AVG. 85.6 = 74.4%

P110/120 Exam 2

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Tuesday Nov 11 Chpt. 10 Electricity Basics  

Thursday Nov  13 Chpt. 11 Electromagnetism  

Tuesday Nov 18  Electrical Generation HW7

Thursday Nov 20 Chpt. 12 Solar electricity  

Tuesday Nov 25   Kinetic sources  

Thursday Nov 27   Thanksgiving  

Tuesday Dec. 2 ???? The Future  

Thursday Dec. 4 ???? The FutureHW8( replaces

Art. sum 3)

Tuesday Dec 9 ???? The Future  

Thursday Dec 11 ???? The Future Term paper

       

Tuesday, Dec 16 2008   FINAL EXAM 7:15 PM

Revisions to course Schedule

http://www.whrc.org/carbon/ (Woods Hole Research Center)

Sediments and sedimentaryRocks could account for another6x107 Petagrams! (www.physicalgeography.net/9r.html)

H&K Fig. 9.6:

Feedback(positive

and Negative)

“Butterfly effect” in complex systems

Green House gases• Contributions to green house effect

depend on IR absorption, concentration and lifetime in the atmosphere.

GAS Sources GWP

Lifetime (yr)

2003 conc.

ppmCO2

(5500 MT/y)Burning organics/

deforestration1 100 373

CH4

(600 MT/y)

Rice fields, landfills, animals

21 10 1.7

NOx

(16 MT/y)

Fetilizer/defor-estration, vehicles

310 170 0.31

CFC’s

(1MT/y)

Aerosol sprays, refrigerators, ACs’

1300-12000

70-100 0.003

NF3

(<2-3kT/y)

Plasma cleaning FP displays etc.

17000 550-750 0.00045

GWP: “Global Warming Potential”: the ability of the gas to trap IR light (heat).

Carbon Sequestration (“Clean coal” as of ~ 2000)

Research and Creative Activity, Oct 2008, IU OVPR publication

Note that “clean coal” is a term that has been around for a long time, but ithas only recently morphed into this incarnation. Originally it referred simply to using low-sulfur coal, then to including emission control measures, and finally to include limits on CO2 emissions. It’s true meaning in the mind of the useris therefore to be taken with some appropriate degree of skepticism!

Kyoto Protocol (1997-99)

http://en.wikipedia.org/wiki/Kyoto_Protocol

Green: Signed and ratifiedYellow: Signed with ratification pendingRed: Signed and declined to ratifyGrey: No position

Built on Rio Summit of 1992, been “in force” since Oct. 2005. Goal is to reduce developed nations CO2 emissions by 5% from 1990 levels

http://www.mardiros.net/atmosphere/atmosphere_structure.html

10 ppm ozone at ~ 50 km compared to40 ppb ozone in the troposphere!

http://www.atm.ch.cam.ac.uk/tour/part2.html

Ozone levels at Halley Bay station (Antarctica)

TOMS Satellite movie(Total Ozone Mapping Spectrometer)

http://www.atm.ch.cam.ac.uk/tour/anim_toms.html

TOMS Satellite movie(Total Ozone Mapping Spectrometer)

http://www.atm.ch.cam.ac.uk/tour/part2.html

http://en.wikipedia.org/wiki/Montreal_Protocol Sept. 2006

Montreal Protocol (1987-9)

http://en.wikipedia.org/wiki/Montreal_Protocol

An agreement to limit the emission (and eventually eliminate the use) of CFC’s that contribute to Ozone depletion. In force as of 1989, modified several times (most recently Beijing 1999).

Has been hailed as one of the UN’s most successful international agreements.

Thermal Pollution

• Remember, all energy production eventually leads to thermal energy being dumped into the environment.

• To carry the waste heat away from a 1000MWe power plant requires about 104 gallons/second (for an 8K temp. rise).

• In an increasing number of (local) applications, some of this waste heat is used to heat local buildings (“co-generation”)

U. Cincy Cogeneration Plants

http://www.uc.edu/facmgmt/utility.asp

Two generating stations: 47MW combined.

Annually produces:

245M kWh

Heat to 9Msq.ft of bldg space

Various fuel options can be used.

Impact of Thermal Pollution

• Reduced oxygen content in lakes/rivers/ponds the heat is released to.

