

Teenager invents solar panel made from human hair - sophacles
http://www.dailymail.co.uk/sciencetech/article-1212005/Teenager-invents-23-solar-panel-solution-developing-worlds-energy-needs-human-hair.html

======
electromagnetic
The science is rather sound on this; melanin has been shown to produce a
photosynthesis effect with ionizing radiation. Incidentally, this likely means
the solar panels would actually be able to work at near maximum efficiency on
partially cloudy days, even on a lightly clouded day it should still work
well.

It generally takes much less water to _deflect_ visible light and reduce the
efficiency of a silicon solar panel than it takes to _absorb_ the UV that is
producing power through the melanin.

What I believe is important here is the melanin. If an efficient and stable
way is found to manufacture a melanin-based solar panel, it could be used in a
wider range than many traditional solar panels. I suppose the ideal would be
to produce a traditional solar panel that is transparent to UV, allowing it to
be caught in a melanin-based solar panel. In theory you could double the power
output of a solar panel and extend its power production into cloudier periods.

~~~
physcab
"It generally takes much less water to deflect visible light and reduce the
efficiency of a silicon solar panel than it takes to absorb the UV that is
producing power through the melanin."

I'm confused by this statement. I'll try to clarify.

Melanin's absorption spectrum can be found here:
<http://www.cl.cam.ac.uk/~jgd1000/melanin.html> As you can see, it has high
absorption from 300nm-700nm which is in the UV-Vis range.

Similarly, silicon's absorption spectrum is here:
[http://www.wsi.tum.de/Research/StutzmanngroupE25/Research/Ph...](http://www.wsi.tum.de/Research/StutzmanngroupE25/Research/Photovoltaics/tabid/220/Default.aspx)
So it absorbs much more in those wavelengths so that's why you're bound to get
higher efficiencies.

Alternatively, water's absorption spectrum can be found here:
[http://en.wikipedia.org/wiki/File:Water_absorption_spectrum....](http://en.wikipedia.org/wiki/File:Water_absorption_spectrum.png)
Water does not have a high absorption in this region. So clouds will not
absorb wavelengths in this region.

And sorry to nitpick, but nothing _deflects_ light. Light is absorbed,
transmitted, and emitted. If it is emitted in the direction from which it
came, its called reflectance.

~~~
lutorm
Light can scatter (Rayleigh scattering, Thompson scattering), which does not
involve an absorption/emission event (unless you are talking about resonant
scattering for example in the Lyman Alpha line).

That's how clouds work. The albedo of clouds is very high, so little is
absorbed. Nevertheless, the small water drops scatter the light.

~~~
physcab
Sure. I was thinking more from the material perspective, but yes there are
other phenomena to consider.

------
craighyatt
Debunked here:
[http://sites.google.com/site/edwardcraighyatt/hairsolarpanel...](http://sites.google.com/site/edwardcraighyatt/hairsolarpanelnepal)

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unwind
Huh ... Does the Daily Mail generally publish hoaxes?

~~~
NathanKP
I think it must be a hoax.

~~~
onreact-com
Yes, it's a hoax. See here: <http://news.ycombinator.com/item?id=817099>

------
doodyhead
I'm impressed in principle, but I'll believe it when I see an article in The
NY Times, The Washington Post, or The Economist. That those reporters have
chosen to ignore it gives me cause for concern.

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ars
It looks like just a small amount of hair on there. I wonder about the watts
per area.

I bet it would take a massive amount of surface area compared to regular solar
cells.

It's a very cool demonstration/proof of concept, but it's not practical for
actual use. (But might have a niche in places where other sources of
electricity are non-existent.)

~~~
roc
I get the feeling a windmill and water tower might be a more durable,
effective and all-around useful solution for those areas.

Anyone who found it cost effective to wind human hair around terminals by hand
every few months likely has more basic needs to be met than simple
electricity.

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muon
The news is only as good as it's source. I am sceptical about the claim. Would
love to see this news in science magazines like New Scientist or Scientific
America, before buying it.

------
ars
Measuring when you have a florescent light so close to the wires is cheating -
the ballast will induce current in them.

~~~
electromagnetic
Hardly, they're reading DC not AC, the ballast will induce a few milliwatts
(at the max) in the wires and at 50~60HZ this will likely be within the margin
of error on a hand-built solar panel anyway. (Ed: The electrical meter likely
wouldn't detect the interference as AC is generally self-cancelling
interference on a DC line, unless diodes are in use)

Induction between two wires is exceptionally low. Unless the two copper wires
share the same ferrite core, you'll get diddly squat out. Noise in an
electrical signal, is very different from noise in power, which would require
an actual imbalance in the AC outputs, IE a power plant running at 50HZ and
one running at 55HZ will produce a very unstable power supply.

