solar photovoltaic
TRANSCRIPT
How do Solar Cells Work?
Light (solar radiation) arrived on the earth in the form of energetic photons.
http://www.humanthermodynamics.com/sun-photon-diagram.jpg
Photons are powerful enough to knock electrons around
http://blueox.uoregon.edu/~karen/astro123/images/virtual_photons.gif
The Photoelectric Effect
Observed and Described 1839… by Becquerel, Hertz, and Thomson.Explained by Einstein 1905
Solar Cell Structure:
a. Encapsulateb. Contact Gridc. The Antireflective Coating (AR Coating)d. N-Type Silicone. P-Type Siliconf. Back Contact
http://www.specmat.com/Overview%20of%20Solar%20Cells.htm
Two Essential LayersA = n-type silicon (has free electrons)
B = p-type silicon (has free electron holes)
Sunlight knocks electrons from B to A.
• The electrons have to travel the circuit to get back to layer B.
Practical Stuff• Solar Cells produce direct current (like regular
batteries)
A typical single crystal silicon PV cell of 100 cm2 will produce about 1.5 watts of power at 0.5 volts DC and 3
amps under full summer sunlight (1000Wm-2). http://www.corrosion-doctors.org/Solar/cells.htm
• Solar Cells are about 10 -25% efficient
• Power in Watts = Volts x Amperes
Need to configure panels to desired
voltage and amperage
http://windom.cybox.com/boat/systems/wiring/wind_solar.GIF
How much does it cost?
“To give you an idea of how much a house system would cost, let's consider the Solar House -- a model residential home in Raleigh, North Carolina, with a PV system set up by the North Carolina Solar Center to demonstrate the technology. It's a fairly small home, and it is estimated that its 3.6-kW PV system covers about half of the total electricity needs (this system doesn't use batteries -- it's connected to the grid). Even so, at $9 per Watt, this installed system would cost you around $32,000. “
http://www.howstuffworks.com/solar-cell7.htm
Vidoeshttp://video.nytimes.com/video/2007/07/06/business/1194817104324/possibilities-in-solar-
energy.html?scp=3&sq=solar&st=cse
5:56
http://renergycafe.com/political/obama-our-renewable-energy-future/Obama’s Energy Campaign Speech 13:19
http://thisweekwithbarackobama.blogspot.com/2009/02/obama-speaks-at-department-of-energy.htmlObama 8 min