• Changes in reproduction, growth and behaviour throughout the food chain; e.g. algae plumes

• Chemical reaction rates increase.• Changes in local temperature gradients

(especially vertical gradients) can upset the natural exchange of nutrients between surface and deep water

Thermal Pollution: Local water sources

Cooling towers

Term paper (see website)

ASSIGNMENT: You are to research some technology related to energy (production, conservation, mitigation of side effects, etc.) that has been implemented recently or has been proposed for use at some point in the future. The paper should describe the technology in sufficient detail for an intelligent but uninformed reader can understand its function, and it should state (and support) your own argument for why this technology should or should not be implemented in the market place. 

• See the link on the web site for more details.

Possible topics• Fuel cells • Wind farms. • Passive/active solar heating • Geothermal climate control • High-efficiency appliances • Next generation nuclear plants. • Solar Cells, what promise exists in recent materials advances? • Personal transportation options. • Alternative organic fuels • Options for storing radioactive waste from power plants. • Nuclear Fusion • Methane clathrate • Control measures for any pollutant of your choice (including carbon). • Advanced oil recovery methods • Biomass fuels • Cogeneration technologies • Hydrogen economy (this has lots of possible subtopics, storage,

generation, use, hazards etc.) • Future automobile design (again lots of subtopics exist) • The electrical power grid • Real time pricing of electricity• Others of your own choice.

Basics of electricity• There is a force other than gravity that

acts “at a distance” (and is stronger).• This force can be attractive or repulsive• “Static Electricity” comes in two flavours;

we call these positive and negative (like charges repel, unlike charges attract).

• At least some of the charges in metals are very mobile.

• The force is stronger if charges are closer.• We can define a potential energy

associated with the relative location of charges (this is a conservative force).

Basics of electricity (cont.)• The basics on the previous slide form the basis for

all of our electrical technology!• We measure charge in Coulombs (6.24x1018

elementary charges)• In electrical circuits, you have an “electromotive

force” that provides the “push” (V: VOLTAGE, measured in VOLTS, a potential energy difference per unit charge 1 V = 1J/1 Coulomb) DEMO.

• Moving charges carry the energy (I: current, measured in AMPS 1 A =1Coul/sec).

• Power = I*V (1 watt = 1volt*1 Amp)• The ratio of voltage to current is called the

resistance of the circuit– OHM’s Law: V=IR (R measured in OHMS, )

Resistance• Electrical resistance is much like thermal

resistance, it depends on the length and cross section of the wire, and on the material the wire is made of.

• R = l/A : resistivity

• (e.g. Cu 1.69x10-8 m; Al 2.75x10-8 m)

– l length of the wire– A cross-sectional area of the wire

• Wires designed to carry a lot of current must have a large cross sectional area.

Ohm’s Law

• The ratio of voltage to current in a circuit (or circuit element) is equal to the resistance of that circuit (or element)

R = V / I

V = I R

I = V/R

• R is measured in OHMS () 1= 1V/1A.

Series and Parallel Circuits

Series circuit: Current is the same in all elements (voltages add)

Parallel circuit: Voltage is the same in all elements (Currents add)

Examples

• Consider a 1200W North American toaster. What current does it draw? If it is used to toast two slices of bread in 1 minute, how much does toasting each slice cost (take $0.08/kWh for the cost of electricity).

• A 50 resistor is connected across a voltage of 120V. What is the power dissipated in the resistor?

Batteries

All batteries have the same basic principle, but the chemical reactions and The materials used for the electrodes and electrolytes) differ. This givesDifferent voltages, internal resistances, masses, operating temps, etc.

H&K p 327

Batteries: Energy Density

http://www.hardingenergy.com/pdfs/ComparisonofApplication.pdf(as of Jan. 2004, note on this scale, gasoline is 12000 Wh/kg and 9500 Wh/l)Compare these numbers to table 10.1 in the text.

North American Power Plants

http://en.wikipedia.org/wiki/Electric_power_transmission

US Electrical power

http://www.eia.doe.gov/fuelelectric.html

Look at the text, whichShows an interestingDistinction betweenUtility producers and Non-utility producersIn terms of this mix.(p 319)

US Electrical Power Generation

U. Cincy Cogeneration Plants

http://www.uc.edu/facmgmt/utility.asp

Two generating stations: 47MW combined.

Annually produces:

245M kWh

Heat to 9Msq.ft of bldg space

Various fuel options can be used.

US Electrical power

http://www.eia.doe.gov/cneaf/electricity/epa/epa.pdf#page=15