Removing heat from cells

[Sparksdisco]

Watched a intresting thing on foxtel (litte bit of popicabout a guy who was using high quality plastic reflectors (which he said could be produced for around $100 to concentrate the light to anothe reflector which somehow removed all the " heat energy" from the sun (UV inferred) and the resulting light traveled down optic fibers and used to light buildings.

Now the question i ask is:

to produce power from a solar pannel it requires photons to move the electrons from the siliclon to produce electron flow

(I think thats right correct me if im wrong)

Now i was wondering if you used the heat filter than would you still have photons or would you remove this when you remove the "heat" energies?

Now if you could do this than you could do this then that would mean cells woud be cooler? and you could use this "heat energy for solar hot water heating? thus incresing the effiiciency of the solar pannel?

Just thinking out of the box and wondering if anyone saw this and had any thoughts on this.

Sorry about the spelling I hope it makes sence

[bee utey]

Sunlight as we get it on the surface of planet earth contains photons of different energy, mainly from infra red (lower), then red to violet, and of course ultra violet (highest). IR just heats stuff up, visible ones help you see, grow plants, and UV wrecks molecules (causing plastic to rot, skin cancer etc.)

Solar panels usually need photons more energetic than red, more like green and blue. Trouble is, any filter that removes lower energy photons (infra red, red) probably blocks some useful ones too. So the best bet is to let the whole shebang fall on your panel, then cool your panel by another means.

I read a post somewhere by a person in the tropics who runs his sprinkler on his panels and gets 20% more power. A good stiff breeze over the panels helps too. So mounting them flat to a hot tin roof is not the best way really. I have mine on a post with a solar tracker, up in the breeze above the house.

[Blknight.aus]

sort of like pumping the air from the gap of a double glaze window into a heat pump to transfer the heat to water?

[bee utey]

sort of like pumping the air from the gap of a double glaze window into a heat pump to transfer the heat to water?
Great idea! Maybe you can get a gov't grant to promote it, like Firepower.

Seriously, $100 to increase the power output of a typical solar panel by 20% would be better spent on a 20% bigger solar panel, methinks.

[Blknight.aus]

not really no.

increasing energy density is the name of the game...

any one can make more power by making it bigger. just look at any yank vehicle they cant build with finesse so they just muscle it up in size.

[bee utey]

Good point. Given a limited area I would spend money on a more efficient panel of the same size, hence more power. Otherwise what counts is dollars per watt of useful output. There are many people working on new technology, such as Sliver cells, I can hardly wait for the new stuff to come out.

[JDNSW]

Until you have the available space covered with collectors, the major concern is cost per watt, not efficiency, with durability as well probably more important. While there are a few applications where the available area is fully used, these would be a very small minority.

Note however that many ways of increasing efficiency will also reduce the cost per watt - for example anything that gets more power from the same amount of crystalline silicon is likely to reduce cost per watt as well as increase the efficiency - but it is the lower cost per watt that makes the panel more desirable, not the increased efficiency.

John

[Blknight.aus]

while thats a fair and valid point if people werent chasing a greater energy density by now we'd all be driving v32 7:1 compression engined vehicles just so we had the ponies on tap to go faster.

have a vague once over on the price drops in various power providing sources batteries, solar panels, wind generators the whole lot. Almost invariabley after a breakthrough that ups the energy density of the suppling item the older stuff of that type becomes cheaper once the new tech pokes its nose into the market. IMHO a good thing because your watts per dollar goes up

[JDNSW]

while thats a fair and valid point if people werent chasing a greater energy density by now we'd all be driving v32 7:1 compression engined vehicles just so we had the ponies on tap to go faster.
.............

A slight difference between a fixed installation and a vehicle - again, the quest in vehicles is not volumetric efficiency, but power/weight and fuel efficiency plus other less obvious considerations such as initial cost, reliability, durability, driveability, maintainability, exhaust emissions; in other words, no simple measure. Same with solar panels, but I suggest that for these cost per watt is a single factor that is more important than any single factor in designing a vehicle engine.

John

[slug_burner]

back to the original question

glass will block IR, thats is why glass houses work, UV gets through excites something in the surface it hits and releases IR which cannot get back out through the glass.

[bee utey]

Until you have the available space covered with collectors, the major concern is cost per watt, not efficiency, with durability as well probably more important. While there are a few applications where the available area is fully used, these would be a very small minority.

I didn't mention durability on vehicle applications as many panels used for camping spend limited time each year outdoors, there you might want watts per kg as much as anything. On houses reliability comes way up the top of your list.


Note however that many ways of increasing efficiency will also reduce the cost per watt - for example anything that gets more power from the same amount of crystalline silicon is likely to reduce cost per watt as well as increase the efficiency - but it is the lower cost per watt that makes the panel more desirable, not the increased efficiency.
John


Chase up the efforts of Origin Energy to build Sliver Cell technology panels, its a national disgrace that the factory to make them isn't being built in Australia. It's a wholly Australian invention!

[JDNSW]

I didn't mention durability on vehicle applications as many panels used for camping spend limited time each year outdoors, there you might want watts per kg as much as anything. On houses reliability comes way up the top of your list.




Chase up the efforts of Origin Energy to build Sliver Cell technology panels, its a national disgrace that the factory to make them isn't being built in Australia. It's a wholly Australian invention!

I suggest that while longevity may not be a major consideration for vehicle applications, durability in the sense of standing up to being knocked about and handled is, much more so than watts per kg.

Nobody in their right mind would build a factory in Australia to make anything for worldwide sale - with a high Australian dollar guaranteed by long term high interest rate policies and high raw material exports, and regulations plus red tape guaranteeing high overhead costs, and often restrictive workplace practices added to high transport costs because we are remote from most major markets, almost anywhere else in the world makes more sense.

John

[victa125]

The fact are, monochrystalyn cells are most efficient at tempreatures below 20c. As a chrystaline substrate exposure to direct sunlight has a two fold negative, excessive heat absorbed by the structure, and a non alignment of the silicate to the azimuth of the rays. Got a theory, wvo too intercool the cells, given an ambient at marble bar 50+ off down the fish and chhippy to collect more reasearch.

[victa125]

The fact are, monochrystalyn cells are most efficient at tempreatures below 20c. As a chrystaline substrate exposure to direct sunlight has a two fold negative, excessive heat absorbed by the structure, and a non alignment of the silicate to the azimuth of the rays. Got a theory, wvo too intercool the cells, given an ambient at marble bar 50+ off down the fish and chhippy to collect more reasearch.

[procrastination inc]

maybe the method in the OP is just using the different refractive properties of different frequencies of EMR to split of the heating IR part of the spectrum and only feed the rest.

re solar cells, some new developments

Solyndra - The New Shape of Solar (http://www.solyndra.com/)

New twist on solar cell design › News in Science (ABC Science) (http://www.abc.net.au/science/articles/2010/02/15/2818151.htm)

Next-generation solar cells get boost › News in Science (ABC Science) (http://www.abc.net.au/science/articles/2009/12/02/2759825.htm)