PHYS 105
Study Guide for SEctiion III Renewable Energy Sources
Solar
Power
Hydropower
Windpower
Geothermal
Biomass
I: Solar
Energy ( ch. 12)
Renewable Energy Basics
: This a very important site with videos
Review the questionnaire for movie III. Make sure you have answered all 15 questions
correctly. Compare your answers at least with one classmate.
Give reasons why we should look for alternatives to fossil fuels.
List at least six sources of renewable energy.
Which renewable sources of energy do not derive their energy from the sun?
List the U.S. renewable energy consumption % from highest to lowest.
How long in minutes does sun light take to reach Earth? ( d = 150 million km , c=
300,000 km/s, t =d/c Ans =8.33 min.)
What is the solar constant?
If we were to capture all the solar energy that is incident in the whole of US, how many
times more energy than we need do we get?
What fraction of the Mojave land is needed to efficiently collect solar energy to meet US energy
needs?
How many gasoline gallons equivalent of solar energy can a 1000 sq. ft roof collect per
day?
How should a house be oriented to take advantage of direct solar energy?
Which area of the US gets the most solar energy?
What is insolation?
What are the advantages and disadvantages of a flat-plate solar energy collector system?
What is the difference between an active and passive collector system? Give examples of
each.
State, mathematically, Stefan=s and Wien=s radiation laws. The middle of the visible solar
spectrum is 0.5 micrometers (500 nano meters). That is also the wavelength were the
intensity is maximum. Using Wiens=s Law
calculate the surface temperature of the sun.
What is the Greenhouse Effect?
List the colors of the visible spectrum (the rainbow) in descanting order of wavelength.
Glass does not transmit infrared radiation 4 to 24 micrometers. What are some
consequences of this as it relates to solar collectors? And to a parked car with all
windows closed? And in the Earth<s
atmosphere?
What were the factors that influenced the growth of the solar panel market in the early
1980s? What led to the decline of use of solar panels after 1985?
What was the major use of the solar panels that were installed in the early 1980s?
What are three factors that need to be considered in the design of a solar home?
Rank the following materials in the descending order of their capacity to store solar
energy: brick, scrap iron, loose stone, wood, water, concrete
Compare the direct-gain and a Trombe wall approach to solar home heating. What is the
advantage and disadvantage of each. Look at fig 4.7 and fig 4.8.
How can a window be used to admit solar energy during winter and block it during summer?
For a flat-pate collector, the heating potential is about 100 0 C (373K)
while the ambient temperature is 200C (293K). Show how this results in a Carnot
efficiency of about 20 %. (See p. 106) [ e% = (Th -Tc/Th) x 100]
Calculate the efficiency for a heat engines that relies on: A spherical collector ( Th =
700k, Tc = 300K) , for a parabolic collector (Th = 1500k, Tc =300k). A record temperature
of 3273 K was set in France. If the ambient temperature is 3000k, What is the Carnot
efficiency of a thermoelectric generator that uses this super hot collector?
What are solar power towers? How do they work?
What are the devices that convert solar energy directly to electricity
called?
What is the photoelectric effect? How did Einstein explain it?
Give examples of devices that use solar cells (photovoltaic
cells)?
What % of solar energy has the wavelength that solar cells can convert to electricity?
What are factors that have discouraged the wide use of solar cells?
Where is the largest solar power plant found? How many MW does it produce?
How is solar cooling possible?
How did Servel and Eloctorux refrigerators work? How is solar energy relevant in these
refrigeration processes?
Give two reasons why solar powered refrigerators would be more useful in less developed
remote tropical areas?
Give a reason why spacecrafts such as the space station have the advantage when it comes
to using photovoltaic cells.
In addition to all the above, please make sure you can define all the
Key Terms such as insolation, collection ratio, solar constant albedo, etc.
Finally, use especiall the multiple cjhoice questions pages 308 to 311
for review.
II. Hydropower:
(
Ch.13)
The link above will lead you to a variety of topics that are relevant to hydropower.
- List the renewable energy sources based on % of usage. High to low
- List the non-solar renewable sources of energy.
- What was hydropower used for 2000 year ago?
- What replaced water wheels in the 16th century?
- Describe the transformation of energy that takes place in the hydrological
cycle (PE to KE and finally to Electrical)
- What % of the solar energy the Earth receives is used up in the hydrological cycle?
- What is the potential energy (P.E.=mgh) of 1 liter (1kg) of water if it is 100 meters
above ground level?
- Calculate the power generated when water falls from a 100 meter height at the rate of 1
liter/sec. See example 5.1
- List the pros and cons of using hydroelectric generators.
- What limits the lifetime of hydroelectric generators?
- On March 13, 1928, the St. Francis dam near San Francisco failed. How many people died
because of this accident?
- How many major dam failures has there been between 1918 and 1958? Based on these
failures is the average death rate per year more than or less than 1 person? Is this
significant compared to other causes such as car accidents? Or Earthquakes?
14 List the % of electricity the following countries get for hydroelectric power
Norway: ____________ |
Canada: ____________ |
Nepal: ___________ |
Sweden:_____________ |
Brazil: ____________ |
USA: _______________ |
New Zealand: ___________ |
|
|
|
15 Wchih region of the US has the highest potential for hydroelectric power?
16. List the five largest Hydroelectric dams in the world (Table 13-1)
17 Use the Multiple qestion for review- pages (405-408)
III.
