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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

#141

Post by hinkley »

logfromblammo wrote: post #138
hinkley wrote: post #129

Earlier quoted context omitted.

Last time I was looking at efficient camp stoves I ran into this guy: https://www.bioliteenergy.com/products/campstove-2 The idea of putting my phone, or any lithium battery really, that close to fire... this plan is not for me.

Couldn't you get around that with a really long USB-A-to-whatever charger cable? Slapping a Stirling engine on a rocket stove just seems like a really good idea to me. My major concern would be the in-backpack weight and volume.

DC doesn’t like long runs, but I believe there’s a battery in that yellow block along with the charge circuitry. If I’m wrong it may warrant another look.

Re: New Material Breaks World Record Turning Heat into Electricity

#142

Post by grecy »

asdfman123 wrote: post #136
grecy wrote: post #124

Earlier quoted context omitted.

They're very noisy, and you have to get them above the trees, which is quite high. Also where I live is not very windy.

That's interesting. I'm curious about your living situation, though. Do you live out there most of the year (are you there right now?), or is it kind of a vacation home? Sounds cool... I'm always interested in off-the-grid living arrangements.

I don't have enough money for a vacation home! I'm full time in the Yukon when I'm not on the road.

Many people up North have solar setups and are off grid, usually with older lead-acid battery setups which work just fine.

Solar is great in the summer when the sun is up for 20+ hours a day, but slim in the winter when we only get ~4 hours of sunlight. Most people supplement with a generator for a couple of hours a day which is what I really hope to avoid with ideas like this TEC on the woodstove.

The stove is already pumping out so much heat, and it's so cold outside I feel like the temperature difference is just begging me to do something with it!

My other dream is to by land on moving water (river, stream) and make a little water wheel that turns an old pickup truck alternator. It will be killer in summer, but it's a problem in the winter because the water will be solid for ~5 months.

Re: New Material Breaks World Record Turning Heat into Electricity

#143

Post by strbean »

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?

Store it as mass!

Re: New Material Breaks World Record Turning Heat into Electricity

#144

Post by Dylan16807 »

forgotmypwd123 wrote: post #59
Dylan16807 wrote: post #29

Earlier quoted context omitted.

The thing is, a chip generally cools just fine with heat pipes and fins up to 200 or more watts. And the built-in heat spreader gets rid of hot spots very effectively. At that power level a peltier tends to be worse than useless, even if you're putting enormous amounts of power through it. Even if you double the efficiency it's still a bad option.

Overclocked threadrippers can hit 500W[1]. I can see peltiers and 'vapochill' style phase-change cooling making a comeback... 1. https://www.anandtech.com/show/13124/the-amd-threadripper-29...

Phase change yes. Or water chillers.

I can't imagine why anyone would be more inclined to use a peltier as wattage increases. Higher wattages make that idea progressively worse unless you have some very specific and strange requirements.

Re: New Material Breaks World Record Turning Heat into Electricity

#145

Post by m463 »

Matumio wrote: post #130
comicjk wrote: post #121

Just to clarify why these aren't used everywhere: heat-to-power devices act as insulation (compared to just letting the heat escape). If you have something that you're trying to keep cool, like a CPU, a system that shunts heat straight to the surroundings will always give better cooling than a system that puts layers in between. Contrariwise, if you have a need for electricity, mechanical heat engines will almost alw…

But there are some pretty cool applications. Apparently the heat difference between a buried water-pipe and the surrounding earth is already enough to power a wireless sensor, which can transmit data to localize leaks, for example.

Voyager 2 and 1 are powered by thermocouples and a chunk of plutonium.

(I ordered them that way because Voyager 2 was launched first)

Re: New Material Breaks World Record Turning Heat into Electricity

#146

Post by trhway »

scottlocklin wrote: post #125
starpilot wrote: post #115

Earlier quoted context omitted.

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.

Thermoelectrics you can order from a catalog have real world efficiency ~6%, which is on the order of what a well engineered practical Sterling engine will do for converting heat to electricity without any moving parts to wear out, exotic working fluids/seals, or ... complete lack of supply chain for any of the above. If this new material pans out it could be on the order of 24% efficient, which would be preposterous…

>would be preposterously better than any heat engine you can fit in an Alaska cabin.

Or a cabin on Mars. Solar and nuclear would be used on Mars. For nuclear - with 20% efficiency i think it would allow to use simple RTG (Matt Damon style) instead of full blown nuclear reactor with working fluids, pumps, turbines, etc.

Re: New Material Breaks World Record Turning Heat into Electricity

#147

Post by hinkley »

Dylan16807 wrote: post #144
forgotmypwd123 wrote: post #59

Earlier quoted context omitted.

Overclocked threadrippers can hit 500W[1]. I can see peltiers and 'vapochill' style phase-change cooling making a comeback... 1. https://www.anandtech.com/show/13124/the-amd-threadripper-29...

Phase change yes. Or water chillers. I can't imagine why anyone would be more inclined to use a peltier as wattage increases. Higher wattages make that idea progressively worse unless you have some very specific and strange requirements.

Are you talking about the giant Peltiers that flopped in the late 90's and early 00's? Nobody is talking about that. I'm talking about micron, maybe millimeter-scale peltiers to increase the thermal conductivity of the absolute worst spots on the chip. That may mean a particular ALU, or it could mean circuits with far more layers than we can manage now (due to yields and thermal limitations)

Re: New Material Breaks World Record Turning Heat into Electricity

#148

Post by arghwhat »

learc83 wrote: post #83
arghwhat wrote: post #75

Earlier quoted context omitted.

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…

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

I'd argue that a steam setup is considerably easier and more proven, but a Stirling engine is certainly safer and more efficient.

(A homemade setup would not be very efficient regardless of technology chosen, so I'm ignoring complexities of elaborate high-performance boilers.)

Re: New Material Breaks World Record Turning Heat into Electricity

#149

Post by arghwhat »

debrice wrote: post #120
arghwhat wrote: post #75

Earlier quoted context omitted.

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.

I doubt there's enough heat to extract there. Low-pressure exhaust gas is useless, and I don't think a metal chimney exiting out through a wall would conduct enough heat on the outside on its own.

Re: New Material Breaks World Record Turning Heat into Electricity

#150

Post by arghwhat »

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…

> Even if I only get a combined total of 100W

Quoting Wikipedia:

> The typical efficiency of TEGs is around 5–8%

To get 100W out at 5% efficiency, you'd need to put 2kW in, 1.9kW of which has to be moved away to keep the cold side cold with perfect cooling.

Realistically speaking, the cooling will not be that efficient, and will probably cost you a bit more energy. I'd ballpark that to 2.5kW lost total for 100W of charging.

That's pretty significant.

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