<story><title>13-Year-Old Makes Solar Power Breakthrough by Harnessing the Fibonacci Sequence</title><url>http://inhabitat.com/13-year-old-makes-solar-power-breakthrough-by-harnessing-the-fibonacci-sequence/</url></story><parent_chain><item><author>felipemnoa</author><text>The comparison is against a flat row of cells that do not track the sun. I suspect that it will not do better compared to an array of cells that do track the sun.&lt;p&gt;Basically the tree of cells are arranged in different angles so that as the sun moves some of them will always be receiving optimal sunlight when their normal is parallel with that of the incident light.&lt;p&gt;Very nice insight, especially for a kid his age. I certainly would not have thought of it.</text></item></parent_chain><comment><author>uvdiv</author><text>&lt;i&gt;&quot;Basically the tree of cells are arranged in different angles so that as the sun moves some of them will always be receiving optimal sunlight when their normal is parallel with that of the incident light.&quot;&lt;/i&gt;&lt;p&gt;Except it&apos;s trivially impossible to generate more energy like this (as he claims)! If a set of solar panels is independent and non-interacting (e.g., they don&apos;t shade or heat each other), then  their total power output is simply the sum of their individual power outputs. And so their total energy outputs (integrated power) is the sum of their individual energy outputs. (Necessary distinction because their power peaks may occur at different times).&lt;p&gt;P_tot = Σ P_i&lt;p&gt;∫ P_tot dt = ∫ (Σ P_i) dt = Σ (∫ P_i dt)&lt;p&gt;E_tot = Σ E_i&lt;p&gt;If there is an unqiue optimal orientation for a single static panel (which under realistic assumptions there is) -- optimal in terms of maximizing energy output, E -- then the optimal orientation of a array of independent solar panels is just the same orientation, iterated. Combine inferior panel orientations, and their total remains inferior.&lt;p&gt;E_i &amp;#60; E_opt (for i &amp;#60;- 1..N)&lt;p&gt;Σ E_i &amp;#60; N * E_opt&lt;p&gt;And all those panel angles in his &quot;tree&quot;, facing non-South, up, down, towards a wall... they are individually inferior to the single 45° south-facing panel in his static array. So combined together they are still inferior.&lt;p&gt;Where did his experiment go wrong? I&apos;d start with the shade issue. The whole setup is in intermittent shade (note the tree shadows); and one experiment is sitting near the ground, the other is mounted on a pole. Looks like different shade environments. His output graphs show that the entire flat array is sometimes in total shade, at a time when the pole-mounted &quot;tree&quot; is not:&lt;p&gt;&lt;a href=&quot;http://www.amnh.org/nationalcenter/youngnaturalistawards/2011/aidan.html&quot; rel=&quot;nofollow&quot;&gt;http://www.amnh.org/nationalcenter/youngnaturalistawards/201...&lt;/a&gt;&lt;p&gt;Another fatal flaw (I had to look this up to check) is that he is measuring voltage, not power, and they are not linearly related in photovoltaics. Actually, the open-circuit voltage (what you get if you stick a voltmeter over a solar cell, when it&apos;s not hooked up to a load) is &lt;i&gt;practically independent&lt;/i&gt; of irradiance:&lt;p&gt;&lt;a href=&quot;http://i.imgur.com/SWGjV.png&quot; rel=&quot;nofollow&quot;&gt;http://i.imgur.com/SWGjV.png&lt;/a&gt;&lt;p&gt;This from the solar module datasheet here:&lt;p&gt;&lt;a href=&quot;http://www.bpsolar.us/products/3-series-solar-panels-polycrystalline&quot; rel=&quot;nofollow&quot;&gt;http://www.bpsolar.us/products/3-series-solar-panels-polycry...&lt;/a&gt;&lt;p&gt;Open-circuit voltage going from 200 W/m^2 to 1,000 W/m^2 only increases from 34 V to 38 V. Power output, with a real load, would go up by about 5 times.&lt;p&gt;So, he never really measured energy production, or anything that remotely approximates it.</text></comment>
<story><title>13-Year-Old Makes Solar Power Breakthrough by Harnessing the Fibonacci Sequence</title><url>http://inhabitat.com/13-year-old-makes-solar-power-breakthrough-by-harnessing-the-fibonacci-sequence/</url></story><parent_chain><item><author>felipemnoa</author><text>The comparison is against a flat row of cells that do not track the sun. I suspect that it will not do better compared to an array of cells that do track the sun.&lt;p&gt;Basically the tree of cells are arranged in different angles so that as the sun moves some of them will always be receiving optimal sunlight when their normal is parallel with that of the incident light.&lt;p&gt;Very nice insight, especially for a kid his age. I certainly would not have thought of it.</text></item></parent_chain><comment><author>yxhuvud</author><text>Moving parts cost a lot though. There is a reason for trees not to have them.</text></comment>