1. Solar Energy BasicsSolar Energy Basics
Thermal and PVThermal and PV
Joe RandJoe Rand
KidWind ProjectKidWind Project
joe@kidwind.orgjoe@kidwind.org
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
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
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
13.
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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…
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: 1.5-2 hrs
• Beans: 2-3 hrs
• Meats: 1-3 hrs
• Bread: 1-1.5 hrs
24. • 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.
Solar Electric Systems
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.
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
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
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
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
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!
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.
http://www.industcards.com/solar-usa.htm
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:
http://www.lged-rein.org/solar/stmartins/sre_stmartins4.jpg
http://www.lged-rein.org/solar/solar_sre_stmartins.htm
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:
http://www.nrel.gov/data/pix/Jpegs/13736.jpg