~~~
joe_bleau
I would have thought the CFL ballast would run in the kHz range, not 50-60 Hz.

The DMM appears to be reading voltage, and its input is probably pretty high
impedance, so it may very well be sensitive to the hash from the ballast (the
meter's input protection circuits may be rectifying the AC).

I'm thinking hoax.

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duskwuff
The photos of his "solar panel" look incredibly suspicious:

[http://i.dailymail.co.uk/i/pix/2009/09/08/article-0-06546E62...](http://i.dailymail.co.uk/i/pix/2009/09/08/article-0-06546E62000005DC-46_468x286.jpg)

[http://i.dailymail.co.uk/i/pix/2009/09/08/article-0-06546F9D...](http://i.dailymail.co.uk/i/pix/2009/09/08/article-0-06546F9D000005DC-575_468x313.jpg)

Single strands of hair strung randomly around a grid? This cannot possibly be
an effective approach. But there's an even easier way to prove it's a hoax --
human hair is not an electrical conductor, and doesn't produce electricity
under sunlight. (This takes about fifteen seconds to test for yourself with a
multimeter.)

------
bcl
I don't know if the science behind this is sound, so assuming that it is:
According to the article the panels are expected to be manufactured for 1/4
the cost of current panels of similar wattage. But it also says the hair
"...lasts a few months", which means that they are much higher maintenance
than silicon based panels which last at least 5 years with current designs.

So TCO may be higher for the hair panels, especially if longer strands of hair
are needed.

As far as the validity of this goes, I need more hard facts before I can make
a decision. Those hair strands aren't packed in there very tightly, so getting
9v/18W out of that panel is fairly unbelievable.

------
kragen
£23 ≈ US$38. At 18W that's US$2.11 per watt. That is indeed about half the
price of silicon solar panels last I checked. I have no knowledge of these
properties of melanin, so I don't know if this is a hoax.

~~~
ars
That's the price of the parts, but does not take into account the cost of
labor to manufacture it, or to acquire the hair.

~~~
kingsley_20
These guys own a big chunk of the world hair market:
[http://www.zimbio.com/TTD/articles/16/Hair+offering+at+tirup...](http://www.zimbio.com/TTD/articles/16/Hair+offering+at+tirupati)
. As long as superstition and India's population remain stable, at least
supply shouldn't be a problem :)

~~~
startingup
Hey, hey, let's go easy on the "superstition" part, OK? :)

One man's religion is another man's superstition, I guess! And shaving off the
hair is pretty harmless, as "superstitions" go -I mean, I got a lot of friends
pretty non-superstitious types who shave off their hair here in the valley.

~~~
pwmanagerdied
Any man's religion is superstition.

~~~
eru
Alanzo is our Church. That's a cold, hard, simple fact and not a mere
superstition of the Cult of the Least Fixed Point.

~~~
jacquesm
Alanzo ? Don't you mean Alonzo ?

~~~
eru
Of course. Thanks for the correction.

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chaosprophet
Hmmmm... If that works and is going to be used for lighting, then combining it
with a pulse width modulator of about 50pc duty cycle should double the supply
duration.

------
Gibbon
I posted another article on these solar panels several hours earlier:
<http://news.ycombinator.com/item?id=812551>

The bottom of the article includes a link to a research paper:

[http://precedings.nature.com/documents/1312/version/1/files/...](http://precedings.nature.com/documents/1312/version/1/files/npre20071312-1.pdf)

------
brk
This doesn't make any sense. It costs (according to the article) $38US to
produce about 18W of electricity, a little over $2/W.

I'm currently buying solar panels from China for $1.85/W US in small
quantities, and they generally throw in the charge controllers as well.

The article also implies that the hair needs to be replaced at some regular
interval.

Hardly newsworthy.

~~~
kragen
Where do you get your panels? <http://www.wholesalesolar.com/solar-
panels.html> lists prices from about US$3 to about US$10 per watt for panels
in the 100-200W range and nothing below 100W, and
<http://www.solarbuzz.com/Moduleprices.htm> has this lovely graph by month up
in the US$4.40 range. I see <http://www.ecobusinesslinks.com/solar_panels.htm>
lists some panels for US$1.85 per watt, but the discrepancy is worrying.

~~~
brk
Direct from the manufacturers and/or their factory reps. This is for panels in
the 50-100W range.

~~~
huherto
Just curious. What do you use your panels for? Personal use or do you build
stuff to sell.

