13-Year-Old Makes Solar Power Breakthrough by Harnessing the Fibonacci Sequence Read more: 13-Year-Old Makes Solar Power Breakthrough

[Otorongo]

13-Year-Old Makes Solar Power Breakthrough by Harnessing the Fibonacci Sequence

After studying how trees branch in a very specific way, Aidan Dwyer created a solar cell tree that produces 20-50% more power than a uniform array of photovoltaic panels. His impressive results show that using a specific formula for distributing solar cells can drastically improve energy generation. The study earned Aidan a provisional U.S patent – it’s a rare find in the field of technology and a fantastic example of how biomimicry can drastically improve design.

Aidan Dwyer took a hike through the trees last winter and took notice of patterns in the mangle of branches. His studies into how they branch in very specific ways lead him to a central guiding formula, the Fibonacci sequence. [..]

To see why they branch this way he built a small solar array using the Fibonacci formula, stepping cells at specific intervals and heights. He then compared the energy output with identical cells set in a row. Aidan reports the results: “The Fibonacci tree design performed better than the flat-panel model. The tree design made 20% more electricity and collected 2 1/2 more hours of sunlight during the day. But the most interesting results were in December, when the Sun was at its lowest point in the sky. The tree design made 50% more electricity, and the collection time of sunlight was up to 50% longer!”

His work is certainly piquing the interest of the solar industry, and even more impressively he is demonstrating the power of biomimicry — a concept that many see as the pinnacle of good design, but one that thus far has been exceptionally difficult to achieve. Way to go!

http://inhabitat.com/13-year-old-makes-solar-power-breakthrough-by-harnessing-the-fibonacci-sequence/

A very practical lesson from the book of nature...

Edited August 19, 2011 by Otorongo

[Kee]

Fantastic find and an even greater story. Love stuff like this

[dollarjuice]

It's true in every aspect...

Nature always knows what's best.

[synchromesh]

Awesome.

 

 

[CβL]

Something about this seems off. I'll have to investigate more. As much as I understand that Fibonacci spacing is optimal for many things, I can't see how it would work better than a flat array with a feedback control system.

[nabraxas]

Solar-panel "trees" really are inferior (or: "In which hopelessly inept journalists reduce me to having to debunk a school science project")

Some poor 13-year-old kid is all over the news as having made a "solar breakthrough". The news is to blame. All the usual suspects -- popular environment blogs, tech magazines -- blindly parrot the words of this very misinformed (not to blame him, he's an unguided 13 year old) kid.

Essential summary:

He's comparing arrangements of solar panels to maximize total electricity output

One is a conventional, flat, 45°-tilted (roughly latitude), south-facing array

The other is an oddly-arranged "tree" with panels facing all directions: up, down, towards a wall... (some Fibonacci mysticism involved here)

(Writeup has photos of both setups, and graphs of data)

Both experiments have equal numbers and types of solar cells

He measures the (open circuit) output voltage over the cells connected in series

He thinks the "tree" is superior (generates more electricity) than the optimal flat array

This is, I'm sad to say, clear nonsense. I'll take this in two parts: one, why his experiment is, unfortunately, completely broken (sorry again). Two, why the imagined result is impossible nonsense.

Broken experiment

Most importantly, by mistake he did not measure power outputs from the solar cells. Instead he measured voltage, without a load attached ("open circuit"). They are barely related -- in solar cells, voltage is actually almost a constant, independent of power.

The actual power delivered by a solar cell is not linearly related to the open-circuit voltage; actually, as a semiconductor, it has a horribly nonlinear relationship. Here's the current-voltage (I-V) curve:

VOC denotes the "open circuit" voltage: when there is no load attached, and no current flows (I = 0). Power goes as V*I; a real solar system will maximize efficiency, by working at the point on the I-V curve which maximies power (PMAX).

The kid is measuring VOC. As it happens, this is practically independent of power output! Here's how the I-V curve changes with incident solar power ("irradiance", areal density of radiation in [W/m2]). As this solar module datasheet shows, VOC is almost a constant, regardless of incident light!

In this module, VOC stays close to 35 V, over a 5-fold range in irradiance. Whether the incident light is bright or dim, the open-circuit voltage is the same.

