Chapter 16 APES Energy
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- 1. Why has energy supply been a problem since ancient times?
- As standard of living increases energy needs increase
- 2. What is energy?
- Refers to the capacity or ability to do work
- What are the various forms of energy (and some examples of each)?
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potential energy: energy source that has not yet been used - stored energy - ex nuclear energy, coal, fuel oil
kinetic energy: motion
thermal energy: energy of the random motion of molecules - 3. What are the 1st and 2nd Laws of Thermodynamics?
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⬢ 1st Law of Thermodynamics: Energy can be converted from one form to another, but cannot be created or destroyed
⬢ 2nd Law of Thermodynamics: Waste heat is always created. During conversions, some energy is converted to heat and the entropy of the system increases. Entropy is unusable energy, disorder, randomness - What is entropy?
- Entropy is unusable energy, disorder, randomness
- What is meant by energy quality?
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⬢ Energy quality - availability of energy to do work
High quality: organized
Low quality: disorganized - What is work?
- Work is exerting a force over a distance (Work = force x distance)
- What happens (in terms of energy quality and entropy) when work is done?
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Sequence when work is done: Potential energy --> kinetic energy --> heat
entropy increases, energy quality decreases - What is energy efficiency?
- Refers to both first-law efficiency and second law efficiency where first law efficiency is the ratio of the actual amount of energy delivered to the amount of energy supplied to meet a particular need, and the second-law efficiency is the ratio of the maximum available work needed to perform a particular task to the actual work used to perform that task.
- What is the difference between 1st and 2nd law efficiency?
- The 1st law is the energy used for how much work you have done and the 2nd law is how much you used vs. the minimal amount needed to do the work
- Describe the relationship between standard of living and energy consumption.
- As standard of living increases so does energy use.
- The US has 5% of the world’s population and accounts for what % of world energy consumption?
- 25%
- 8. What % of US energy comes from fossil fuels? What are the 3 main fossil fuels?
- 91% from fossil fuels. Coal, Oil, and natural Gas.
- What are fossil fuels?
- Produced from plant and animal materials and are forms of stored solar energy in our geological resource base.
- What are alternative energy sources?
- Geothermal, nuclear, hydropower, and solar. (sources to replace fossil fuels)
- What are renewable energy sources?
- Sources not depleted. (Solar and Wind)
- The overall 1st law efficiency for the US is 50%. If we used 85 exajoules of energy in 1999, how many exajoules were actually used to do useful work.
- 42.5 exajoules
- What happened to the rest of the energy?
- wasted
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What are the units used to measure energy?
Joule
Calorie/ kilocalorie
BTU
Quad/ exajoule
Kwh - x
- What is power and how is it different from energy?
- Power- rate of energy use
- What are the units used to measure power?
- Watt, kilowatt, megawatt,gigawatt,horsepower
- What is meant by conservation, energy efficiency and cogeneration?
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Conservation- getting by with less demand for
Energy efficiancy- ration of output obtained from given input
Cogeneration- using waste heat to useful work - The 3 areas that have the greatest potential for energy savings are building design, industrial energy use, and automobile design. Briefly describe how each can be made more efficient.
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building design- use passive solar, insulation
industrial- efficient machinery, cogeneration, solar energy
automobile design- better fuel efficiancy, hybrid cars, fuel cells - What is the role of personal behavior in saving energy?
- Make sacrifices or changes in order to help.
- What is meant by hard path and soft path energy policy?
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hard- is changing or adding hardware
soft- is changing people's behavior - 16. What is integrated energy management?
- use a diversity of fuels, use renewable fuels.
- What is sustainable energy development?
- provide reliable sources of energy, not cause serious harm to enviroment, ensure future generations have quality enviroment and amounts or resources