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Power

Can This Simple Invention Convert Waste Heat Into Electricity? (ajc.com) 48

Nuclear engineer Lonnie Johnson worked on NASA's Galileo mission, has more than 140 patents, and invented the Super Soaker water gun. But now he's working on "a potential key to unlock a huge power source that's rarely utilized today," reports the Atlanta Journal-Constitution. [Alternate URL here.]

Waste heat... The Johnson Thermo-Electrochemical Converter, or JTEC, has few moving parts, no combustion and no exhaust. All the work to generate electricity is done by hydrogen, the most abundant element in the universe. Inside the device, pressurized hydrogen gas is separated by a thin, filmlike membrane, with low pressure gas on one side and high pressure gas on the other. The difference in pressure in this "stack" is what drives the hydrogen to compress and expand, creating electricity as it circulates. And unlike a fuel cell, it does not need to be refueled with more hydrogen. All that's needed to keep the process going and electricity flowing is a heat source.

As it turns out, there are enormous amounts of energy vented or otherwise lost from industrial facilities like power plants, factories, breweries and more. Between 20% and 50% of all energy used for industrial processes is dumped into the atmosphere and lost as waste heat, according to the U.S. Department of Energy. The JTEC works with high temperatures, but the device's ability to generate electricity efficiently from low-grade heat sources is what company executives are most excited about. Inside JTEC's headquarters, engineers show off a demonstration unit that can power lights and a sound system with water that's roughly 200 degrees Fahrenheit — below the boiling point and barely warm enough to brew a cup of tea, said Julian Bell, JTEC's vice president of engineering. Comas Haynes, a research engineer at the Georgia Tech Research Institute specializing in thermal and hydrogen system designs, agrees the company could "hit a sweet spot" if it can capitalize on lower temperature heat...

For Johnson, the potential application he's most excited about lies beneath our feet. Geothermal energy exists naturally in rocks and water beneath the Earth's surface at various depths. Tapping into that resource through abandoned oil and gas wells — a well-known access point for underground heat — offers another opportunity. "You don't need batteries and you can draw power when you need it from just about anywhere," Johnson said. Right now, the company is building its first commercial JTEC unit, which is set to be deployed early next year. Mike McQuary, JTEC's CEO and the former president of the pioneering internet service provider MindSpring, said he couldn't reveal the customer, but said it's a "major Southeast utility company." "Crossing that bridge where you have commercial customers that believe in it and will pay for it is important," McQuary said...

On top of some initial seed money, the company brought in $30 million in a Series A funding in 2022 — money that allowed the company to move to its Lee + White headquarters and hire more than 30 engineers. McQuary said it expects to begin another round of fundraising soon.

"Johnson, meanwhile, hasn't stopped working on new inventions," the article points out. "He continues to refine the design for his solid-state battery..."

Can This Simple Invention Convert Waste Heat Into Electricity?

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  • claims (Score:5, Interesting)

    by iggymanz ( 596061 ) on Sunday December 07, 2025 @09:47PM (#65842459)

    Johnson claims 40 - 60 % efficiency with large temperature spread of 600 degrees C.. and that's beautiful and wonderful.

    Thus far experiments at lower temperature differences have been done, I see on net 180 degrees with 17 percent which actually is ok too. The theoretical max there would be 38 percent.

    But, anything near the 40 to 60 percent theoretical value hasn't been demonstrated in repeatable experiment, he's working up to that. So, is Johnson just overhyped about the invention or can he (or anyone) deliver? for that matter, even 20 percent at lower temp differences might be good for a lot of things anyway.

    • Re: (Score:1, Funny)

      by Anonymous Coward
      Could I shove this up my ass to provide power to my personal electronics? (iPhone, headphones, chargers)
      • Re: (Score:2, Funny)

        by iggymanz ( 596061 )

        I've seen tenth of a watt with 50 degree C temperature differential reported. So on a brisk winter day of -17 C you'd need 50 friends or johns or M type gimps to prostrate themselves in a circle with their exposed rumps in the air towards the center, and from your pivot man position in the center jam a silicone heat sink greased JTEC up each their asses to get the 5W to charge a smartphone.

        • I've just realized that with the M-type gimps in typical configuration you could use a modified ball gag to augment the anal collection and only need 25 of them. Proper gimpsuits for the outdoor temperature would ensure a longer collection period to avoid hypothermia before the phone is charged.

      • by XXongo ( 3986865 )
        No.

        Thermal converters need a temperature difference to produce power.

        (serious answer to a frivolous question).

      • "Could I shove this up my ass to provide power to my personal electronics?"

        Yes, you can consider it as a solar panel for places where the sun doesn't shine.

