Dual axis solar tracker

Discussion in 'The Projects Forum' started by Majid Ali, May 21, 2015.

  1. Majid Ali

    Thread Starter New Member

    May 21, 2015
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    Anyone help me by sharing circuit diagram or simulation of dual axis solar tracker using pic 16F877A with DC gear motor OR dual axis tracker by using arduino
     
  2. williamj

    Active Member

    Sep 3, 2009
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  3. wayneh

    Expert

    Sep 9, 2010
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    Just FYI, the Earth has only one axis. You don't really need two.
     
  4. Kevin Mitchell

    New Member

    Aug 19, 2015
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    as i learnt from my Renewable energies Course, planet Earth has one axis yes, but that axis is ~23º to a vertical plan with the sun, somehow you have to compensate right? that's why there is dual axis, one for the earth axis the other for to compensate the 23º.
     
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    How much does the Sun angle change from Winter to Summer? The output from the panel is not affected much by seasonal changes.

    Read this forum thread.
     
  6. Kevin Mitchell

    New Member

    Aug 19, 2015
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    the percentage is not too high to consider. but we're talking about solar trakcers, which summer or winter it gives the panels maximum output. that's like around 40% more power from the panels during a day.
     
  7. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Are you claiming that adding the second axis to a solar tracker adds another 40% to their output? More like 5%. I see ~33% for the first axis and 5% for the second axis. If you manually adjust the elevation of your panels twice a year you can get most of that without motorizing the second axis.
     
  8. Kevin Mitchell

    New Member

    Aug 19, 2015
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    ~38% more power. the only i could do to the tracker is maintenance of the motors and make a "cheat test" to the controller. twice a year. still more than 30% production is a lot to consider having a tracker.
     
  9. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    I have yet to see a solar panel installation where any tracking at all was used.

    I assume the replacement cost of the panels themselves (plus anything else they may take down) far exceeds the cost benefit of a few percentage points of power. Thus they are securely mounted firmly to the base structure.

    After all, it is hard to predict the strength of the wind. I personally have seen sturdy trees knocked down like bowling pins during hurricanes.

    If I was to take the risk of making a moving mount to a large sail-like device I would not attempt to measure where the sun appears to be at any given moment. Clouds, dust, pranksters and such can throw off a measurement. However, for hundreds of years the sun's exact position in the sky has been predicted, if just for the use of mariners to be able to tell where they are. And yes, they do compensate for the effects of the atmosphere.

    So don't measure where the sun is, compute it and point at that.
     
  10. wayneh

    Expert

    Sep 9, 2010
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    From adjusting for the season? No way. For one thing, I could aim in the middle and thus never be more than 11.5° off optimal. Would it ever be worth switching off of that? Maybe if the adjustment is dead easy. But there's no way it would be worth changing more than twice a year.
     
  11. GS3

    Senior Member

    Sep 21, 2007
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    I find your views intriguing and wish to subscribe to your newsletter.
     
  12. GS3

    Senior Member

    Sep 21, 2007
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    No. At the equinoxes the altitude of the sun above the horizon is equal to 90º minus the latitude (if the latitude is 15º the sun is 75º above the horizon). Then it swings 23 higher and 23 lower over the course of the seasons. So for latitude 40º the altitude of the Sun will oscillate between 73º and 27º.

    Many solar plants use dual axis tracking in its different forms: altitude/azimuth and equatorial mount.
     
  13. GS3

    Senior Member

    Sep 21, 2007
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    Really? How many have you seen in total?

    https://en.wikipedia.org/wiki/File:3_MW_CPV_project_in_Golmud,_China.jpg
    https://en.wikipedia.org/wiki/File:CPV_dual_axis_tracker.JPG

    I believe the immense majority of PV solar panel plants I have seen were alt-azimuth dual tracking. I doubt there would be any PV plants using no tracking. I would be very surprised.
    So what is it? Do or don't?

    EDIT: After some searching I have found some pretty big PV plants with fixed panels.
    http://www.businesswire.com/news/ho...YOCERA-Supplies-2MW-Modules-Solar-Power-Plant
    http://solarenergypowerplants.blogspot.com.es/2010/11/dulcinea-solar-plant.html
    http://solarenergypowerplants.blogspot.com.es/2010/11/arnedo-solar-plant.html
    So I guess both types are common. It is obvious that fixed panels are simpler but less efficient so each installation focuses on a different aspect.
     
    Last edited: Oct 19, 2015
  14. wayneh

    Expert

    Sep 9, 2010
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    Agreed, my mistake. It doesn't change my point that aiming at the middle comes darn close to optimal even with no changes. Changing with the seasons - not continuously - gets incrementally closer to optimal.
     
  15. GS3

    Senior Member

    Sep 21, 2007
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    For plants with alt/azimuth mounts, and it seems it is most of them, tracking is done on two axis anyway.

    I do believe though that these plants probably compute sun position rather than having some photosensor tracking device.
     
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