parabolic mirror aimed at a solar panel...

[casper ghost]

Hi. Just watching Myth Busters on tv, they are building a parabolic mirror to burn down a ship!. We wondered if anyone had aimed one at a solar panel to get more from the sun and would it work or blow up the panel?

[Justme]

You would need to target the entire panel evenly to gain the most from it.

 

It is actually standard practice on industrial arrays.

[Nickhlx]

You would need to target the entire panel evenly to gain the most from it.

 

It is actually standard practice on industrial arrays.

 

 

.....assuming you can get the heat away fast enough...

 

 

I like solar....

 

Nick

[Chris J W]

.....assuming you can get the heat away fast enough...

 

 

I like solar....

 

Nick

 

Combine with a solar-water-heater ...

[Biggles]

I watched a program on just that subject the other day. It works very well by all accounts.

 

Biggles

[Smelly]

but how much would a parabolic mirror set you back?

[Keeping Up]

You would need to target the entire panel evenly to gain the most from it.

True. Most solar panels have a number of cells in series, and the output current is limited by the output of whichever cell is most in the dark.

[Rick-n-Jo]

You would need to target the entire panel evenly to gain the most from it.

 

So you don't want parabolics, which focus the light on to a spot, but angled flats?

[Justme]

So you don't want parabolics, which focus the light on to a spot, but angled flats?

 

 

That depends on how big the spot is.

 

Basically its a concentrator so if you had a 10m2 parabolic aiming at a 1m2 array you would gain a 10 fold increase in power (assuming as has been said the heat can be dealt with)

 

I would think that the reflector is going to be close cost wise to an array any way.

[Bobbybass]

Didn't they use one of those to try and cut James Bond in half ?

 

Bob

[grahoom]

but how much would a parabolic mirror set you back?

 

 

http://cgi.ebay.com/HUGE-25-ACRYLIC-PARABO...=item2a026b26ca

 

 

25" - $129

 

apparently a glass one that size would cost $1500 or so.

[Nine of Hearts]

Didn't they use one of those to try and cut James Bond in half ?

 

Do you expect me to reply to that?

[grahoom]

Didn't they use one of those to try and cut James Bond in half ?

 

Bob

 

 

 

IT WAS A LASER!

[Chris Pink]

That depends on how big the spot is.

 

Basically its a concentrator so if you had a 10m2 parabolic aiming at a 1m2 array you would gain a 10 fold increase in power (assuming as has been said the heat can be dealt with)

 

I would think that the reflector is going to be close cost wise to an array any way.

 

Would not a parabolic arc in one plane serve?

 

something like this; ebay link

 

or a few tiles made of this material?

Edited November 25, 2009 by Chris Pink

[grahoom]

Would not a parabolic arc in one plane serve?

 

something like this; ebay link

 

or a few tiles made of this material?

 

Chris your link was wonky - here it is LINK

[number four]

what i think you are talking about is a heliostat

 

 

 

http://www.iwilltry.org/b/projects/build-a...g-and-lighting/

[Chris Pink]

what i think you are talking about is a heliostat

 

 

 

http://www.iwilltry.org/b/projects/build-a...g-and-lighting/

 

nah, that's just a method of tracking, the idea behind a parabolic reflector/collector is that parallel lines (rays of sunlight) are focussed on a point by a parabola.

 

My idea is that with a parabolic reflector in one plane, instead of a point the light will be focussed along a line. Because nothing is perfect, ie your line is not infinitely thin, there is a ratio involved where your line is, optimally, the width of the PV panel and the collector is as big as you can practically make it.

[WotEver]

To achieve any more than a heliostat the parabola (or semi-parabola) would need to be considerably larger than the solar panel. Anything less than twice the area of the panel would be pointless. For anyone with a reasonable number of PV panels that would be a pretty enormous mirror.

 

Tony

[Trilby Tim]

but how much would a parabolic mirror set you back?

A friend of mine experimented with making a parabolic shape by spinning a dish of plaster of paris until it set and then covering with tin foil. Worked suprisingly well. Telescope mirrors are often a spinning dish of mercury, so same principle.

[WotEver]

Telescope mirrors are often a spinning dish of mercury

I didn't know that. Something ELSE new learned today

[DHutch]

Yeah, having done a project on mass solar gereration, one thing that is common to most systems is that you use mirror. Although use of mirrors with photovoltaics seams less common.

 

Few photos

 

 

Solar Trough.

Fluid (typicaly oil) heated in tube, used to make steam to run turbines. Or to simply heat stuff.

 

Power Tower.

Big tower, big array of flat solar tracking pannels aiming at it, heat used to make elec.

 

PV Field

No mirrors found at all.

 

 

 

Daniel

[casper ghost]

Yeah, having done a project on mass solar gereration, one thing that is common to most systems is that you use mirror. Although use of mirrors with photovoltaics seams less common.

 

Few photos

 

 

 

 

Power Tower.

Big tower, big array of flat solar tracking pannels aiming at it, heat used to make elec.

 

Well, not sure I can fit that on the roof and still get under bridges...

[John Orentas]

Parabolic mirrors are the effective bits of both searchlights and astronomic telescopes, unlike spherical or ellipsoidal forms they have a defined focal point.. Smaller glass aluminised ones are not expensive, they are vacuum formed on a steel die, there are also usually low cost 'spun' aluminium types.. Very large ones however tend to be electro-formed on to a very accurate former and later plated with Rhodium, they are very dimensionally stable and what is removed is only the nickel which has been deposited (a bit like the chrome plate coming off a bumper bar) these are expensive, several thousand pounds for a 600 mm diameter model.

 

Even larger mirrors for telescopes are traditionally ground from a huge lump of glass, a process taking months or even years in some cases, the cost can be imagined..

 

For a use as originally outlined, to be used with a solar panel a mirror as above would not be suitable as you certainly would not want the light to come to a focus, an ellipsoidal would be more suitable though it could be argued that simply using a larger panel would be more cost effective.

Edited November 26, 2009 by John Orentas

[Bobbybass]

 

 

IT WAS A LASER!

 

"I'm sorry Mr Bond.....but the batteries have sulphated and the invertor has tripped out..

Can we continue with a log saw ?"

[ARTYFARTY]

Can anyone tell me where to get parabolic mirrors in the UK?