Of course, PMAX (not shown) goes up roughly linearly with solar input. You must expect this: when you have 5x more solar power input, you have ~5x more electric output. But in Power = Voltage * Current, it is current, not voltage, which increases. (For those who are familar wiht physics, this is reasonable because: twice the brightness doesn't mean twice as much energy per photon, but twice the number of photons. The voltage reflects the energy of individual excited electrons: an electron with 1 eV energy can travel against a 1 V potential difference. The maximum current depends on the number of such excited electrons. More light means more excited electrons, but each with the same energy.)

End result: measuring the solar cells' VOC over time, and adding them up, is garbage data, and has nothing to do with energy production.

Unreasonable theory

As for why the result is impossible. I'm not sure I understand the confusion by which people think there could be some advantage, to orienting panels at sub-optimal angles. That somehow combining sub-optimal panels, together, makes them generate more energy in the net. Here's my argument, in case it helps clear up misconceptions.

Take an collection of solar panels (indexed by 'i'). Their power output is the some of their individual outputs. So, their total energy output (power integrated over time) is also the sum of their total energy outputs.

Ptot = Σ Pi

∫ Ptot dt = ∫ (Σ Pi) dt = Σ (∫ Pi dt)

Etot = Σ Ei

Suppose some orientation of a solar panel, 'OPT' (maybe south-facing, latitude-tilted), is superior to some others, index them by 'i' (say, facing north, down, up, towards a wall...) Then adding together 'N' such panels, in any order, is strictly worse than a uniform array where all panels are at their individually-optimal angles:

Ei < EOPT (for i <- 1..N)

Σ Ei < N * EOPT

So: if the individual angles in the "tree" are worse then the 45°-tilted south-facing panels in the flat array (they obviously are), so is their combination.

(Implicit assumption: that the panels are non-interacting, e.g. they do not obstruct (shade) each other, or heat each other, etc. The panels in the "tree" do actually shade themselves, which makes them strictly worse and does not change this result).

Open questions

How did this confused science project became international news?

http://webcache.googleusercontent.com/search?q=cache:JmlMNqVPKlsJ:uvdiv.blogspot.com/2011/08/solar-panel-trees-really-are-inferior.html+http://uvdiv.blogspot.com/2011/08/solar-panel-trees-really-are-inferior.html&cd=1&hl=en&ct=clnk&gl=us&source=www.google.com

Edited August 21, 2011 by nabraxas

[Slybacon]

^^^ Thanks. It appears that the media these days are just going nuts on anything Green. The word Green is about as affective as using the word peace. If you know what I mean....

[Dolos]

^^^ Thanks. It appears that the media these days are just going nuts on anything Green. The word Green is about as affective as using the word peace. If you know what I mean....

 

I know what you mean....

peace man....

[Lorax]

Even considering what your saying nabraxas, this tech could lead to a breakthrough if someone more informed was to pick up the project, trees have had millions of years to develop ideal solar absorption techniques. Are humans really saying we know better, the entire planet is based on geometric patterns like the Fibonacci sequence anyway, theres bound to be a good reason behind it, just saying.

[teonanacatl]

Trees are also fairly ineffective at absorbing light and converting it to energy. Leaves have many functions only one of them is absorbing light.

[Sheather]

They also have to compete with other trees. The shortest ones get less sun than the taller ones. I think the solar panel equivalent of the natural world would be ground cover or algae.

I've yet to see a funky solar tree be built. If the tech is so revolutionary the big corps would have started rolling it out and there would be advertising and so forth.

[devance]

http://www.rexresearch.com/squier/squier.htm

faint, very faint buzz, as if some microscopic mosquito had had his song made audible. The operator rapidly rapidly turning the knobs on his couplers and condensers, raised his hand: suddenly, through the changing radio signals which were clamoring for attention together in the receivers came his voice; "There --- the loud, easily heard one is New Brunswick; the fainter, lower one is Nauen, in Germany".

If all this had taken place in the great Arlington station one would not have wondered, save perhaps at the inability to tune out all radio but Nauen. But it was a little portable house erected in thick woods near the edge of the District of Columbia and the signals were received through an oak tree for an antenna.

