Would Reflecting Mirrors Make Solar Energy?

Question

If there were many reflecting mirrors to double and triple the light received by photovoltaic cells, would that increase their efficiency?

Answer 1

This question is worth a look because while it's true that solar cell panels have a relatively low photovoltaic efficiency, why not keep bouncing the same beam of light on it, sort kind of like redepositing the same bad check at the bank until it goes through? Assuming that unabsorbed light reflects from the solar panels (it's a different problem if the reflection is diffuse), we can create a well between a solar panel and a mirror set at an angle to it, so that light infall reflects repeatedly inside it. It's an interesting problem, because I can see that there's a lot of design tradeoffs involved here, and it would depend on how light is scattered from the solar panels. Enough usable light has to be scattered from the solar panels to make it worthwhile, it's no good if the scattered light is at a different wavelength that's not absorbed by the panels.

I'm SURE solar panel engineers have already thought of this angle, pun fully intended.

Addendum: For those that think that efficiency of solar cells is "very high", check out the link to a chart showing that most solar cell technologies are from 12% to 24% efficient in converting sunlight.

Answer 2

Yes and no, the efficiency of solar radiation that is relfected can be made high but it will always go down since some light will scatter.

Solar cells collective radiation received would probably go up a bit in efficiency but you are really limited by the fact that they are only 15 percent efficient in theory. So while you'd have more energy available most of it would be wasted.

The output would "go up" because of more light on the surface but it would max out pretty fast no more than 5 or 6 mirrors of the same basic collecting size would be of any help because of the low efficiency of conversaion to electricity and the amount of energy in the output difference probably wouldn't justify the cost of the mirrors .

However multiple mirrors can be concentrated in the same spot and then their collective light is much brighter and hotter, focus them on a grill with some coolant or water pumping through and you will get steam which can then be converted into energy.

It is rumored that the ancient scientist Archimedes actually developed a "weapon", although 2000 years later it seems seems that marketing MAY have somewhat oversold the idea since this probably was just a series of mirrors upon a hilltop near a harbor that the Romans were attacking (Archimedes was Greek).

I say MAYBE it was a tad oversold, when "advertized" as Archimedes new "Solar Death Ray" when the reality of the situation was more close to Archimedes new "Solar 'kinda-sorta warmer if your in the way' Ray".

Answer 3

Unless they were aslready performing to capacity (which is most unlikely), this would make sense, right? However, energy cannot be created nor destroyed, and light is a form of energy. So I'm not positive, but there are a couple points to ponder. I'll get back to you if I find out anything else.

Upon further pondering, I vote yes, as mirrors would redirect photons toward the cell, thereby increasing intake of energy and therefore efficiency.

Answer 4

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Answer 5

I don't think so, because directing solar energy using a mirror can increase the temperature on the cells. And the eficiency of solar cells will diminish with increase in heat.

The best advice is to maintaing them clean and cool.

Answer 6

Not their efficiency per se, though it would provide more energy to the panels, resulting in more output from them. Note that panels must be designed for this application or they will be overloaded by the reflectors and fail. Such mirrored arrays have been around for a while, and you can find them on the web pretty easily.

Good thinking, but someone beat you to it this time.

Answer 7

Yes, that is the principle of one of the two types of solar energy. In this way, you can produce vapor from water. It works like traditional heating plants but this tecnology doesn´t burn oil and therefore, pollution is almost zero.

This type of technology is vastly used as heating system for buildings in many countries.

The other type of solar production system is based on the effect of light (solar rays) producing electricity. Photovoltaic, as you said. In this technology mirrors are not used, because efficiency is very high already.

This type of technology is used for electrity power plants.

One of them use very small mirrors as you suggested.


Millions of kilowatts are produced worldwide using solar technologies. It is a real business of billions for many companies worlwide.

Some companies are researching on hybrid heat-photovoltaic panels. Its use is targetted to big buildings, to provide both electricity and heating. In this case, it seems that photovoltaic electricity and direct rays provide heat enough and cost of mirrors doesn´t justify increase of performance.

Some countries in Europe and Asia have developed special conditions for citizens and companies to take advantage of this technology, not only for saves in electricity bill but to generate money reselling electricity to electricity operators. Banks use to give special low rate loans in those countries because it is a low risk business.

I can provide very detailed description of those business in Spain, and some information about other european and asian countries if you require it.

Answer 8

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Answer 9

The efficiency of the cell if fixed, it would collect more light to be converted at the effciency.