Solar Energy

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Solar Energy

• 2010

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Solar Energy and NASA

• NASA developed solar cells for the space program
• Used to recharge batteries and powering some
  systems in spacecraft
• Scientists goal was to decrease weight and
  increase efficiency.
• They used to convert 6 of sunlight into
  electricity to a present 15 conversion rate
• Today solar cells are used aboard satellites and
  even the Mars rovers Spirit and Opportunity

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Spirit and Opportunity

• This mission was originally supposed to last 3
  months and it continues today 74 months later.
• The solar panels that totally run these rovers
  have gone above and beyond their duty

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Solar Cells

• Also called ---photovoltaic (photo meaning light
  and voltaic meaning producing electricity
• Made with silicon which is plentiful and makes up
  ¼ the Earths crust -----AKA sand
• Silicon is purified to a high degree (this is
  where the cost comes in to play)

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How do they work?

• Made of 2 layers
• 1. thin disc of almost pure silicon crystal with
  a little of Boron added
• This part has a positive electrical charge or
  called P type silicon
• 2. Thin layer of silicon crystal is formed over
  the P type but with phosphorus added
• This part has a negative charge or called N
  type silicon

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How do they work? cont.

• Two halves cancel each other out and it becomes
  neutral
• Sunshine hits both layers and creates a flow of
  electrons
• Viola electricity!!!

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Video clip

• solar cells