Chapter 24 Energy Conservation
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• Solar energy and wind energy are two
alternative resources to oil, coal, and
other nonrenewable resources.
• The use of solar energy to produce
electricity is called photovoltaics.
• Photovoltaic cells convert solar energy
into electrical energy.
• Some of the functions of an inverter in
a photovoltaic system include turning
the system on after sunrise, monitoring
the electricity produced, and turning the
system off after sunset.
• Most states offer incentives and rebates
to people and businesses that install
energy-saving devices.
• Wind turbines are very tall, which allows
them to catch the faster wind speeds
found at higher altitudes.
• The wind turbine produces electrical
energy.
• When the wind blows, it turns the blades
on a wind turbine, which is attached to
the armature of the generator.
• Developers who are building wind
turbines build in areas with high winds
and a lot of windy days.
Test Your Knowledge
Do not write in this book. Write your answers on
a separate sheet of paper.
1. ______ lights are best used in areas where
they will be turned on and left on for
long periods of time.
2. While waiting for water to get hot, a(n)
______ can be used to return cold water
to the water heater.
3. Which water heater is more effi cient: one
with an energy rating of 240 therms or
one with a rating of 265 therms?
4. For what purpose is SEER used?
5. Which air conditioning unit is more
effi cient: one rated 12 or one rated 15?
6. Describe the basic concept of geothermal
system operation.
7. What type of glass is used in windows to
reduce heat gain in the summer and heat
loss in the winter?
8. How can the albedo of a roof be
increased?
9. What are two benefi ts of porous
concrete?
10. What is the main function of a
photovoltaic cell?
11. List at least four functions of an inverter
used to tie a photovoltaic or wind
generating system to the grid.
12. Why do taller wind turbines generate
more electricity than shorter wind
turbines?
13. What is done to prevent wind turbines
from destroying themselves at very high
speeds?
14. Why are large spaces left between wind
turbines?
Activities
1. See if you can locate a demonstration
home near you. Pay them a visit and
list how many different energy saving
devices are shown.
2. What is the latitude where you live? Are
there any solar collectors mounted on
buildings near you? List their locations.
At what angle to the sun are the
collectors mounted? Why was that angle
selected? On what side of the building
are they located (North, South, East, or
West)? How much water can they heat
with their system?