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.
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…”
Many many proposals have been made in the past to utilize waste heat, some with success, others not so much. One of the few that have worked is taking waste heat from industrial processes, connect that to a regular heater (usually gas powered) and connect that up to tens of thousands of homes as a central heating source.
One of the big issues is waste heat is usually in a very low energy high entropy form. The way we normally use extract work from energy is by moving it from a high energy low entropy state into a low energy high entropy state. This is due to the laws of physics and can’t be worked around, so extracting anything useful from waste heat is very hard. Most projects involve simply transporting the heat and using it as heating, that way no transformation is required for it to be useful.
I don’t know if this dude is onto something, but with the laws of physics being what they are, I would be surprised if what he has actually works very well. Like enough that it’s worth doing.
It’s for example very easy to plop a tec (peltier) device onto something a bit warm, cool the other side with the surrounding atmosphere, and out comes electric energy. Useful energy and with a lot of devices you get out a lot of power. However it is not worth doing, those devices cost money to produce and install and would need some maintenance. This makes the power it produces more expensive than what we get from even expensive regular power sources. And the power is only there locally, transporting electric energy is pretty hard. So it isn’t all that useful and not economically attractive. So it’s never done. Usually it’s better to put that time and money into making the thing producing the waste heat more efficient, that pays off a lot more often.
Yeah converting waste heat into useful energy sounds very very much like “making entropy go down.” We know we can make entropy go down in one spot by increasing it even more in others. But for them to do that here… they’d be turning high entropy into low entropy PLUS more high entropy, which sounds circularly self-fueling or essentially a perpetual motion machine.
Most of our electrical generation capabilities use heat at some point to boil water, but what makes that work is water’s phase change behavior, accessible temperature for that phase exchange, and water’s ubiquity. If he can find another water that does something equally useful but at lower temperatures, without exotic materials… I mean John Galt can fuck right off.
If they can pull this off: amazing. But it sounds very much like a quixotic adventure for a legendary inventor’s final days. Someone call me when they have something applicable.
The inventor/founder at the center of the article, Lonnie Johnson, was on the team at JPL that designed and implemented the thermoelectric generators (heated by radioactive decay from plutonium-238 pellets) on the Galileo spacecraft sent to Jupiter. So I would expect that he’s more familiar with the thermodynamic and engineering challenges than even a typical expert.
The PR fluff put out by the company mentions that the theoretical basis for this specific type of generator was worked out a while ago but needed materials science to advance to the point where this type of generator can be thermodynamically and commercially feasible.
Looking at how this generator is supposed to work, it’s interesting in that it does rely on the movement of fluid, but is supposed to be a totally closed loop, to be a bit different than the pure solid state, semiconductor-based Seebeck generators that are already well known.
The other area talked about in this article is that they believe that it can be effective with lower temperature differentials than any previous technology, which might make a huge difference in whether it can be deployed to more useful places and thereby make it economically feasible more easily than prior concepts.
In the end, if these generators can output some electric voltage/current, it might just take on similar generation characteristics as photovoltaics, which could mean that hooking these up to the grid could draw on some of the lessons learned from the rise of grid scale solar.
Thank you. I made a comment about it being a shame that we don’t capture the waste heat from some process a while back and someone quipped something like “2nd law of thermodynamics moment”. I went and did some reading, but couldn’t make sense of it. Your explanation makes sense.
So yes, the law says there is some unavoidable, unusable waste heat, the question is how much of that heat is really unusable?
For example, you have lava at around 1,000 degrees. You certainly can harvest energy from that, hit some water with it and spin a turbine.
For the most part, once we get under 100C we run out of ideas on how to realistically harvest energy out of it, but there’s still a pretty good delta between that an ambient. The claim of this article is he has an approach to harvest energy at an even lower temperature delta.
If it got to harvesting all of the temperature delta of a system, then we can say “not at all possible based on current understanding of physics”, but if the process leaves some waste heat unharvested, then it’s not yet violating that law. The law just says it gets less and less likely as the amount of heat in question diminishes.
A passive heat pump can generate power below 100C. That’s still plenty warm enough to travel up a water column, across a cooling tank, and down to a closed loop or exit. +A turbine to capture the falling water.
No idea how much energy it can capture. It seems obvious? So probably not much.
Even with the comment making a lot of sense, if someone has a good summary / write up / video that helps build an intuition or understanding a bit more of thermodynamics then I’d love the recommendation
Great write-up. I’m so glad my college thermodynamics classes armed me with proper skepticism.
Assuming it’s cheap and reliable, exploiting geothermal resources for a local power solution would be useful in some places, I would think.
The laws of physics didn’t need breaking when the heat pump was invented to circumvent theoretical limits. Maybe its that kind of deal. He has a phenomenal track record, might be worth waiting for.
Peltier devices have horrible efficiency. Juice would not be worth the squeeze.