# Using mirrors with solar pannels?



## Oilpatch197 (Apr 18, 2004)

Using mirrors with solar pannels?

What if you could have mirrors on rotator that was a such a angle it would reflect MORE light to the solar pannels? Would this work for maxium performance?


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## MELOC (Sep 26, 2005)

i heard that you can do that but the energy you use to constantly move the mirrors makes it only mildly effective.


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## SolarGary (Sep 8, 2005)

Hi,
There are a couple schemes that use reflectors:

http://www.builditsolar.com/Experimental/experimental.htm

The one labeled "Inflatable Heliostat" is one that I built in partenership with another guy. It does work pretty well, but it turns out to be fairly complicated -- not sure its worth it.

The other one is labeled "Paper on PV powered irrigation system" --its down toward the bottom of the page. I just ran across this paper today, and was thinking that the reflector scheme they show looks pretty good. Its cheap, and it is claimed that it increases the panel output by 30%. It does required that the whole PV rig be tracked, because the reflectors are fixed, but this also provides more output. I am curious what people think about this?

Gary
www.BuildItSolar.com


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## Jim-mi (May 15, 2002)

Don't forget to factor in wind when thinking mirrors.
Because of the wind I can't even consider them.
Yes one could get more out of pannels with reflectors


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## rambler (Jan 20, 2004)

Depends on what kind of collector - you will fry one with the heat if it's not designed for it. Not sure if you mean photovoltic, or heat collector pannel, but you can burn up either....

Moving the panels to track the sun, or moving mirrors to aim the sun takes energy, and requires flimsy or spendy mechinisms, so the increase in output is often eaten up & best to just use the $$$ to make more collectors.

--->Paul


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## SolarGary (Sep 8, 2005)

rambler said:


> Depends on what kind of collector - you will fry one with the heat if it's not designed for it. Not sure if you mean photovoltic, or heat collector pannel, but you can burn up either....
> 
> Moving the panels to track the sun, or moving mirrors to aim the sun takes energy, and requires flimsy or spendy mechinisms, so the increase in output is often eaten up & best to just use the $$$ to make more collectors.
> 
> --->Paul


Hi,
This was a PV collector.
I don't think the reflectors that they used would not increase the sun on the panel anymore that lots of things that occur naturally (like mounting your panels where they get the reflection from a snowfield). I am guessing the PV panels are designed for this kind of thing.

I guess my thought was that PV panels are about $50 a sqft, and the reflectors looked like $2 a sqft (very simple), and they increase the output by 30% -- does that not seem like a pretty good deal?
The tracking does add some cost, but also increases about power output for the day by around 25 or 30% -- many people seem to use the commercial trackers. It seems like there is little to go wrong with a tracker like the Zomeworks one that has no motors or electronics (and consumes no energy)?

I'm more into solar thermal stuff, but this seemed like a pretty interesting idea to me.

Gary
www.BuildItSolar.com


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## Jim-mi (May 15, 2002)

A few years ago there was a company> Mid Way Labs < out of the Chicago area that made a interesting unit with "concentrators" aimed at a single row of PV cells. Several rows were in parallel. The unit needed to use a tracker system to really work. ....and it did.
I remember doing some serious talking with the guys who developed the system. (at the MREA fair in the mid 90's)
Unfortunately..........they and their concept are not around anymore.
One of the things that bothered me then- and now- was about serious degradation of the cell from the gosh awfull intense heat from.."more than one sun"..on the cell.
Yes they even tried running water (enclosed pipe) to cool the cells.
For several years there was a huge number of modules available from the dismanteled Carrizo Plains power plant (installed 1984). these modules were in different shades of "browning" and so the price varried.
I got two sets of the "Gold trilam's".......and they are still cranking out the amps.....even tho they are slightly brown.

Bottom line; As has been said, spend you $$$ on another pannel and leave the mirrors in the bedroom.

rant off


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## mightybooboo (Feb 10, 2004)

A lot of solar panels lose efficiency as heat gains.
Thin film panels are the most resistant to this.
That is why top efficiency is a cold clear winter day with snow reflecting light.

In hot climates like Australia,these heat resistant panels are highly touted
http://www.solardirect.com/pv/pvlist/pv-unisolar/pv-unisolar.htm

BooBoo


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## RobD (Mar 2, 2006)

I thought I heard of a company now using fresnel lenses and getting a patent on them.


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## mightybooboo (Feb 10, 2004)

RobD said:


> I thought I heard of a company now using fresnel lenses and getting a patent on them.


I think I heard also of a company making solar hot water from the panels with lenses.All in all,not for me,I like the plug it in and forget it simplicity and established durablity of current panels.

BooBoo


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## mightybooboo (Feb 10, 2004)

Jim-mi said:


> For several years there was a huge number of modules available from the dismanteled Carrizo Plains power plant (installed 1984). these modules were in different shades of "browning" and so the price varried.
> I got two sets of the "Gold trilam's".......and they are still cranking out the amps.....even tho they are slightly brown.


Some of those panels came out of Hesperia,Ca too.
Glad to hear yours are still online.

BooBoo


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## Jim-mi (May 15, 2002)

A second to booboo's line about simplicity and durability.
Those sets of "Trilams" (They were NOT mirrored) that I have are now 25 years old..........And going strong thankyou.
-----They have gone thus far under just "one sun" ... as intended.
I highly dought that any cell under a fresnel lens or mirrors or "concentrators" will have any longevity at all.

KISS


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