1. Introduction to Solar Photovoltaic (PV) Systems – Part 2
Introduction to the Concepts of:
Sustainability (The Big Picture)
How Solar Photovoltaic Cells work
How Solar Photovoltaic (PV) System works

2. Agenda Ice Breaker Game Lecture on: PV Cell Lab
Sustainability (The Big Picture)
How Solar Photovoltaic Cells work
How Solar Photovoltaic (PV) System works
PV Cell Lab

3. Ice Breaker Group Activity
Your teacher will assign each of you a word and you need to define it in your own words.
Write down your own definition on a piece of paper.
Your group can help you if you are completely lost on how to define the word.
Go around the classroom and read your word and your own definition out loud.

4. Ice Breaker: Energy Photovoltaic Power Voltage Fission Physics
Direct Current (DC)
Alternate Current (AC)
Power Inverter
Energy Management
Current
Efficiency
Sustainability
Electric Circuit
Conservation of Energy
Charge (Electrons)
Environment
Fusion
Series Circuit
Parallel Circuit

5. The Big Picture – Sustainability: Capacity to Endure
Environment
Economic
Social
Human Consumption
Natural & Physical Resources
Energy
Biofuel, Biomass, Geothermal, Hydropower, Tidal, Wave, Wind, and Solar

6. Solar Technologies Solar Energy Solar Power Biological Environments
Architecture & Urban Planning
Biological Environments
Photovoltaics
Water Heating
Building Heating
Photosynthesis
Charge Controller
Batteries
Inverter

7. Nuclear Energy (Fusion)
Energy Conservation
Energy cannot be created or destroyed, it can be only transferred from one form to another.
Sun
Earth
Nuclear Energy (Fusion)
Solar Radiation
Photovoltaic Systems
Electrical Energy

8. Semiconductor Devices – Basics
Charge can be positive (holes) or negative (electrons)
Silicon (Si) is an atom with 4 valence electrons.
In pure silicon it is difficult to control conductivity.
n-type semiconductor – Silicon with impurity atoms having 5 valence electrons.
p-type semiconductor – Silicon with impurity atoms having 3 valence electrons.

9. Physics of Photovoltaics
N-type silicon
Pure silicon
P-type silicon

10. How Photovoltaics Work?
A negatively charged electron in the n-type silicon layer is repelled by the diode and can’t move through to the p-type silicon layer. {
N-type Silicon Layer
Junction where electrical field or diode is formed
P-type Silicon Layer { {
A negatively charged electron in the p-type silicon layer can move through the diode to the n-type silicon layer.

11. PN - Junction

12. How Photovoltaics Work?
Solar energy (photons of light) hit the cell, passing through the n-type layer and releasing electrons from atoms in the p-type layer. These electrons pass upwards through the diode and to the n-type layer.
N-type Silicon Layer
Junction where electrical field or diode is formed
P-type Silicon Layer
PN Junction

13. How Photovoltaics Work?
Metal conductors are added to the top and bottom of the cell and are connected to an electrical load. This creates an electrical circuit.
Metal Conductor
Junction where electrical field or diode is formed

14. Light Emitting Diode (LED)
A LED is an electronic light source.
When a voltage is applied, electrons combine with holes and energy is released in the form of light.

15. A Photovoltaic (in Concept)
In concept, a Photovoltaic is an LED working in reverse.

16. Photovoltaics

17. Cell -> Panels -> Arrays

18. Efficiency of Photovoltaics

19. Photovoltaics - Efficiency

20. How to Improve Efficiency?
Higher Efficiency = Lower Ohmic Losses
Ohmic Loss – Occurs when charges move through a conductor.
Higher Efficiency = Lower Dielectric Losses
Dielectric Loss – Occurs when plates and/or any other adjacent contacts or surfaces are charged or discharged.

21. Photovoltaic System (One)
Components of a Photovoltaic System

22. Photovoltaic System (Two)

23. Photovoltaic System Components
Inverter
Converts DC power from solar array to AC for use in your home
Wiring
Connects the system components
Batteries
Used to store solar-produced electricity for nighttime or emergency use
Charge Controller
Prevents batteries from being over charged
Disconnect Switches
Allows power from a PV system to be turned off
Electrical Meter
Measures electrical production and use

24. Deep Cycle Batteries and Inverters
Deep Cycle Batteries are designed to be discharged down as much as 80% time after time, and have much thicker plates.
Can’t provide large current surges.

25. Inverters
Inverter is the device that transforms direct current (DC) to alternating current (AC).
Can provide 115VAC from a 12 VDC.
Consider Efficiency and Power Rating.
Efficiency =

26. Wiring Photovoltaics - Series
Photovoltaics in Series
Increases Voltage
Available current is limited by individual photovoltaics.
135 W
12 V
11.25 A
Ammeter
11.25 A
Voltmeter
36 V

27. Wiring Photovoltaics - Parallel
Photovoltaics in Parallel
Increases Available Current
Individual connected photovoltaics should be rated for the same voltage.
Ammeter
33.75 A
Each
Panel:
135 W
12 V
11.25 A
= 405 W
Voltmeter
12 V

28. DC versus AC Direct Current (DC) Alternating Current (AC)
Can be stored.
Can only be sent over short distances due to losses.
Easy to manipulate
Change level (Voltage)
Flow rate (Current)
Alternating Current (AC)
Can’t be stored.
Can be sent long distances with low losses.
Difficult to manipulate
It is possible but requires usually larger and more complex circuits and devices.

29. Solar Modules and Arrays

30. Solar PV Systems Cells are the building block of PV systems
Typically generate watts of power
Modules or panels are made up of multiple cells
Arrays are made up of multiple modules
A typical array costs about $5 – $6/watt
Still need lots of other components to make this work
Typical systems cost about $8/watt

31. Florida Solar Energy Center

32. PV Modules have efficiencies approaching 17%
Florida Solar Energy Center

33. Florida Solar Energy Center

34. Solar Panel Solar panel by BP Solar at a German autobahn bridge
Solar panels are devices for capturing the energy in sunlight. The term solar panel can be applied to either solar hot water panels (usually used for providing domestic hot water) or solar photovoltaic panels (providing electricity).
Solar panel by BP solar at a German autobahn bridge. pic taken 4/04 by Thomas Springer.
Solar panel by BP Solar at a German autobahn bridge

35. Florida Solar Energy Center

36. PV Cell Laboratory - Tomorrow
The purpose of this lab is to give students experience constructing operating circuits while reviewing the following ideas/concepts:
• Voltage
• Current
• Power
• Energy/work
• Photoelectric effect
• Series/Parallel circuit design
• Efficiency