1. Solar Energy Basics
Thermal and PV

2. Solar Energy – A Bright Idea!
“I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait ‘til oil and coal run out before we tackle that.” - Thomas Edison

3. People have been harnessing solar energy for a long time!
Solar collector for
heating water
A home in California in 1906

6. Sun Angles

7. Solar Photovoltaic (PV)
Two Main Categories:
Solar Thermal
Solar Photovoltaic (PV)
Water heating and cooking
Electricity production

8. Solar Thermal Energy
Cooking
Water Heating

9. Solar Water Heating

10. Solar Water Heating
Solar water heating is the most efficient and economical use of solar energy
Residential systems start at $2500 and typically cost $3500-$4500 installed
Savings of $30-$75 per month, lasting 20 years
Tax credits and state rebates available

11. How Does it Work?

12. How Does it Work? Systems can be passive or active
Passive systems only found in warmer climates, as they are prone to freezing
Active: Roof-top collectors heat glycol which then passes through a heat exchanger in the storage tank to heat water
Electric pump can be run on solar PV

16. Solar Hot Water Classroom Experiments
Design your own SHW collector
Variables:
Color of collector
Tubing length, pattern, material
Light intensity
Insulation
Use of reflective materials
Rate of water pumping
Etc…

17. Solar Cooking

18. Benefits of Solar Cooking
Consumes no fuels/wood
No loss of trees & habitat
Trees sequester carbon
Generates no air pollution
Generates no greenhouse gases
Produces no smoke
Cooking smoke kills over 1.6 million people each year, mostly women & children, according to a recent report
Eliminates fire dangers

19. More Benefits of Solar Cooking
Eliminates work
No daily search for firewood
2 Billion people rely on wood for cooking fuel!
No risks to women and children
Frees time for other activities
No need to stir food
Helps to liberate women

20. More Benefits of Solar Cooking
Cooks foods slowly and thoroughly
Preserves nutrients
Foods will not burn
Pots are easy to clean; less clean water is needed
Use for canning vegetables
Use for dried fruit
Kill insects in dry grains

21. Solar Cooking How Long Does it Take?
Vegetables: 1.5 hrs
Rice/wheat: hrs
Beans: 2-3 hrs
Meats: 1-3 hrs
Bread: hrs

22. Fun Student Projects!

23. Solar Electric (Photovoltaic)

24. Solar Electric Systems
Photovoltaic (PV) systems convert light energy directly into electricity.
Commonly known as “solar cells.”
The simplest systems power the small calculators we use every day. More complicated systems will provide a large portion of the electricity in the near future.
PV represents one of the most promising means of maintaining our energy intensive standard of living while not contributing to global warming and pollution.
Photovoltaic (PV) systems convert light energy directly into electricity. They are commonly known as “solar cells.” The simplest systems power the small calculators we use every day. More complicated systems will provide a large portion of the electricity in the near future. PV represents one of the most promising means of maintaining our energy intensive (with appropriate and technically viable efficiency gains) standard of living while not contributing to global warming and pollution. Solar Photovoltaics is the future of energy!

25. How Does it Work?
Sunlight is composed of photons, or bundles of radiant energy. When photons strike a PV cell, they may be reflected or absorbed (transmitted through the cell). Only the absorbed photons generate electricity. When the photons are absorbed, the energy of the photons is transferred to electrons in the atoms of the solar cell.

26. How Does it Work?
Solar cells are usually made of two thin pieces of silicon, the substance that makes up sand and the second most common substance on earth.
One piece of silicon has a small amount of boron added to it, which gives it a tendency to attract electrons. It is called the p-layer because of its positive tendency.
The other piece of silicon has a small amount of phosphorous added to it, giving it an excess of free electrons. This is called the n-layer because it has a tendency to give up negatively charged electrons.

27. How Does it Work?

28. Helpful PV Animations

29. Best Place For Solar Panels?
South Facing roof, adequate space
No shading (time of year, future tree growth)
Roof structure, condition

30. Large Scale PV Power Plants
Prescott Airport Location: AZ Operator: Arizona Public Service Configuration: 1,450 kWp
SGS Solar Location: AZ Operator: Tucson Electric Power Co Configuration: 3,200 kWp
We have looked at various sources of distributed PV so far. On the other hand, utility companies are becoming more and more interested in centralized PV. These are two examples of PV in large centralized arrays. The right as 1,450 kWp system and the left has a 3,200 kWp system. To put this into perspective a large house might use 4-5kW.

31. Centralized Wind-Solar Hybrid System
In hybrid energy systems more than a single source of energy supplies the electricity.
Wind and Solar compliment one another
This is an example of a centralized wind-solar hybrid system. Wind and Solar compliment one another. If it is cloudy and windy, the wind mills make up for the drop in solar energy. If it is not windy on a clear day, the solar panels can make up of the lack of wind energy. In hybrid energy systems more than a single source of energy supplies the electricity to the load.
Sources:

32. Solar Concentrators
These 20-kW Solar Systems dishes dwarf visitors in Alice Springs, Australia.
The concentrators use an array of mirrors to focus sunlight onto high-efficiency solar cells.
Four supports hold the cells in front of the mirrors
The supports also supply cooling water and electrical connections
Using solar concentrators can make economic sense when you are talking about centralized systems because mirrors cost less than PV. Each dish is a 20-kW Solar System in Alice Springs, Australia. The concentrators use an array of mirrors to track and focus sunlight onto high-efficiency cells. Four supports hold the cells in front of the mirrors; the supports also supply cooling water and electrical connections.
Sources:

33. How Does the Color/Wavelength of Light Affect PV Efficiency?
Test 5-8 colors using different backgrounds on PowerPoint Slides
Purple
Blue
Green
Yellow
Orange
Red
White

34. Approximate Wavelength: 390-455 nanometers

35. Approximate Wavelength: 455-492 nanometers

36. Approximate Wavelength: 492-577 nanometers

37. Approximate Wavelength: 577-597 nanometers

38. Approximate Wavelength: 597-622 nanometers

39. Approximate Wavelength: 622-780 nanometers