Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
×
Science

High-Power Thermoelectric Generator Utilizes Thermal Difference of Only 5C (newelectronics.co.uk) 100

A silicon-nanowire thermoelectric generator has been developed by a team of researchers from Waseda University, Osaka University, and Shizuoka University. From a report: According to the Japanese researchers, this experimentally demonstrated a high-power density of 12 microwatts per 1cm2, enough to drive sensors or realise intermittent wireless communication, at a small thermal difference of only 5C. Silicon-based thermoelectric generators conventionally employed long, silicon nanowires of about 10-100nm, which were suspended on a cavity to cut off the bypass of the heat current and secure the temperature difference across the silicon nanowires. However, the cavity structure weakened the mechanical strength of the devices and increased the fabrication cost. The team says their generator has overcome this issue.

"Because our generator uses the same technology to manufacture semiconductor integrated circuits, its processing cost could be largely cut through mass production," says Professor Takanobu Watanabe of Waseda University. "Also, it could open up a pathway to various, autonomously-driven IoT devices utilising environmental and body heats. For instance, it may be possible to charge your smartwatch during your morning jog someday."

This discussion has been archived. No new comments can be posted.

High-Power Thermoelectric Generator Utilizes Thermal Difference of Only 5C

Comments Filter:
  • by ZorinLynx ( 31751 ) on Monday July 09, 2018 @01:03PM (#56917998) Homepage

    Being able to efficiently convert heat into energy is a holy grail. Are these TEGs better than previous tech when you have large differentials?

  • by Nutria ( 679911 ) on Monday July 09, 2018 @01:07PM (#56918030)

    Unless my math is wrong, that's less than an eighth of a watt per square meter.

    • It might be enough to drive sensors or realise intermittent wireless communication though.
      • useful wireless? no, I think not, for lowest power class 3 bluetooth for example that 1.2 microwatts of the square centimeter is off by factor of 1000.

        • by Zocalo ( 252965 ) on Monday July 09, 2018 @01:21PM (#56918122) Homepage
          Depends on what OP meant by "intermittent". There are plenty of telemetry sensors that only need to transmit a tiny amount of data at intervals in excess of an hour, or in the event of a given condition being met, for which 12 uW/cm^2 might be more than enough to charge up a battery or capacitor with enough juice to do so when the time comes.
          • I was going to say that too, but I guess iggymanz is the expert, so I think we should notify the researchers.
            • I know, pesky math and physics can be such a downer. how long are you going to have to charge for 1kb payload packet of bluetooth class 3 power?

              • I'm not sure. I'll go let the researchers know that it isn't possible to do what they say might be possible. Be right back!
        • That makes sense. It doesn't matter if you have 1 centimeter or 1 meter or 1 kilometer of generator - you will be "off by a factor of 1000".
          • Don't think about this in 2D like it's a solar panel. Fold it up and you can get 100 square centimeters in a compact space. Now if you can keep it generating electricity then that's great, but more likely you'll need to store up the electricity in a supercap.

        • I'm working on stuff that needs a decade or two battery life (no recharge) and is wireless. Give it a hundred square centimeters and you're in a good range to help with this. The snag though is that temperature doesn't change a lot, but if you can store the electricity in a capacitor then it helps extend the battery life.

    • by DrTJ ( 4014489 ) on Monday July 09, 2018 @01:40PM (#56918266)

      "experimentally demonstrated a high-power density of 12 microwatts per 1cm2"

      Somebody need to work on their adjectives. Solar panels are in the order of 10-20 mW/cm, i.e. 1000x more.

      If 12 uW/cm qualifies as "high-power density", then solar panels must be "super-power density".

      Maybe the researchers are from Krypton.

      • by AmiMoJo ( 196126 )

        Solar is the default option because it's cheap and pretty good, but often you want to put sensors in places where there isn't much light. Inside buildings, underground (there is a lot of infrastructure down there), underwater, in permanently shadowed areas etc.

        In those cases a small thermal gradient might now provide enough energy to do something useful. And 5C is only the lower limit, often there is a much larger gradient available if you have things like running water.

    • Unless my math is wrong, that's less than an eighth of a watt per square meter.

      Can you say "LOW, LOW duty Cycle"? You'd be better off with a small solar cell over this..

      • A 5C temperature gradient you can have nearly everywhere.
        A solar cell only works where you habe light, obviously.

        • A 5C temperature gradient you can have nearly everywhere. A solar cell only works where you habe light, obviously.

          9 Degrees Fahrenheit over say half a square meter is NOT that easy to come by and isn't going to net you much energy. But my point is a solar collector might be a better choice in a lot of cases because it's a lot smaller size for the same energy. Batteries and other storage devices can take up the gaps and you'd still have size to spare. Not to mention that most temperature differentials are caused by solar heating anyway, at least the ones you would want to be using.

  • by Anonymous Coward on Monday July 09, 2018 @01:09PM (#56918040)

    I just leave it at home on the charger.

  • This is a very useful signal detection implementation for low temperature gradients, useful in monitoring range fluctuations, and is obviously not useful for power generation beyond that needed to drive monitoring circuitry and software to communicate those gradient changes.

    More like for nuclear power plants or battery cells with temperature operation limitations, or for use in industrial and commercial processes, where you need to run a resin at a specific temperature range to cure it before you apply it.

    K

  • "For instance, it may be possible to charge your smartwatch during your morning jog someday."

    My automatic watch has been running without batteries for years, and all I have to do is wear it.

    Millennial, please sell me again why I need this solution that lacks a problem...

    • Is your watch smart? Does it connect to Facebook and Twitter? It doesn't? That is a problem.
      • Not connecting to Facebook and Twitter might be a feature that people are willing to pay less for!

    • by Anonymous Coward

      They might say they use their watch for telling the time about as often as they use their cell phone for making phone calls.

  • Way less efficient than a low temperature differential Stirling, but plenty of room for improvement. It could also use the coldness of space as the heat sink using some new tech... can't find the link at the moment, but there was a TED talk on it.
  • Doesn't take much (Score:4, Interesting)

    by foxalopex ( 522681 ) on Monday July 09, 2018 @03:14PM (#56918966)

    I have a solar powered Casio watch that does atomic clock synchronization every day. It's pretty cool in that it keeps very accurate time and has been running for years and years. All it needs is some ambient office lighting to keep it charged everyday. I've heard the rechargable lithium battery will eventually wear out however.

    • My Citizen WR 100 SolarTech will be 19 years old in September, and still works wonderfully. It doesn't have atomic time sync, but keeps time accurately enough that there's no drift during the 6 months between Daylight Saving settings.

      Another poster mentioned his uses a capacitor not a battery - I'm not an electrical engineer, but don't capacitors drain faster and have a voltage drop-off as they drain? My watch keeps time even without charging - I can leave it in a drawer for 2 months and it's still goin

      • I decided to google it, apparently there's an entire Wikipedia article on the Eco-Drive watches (I forgot that was the name of the range my model belongs to.) According to the article and its references, it has a secondary battery that will live 20 to 40 years [wikipedia.org].
  • I gotta go to bed.

The nice thing about standards is that there are so many of them to choose from. -- Andrew S. Tanenbaum

Working...