    • Re:claims (Score:5, Insightful)

      by Waffle Iron ( 339739 ) on Sunday December 07, 2025 @10:23PM (#65842491)

      For the example in TFS of 200F water and assuming room temperature exhaust, Mr. Carnot says that the max possible efficiency is less than 20%. Any real world engine, including this one, probably ends up at a low-to-mid single digit percent efficiency. IOW, the vast majority of the heat would still be wasted.

      The operator of the facility generating the waste heat might get more energy savings at lower cost by tweaking their processes to be a few percent more efficient in the first place, instead of trying to recover this low-grade energy source with an elaborate engine and plumbing.

      • Playing devil's advocate, there may be some give on the "assuming room temperature" part. I recall reading about "negative thermocouples" a while back where they played tricks with materials and geometry to get a high view factor into cold space straight from the ground and used basically 2.7K of the sky as a heat sink.

      • Carnot efficiency is a horrible way to view heat engines or any other thermodynamic process on earth. Yes, it’s absolutely correct for absolute efficiency but we exist in a bath of infinite (on human scales) thermal energy. Say the Carnot efficiency was maximized at 100C over room temperature of 300k, that would be 25% or 1-(300/400) because it penalizes you for the heat you got for free, the 300C. But look what happens if you take the efficiency to 100%, your exhaust or low temperature thermal res
        • Efficiency is based on differences in energy that are economically accessible, not on some rambling theories in a newline-free paragraph.

          You can access room temperature. You can' economically access the blackness of outer space from the earth's surface. Likewise, you can access the negative terminal on your battery, but not some static charge in the upper atmosphere.

          You pump X amount of energy into a heat engine, it expels that energy to an accessible exhaust, and typically 70 to 95 percent of that energy i

          • Efficiency is based on differences in energy that are economically accessible, not on some rambling theories in a newline-free paragraph.

            Carnot efficiency is based on absolute efficiency, not economical efficiency. Exergy is a mechanical engineering principle of relative efficiency or process efficiency with respect to ambient temperature though I understand it is a bit arcane if you don’t have a degree. I have a masters in mechanical engineering and have defended the exergy approach in a university at the graduate level to a company in front of three professors of mechanical engineering as well as using it at my job.

            You can access room temperature. You can' economically access the blackness of outer space from the earth's surface.

            You cannot acc

        • > The far more sensible way to view things when living in an infinite thermal bath of energy separated from absolute zero by a high value resistance is exergy defined as the available energy to do useful work.

          We do not live in an infinite thermal bath of energy. It is, in fact, very very finite.

          Exergy is based on the environment; Specifically, if you take some environment and bring the energy to equilibrium. This will be important in a bit, because you say a very dumb thing...

          > Say the Carnot efficie

          • You definitionally can not use any of the energy at 300C because that's your rejection temperature. You're not "using 100% of the heat energy you paid for" not only because you did not pay for the ambient heat, you have no mechanism in this scenario to move it to a lower temperature reservoir (and extract work from it) because it's already the lowest temperature in your system - by definition.

            Yes, but exergy is integral to mechanical engineering specifically because it’s useful and informative to look at it this way. Your thermal cycle starts at ambient, has a high temperature reservoir to drive heat flow, does work converting the kinetic energy of the thermal system to useful work lowering the temperature, and returns to ambient at the starting position. Exergy, reduced to a grade school level of understanding, is specifically understood from ambient just as if your ground in an electri

  • I will be interested when they have a working prototype that comes close to the claimed efficiency. I predict that will not happen.

    • Do capitalism's efficiency claims come close to reality?

    • The co-generation idea has been around for decades. Although there are some successful implementations, there are many problems to surmount to make it practical and profitable.

      One of them is energy output efficiency for the lifecycle of the heat source, customers to buy the energy output, competition from other energy sources (like artificially low petro-energy costs), and sufficiently cheap capital to make the return on investment work over the projected life.

      Didn't happen before, and it's unlikely to happ

  • You betcha, it was developed by the new method of vibe engineering.

  • They had closed loop turbines filled some gas that were using hot water (100F / 40C) from hot springs to generate electricity for a whole town.
    20 years ago ...

  • by 93 Escort Wagon ( 326346 ) on Sunday December 07, 2025 @11:34PM (#65842559)

    Worked for NASA... *yawn*. Holds 140 patents... yeah, so what?

    But this dude also invented the Super Soaker - now THAT's legit guy cred!

    • But this dude also invented the Super Soaker - now THAT's legit guy cred!

      It'd make my year if he went back to that. Ever since Hasbro bought them, they've looked like these useless contraptions made by Dr. Seuss [fandom.com]; we need to get back to the CPS2000 [isoaker.com] and the other turn-of-the-century models that were actually effective at their intended purpose.

