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New Material Breaks World Record Turning Heat into Electricity

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Re: New Material Breaks World Record Turning Heat into Electricity

#111

Post by abdullahkhalids »

8bitsrule wrote: post #91
learc83 wrote: post #83

Earlier quoted context omitted.

A small stirling engine would be easier and safer than a steam setup.

The good ol' Stirling engine was tried out -- at a few locations in the US Southwest 10 years back -- to generate megawatts of solar-powered electricity (25kW per engine) at the focus of parabolic mirrors. It got beat out by subsidized Chinese-produced PV panels (SES was forced into bankruptcy). https://en.wikipedia.org/wiki/Applications_of_the_Stirling_e... https://en.wikipedia.org/wiki/Mount_Signal_Solar

My senior year project ten years ago was exactly this - solar thermal + a Stirling engine. When we started the project, we estimated it 20% or so cheaper than solar PV. In that one year solar prices halved or so, leaving us at a dead end.

I ended up consulting with leather plant for their hot water needs via solar thermal. At least that is still viable.

Re: New Material Breaks World Record Turning Heat into Electricity

#112

Post by Craighead »

bagacrap wrote: post #104
pharke wrote: post #97

If an advanced civilization continued to improve the efficiency of this effect would they eventually use it to capture the majority of the energy output of their local star? You could have a shell of high efficiency solar satellites surrounded by another shell of high efficiency Seebeck satellites. What would this look like from a distance? Would they be able to capture enough energy so their star would be indistingu…

What would they use all that energy for, and how would they use it in a way that wouldn't radiate heat or light on par with the amount captured?

Move the star out of the way of a blackhole, or, move the star and the orbiting planets anywhere desired.

Re: New Material Breaks World Record Turning Heat into Electricity

#113

Post by lopmotr »

zbrozek wrote: post #107
lopmotr wrote: post #105

Earlier quoted context omitted.

I think it's correct. Heat is the flow of thermal energy. A portion of that flowing energy is converted to electrical energy. Perhaps you're confusing heat with thermal energy? There must be some heat flowing to generate electrical power because of the 1st law, so even if the effect is described as being due to a temperature difference, in practice, you also need a heat flow to be useful. Your quote about "without an…

Heat is the energy, not the flow. That flow is flux or power. A temperature difference is how we perceive or measure a difference in thermal energy density between two places, and is the potential that drives heat flux. A thermoelectric barrier between those two wells can extract energy from that flow, within thermodynamic limits.

Yes, I was a bit sloppy. It's the flowing energy, not the flow of energy. The point of my comment was to distinguish heat from stored thermal energy so the distinction isn't so important in that context.

Re: New Material Breaks World Record Turning Heat into Electricity

#114

Post by 8bitsrule »

abdullahkhalids wrote: post #111
8bitsrule wrote: post #91

Earlier quoted context omitted.

The good ol' Stirling engine was tried out -- at a few locations in the US Southwest 10 years back -- to generate megawatts of solar-powered electricity (25kW per engine) at the focus of parabolic mirrors. It got beat out by subsidized Chinese-produced PV panels (SES was forced into bankruptcy). https://en.wikipedia.org/wiki/Applications_of_the_Stirling_e... https://en.wikipedia.org/wiki/Mount_Signal_Solar

My senior year project ten years ago was exactly this - solar thermal + a Stirling engine. When we started the project, we estimated it 20% or so cheaper than solar PV. In that one year solar prices halved or so, leaving us at a dead end. I ended up consulting with leather plant for their hot water needs via solar thermal. At least that is still viable.

Interesting. I just learned about that energy combo, and Stirling also makes a lot of sense for someone with a non-solar heat source!

Amazing how China came along at the time it did. The hardball politics aimed against US solar startups since Carter has been a fascinating tale with little mainstream coverage.

Re: New Material Breaks World Record Turning Heat into Electricity

#115

Post by starpilot »

grecy wrote: post #96
esotericn wrote: post #74

Earlier quoted context omitted.

Won't this reduce the thermal output of your stove quite significantly? I suppose that might not be a problem in practice (most wood stoves I've used end up overheating the room if you're not careful), but it's not like it's free energy :P

> Won't this reduce the thermal output of your stove quite significantly I'm going to chime in and say that I think it will be insignificant. I don't know for sure, but I really doubt you could do much to cool the stove. When it's cold in the Yukon, I'm literally stuffing in ~8-10 big logs every ~12 hours. It's not at all uncommon for the base of the chimney to be glowing red. Obviously not ideal, but it happens. Whe…

Thermoelectrics have terrible efficiency, that's why they're hardly used despite the fact that waste heat is literally everywhere. Your computer, your phone, your car engine, everywhere there is energy to be recovered. In theory, any heat-based powerplant could use them, but instead they all boil water and drive steam through turbines, which is much more efficient.

