pv panels
DESCRIPTION
PV Panels. Nate Trachimowicz And Evan Graves. How panels work. Silicon is doped with different chemicals Providing the desired properties of the resulting compounds Based on valence electrons One compound or side, is made to be electro- negative (N-type) - PowerPoint PPT PresentationTRANSCRIPT
PV Panels
Nate Trachimowicz
And
Evan Graves
How panels work
Silicon is doped with different chemicals Providing the desired properties of the resulting
compounds Based on valence electrons
One compound or side, is made to be electro-negative (N-type)
The other side, being electro-positive (P-type)
N-type
P-type
N-Type:
Semiconductors with an excess of electrons
P-Type:
Semiconductors with an absence of electrons
The Electrons(remember having 4, is stable)
Making Electron Pairs
Load
N-side
“Extra”
P-side
“Holes”
Light Band Gap Electricity Each element has a band gap:
The difference in energy between the valence band (electron bound to an atom) and the conduction band (electron free to move between atoms).
Measured in electron volts, eV Metals have a low band gap,
electrons flow easy Each wavelength of light has an associated energy
Silicon band gap is 1.1 eV which peaks in the infrared region (980 nm )
Different elements and materials provide a spectrum of options to absorb the sun’s energy.
Thin-Film Materials for High Power-to-Weight-Ratio Space
Photovoltaic Arrays copper, indium, and sulfur, or copper, indium,
gallium, and selenium CuInSe2/CuInS2/CuGaSe2 Decomposition of single-source precursor to
produce CuInS2.
Higher efficiency tricks
The foundation of the new UNI-SOLAR PVL is the Triple Junction silicon solar cell unique to UNI-SOLAR .
Each cell is composed of three semiconductor junctions stacked on top of each other.
This spectrum splitting capabilityis the key to higher efficiency.
Higher efficiency tricks
When a photon excites an electron, or kicks it. It will probably fall back into orbit losing energy as
heat. This is known as recombination.
The trick to constructing high efficiency solar cells lies in minimizing recombination.
Price Comparison, thin film
Product Price $/W
Unisolar PVL-31T roof laminate 168.65 5.44
Unisolar PVL-116T roof laminate 597.89 5.15
Shell ST20 161.10 8.05
Shell ST40 214.44 5.36
Good sites
http://murray.newcastle.edu.au/users/students/2004/c2003616/intro.htm
http://www.webelements.com/webelements http://www.grc.nasa.gov/WWW/RT1999/5000/5410hepp.
html http://www.madsci.org/posts/archives/aug98/901775020.
Eg.r.html