Photovoltaics / Solar Panels

Phantasm	Photovoltaics / Solar Panels « on: 2010-07-30, 06:42:52 »
Group: Guest	Hello! Did you know the most efficient means of producing electricity is a title held by solar technology? Specifically: http://www.panacea-bocaf.org/solar%20sterling.png Not the best pic, but you get the idea... A dish focuses the sun's energy onto a sterling engine http://en.wikipedia.org/wiki/Stirling_engine see above link for how a sterling engine works, essentially it has a hot side, and a cool side... the hot side makes gasses expand and push a cylender through one portion of its cycle... the gas then flows to the cold side where it condenses and pulls a cylender through another portion of the cycle... Great technology, but you can do more with this sort of thing... You can perform metalurgy, you can create copius quantities of steam, (Which you can use to dramatically decrease the activation energy of various reactions as well as increase the efficiency of others) with steam you get high pressure applications as well... Anyway, sterling solar is one route - another route is your good ol fashioned solar panel So how does it work? Silicon is the primary component of the solar panel since it exhibits photovoltaic effects... When you create a chunk of silicon for a solar panel, what you get is a crystal latice of silicon... Think of a quartz crystal.. it has lots of micro fractures/fissures etc... When you do that with silicon, you get whats called Polycrystaline silicon - which isnt the best for solar panels, but it works... What works better is monocrystaline silicon... The mainstream industrial method for producing monocrystaline silicon is to put a seed crystal into a molten vat of silicon under controlled conditions and slowly twist it out of the vat... Like sugar growing on a toothpick, you get a huge chunk of crystal forming on your seed crystal. This huge crystal is then sawed into thin wafers that are used to make microchips or solar cells... I understand though that you can also create monocrystaline silicon using huge amounts of energy for electrolysis of molten silicon When you have your monocrystal silicon you want to use for your solar panel, you need a circuit though, so you need to create an energy potential so electrons will flow. http://www.solarpath.org/wp-content/uploads/2009/02/solarcell-238x300.jpg Basically, each silicon atom in a monocrystaline silicon latice will have 4 bonds If you dope silicon with boron (found in sea water) you get your crystal latice and every so often there's a missing bond since boron only makes 3 bonds. This makes for slightly fewer electrons in the local area. This is the P-type layer If you also dope a portion of silicon with phosphorus (found in.... pee) you will get a crystal latice that has an extra bond every so often since phosphorus makes 5 bonds. this makes for slightly more electrons in the local area. This is the N-type layer Electrons collecting in the silicon from the photovoltaic effect will flow according to the potential created between these two areas You will however need to create pathways for the electrons to flow... The phosphorus side (n-type) is the side exposed to light, in order to harvest electrons, you need to create whats called a grid on the surface to easily allow the electrons to be collected off of the crystal - this can be conductive powder or metal http://en.wikipedia.org/wiki/File:Solar_cell.png Above you can see the horisontal collecting grid lines... They will eventually complete the circuit to the P-type side.. which is just an aluminum backing to the crystal More info here http://www.specmat.com/Overview%20of%20Solar%20Cells.htm Now, before you start thinking that this is all too complicated for you to do on your own... think again All you need is electricity (and an understanding spouse) With an induction heater, you can heat just about anything one way or another... Essentially, you can perform molten electrolysis of silica to remove oxygen and create a mono crystal - you can also imbue the crystal with boron or phosphorus by coating the surface and heating until boron/phosphorus diffuses into the crystal You could trickle-charge a capacitor bank for this - but did you know you can also create DIY Capacitors? Ive got a great link for that too...

Phantasm	Re: Photovoltaics / Solar Panels « Reply #1 on: 2010-07-30, 07:19:01 »
Group: Guest	Something else you can consider is that you can spilt the incoming light into its various wavelengths and direct the individual wavelengths to specific solar cells that are suited to the corresponding wavelength of light... essentially changing how you dope the silicon adjusts the ideal wavelength the wafer can collect You can then re-combine the 'waste' light that you cant harness using the photovoltaic effect and focus it for producing heat energy