Re: New Material Breaks World Record Turning Heat into Electricity

#116

Post by pharke »

ailideex wrote: post #106
pharke wrote: post #97

If an advanced civilization continued to improve the efficiency of this effect would they eventually use it to capture the majority of the energy output of their local star? You could have a shell of high efficiency solar satellites surrounded by another shell of high efficiency Seebeck satellites. What would this look like from a distance? Would they be able to capture enough energy so their star would be indistingu…

> Would they be able to capture enough energy so their star would be indistinguishable from the ambient temperature of space? You would still see infrared: https://en.wikipedia.org/wiki/Fermi_paradox#Conjectures_abou... > Such a feat of astroengineering would drastically alter the observed spectrum of the star involved, changing it at least partly from the normal emission lines of a natural stellar atmosphere to thos…

You're ignoring the point I was making about capturing the infrared waste heat. It seems counterintuitive for a civilization to go to the effort of encasing their star in a shell of satellites while dumping energy as waste heat. Surely there must be some way of utilizing that energy and my conjecture was that advances in the efficiency of the Seebeck effect might lead to a way to fully utilize that waste.

Re: New Material Breaks World Record Turning Heat into Electricity

#117

Post by Misdicorl »

ailideex wrote: post #106
pharke wrote: post #97

If an advanced civilization continued to improve the efficiency of this effect would they eventually use it to capture the majority of the energy output of their local star? You could have a shell of high efficiency solar satellites surrounded by another shell of high efficiency Seebeck satellites. What would this look like from a distance? Would they be able to capture enough energy so their star would be indistingu…

> Would they be able to capture enough energy so their star would be indistinguishable from the ambient temperature of space? You would still see infrared: https://en.wikipedia.org/wiki/Fermi_paradox#Conjectures_abou... > Such a feat of astroengineering would drastically alter the observed spectrum of the star involved, changing it at least partly from the normal emission lines of a natural stellar atmosphere to thos…

Only if the 2nd law of thermodynamics holds. When speculating about advanced civilizations building Dyson spheres, why not speculate about the bedrock of science as well?

There are (probably) other paths to avoiding this conundrum as well. Spitballing here, but perhaps the 'satellites' in this case can be pairs of orbiting black holes which emit the waste heat in a band we don't detect (gravitational waves).

Re: New Material Breaks World Record Turning Heat into Electricity

#118

Post by UncleEntity »

grecy wrote: post #71
galangalalgol wrote: post #68

Earlier quoted context omitted.

Could you chain 3 of them using a tank of coolant at room temp as the between value. Or make it water and put the TEC on the cold side of the tank

The plan is to have a tank of glycol coolant sitting outside (at around -20C to -40C ambient) and mount a radiator outside. I'll use a fish tank pump or similar to circulate the coolant. Put water cooling blocks onto the TECs so the wood stove heats one side to around 100C to 200C, and the cold coolant coming in brings it back down, to hopefully get a temperature difference in the range of 100C (ish). It's all just a…

You could use the waste heat that goes up the chimney to warm the fluid with something like an automotive intercooler and set the system up backwards, maybe?

Re: New Material Breaks World Record Turning Heat into Electricity

#119

Post by pharke »

bagacrap wrote: post #104
pharke wrote: post #97

If an advanced civilization continued to improve the efficiency of this effect would they eventually use it to capture the majority of the energy output of their local star? You could have a shell of high efficiency solar satellites surrounded by another shell of high efficiency Seebeck satellites. What would this look like from a distance? Would they be able to capture enough energy so their star would be indistingu…

What would they use all that energy for, and how would they use it in a way that wouldn't radiate heat or light on par with the amount captured?

A good use might be computing power whether its for storing the minds of everyone in the civilization or powering one big mind or simulating universes or maybe it's all dedicated to finding a way to reverse entropy.

If we're assuming a highly advanced civilization aiming for maximal efficiency I would hope that they have figured out how to make all of their electrical systems out of high temperature superconductors.

Re: New Material Breaks World Record Turning Heat into Electricity

#120

Post by debrice »

arghwhat wrote: post #75
grecy wrote: post #64

I've always wanted to build a little hobby project where I put TECs on top of my wood stove and have a radiator outside with coolant to get a nice big heat difference (maybe 100C to 200C) across them and make power in winter when solar isn't so great in the Yukon. I know it won't be a massive amount of power, but given it will be 24/7 for about 6 months of winter when the wood stove runs, I think it will be a useful…

You'd be actively cooling your wood stove by much more than the power you'd extract, and you won't get more than enough to charge a phone or laptop. TECs are just terrible. You'd get much better result by making a small steam plant with the same setup: boil water on stove, drive plant (turbine or piston), condense outside, repeat. However, if you really want to do this with TECs, stack them to lower the per-unit temp…

I’d suggest doing that operation on the outdoor side exhaust where the heat loss would be irrelevant.
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