October 11,2013
ECEN 2060
Lecture 21
Fall 2013
Homework Problems\Chapter 5 problems
Solar Spectrum
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Power Spectrum Planck’s Law Total energy Radiated Stefan-BoltzmannLaw
Suns Spectrum for T= 5800
Types and Efficiencies of Some Solar Cells
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The Useable Solar Spectrum
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Photon Activation
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Requirement for creating an electron hole Pair is hν> Eg
h
Holes or the Absence of an Electron in the Conduction Band
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Cut-off Wavelengths
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The issue is that you can not use the long wavelength solar energy and the short wavelengths lose the energy above the band-gap to heat.
Example
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For A=100 2cm 2/40 cmmaI sc 212 /10 cmAIo
Equivalent Circuit For Shading
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A more complete Equivalent Circuit
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Series Resistance
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Contact resistance, resistance in diode outside of the junction region
Series Resistance Added in
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Total Equivalent Circuit.
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Combinations to Get to Useful Size
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Modules to Arrays
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1 Voltages for cells add in series2 Currents for each cell add in parallel
Examples Under Standard Test Conditions
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Effects of Changes in Temperature
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Bypass Diode Reduces Voltage Across Shaded Cell
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