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1. ENERGY FROM THE SUN SOLAR PHOTOVOLTAIC TECHNOLOGIESEDUCATION MODULE (SPV01PP) CACTUS MOON EDUCATION, LLC www.cactusmooneducation.com

2. INDEX • Slide 1 Front Sheet • Slide 2 Index • Slide 3 The Photovoltaic Solar Cell • Slide 4 How a Solar Cell is Formed • Slide 5 How a Solar Cell Works • Slide 6 The Photovoltaic Module • Slide 7 The Inverter • Slide 8 Solar Photovoltaic Technologies • Slide 9 Flat Plate PV • Slide 10 HCPV • Slide 11 Thin film PV • Slide 12 A PV Solar System

3. The Photovoltaic Cell • The basic building block of a photovoltaic solar/electric system is the Photovoltaic cell, or solar cell. • The most common material used to make a solar cell is silicon. • The silicon is heated in a furnace out of which a single crystal ingot is drawn. • The ingot is sliced into wafers to be processed into a solar cell.

4. The Silicon wafer is “doped” on one side with a P-type material such as Phosphorus 1 The wafer is then doped on the other side with an N-type material such as Boron 2 N-Type P-Type At the junction of the P and N type areas a “depletion” layer forms 3 A top electrode array and an aluminum backplate are added to the wafer 4 How a Solar Cell is Formed Silicon Wafer

5. The electronic charges within the doped material create an electric field across the depletion layer 1 When sunlight strikes the cell it can knock an electron out of its atomic orbit 2 + + + + + - - - - - The electric field sweeps the electron towards the top electrodes 3 The flow of charges makes an electric current which powers the attached electric circuit 5 How a Solar Cell Works e + The gap or “hole” left by the electron is swept to wards the back plate 4

6. The Photovoltaic Module The output voltage of a silicon photovoltaic cell is approximately 0.7 Volts. Multiple cells are connected together to make a photovoltaic module.

7. The Inverter • The electricity generated by a photovoltaic module is Direct Current or DC. • Most electrical appliances use Alternating Current or AC. • Electronic circuits in an Inverter turn the DC power into AC power.

8. Solar Photovoltaic Technologies • Photovoltaic modules can be manufactured and used in a number of different ways. • The Flat Plate PV module is the most common and is the one shown in the previous slides. • High Concentration PV or HCPV uses a lens or a mirror to capture the solar energy and concentrate it onto a solar cell. • Thin Film solar cells are manufactured by evaporating very thin layers of the photovoltaic material onto a glass or plastic backing.

9. Flat Plate PV • Flat Plate PV modules are the most commonly used. • They are manufactured from single crystals or multiple crystals of silicon. • Flat Plate PV modules can typically convert 14% of the incident sun’s energy into electricity.

10. HCPV • Instead of covering a large area with photovoltaic material, HCPV harvests the sun’s energy using a relatively cheap plastic lens or a glass mirror. • The solar energy is then “concentrated” onto a small piece of photovoltaic material. • HCPV systems can convert between 20% and 40% of the incident solar energy into electricity.

11. Thin Film PV • Thin Film PV cells are manufactured by coating a glass or plastic sheet with a very thin layer of photovoltaic material atoms. • Large areas of glass or plastic can be covered using this technique. • Thin film PV modules can typically convert 9% of the incident solar energy into electricity.

12. 1 PV modules 1 DC disconnect switch 2 3 Inverter 7 4 Solar generation meter 4 5 6 2 3 AC disconnect switch 5 House service entrance 6 7 Utility kWh meter A PV Solar System A complete residential PV Solar System contains several components.