1. ME 556 Solar Energy Conversion Lecture 9

2. Radiative Properties: Selective Surfaces & Transparent Materials

3. Calculating Total Emittance Assuming no direction effects f is the Black Body fraction for a particular wavelength band

4. Ideal Selective Surface

5. Program to calculate band radiation http://energy.sdsu.edu/testcenter/testhome/javaapplets/planckRadiation/blackbody.html

6. 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

7. Real Selective Surface

8. Specular Reflectors

9. Radiation on Transparent Media

10. Snell’s and Fresnel’s Laws Only treats one surface

11. 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)

12. Reflected light is often Polarized

13. LCD Display