Wind Power:(Ch.
12)
The links below are relevant to Wind power.
Please study the
Quick Facts about Wind
Energy
This link is also relevant to wind power
- What makes the wind to blow?
- What % of solar energy is used to generate wind?
- There is a record that wind power was used by Egyptians 7000 years ago. For what purpose
was it used?
- Explain why the breeze is from sea to land during a hot summer day and land to sea at
night?
- Up to how many horse powers were large sailing ships able to extract from the wind in
the 19th century?
- What are some advantages wind power has over solar cells?
- If the wind velocity doubles by what factor does its power generating capacity increase?
- What is the maximum theoretical efficiency of a wind mill
Study fig. 12-9. List the type all the of wind turbines represented in the figure with
their efficiencies. What is the maximum possible efficiency for a wind turbine?
- What are the major uses of small windmills?
- What are the major uses of large wind turbine farms?
- Which state produces 75% of the world wind generated electricity?
- What motivates California to develop windmill farms?
- Does SC have a great potential for developing wind turbine farms? (see
Table12-1 p.364))
- What are some problems associated with wind power?
- Use the Multiple qestion for review- pages (374-376)
IV OTEC (see
page 392 in the Text Book)
The following link gives some history and describes open and closed OTEC systems with
clear diagrams
- What does OTEC stand for?
- Who originally developed the OTEC concept?
- Who was the first to build an OTEC?
- According to George's Claude (see page 145) what are the advantages envisioned that
OTECs would have over hydroelectric and fossil fuel powered power plants?
- Besides generating electricity, what can OTECs possible do?
- Which type of OTEC uses ocean water as a refrigerant?
- Which type of OTEC uses ammonia as a refrigerant?
- Which type of OTEC can distill water as it generates electricity?
- How can OTECs help generate hydrogen?
- Why is hydrogen important? (Hint: search for fuel cells.)
- If the surface temperature of an ocean is 270C while at a depth of 100 meters
it is 7 0C. What is the ideal efficiency of an OTEC power plants that utilizes
this temperature gradient? ( e% = (Th-Tc)* 100/Tc. If your answer is 26%, it is wrong! It
should be about 7%. Please convert the temperatures to Kelvins before you use them in the
formula. See example 5.4)
V.
Tidal Power (See power from waves. Page 387-392)
Use the above link and the one below to learn more about tidal power
another link to tidal
power
How awesome is tidal
power -China
Tidal Power for New
York City
- What causes the tides?
- Why does one see two tides in a 24-hr period instead of one?
- How is tidal power similar to hydroelectric power? What are the differences between the
dams for a river and for tides?
- What are some major problems associated with using tidal power?
- What fraction is the efficiency of tidal power compared to hydroelectric power?
- What fraction of world hydroelectric power capacity does tidal power
represent?
- Why is tidal power not widely used?
- What fraction of US potential for power does tidal power represents
compared to hydroelectric?
- Explain how Tidal Electric Alaska plans to store tidal power
generated electricity?
- List the location of the three large operational tidal power plants in the
worl
https://www.youtube.com/watch?v=tSBACzRE3Gw
https://www.youtube.com/watch?v=5v23_5dvgWM
VI. Geothermal(Ch.9)
The course site below discusses geothermal as well as OTEC, It also has a lot of links to other sites that
you need to look at. A geologist prepared it.
http://www.colorado.edu/GeolSci/courses/GEOL3520/Topic8/Topic8.html
- How does the earth get hot at its core?
- What is the temperature of the Earth at its inner core?
- What is the temperature of magma at the depth of 80 to 100 km?
- What is the present electric generating capacity of Geysers Geothermal Power Plant found
near San Francisco? (see fig 5.15)
- If a geothermal; power plant utilizes Th = 400K and Tc =300K, what is its maximum ideal
efficiency?
- List the six categories of geothermal resources and state briefly how they can be used?
(see page 159-160)
- Which type of geothermal is the most promising? What its percentage
capacity compared to all the other types of geothermal resources?
- Which country gets about 2/3 of its energy need s from geothermal source?
- What % of world energy can geothermal sources potentially provide?
- What are some of the pros and cons of geothermal power? (Check the link for Geothermal
above)
VII. Bioenergy (Ch. 11)
Biomas
http://www1.eere.energy.gov/biomass/pdfs/biomass_basics.pdf
- What is the process by which plants make hydrocarbons?
- Write down balanced chemical equations that show the formation of glucose and sucrose?
- What is biomass
- What is the ideal efficiency of a photosynthetic process? (
- What % of the visible spectrum is or can be used by plants for photosynthesis?
- Why do plants appear green?
- What was the major fuel for cooking and heating for early man? For US before 1880? And
many developing countries?
- When can we say biomass is renewable?
- If we do not replant, is biomass renewable?
- What are the pros and cons of biomass?
- Estimates show we can meet all our energy needs if we burn all the crops we cultivate or
if we use a large portion of our land to harvest fast growing trees. Is this a good idea?
- What % is organic and what % is
inorganic (glass and metal)?
- What can be done to isolate the inorganic waste?
- how grbage be used by electric power plants for fuel? How does this affect
landfills?
- Give some pros and cons for using Municipal Stolid Waste as fuel. .
- What is the difference between ethanol and gasohol?
- What are the problems associated with producing ethanol?