

New spongelike structure converts solar energy into steam - davidbarker
http://newsoffice.mit.edu/2014/new-spongelike-structure-converts-solar-energy-into-steam-0721

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pflanze
Isn't limescale going to make this unusable quickly? Perhaps those structures
will need to be moved through acid baths periodically and automatically. What
about dirt? I guess that's the joys of research when you've got a practical
usage in mind--all of the issues that lie ahead.

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mikexstudios
Link to paper:
[http://www.nature.com/ncomms/2014/140721/ncomms5449/full/nco...](http://www.nature.com/ncomms/2014/140721/ncomms5449/full/ncomms5449.html)

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PeterWhittaker
85% efficiency - wow!

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msandford
Once you run it through some kind of thermodynamic cycle to turn steam into
electricity, the efficiency will drop.

There's a limit to how efficient those processes are. For the kinds of
temperatures we can easily handle with the technology we have, it's not so
rosy.

Steam plants are between 30% and 60% efficient depending on how fancy (and
thus expensive to build) they are.

[http://en.wikipedia.org/wiki/Thermal_efficiency](http://en.wikipedia.org/wiki/Thermal_efficiency)

So if you figure the steam plant might be 45% efficient and the steam
production is 85% efficient you end up with 0.45 * 0.85 = 38.5% total
efficiency.

Better than off-the-shelf PV panels available today. But this method requires
solar concentration by a factor of 10x which will definitely add cost. If it's
better that PV at that point would remain to be seen.

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chr1
Though you don't necessarily need to convert it to electricity, and can use
the steam for something else, like desalination of sea water.

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waps
Nothing lasts in sea water. Least of all sponges. I doubt that's a practical
application.

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kordless
Just wash it off.

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waps
Incidently, detergent is one of those things that won't work well in seawater.
Plus seawater is corrosive. So even if you do manage to clean things, they're
not as reusable as they otherwise would be.

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trhway
I wonder how their new type of graphite sponge would work in a battery.

