Device uses wind to create ammonia out of air

Take that ammonium, burn it, have heat, power a steam engine, infinite energy?

Where does that energy come from? 1st law of thermodynamics?

The energy comes from the sun, without it the atmosphere would freeze and this device wouldn't work.

The power could come from anything (solar, wind, wave) other than the dominant current source for all ammonia, the Haber Process. TFA mentions this in the headline? Could this be done before by just using water+air+solar, yes it could. Frankly, this is just a proof of concept and any commercial solution would be different for scaling reasons.

Professor Aldo Rossa started popularizing a lot of this in the 80s. https://patents.google.com/patent/US4107277A/en

Having something other than a fossil fuel source for the most common fertilizer in the world seems useful. Also, it's easier, cheaper and safer to ship ammonia around than Hydrogen since it's a low pressure liquid and more energy dense. People have been talking about using it as a shipping fuel for decades.

You didn't read the article? "The process requires no external power" right after the headline.

For our purposes solar power is effectively perpetual motion.

Like you said, the energy comes from somewhere. If I had to guess, it's effectively solar powered (the catalyst lowering the activation energy enough that photons can actually do the work), plus indirectly solar powered in that you need wind to physically move the compounds around.

And how does the presented device make use of solar power? Wind movement?

This is under-explained, isn't it? The reaction has to be endothermic, so it must be taking in ambient heat. Would be useful if someone dug up the actual paper rather than the press release.

One aspect of these miracle solutions to watch out for: the catalyst is often very expensive and has a finite lifespan.

Edit: actual paper https://www.science.org/doi/full/10.1126/sciadv.ads4443

Edit: got to the bit in the paper where they describe the process; "contact electrification". This appears to be an electrostatic phenomenon like tribocharging (the old "rub a balloon on your hair" trick). Water droplets hitting the catalyst generates enough potential at the surface to trigger a reaction. So I suppose the energy input is actually in the spray+pump of the experiment, or wind in the outdoor example.

The resulting output is extremely dilute. Raising the concentration is likely to consume more energy for generating an actually useful output.

There is the smoking gun:

> resulting in ammonia concentrations ranging from 25 to 120 μM in 1 hour

Not usable as fuel. You'd need to separate the ammonium from the water using a energy intensive process (cooking or such).

I have read the research paper and the energy appears to come mostly from the pump, because the flow of gas and vapor in the device causes contact electrification, which helps the redox reaction.

They have not given any numbers about the energy consumed by the pump, but at least in this experimental devices it is likely that the amount of ammonia that is produced is very small for the energy consumed by the pump, in comparison with other synthesis methods.

For now, the ammonia is produced as a solution in water with very low ammonia concentration. Perhaps this could be usable directly as a fertilizer for plants. For any other uses, concentrating the ammonia produced in this way would require a large amount of additional energy.

In the form presented now, this method of ammonia synthesis would be too inefficient, but the authors hope that the efficiency can be improved some orders of magnitude.

I see what you're saying in the sense of passive energy collection, but perpetual motion strikes me as a terrible metaphor. Perpetual motion would imply so many thing about the universe that solar can't deliver.

If you consider solar only working for 50% of the day on average, "perpetual".

If it requires no external power what's that bigass battery pack at the base for?

Direct solar energy output, perhaps. Seems potentially simple to boil it off with heat.

At that point in the presentation, I'd probably sarcastically ask if they were accidentally measuring how many dogs mark their territory in a 100 foot radius of the device, per hour, via their collector.

I find it surprising that the paper has no discussion whatsoever of the thermodynamics of the process. The overall reaction is very endothermic (you can burn ammonia in oxygen as fuel!), so the only way it’s happening at all is that it’s approaching equilibrium, presumably driven by the increase of entropy available by creating a low concentration of ammonia in whatever weird phase it’s created in. Getting high concentrations from a similar process is going to need some energy-consuming step to shift that equilibrium.

Worse, they seem to be using some chilled object to condense ammonia solution from the air, so you’re also paying the energy cost of keeping it cold, which means you’re paying the full cost of producing a lot of water from atmospheric water vapor. Maybe a future improvement could start with liquid water.

They did attempt to control for the ammonia concentration in the collected water without their catalyst. But they did not try to calculate the equilibrium concentration of ammonia in water exposed to the atmosphere.

You can catalytically oxidize ammonia in water solution. The energy generated is more than enough to overcome the energy released during solvation.

The droplet size appears to be critical here.

For Science!

For the purposes of anyone reading this, you can make a perpetual motion machine using solar power. I'm pretty sure modern engineering and materials are sophisticated to make a machine of some sort that collects energy during the day and stores it over night in order to continuously move for...I don't know, several hundred, several thousand years? Nothing overly sophisticated, since I wouldn't necessarily trust bearings or motors or hinges to last that long, but something that performs work without needing to be touched for multiple lifetimes.