Holographic Solar Collectors

An anonymous reader writes "The MIT Technology Review is reporting that Prism Solar Technologies has developed a technique to use holograms to concentrate light onto photovoltaic (PV) cells. While the implementation is only about a 10x increase over PV cells without collectors such as mirrors/lenses (mirror/lens approaches can do 100-1000x), it is a great deal simpler, more compact, and cheaper. Also because of the concentration, there is less need for physical PV cell real estate compared to crystalline PV silicon cells of similar output."

Comments

Only 10x? That's huge!

[chriss]

10x increase for the holographic cell may sound bad compared to 100x-1000x for mirrors/lens. But in the installations I know that use mirrors or lenses they take up most of the area. If 10% of the whole surface was PV cells and 90% were e.g.. mirrors (a very conservative assumption, I think the PV cells will cover less then 1%) you would gain an effective increase of 100x instead of 10x. (This is not entirely true, since these new PV cells are only part energy creating silicon, most of their surface is just the holographic lense. But still a massive space saver compared to classical mirrors.)

Plus you will usually have to place mirrors on the ground due to their weight and the weight of the motors attached to them to make them follow the sun. In contrast you can place PV cells on almost any surface, although you will loose a lot of efficiency if you can not orient them towards the sun.

If you completely ignore that there are theoretically more efficient methods of concentrating the energy onto PC cells, you still get a 10x improvement over the typical installation (on a roof, with no fancy mirrors at all). And then 10x is huge.

Re:Holograms?

[chriss]

Since you can create multiple refractions inside a hologram, you can create a much better lense than with diffraction gratings. So while both are basically flat lenses, the holographic version is much more efficient.

We used a similar product in 2001

[goldarg]

Back in 2001 the Tucson Citizen did a project where they powered a Sun Colbalt Qube 3 off of solar power using a set of panels based on a very similar if not the same technology.

The panels they came from a company called TerraSun and the one I have on my desk left from the project looks remarkably like the one in the article.

Archive.org still has some pages from the site which is long defunct http://web.archive.org/web/20010807151516/www.sola rexplorer.net/gallery/index.php?TopicID=panels

Google finds reference to the technology that TerraSun was developing http://www.wapa.gov/es/greennews/2001/may14'01.htm

Re:Solar collecting is good.

[networkBoy]

"thats a good link, can you read it back for me over the phone ?"
Sure:
ache tee tee pee colon whack whack dub dub dub aw fuckit dot see oh em

How about Fresnel lenses?

[dinther]

Concentrating light onto PV cells has been done before. The main problem is that the PV cells get too hot and degenerate quickly. Bulky panels using mirrors or lenses can be solved using flat fresnel fenses. Now the question remains, how to cool these things. It dawned to me that the panel created so far is in fact very similar to the solar water heaters. Why not combine the two? A fresnel lens concentrates the light onto a PV panel that is protected against heat by water flowing up between two layers of glass (Hot water rises) circulating as it does in traditional solar hot water systems. The water takes out the heat producing IR radiation leaving all the good electricity generation radiation for the PV panel. This way you can put up one panel producing both hot water and electricity.