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Passive Low-Tech Solar Tracking

Use the Expansion of Metal Rods to Steer a Solar Panel Towards the Sun
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How do you keep a solar panel aimed at the sun without making the price of the tracking system comparable to the solar panel? My solution is to use black aluminum channeling that expands when the solar panel is pointed away from the sun and the sun hits it and makes the solar panel point back towards the sun. This would require a linkage with a great amount of mechanical disadvantage or a bi-metalic strip. If it were cloudy then you wouldn't be collecting that much power anyway, but at least you would have a cheap, robust system that is so low-tech that it would last long enough to get a return on your investment.
elvatoedwardo, May 13 2004

Passive tracker search http://www.google.c...8&q=passive+tracker
[Gromit, Oct 17 2004]

Passive Solar Tracker http://www.solartra....au/index-tess1.php
Retail sales in AU. [servant74, Nov 21 2009]

El Cheapo solution http://www.redrok.com/elcheapo.htm
El Cheapo solution from redrok.com [servant74, Nov 21 2009]

[link]






       Those rods will be a special alloy and expensive. Three photo cells set up as a convex corner cube and a microprocessor to read them and control two small motors is probably still cheaper.
kbecker, May 14 2004
  

       you could use nitinol wire which has a shape memory activated by heat. it has high torque and is relatively inexpensive.
macrumpton, May 14 2004
  

       Can't you make a circle of black bags filled with air and allow the sun's heat to expand these and rest the panel above them on a pole, using some 'opposite direction' joint on an intermediary contact platform (like those 'wrong-way-wobbly-stand-on'things in kids playgrounds), so when the bags push 'up' against the middle platform the panel actually leans toward the most inflated bag. i.e let the sun guide the panel. A bit simplistic, I know, but I've been drinking cider. I think the physics works.
weedy, May 14 2004
  

       :)
dpsyplc, May 14 2004
  

       That reminds me of a tracking system that uses highly compressed CO2. There are reflectors so that the sun heats up a tank on the opposite side of the solar panel causing the liquid CO2 to shoot into the other tank and tilt the panel towards the sun. But after hearing your idea, then maybe there's a cheaper way to do it with bags made of used inner-tube.
elvatoedwardo, May 20 2004
  

       Yep it would make a difference. ... I just added a couple of links you might want to check out.
servant74, Nov 21 2009
  
      
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