It is not a joke nor a scientific curiosity, this strange discovery of Gen. George O. Squire, Chief Signal Officer, that trees --- all trees, of all kinds and all heights, growing anywhere --- are nature's own wireless towers and antenna combined. The matter first came to his attention in 1904, through the use of trees as grounds for Army buzzer and telegraph and telephone sets, which, in perfectly dry ground and in a dry season, functioned poorly or not at all with ordinary grounds. Right then he began experiments with a view to seeing what possibilities, if any, the tree had as an aerial. But in 1904 radiotelegraphy was far more undeveloped than at present, and vacuum amplifying tubes were not thought of.

During the war the Signal Corps established a chain of special receiving stations in different localities to copy and record enemy and allied radio messages. Some of those stations were instructed to test the efficiency of growing trees as receiving antennae.

With the remarkably sensitive amplifiers now available, it was not only possible to receive signals from all the principle European stations through a tree, but it has developed beyond a theory and to a fact that a tree is as good as any man-made aerial, regardless of the size or extent of the latter, and better in the respect that it brings to the operator's ears far less static interference.

This is a rather broad statement, yet there beyond the Capital of the nation stands a little portable house, the oak tree, a small receiving set and a couple of enlisted men and an officer on duty; and the curious may, with permission, hear for themselves that the signals so received are neither faint not interrupted, but strong, full-toned dots and sashes even when they come from far-off Nauen. Page after page is copied daily from the propaganda material which Nauen sends out by the ream. Lyons, Poldhu, ships at sea, even the NC-4 on her way, are heard plainly. As for New Brunswick or nearby Arlington --- they deafen the listener if he is unwise enough to try to "take" them otherwise than with the phones lying on the tables.

It will puzzle the amateur as it has puzzled the experts, how a tree, which is certainly well grounded, can also be an insulated aerial. The method of getting the disturbances in potential from treetop to instrument is so simple as to be almost laughable. One climbs a tree to two-thirds of its height, drives a nail a couple of inches into the tree, hangs a wire therefrom, and attaches the wire to the receiving apparatus as if it were a regular lead-in from a lofty copper or aluminum aerial. Apparently some of the etheric disturbances passing from treetop to ground through the tree are diverted through the wire --- and the thermionic tube most efficiently does the rest.

It is interesting to learn that the tree behaves very much like any other aerial; it receives better in dry clear weather than in muggy, damp weather. It plucks messages from the ether more clearly at night than in the day. It is affected very little by rain. It is affected not at all by the presence of other trees; so far as has yet been ascertained it makes little difference whether one drives his nail in a tree in the forest or a lone tree on the plain. Certainly it makes no difference that amounts to anything whether the tree be just an ordinary tree or a giant; it was a 60-foot oak over which the very awe-struck correspondent heard Nauen telling a waiting world what good people the Germans really are. And to prove that it made no particular difference what kind of tree was used the officer in charge switched to a pine tree, which received equally well.

A dead tree will not do, and a tree not in leaf is not so sensitive as one in full foliage. It makes much difference where the nail is driven. General Squier calls the proper place the optimum point, and experimentally it has been determined that two-thirds of the distance from ground to top is the best place -- in a 60-foot tree, 40 feet from the ground.

One nail is sufficient, and it may be any kind of nail; but copper is preferred as not rusting. In practice, if a tree station is to be at all permanent, several nails would be driven and connected to the same wire, each additional nail up to 6 or 8 making the diverted current a little stronger. But 40 nails apparently produce no clearer signals than half a dozen.

The tree may serve as a receiving station for several sets, either connected in series with the same material or from separate terminals.

Some skeptics have expressed the belief that it was not the tree, but the wire leading to the nail in the tree which was the real aerial. The absurdity of thinking a 40-foot wire could receive the widely differing wave lengths which come through the tree station is obvious, but to set any doubt at rest, the wire to the tree has been hung to the nail by means of an insulator, when the signals immediately cease, only to come in as strong as ever just as soon as the connection is again established.

[psilosophical]

thanks. interesting post ^