Clean Power

Published on July 23rd, 2014 | by Jo Borrás


More Steam From Less Energy, Thanks to Creepy Sponge Thing

July 23rd, 2014 by  



A new, sponge-like material developed engineers at MIT can convert water to steam using just 1% of the sunlight required by conventional steam-producing solar generators. Floating above the water and looking an awful lot like the Smog Monster from this 1971 Godzilla movie, this spongy substance is made by spreading graphite flakes onto layers of carbon-based foam.

Most importantly for the generation of steam energy, the foam is also riddled with tiny pores that allow water – through capillary action from applied heat – to make its way up through the material, and is reportedly capable of converting as much as 85% of its received energy into steam-producing goodness.

Steam, of course, can be put to use in a variety of industrial machines and engines, and can also be used to generate electricity through the use of steam engine powered generators. That’s not where it stops, though. “Steam is important for desalination, hygiene systems, and sterilization,” says Hadi Ghasemi, a postdoctoral MIT student who ran the material development. “Especially in remote areas where the sun is the only source of energy, if you can generate steam with solar energy, it would be very useful.”

While not in the same energy-production league as some supercritical solar steam generators, the MIT team believes their new graphite/carbon sponge will have a commercial edge thanks to its low manufacturing cost and comparatively cheap materials. In addition, the new MIT sponge and may be suitable for a new range of similarly inexpensive and compact, steam engines, particularly as this new method of steam generation offers a significant improvement over conventional thermal solar arrays.

You can check out a still from Godzilla vs. the Smog Monster, below, and let us know if you think MIT’s new invention looks like Hedorah (the Smog Monster’s proper name) in the comments section, below. Enjoy!


Godzilla vs. the Smog Monster (Hedorah)


Source | Images: Gizmag.

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About the Author

I've been involved in motorsports and tuning since 1997, and write for a number of blogs in the Important Media network. You can find me on Twitter, Skype (jo.borras) or Google+.

  • Amar_Kumar

    This cannot create high pressure steam, do not believe it can replace mirror.

  • I get the purpose of the sponge. It has to do with surface area and boiling via bubble nucleation. That was the purpose of glass bead put into beaker of water in chemistry class. It has something to do with the surface temperature is hotter than the media (water). Or something. It’s in wikipedia probably. Everything is.

    Anyway, how is the steam collected, contained and pressurized to become useful work? Or is this just to get the solar heated thermal fluid hotter faster so it can be used to transfer heat to form steam in a boiler?

    • This is to make steam faster, then put it to work.

    • jonbohmer

      Exactly my issue also. In order to collect the steam they would need a transparent collection vessel on top. The problem with transparent vessels is that they are not very good at dealing with the high pressures created by the steam. The other issue is that this need the concentrated light to be beamed down at it from the top, which is exactly opposite of what is desired. They would need to beam down using a mirror on top, which certainly removes the advantage of using fewer mirrors. I am afraid this invention is too impractical for real world use.

      • sault

        Could you collect the steam from a port on the side of the vessel instead of on top. You would need a small gap for gas to move between the sponge and the top plate of the vessel, but it shouldn’t be too difficult. If the sponge just floats on the top of the water or the water supply continually keeps the water level covering the sponge, then concentrating the sunlight and having it enter the top of the vessel shouldn’t be too hard. Just look at the beaker in the picture…the light is coming in from the top and the sponge is floating there, making steam no problem.

        My main concerns with this technology are that it will need extremely pure water or the sponges will get clogged with minerals and sediment in a hurry. It will also need large condensers to bring that pure water back to a liquid state. Finally, can the carbon material withstand the high temperatures that lead to high system efficiency while also withstanding the vigorous boiling action that these temperatures would cause.

        • jonbohmer

          You can take the steam out on the side but you still need to cover the top with a glass surface since the light has to come from the top. It would have to be under high pressure, so maybe it could be solved with a dome shape (or inverted dome). Still, today’s boilers consist simply of vertical steel pipes – so much simpler and so much cheaper…

          The carbon material I am not worried about in terms of temperature or pressure. The pores would get clogged though, as you say…

          Condensers are the Achilles heel of any steam system. The size of this would not be any bigger than for other steam systems. It is more interesting to look at Sterling/Ericsson cycles which use zero water and need no boiling or condensing, just hot air.

  • JamesWimberley

    Bonus points for the Smog Monster.

    The major gain claimed by these MIT researchers over previous work (like that at Rice U reported here, link, using nanoshells in suspension) is not so much in efficiency but in the much lower solar concentration needed: 10 rather than 100. So the collector mirror can be much smaller and less precisely tracked.

    • Thanks! Great addition.

    • jonbohmer

      And with 10 instead of 100 mirrors the energy output would also be only 10%. I still don’t understand what problem they have solved. Making steam with concentrated solar was never hard, expensive nor inefficient.

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