Hello,

I am doing a project for school and was wondering if someone could help me understand the anatomy of solar panels. I am trying to improve the output of a solar panel by focusing and magnifying the sun's solar energy. I am thinking of using some kind of lens, possibly a Frensel lens. The question is, where on the solar panel should I plan to focus the light? Let's take an amorphous type solar panel for example, something I have access to. Or a monocrystalline panel. It sounds like a dumb question but I am thinking that the whole surface of the panel is semi-conducting so anywhere would work, right? Or are there certain spots on the surface of the panel that are designed to be the absorbers of light? Any help would be appreciated. Thanks.

 

The entire panel is sensitive, don't focus to a sharp point, just focus on the entire panel.

I take it you are aware that such a scheme will require accurately tracking the sun, as a slight misalignment will mean it's not focused on the panel any more.

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A solar panel is most efficient when it's illuminated uniformly. All you'll do with a big lens is melt it.

 

Yes. That would be a problem. It could be solved by mechanically moving the lens to face the sun and provide focus on the panel. Since the sun's path is predictable, a simple set-up could slowly move the lens throughout the day to provide maximum efficiency.

 

A setup more along the line of a solar oven which uses reflectors may work better. You should be able to intensify the light without focusing on a single spot. There still is the possibility of cooking the solar cell if you collect too much light. The materials are cheap, cardboard or plywood and aluminum foil.

Since solar tracking is required to make it work you might set it up to point a bit off the sun when it is too bright. Dead on with clouds.

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What if the lens isn't powerful enough to melt the panel? What about a think layer of water sealed between two sheets of acrylic? Focus the light on the panel has to somehow improve the efficiency.

 

If you look at some commercial solar sites you will see they use reflectors.

If you stick a focussing lens between the panel and the Sun, the total illumination of the panel stays the same.!!!
Unless the panel area is smaller than the lens area.

All you will do is burn a spot on the panel.

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Interesting idea...do you think the backside of the reflectors would block the sun's light when the sun is not directly above the panel, and thus reducing the total daily output?

 

If they can use them to boil water you should be able to build one to increase the light level.

There are numerous designs for solar collectors and ovens. What I was thinking about was to place the photo cell facing down and reflect light up to it with panels off to the sides. Much like a reflector telescope but you do not need near the precision. Maybe several reflectors curved in just one dimension.

If you design the unit to collect enough light when it is cloudy you will have too much when there are no clouds. If you add a tracker to follow the sun you can move the collector to keep it from cooking the cell/panel.

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Sort of like a parabolic mic?

 

Same principal but focus should be less sharp to cover entire solar cell.

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i think that a lens doesn't work to improve efficiency

as you consentrate more solar energy it is manly in the form of heat and one of the things that Photovoltiac cells make less efficient is heat


for heating up water in solar colectors it does work and i made one proto type in small dimentions to messure the differance with if you don't colect more sun (enlarging the sqr meter catchment area)

i only used mirrors no lenses

Robert-Jan

 

Aluminum is used to coat the mirrors on telescopes. I think it should work well for your purpose. My SO has done more work with this sort of think suggest heavy duty Renyolds Wrap over a smooth surface. The smoother you keep the foil the more efficent it will be. But this is not a big deal since you do not want a sharp focus and can always make the collector a bit bigger to overcome inefficency.

It would be interesting if you posted updates on your progress.

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Moneer,
As you say this is a school project so why bother with lens or mirrors and go and make a simple tracker for the PV panel. It will get upto 30% more power by tracking the sun. All you need is 2 green led's and a simple circuit to sense the sun and a reasonable delay to stop the hunting. As this is your school project I'm giving you another angle to try and I won't give you the whole fruit an biscuits but I will assist you if you choose this option.

Cheers Bryan

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mirrors + solar tracking if your not on the equator chances are it won't burn up panels are rated as if they work on the equator (to con us into thinking they are more powerful than they really can be) so con back and get the extra light

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