1. Solar Panel Efficiency Presented by Logan Markle, Wesley Patton, and Collin Rhodes

2. Overview ○ History of solar cells ○ Current solar cells ○ Cell structure and designs ○ Organic vs Inorganic cells ○ Concentrating Sunlight ○ Thermodynamic cycles ○ Innovations ○ Conclusions

3. Cool Facts ○ We are able to utilize 85% of the sun’s energy in theory (but as of now our technology only allows us to harness about 25%) ○ The 15% we can’t utilize is dissipated in the atmosphere. Neat O!

4. History of Solar Cells ○ 1839 – Alexandre Edmond Becquerel observed the photovoltaic effect through an electrode in a conductive solution which was exposed to light ○ 1883 – Charles Fritts developed a solar cell using selenium and a thin layer of gold foil to form a device that had less than 1% efficiency ○ 1954 – April 25, Bell Labs announced the first practical silicon solar cell which had 6% efficicency ○ 1985 – 20% efficienct solar cells were created by the Centre for Photovoltaic Engineering at the University of New South Wales

5. Current Solar Cells ○ 2012 – 3D PV cells with 30% + energy efficiency (still relatively inefficient) ○ Takes many panels to produce the power needed for large populations ○ Fragile and don’t have long shelf lives

6. Cell Structure and Design ○ Large grain solar cells 8 ○ Periodic silver nanowires 4 Types of Solar Panel http://www.c-changes.com/types-of-solar-panel

7. Organic vs Inorganic Cells Organic ○ Cheaper to produce ○ Produce less energy than Inorganic cells ○ Degrade quicker than Inorganic cells ○ Cost to produce still too high to be viable Inorganic ○ More expensive to produce than Organic cells ○ Produces more energy than Organic cells ○ Takes longer to degrade than Organic cells

8. Concentrating Light Mirrors: Why are they important? ○ Concentrate sunlight on the solar cell ○ Allow more power to be produced What shape of mirror is best? ○ Answer: Hyperboloidal http://www.georgehart.com/skewers/hyperboloid- surface.jpg

9. Thermodynamic Cycles ○ Steam Rankine systems ➢ work best for temperatures up to 600°C 1 ○ CO2 recompression Brayton cycles ➢ work better than the Rankine system between 600°C and 1000°C 1

10. Picture of Steam Rankine System http://www.azwater.gov/azdwr/waterManagement/documents/TheWaterDemandofPowerGeneration.pdf

11. CO2 Recompression Brayton Cycles http://www.netl.doe.gov/research/coal/energy-systems/turbines/supercritical-co2-power-cycles

12. Innovations o Thinner barriers in the quantum structure 4 o Induction motor 5 o Latent thermal energy storage (LTES) integrated concentrated solar power (CSP) plants 5 Induction Motor Working Principle Animation https://www.youtube.com/watch?v=MnQXnEiIUI8

13. Conclusions ○ Solar cells now are still inefficient, but with further research and developments, all of humanity’s energy needs could be met. ○ Current ideas are improving efficiency and accessibility

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