ME 556 Solar Energy Conversion Lecture 9. Radiative Properties: Selective Surfaces & Transparent...
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Transcript of ME 556 Solar Energy Conversion Lecture 9. Radiative Properties: Selective Surfaces & Transparent...
![Page 1: ME 556 Solar Energy Conversion Lecture 9. Radiative Properties: Selective Surfaces & Transparent Materials.](https://reader036.fdocuments.us/reader036/viewer/2022082423/5697bfc81a28abf838ca8337/html5/thumbnails/1.jpg)
ME 556 Solar Energy Conversion
Lecture 9
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Radiative Properties:
Selective Surfaces & Transparent Materials
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Calculating Total EmittanceAssuming no direction effects
f is the Black Body fraction for a particular wavelength band
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Ideal Selective Surface
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Program to calculate band radiation
http://energy.sdsu.edu/testcenter/testhome/javaapplets/planckRadiation/blackbody.html
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Real Selective Surfaces• Put a thin layer of good absorber on a poor emitter (thin film
coating)• Put very small metal particles on the surface (black chrome or
black gold)• Alter the surface roughness with small cavities
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Real Selective Surface
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Specular Reflectors
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Radiation on Transparent Media
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Snell’s and Fresnel’s Laws
Only treats one surface
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Polarization
NOTE: The bars shown on the polarizer in Figure 1 are for illustration only. Actual polarizers can be made with very fine wires that resemble bars, but then they would run the other way (horizontal bars allow vertically polarized light to pass)
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Reflected light is often Polarized
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LCD Display