t think they need to be white hot…

Well, the 40% efficiency breakthrough at the link I posted does require white hot, but yeah, IRPVs in general have been a thing for awhile and 40% for multilayer PVs that have IRPVs as a layer is not new, as I recall.  The new thing here is that if you can just use a single layer for a white hot source, that could be a good thing depending on how to get the white hot source. 

As for the stirling/rtg; I don't like the moving parts of the stirling engine sol'n either, but given materials these days I think they could make one with a single moving part (an inductively tapped magnetically floating piston) that could last a very long time

Edited April 17, 2022 by darthgently
spelign erorrs

[magnemoe]

11 hours ago, Nuke said:

you might need to give them some active components to condence their heat into a smaller area and then heat up a non-nuclear material. but that loop will probibly cost some efficiency. i believe you can also use white phosphorous to convert radiation into heat and light. but that stuff is dangerous and wants to explode under even ideal conditions. there might be a middle ground between an rtg and a nuclear reactor that one could explore. solid state nuclear reactor sounds like a nice technology to have. perhaps have a magnetically contained fission core surrounded by tpvs (now i need to go look up the magnetic properties of fissionables). 

Yes this sounds nice for an nuclear reactor in space. Other uses, car exhaust sounds smart. But this become much more relevant if they can reduce the temperature gradient. 

[GDJ]

Pretty cool stuff!
 

Would these chips have the same issue with heat soaking from one side to another like standard Thermovoltaic cells? I know that with those the insulation between the cold side and hot side must be  pretty stout, or do these act like solar cells in the near and far infrared range?

 

[sevenperforce]

That's super cool!

^{See what I did there}

[Nuke]

8 hours ago, GDJ said:

Pretty cool stuff!
 

Would these chips have the same issue with heat soaking from one side to another like standard Thermovoltaic cells? I know that with those the insulation between the cold side and hot side must be  pretty stout, or do these act like solar cells in the near and far infrared range?

 

from the sound of it these only seem to work on radiant heat. but you probibly need to keep the cell cool just like any other solar panel. from the picture there seems to be a water block on the cell. this thing would be put in close proximity to a very hot thing and so needs more cooling than a solar panel. i dont think this is like a tec where you need a cold side in order to generate electricity, but you do need to keep it cold to maximize efficiency.

[darthgently]

57 minutes ago, Nuke said:

i dont think this is like a tec where you need a cold side in order to generate electricity, but you do need to keep it cold to maximize efficiency.

I agree.  It will be interesting to see if there would be a net gain in space where it can be so hard to lose heat.  Maybe some kind of passive device like what the JWST uses to reflect heat out the sides or something, some active device as required