ENSC 1005 Lecture Notes - Passive Solar Building Design, Energy Conversion Devices, Energy Returned On Energy Invested

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Monday December 3, 2012
Energy
Solar Energy- 99% of energy that heats the Earth and our homes comes from the
sun- Produced from the nuclear fusion of hydrogen atoms- Solar energy also
produces indirect forms of renewable energy: wind, falling and flowing water
(hydropower), and biomass (result of photosynthesis)
Commercial Energy (energy sold in the marketplace)- makes up remaining 1% of
energy we use- most comes from extracting and burning non-renewable fossil
fuels: oil, coal, and natural gas- 84% comes from non-renewable energy resources
(78% from fossil fuels and 6% from nuclear power) and 16% comes from
renewable energy resources (biomass, hydropower, geothermal, wind and direct
solar energy)
- See FIG. 17.3, p.374
- Future direction of energy use in U.S. will impact Canadians from an economic and
an environmental perspective
Evaluating Alternative Energy Resources- important questions to answer for each
energy alternative
1) How much of the resource is likely to be available in the near future (15-25
years) and the long term (25-50) years
2) What is the net energy yield for the resource?
3) How much money to develop, phase in and use?4) How will extracting,
transporting and using the energy resource affect the environment, human health,
and Earth’s climate? Should the harmful costs be included in the market price of the
resource?
5) How will dependence on the resource affect national and global economic and
military security?
6) What government research and development subsidies and tax breaks will be
used to help develop the resource?
Net Energy total amount of useful energy available over lifetime of resources
minus the amount of energy needed to make it available for use
- Can also be looked at as a ratio of useful energy: useful energy to produce it à the
higher the ratio, the greater the net energy, if ration < 1 there is net energy loss (Fig.
17-8 pg. 374)
Non-renewable Resources
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1) Oil also called petroleum- a thick liquid consisting of chains of hydrocarbons
with nitrogen and Sulphur- fossil fuel formed as a result of dead organic material
buried deep in sediments under high pressure and heat that collected in porous
limestone or sandstone covered by a cap of shale or silt to keep it from escaping
- Extracted by drilling
- Canada has the worlds second largest crude oil reserves
- Burning it produces air pollution and releases the greenhouse gas CO2
- advantages and disadvantages see FIG. 17-15 pg. 381
2) Natural Gas liquid consisting mainly of the hydrocarbon methane- fossil fuel
that lies above reservoirs of crude oil (gas is less dense then oil)- extracted and
transported by pipelines- releases CO2 when burned- advantages and
disadvantages Fig. 17-22 pg. 385
3) Coal solid fossil fuel consisting of mostly carbon with small amounts of Sulphur
and trace amounts of mercury and radioactive material- extracted by surface and
underground mining- releases CO2 and SO2 (Sulphur dioxide), radioactive
particles and toxic mercury when burned- advantages and disadvantages Fig. 17-
24 pg. 387
4) Nuclear Energy solid uranium undergoes controlled nuclear fission in heavy
water (to slow down neutrons so a nuclear chain reaction can be sustained)
producing extreme heat that heats water to produce stream that turns turbines that
turns a generator to produce electricity
- Causes thermal water pollution when water is recycled and can have
extreme environmental impact if there is a major accident
- Highly radioactive wastes must be safely stored for thousands of years
- Advantages and disadvantages Fig. 17-30 pg. 393
Energy Efficiency- 84% of energy used in Canada is wasted (41% due to the 2nd
law of thermodynamics and 43% unnecessarily wasted because of poorly insulated
buildings, fuel-wasting motor vehicles, furnaces)
- Easiest, fastest and cheapest method to get more energy with least environmental
impact:1) eliminate unnecessary waste by making lifestyle changes that reduce
energy consumption, and2) Increase efficiency of energy conversion devices (get
same amount of work out of a device with less energy input) (Fig. 18-4, pg. 404 &
Fig. 18-5, pg. 405)
- Energy efficient models cost more initially but save money in long run by having a
lower life cycle cost (initial cost + lifetime operating costs)
Reducing Energy Waste
1) Make non-renewable fossil fuels last longer
2) Give more time to phase in renewable energy resources
3) Decrease dependency on oil imports
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Document Summary

Future direction of energy use in u. s. will impact canadians from an economic and an environmental perspective. Net energy total amount of useful energy available over lifetime of resources minus the amount of energy needed to make it available for use. Can also be looked at as a ratio of useful energy: useful energy to produce it the higher the ratio, the greater the net energy, if ration < 1 there is net energy loss (fig. Canada has the worlds second largest crude oil reserves. Burning it produces air pollution and releases the greenhouse gas co2. Causes thermal water pollution when water is recycled and can have extreme environmental impact if there is a major accident. Highly radioactive wastes must be safely stored for thousands of years. Energy efficiency - 84% of energy used in canada is wasted (41% due to the 2nd law of thermodynamics and 43% unnecessarily wasted because of poorly insulated buildings, fuel-wasting motor vehicles, furnaces)

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