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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

#91

Post by 8bitsrule »

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.

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

Re: New Material Breaks World Record Turning Heat into Electricity

#92

Post by icegreentea2 »

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…

There are some single layer units that can get up to ~90 of delta_T, but I don't think they're worth dealing with. As a sibling comment points out, you can stack TECs - indeed, you can buy integrated units with very high delta_T that are just pre-stacked TECs.

I think it'd certainly be fun to play with. Some bits of warning - most TECs are physically quite fragile. Not in the sense that you need to be super careful when handling them with your hands, but that heat stresses can totally wreck them. Do NOT hard mount both sides (hot and cold) to different materials - the differential thermal expansion on the two sides has a potentially of ripping your TEC apart. You may be able to get away with a hard mount (such as solder) on one surface, and some sort of thermal transfer material on the other.

Also warning, your hot side is hot enough to start doing weird things with normal solders, which might be the bigger limiting factor.

Re: New Material Breaks World Record Turning Heat into Electricity

#93

Post by icegreentea2 »

hooande wrote: post #77
ragerino wrote: post #66

Earlier quoted context omitted.

That's a cool idea. I came across this link because I want to build cheap small sensor stations using LoRa to transmit data (gps location?, temp, humidity, air quality) to a central server. Solar is not really an option because it needs to be cleaned once in a while.

how big of a temperature difference do thermoelectric materials usually require? is it like dozens or hundreds of degrees over a given period, or something that's likely to be encountered in a normal environment?

Typical applications span the order of tens of degrees Celsius.

Re: New Material Breaks World Record Turning Heat into Electricity

#94

Post by icegreentea2 »

jasondclinton wrote: post #79

Does anyone know if this discovery can be used to boost the efficiency of solar panels? Don't solar panels get incredibly hot?

You can use these types of materials to extract energy from any energy gradient.

In the particular case of solar panels, in order to have a workable thermal gradient, you need to have some sort of conductive path from the solar panel to the cold reservoir (assume the ground under it) - that's extra cost there. Then once you have the TEG running, what you're actually doing is adding an impediment to heat flowing from the solar panel to the cold spot, likely causing the solar panel to be a bit warmer (thus decreasing its efficiency). The increase in energy production per given investment is almost always going to be lower than just getting more solar panels.

You see this is most bulk energy production contexts. It's rare for these energy scavenging techniques to make economic sense. Where you start seeing them make sense is when you have other constraints come into play. You can see this with other aspects of solar generation like solar tracking.

Re: New Material Breaks World Record Turning Heat into Electricity

#95

Post by dghughes »

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…

Hello fellow Canadian :)

Wouldn't a home made Sterling Engine be easier and cheaper? Then use the motion to power a small generator.

But like others commented you may just end up cooling your stove. The Yukon can get pretty cool.

Maybe an old washer motor, a prop to generate power from wind? Or solar in the summer when light is ample.

Re: New Material Breaks World Record Turning Heat into Electricity

#96

Post by grecy »

esotericn wrote: post #74
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…

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.

When it's past -40, I set my alarm for 1am to get up and put in more wood. The stove would just last the night if I didn't, but it's a pain to light it again from scratch every morning, so it's easier to just keep it going.

All of that is to say the wood stove is absolutely pumping out heat 24x7 from ~September to ~April.

If I already have batteries and charge controllers and inverters, why not wire in a handful of TECs.. even if I only get a combined total of 100W, that's worth having over those months the sun is not up for long, and not strong.

Re: New Material Breaks World Record Turning Heat into Electricity

#97

Post by pharke »

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 indistinguishable from the ambient temperature of space?

Our galaxy and others appear to be missing most of the mass i.e. stars that they should have in order to rotate as fast as they do. We put the figure for missing mass at about 80 to 90 percent for our galaxy. What if our galaxy and others are already colonized by advanced civilizations that make maximal use of the power output of stars so it simply looks like we're missing most of the matter that should exist. This could explain why there is a variation in the amount of missing mass between galaxies with some galaxies apparently containing 0% 'dark matter'. No advanced civilization = no dark matter, different amounts = different stages in development of the galactic civilization.

Could this be a solution to the Fermi paradox?

Re: New Material Breaks World Record Turning Heat into Electricity

#99

Post by bwanab »

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…

Sounds like a good beginning to a collaboration novel by Neal Stephenson and Alastair Reynolds.

Re: New Material Breaks World Record Turning Heat into Electricity

#100

Post by etimberg »

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…

https://en.wikipedia.org/wiki/Dyson_sphere
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