Clay Makes For DIY Power Source, Just Add Water

[Robert Murray] starts out showing us some clay formations that house bees. He couldn’t take any of that clay home, but that’s no problem — clay is plentiful, and apparently, you can make a battery with it. Well, perhaps not really a battery. Adding water to zeolite — a clay often used as a filter material — generates heat, and where there’s heat, there can be electricity.

[Robert] uses a salvaged Peltier device, as you find in small electric refrigerators. These solid-state heat pumps usually convert electricity into a temperature differential, but in this case, it is used as a thermocouple, generating electricity from a temperature difference.

The clay used is a very fine aluminosilicate crystal known as zeolite 13X. Once it comes into contact with plain ordinary water, it immediately starts to boil. It’s a neat experiment, and with the Peltier underneath the metal container holding the clay, enough power is produced to spin a small motor. Of course this won’t power anything large, but on the other hand, plenty of things these days don’t take much power. This technique would work with any exothermic reaction of course, but there’s something compelling about the shelf-stability of water and clay.

Beats a potato, we suppose. Batteries don’t have to be difficult to make. It is only hard to make really good ones.

17 thoughts on “Clay Makes For DIY Power Source, Just Add Water

    1. Although you can do similar things to lime, it’s a chemical reaction in that case, but not in this one. This just has a huge area and likes to hold onto water, like silica gel. With lime to get back to the dry substance you had originally you usually use much higher temperatures than this.

  1. Something similar was done in the early ’80’s with hygroscopic salts for solar thermal storage. Heat it under a partial vacuum and dry it out in the summer. Cap it, transport it if necessary. Get it wet in the winter and get your stored heat back (i.e. a chemical heat pump). The Popular Science article mentioned they were doing a 30 year study so I wrote them in 2000 to see how it was going. It worked very well but repeated cycling melted and sealed the surface area so that you couldn’t wet the full volume.

    1. Yep. The devil is in the details: the zeolite particles here have to be specially produced to have that high surface area and lots of pores. Just digging up clay and drying it up in the sun won’t have this effect.

    2. Plus, if you find yourself too warm, you could also rearrange things to use the stored salt to absorb humidity coming from evaporative cooling. A brine doesn’t store as much energy or get as hot, as it’s already been partly diluted, but it doesn’t have the same challenges as with solid salt. these made steam, and a small number of them apparently used a salt to do it.

  2. I’ve always wondered how this dude has made a career out of selling science fair experiments as technological revolutions. People fall for it every time, because they have no ability or desire to actually quantify his claims. Sad to watch.

    1. Posted by the amazing and esteemed… Anonymous.

      Yup the name checks out. He can do it because he actually does SOMETHING… finds those experiments, thinks about possibilities for them, writes or has written a script, films a video, and publishes it. You know.. actually creates something instead of just useless criticism.

      1. But at the same time, it’s disappointing, because the concepts are often great and the quantity and variety of the demonstrations is impressive, but then you look at the idea outside the context of a fun and interesting demo and it’s totally infeasible to do anything with it. For instance, plenty of things can release heat when wet and absorb heat to dry out again. Many of them are even pretty cheap, when you reuse them. But they wouldn’t be cheap or easy if you need a solar heat collector the size of a warehouse with a person on staff to manually move clay around just to capture enough power to run a laptop. Quantifying things matters.

        1. Yeah, plenty of things work, not many scale though. See also every “new! amazing!” tech discovery that’ll “change the world”.

          The latest hot thing (judging by YouTube comments” is people hearing about LEDs generating power. “Well yes, all PV junctions do that but…”

      2. Doing something is worse than doing nothing if you’re wasting everyone’s time. Also, who says I don’t publish anything? Anonymity is just a good way to shield yourself from social consequences. There is no benefit to using your real name on the internet.

    2. What you’re missing is that he is getting people to think about other options. Out of that, some others might go on to do greater things with the seeds he plants into their minds.

  3. It may be a way of storing solar thermal energy for long periods of time (heat is used to recycle the clay via dehydration), but is it the most efficient way of doing so? There are always trade-off and without knowing what they are one solution cannot be recommended over another.

  4. I would rather the focus was on the heat and not ‘producing electricity’.

    There are doubtless better ways to produce and store electrcity.

    This could be used for a hand warmer? Heating an MRE style meal?

    1. On the heat and on absorbing water – since absorbing water also useful, especially as it allows low-tech evaporative cooling to proceed. And since using a peltier to make electricity is very inefficient.

  5. I don’t know with this guy. A lot of his videos seem to cater to the “free energy” crowd or at least vastly exaggerating the usefulness of the stuff he shows. Would love for someone more knowledgeable than me to fact check this guy.

  6. Most of it doesn’t scale, but I haven’t seen a faked demo although what he says in the demos may not be true. A few things, like dessicant materials in general (and possibly the zeolite beads like this), are feasible but it’s not as simple as he makes it look. He usually doesn’t admit when the numbers just aren’t there for the effect he demonstrated. And there’s usually more promising alternatives that don’t have a youtube video available.

    In this case, you can’t use regular clay, and the choice of material and method of drying is important to making a reusable system. Also using a thermoelectric device to make electricity is a poor way to use the stuff – it’s very inefficient, and you’d be better off using the heat directly, or using it as a way to dehumidify a place, or something like that. Assuming you have an efficient way to dry them of course. Silica gel beads are another material that absorbs water, but they release it very readily without a huge temperature increase. Brines of various salts are another option if a fully liquid system might be more convenient. Historically, the salt CaCl2 could be used to power a steam locomotive – but they were recharged using superheated steam, not low grade / waste heat / solar heat. Also it was more common to use caustic soda (lye) for those.

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