SOLAR POWER

Solar Power Video

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© Daniel L. Wilson, Dr. Michael A. De Miranda,

Dr. Thomas J. Siller, & Dr. Todd D. Fantz

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Important Equations

Ohm’s Law, Georg Ohm, 1827

V=I*RI=V/RR=V/I

P=V*I or P=V2/R or P=I2R

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Let’s be Smart Smarts

Let’s review some things we have talked about: Examples of Clean Energy include?

What are some dirty or medium energy systems? A force used to create motion is doing? Energy vs. power? Can energy be created? What turns on our lights: work, energy, or power? Generators, solar cells, and fuel cells generate

what? Turbines use the energy of what? The act of reducing our energy use is called what?

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Power Generation5

Simple Generator Diagram

Figure 1

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Power Generation

Almost EVERY mode of power generation on earth simply relies on trying to make something spin in a circle Wind Water Coal Nuclear

All you need to make power is a magnet, a coil of wire, and some way to move the magnet across the coil.

Nothing is free…EVER! It takes force to move the magnet by the coil. Continued application of force takes power

The exception to this pattern is solar power

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Solar Energy8

Solar Energy Systems

Uses the electromagnetic radiation of the sun to generate electricity

Figure 2From: Laboratory for Computational Science and Engineering, Univ. of MinnesotaURL: http://www.lcse.umn.edu/specs/labs/images/spectrum.gif

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Solar Radiation in the USA

Figure 3From: Virginia Department of Mines, Minerals and EnergyURL: http://www.dmme.virginia.gov/DE/Alternative_Fuels/solar.shtml

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How Much PV to Power the USA?

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30*10^15 W-hr/year of energy neededHow much energy falls per square meter per year in the place we are talking about?• 5000 W-hr/m2/day * 365 day/year = 1.825*10^6 W-hr/m2/yearHow much of this energy can we actually obtain with 30% efficient panels?• Gathered Energy = Available Energy * efficiency = 1.825*10^6 W-hr/m2/year * 0.30• Gathered Energy = 5.475*10^5 W-hr/m2/year How much area do we need to serve the entire country’s needs?• Required Land = Energy Needed/Energy Gathered per square meter• Required Land = 30*10^15 / 5.475*10^5 W-hr/m2/year = 5.48*10^10 m2

• Note: since PV panels are about 1m2 in area, we would need roughly 50 billion panels•Required Land = 55000 km2

How big is this really?•Required Land = 55000 km2 = about 235km X 235km square or about 150mi x 150mi

The red square represents roughly the area of the USA needed to fulfill our current power needs using 30% efficient solar PV.

Parabolic Mirrors

Image 1From: Blog for newenergydirection.comURL: http://newenergydirection.com/blog/2008/12/concentrated-solar-thermal-power/

F - principal focus of the parabolic mirror, FO - axis of revolution of the parabolic mirror

Figure 4From: Oracle Thinkquest Education FoundationURL: http://library.thinkquest.org/22915/reflection.html

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Solar Tower/Stirling

Stirling Engine

Image 3From: Eco-Thinker URL: http://eco-thinker.com/do-it-yourself-solar-death-ray-parabolic-mirror-dish/

Image 2From: TreeHugger.com URL: http://www.treehugger.com/files/2009/04/worlds-largest-solar-power-tower-spain.php

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Solar Updraft Tower

Updraft tower utilizes greenhouse effect

Energy generated from the energy of: Solar

radiation Wind

Image 4From: Roy Spencer, Ph. D.URL: http://www.drroyspencer.com/2009/08/my-favorite-renewable-energy-concept-the-solar-updraft-tower/

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Solar Updraft Tower

Figure 5 From: TerritorioScuola.comURL: http://www.territorioscuola.com/wikipedia/en.wikipedia.php?title=Talk:Solar_updraft_tower

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Photovoltaic Cells

p

n

Silicon with a little Boron

Silicon with a little Phosphorus

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+

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Optimization17

Activities

You will be optimizing your solar cell to generate as much power as possible Optimization is one of the key factors in

any engineering design process It is not just important that something works. It

is important that it works well.

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Let’s Go!

Please make sure to share our limited space with one another

Take your time and enjoy the sunshine

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