  • by John Cavendish ( 6659408 ) on Monday December 08, 2025 @12:01AM (#65842601)

    "... few moving parts ..." sounds great, if it has much higher reliability than existing Stirling engines then the sky is the limit for applications of this device, e.g. existing RTGs efficiency is at about 3%, however usually there is not much translation between claims, a prototype and the shelf product - but I wish them well, would be great to have an efficient and reliable dT -> dV converter.

  • by gurps_npc ( 621217 ) on Monday December 08, 2025 @01:29AM (#65842663) Homepage

    With similar efficiency claims? I am sure there are advantages to this version.

    If the article had compared it to existing sterling engines and mentioned how it was better than existing Sterling Engines, that would have made it interesting.

    Instead they talked about Super Soakers and mentioned all the obvious industrial uses that such a machine could be used for. The things anyone that graduated High School should have been able to think of themselves.

    Was this article written for people that failed High School Physics? Is it an attempt to get an orange skinned fool that was tricked by a Democrat into pardoning him to fund something?

    How did this sad excuse of an article get approved here?

    • My first thought too, especially as there was a recent report somewhere, I think on the BBC but maybe not, on using Sterling engines for energy recovery.

      A few years ago I saw a residential canal boat where the owner had made a small Sterling engine and just parked it on the boat's engine exhaust pipe. All it did was turn a fan, so I guess the aim was to circulate some warm air. Very little power, maybe enough to light an LED.

    • by nojayuk ( 567177 ) on Monday December 08, 2025 @08:12AM (#65843043)

      If the article had compared it to existing sterling engines and mentioned how it was better than existing Sterling Engines, that would have made it interesting.

      Stirling engines actually work but don't return much in the way of mechanical energy for low heat differentials. The usual deal with attempts to scale up and commercialise Stirling engines for electricity generation or other use cases normally involves choosing hydrogen as the working fluid because it's closest to being an "ideal gas" and hence more efficient than the alternatives. The rest of the research budget is spent trying to contain the hydrogen gas with seals etc. before bankruptcy beckons. Step and repeat.

      This re-invention attempts to get round the "blow a seal" problem by using fixed but flexible membranes to contain the hydrogen. I can imagine other issues with this technology that could cause problems in both the short-term and long-term but I'm not sufficiently knowledgeable about the materials etc. involved.

  • by shilly ( 142940 ) on Monday December 08, 2025 @01:40AM (#65842669)

    To my mind, the first and most obvious questions to ask are how this kind of system copes with the well known challenges of working with H2, such as embrittlement, leakage and a propensity to explode.

    • I mean who wouldn't want to use a famously volatile element in a closed system resembling a bomb that said element will be leaking from and be exposed to insane temperatures. Sounds really like a good idea to save 20% on energy while risking vaporizing your factory.
      • by shilly ( 142940 )

        I'm sure they have smart engineers and have thought lots of this through, and have robust and well-tested systems etc. But it still seems like it's inherently hard work for not much payoff. And even the geothermal stuff seems odd; what's so much better about this solution than standard geothermal solutions.

      • by Geoffrey.landis ( 926948 ) on Monday December 08, 2025 @09:33AM (#65843205) Homepage

        I mean who wouldn't want to use a famously volatile element in a closed system resembling a bomb that said element will be leaking from and be exposed to insane temperatures.

        Because the JTEC is an evolved version of the older AMTEC, Alkali Metal Thermal-to-Electric Converter, in which the working fluid was liquid sodium. The version with hydrogen is much easier to work with. AMTEC looked great in small-scale lab experiments, and for a while in the 90s they were heavily pushed as the successor technology to thermoelectrics currently used in radioisotope power systems, but turned out they were too hard to work with. (I still kinda like the technology, though. It's thermodynamically elegant.)

        There's also a JTEC variant that uses oxygen, I believe: https://www.researchwithrutger... [researchwithrutgers.com]

  • Commercialization is 5-10 years away?
  • It's only worthwhile if the capital and installation costs are low enough

  • "All the work to generate electricity is done by hydrogen"

    JFC, all the work is done by heat.

  • This device requires 100 psi Hydrogen to be separated from 0.01 psi Hydrogen by two membranes. Pressurizing hydrogen is very inefficient, and hydrogen is very good at tunneling through most materials. I find it odd that the article and nowhere on the JTEC Energy site is neither the cell half-life mentioned nor just how much energy is required to simply maintain this pressure difference.
  • This seems like hype matt ferrell would go on about on youtube. He loves to hype trash science as if its legit.

  • The first is the Wikipedia page for the invention and the second is the patent application:

    1. https://en.wikipedia.org/wiki/... [wikipedia.org]

    2. https://wecoso.com/wp-content/... [wecoso.com]

  • or rather, what the efficiency would be for the exhaust from the HVAC from a large office building. Or, of course, any factory.

  • 20% of a little energy is more than 100% of no energy. The question should be, "at what temperature differential does the efficiency get high enough to justify the cost of the device?" That's really all that matters.

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