Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Cheap material converts heat to electricity

sciencemag.org

Post reply on HN
Print view View original

41–50 of 96 posts

Re: Cheap material converts heat to electricity

#41

Post by yetihehe »

zionic wrote: post #36
matheusmoreira wrote: post #23

So I can use electricity to mine cryptocurrency and convert the excess heat back to electricity? I wonder how efficient such a thing would be.

I wonder why you don't have a miner-hot-water heater? Use energy to mine and the waste heat to keep your tank warm.

I was trying to find article about some random guy who used mining rig to suprcharge his heat pump [0] but found commercial solutions [1]. Just search "miner heater" on google.

[0] https://medium.com/swlh/heating-my-home-with-crypto-mining-1...

[1] https://greenheat.systems/

Re: Cheap material converts heat to electricity

#42

Post by yjftsjthsd-h »

zionic wrote: post #36
matheusmoreira wrote: post #23

So I can use electricity to mine cryptocurrency and convert the excess heat back to electricity? I wonder how efficient such a thing would be.

I wonder why you don't have a miner-hot-water heater? Use energy to mine and the waste heat to keep your tank warm.

There have been stories of people heating houses that way, actually.

Re: Cheap material converts heat to electricity

#43

Post by m-watson »

pjc50 wrote: post #9

> The polycrystalline tin selenide the team makes is spiked with sodium atoms, creating what is known as a “p-type” material that conducts positive charges. To make working devices, researchers also need an “n-type” version to conduct negative charges. This is literally inventing half a solution. Shockley didn't go to the press when he'd built half a diode. (OK, this is snarky, but I think this is another case where…

I get the snark but this is also Science and their easy to digest news release. It is literally a science journal, not a product release or even engineering journal. I wouldn't say it really fits into the "advancement in the art," or "actual products." It is scientific progress in the material science world (which I know is your last parenthetical aspect of your comment).

Re: Cheap material converts heat to electricity

#44

Post by helixc »

optimalsolver wrote: post #39
JoBrad wrote: post #18

Earlier quoted context omitted.

> Zhao’s team recently reported making an n-type single-crystal tin selenide by spiking it with bromine atoms. And Kanatzidis says his team is now working on making an n-type polycrystalline version. Once n-type and p-type tin selenide devices are paired, researchers should have a clear path to making a new generation of ultra-efficient thermoelectric generators.

So write the paper after that's all done.

You don't understand the difference btw a research paper and a product launch. A paper is to provide inspiration. In this case, a high ZT p-type crystal may indicate a new mechanism that can be applied to searching / designing new thermoelectric materials. It's not for selling you a working device that can be put in your shopping cart.

(I did research in nano thermoelectrics and published a few papers in this field)

Re: Cheap material converts heat to electricity

#45

Post by noselasd »

vlmutolo wrote: post #21
988747 wrote: post #20

Finally! Now we can have an air conditioner that does not require a pipe to blow the hot air outside. Like truly mobile unit.

Unfortunately we'll always need the pipe to blow air outside. The heat has to go somewhere. Even with this invention, if they're converting heat to electricity, they will have to release at least as much heat as they converted to electricity.

Eh, doesn't all modern air conditioner just do heat exchanging? no need to actually blow the air out - but yes you still need a pipe for the heat exchanging medium

Re: Cheap material converts heat to electricity

#46

Post by rpmisms »

layoutIfNeeded wrote: post #28
flavius29663 wrote: post #26

Earlier quoted context omitted.

Why? You could theoretically take out energy from the room in the form of electricity

You can’t. The second law of thermodynamics prohibits it. “It is impossible to devise a cyclically operating device, the sole effect of which is to absorb energy in the form of heat from a single thermal reservoir and to deliver an equivalent amount of work.”

Perhaps not an equivalent amount of work, but if we could capture some of the waste....

Re: Cheap material converts heat to electricity

#47

Post by makomk »

kwhitefoot wrote: post #6

> Those could be installed everywhere from .. water heaters .. to scavenge some of the 65% of fossil fuel energy that winds up as waste heat. Modern condensing gas boilers for domestic use are better than 90% efficient, the exhaust gas is very cool so I don't think that thermoelectric devices have much to offer there.

Yeah, I think the more conventional way to integrate heat-to-electricty into heating applications is the reverse of that: feed the high-grade heat from fuel combustion into the converter, and use the rejected waste heat from it for heating. This gives a big enough thermal gradient to get useful amounts of electricity out, and the waste heat can still be plenty hot enough to be used for heating.

Re: Cheap material converts heat to electricity

#48

Post by marktangotango »

kwhitefoot wrote: post #6

> Those could be installed everywhere from .. water heaters .. to scavenge some of the 65% of fossil fuel energy that winds up as waste heat. Modern condensing gas boilers for domestic use are better than 90% efficient, the exhaust gas is very cool so I don't think that thermoelectric devices have much to offer there.

Isn't the minimum exhaust temperature the same as the temperature of the heated water? How can it be less?

Re: Cheap material converts heat to electricity

#49

Post by chopin »

XorNot wrote: post #30
marksbrown wrote: post #13

Current peltier chips are barely a few percent efficient, break easily and require high temperature differentials. They're used in stove-top fans and RTGs. The latter should be Sterling engines to be ignorant mind. I don't doubt there are some interesting things to be accomplished by shaping the flow of heat conduction but I sincerely doubt it'll be energy generation directly. Thermodynamics isn't something you can j…

The history of moving parts in space missions (RTGs) is why Kepler's mission is degraded: keeping reaction wheels and other spinning things lubricated and moving when you can't get in there and service them is hard.

Why wouldn't airgapped bearings be used for this? Is it too heavy?

Re: Cheap material converts heat to electricity

#50

Post by robbedpeter »

pjc50 wrote: post #9

> The polycrystalline tin selenide the team makes is spiked with sodium atoms, creating what is known as a “p-type” material that conducts positive charges. To make working devices, researchers also need an “n-type” version to conduct negative charges. This is literally inventing half a solution. Shockley didn't go to the press when he'd built half a diode. (OK, this is snarky, but I think this is another case where…

Isn't graphene a high quality p type material as well?

What makes a material p or n?

Post reply on HN