[email protected] engr-10_lec-09_chp6_population_energy.ppt 1 bruce mayer, pe engineering-10:...
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[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt1
Bruce Mayer, PE Engineering-10: Intro to Engineering
Bruce Mayer, PELicensed Electrical & Mechanical Engineer
Engineering 10
Chp.6 Future
Challenges
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Bruce Mayer, PE Engineering-10: Intro to Engineering
FIRST and SECOND Laws ofTHERMODYNAMICS Class Question:
Can Anyone Describe Either of the FIRST or SECOND Laws
of ThermoDynamics?
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Laws of ThermoDyamics
In the Instructor’s Opinion The SECOND Law is the GREATEST of all the “Laws of Physics”
The ThermoDyamic Laws • Describe the Relationships & Connections
Between Work↔Heat↔Energy• Describe and Quantify Reversibility and
IRReversibilty • Explains What’s “The Best we can Do”
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Bruce Mayer, PE Engineering-10: Intro to Engineering
The “Laws” What are they?
First Law of Thermodynamics• Energy can neither be CREATED nor
DESTROYED– But Energy Can be Moved, or Changed to
Other forms
Second Law of Thermodynamics• NATURALLY OCCURRING processes are
Directional– Natural process can go ONE WAY,
but NOT the OTHER
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Reversibility
Reversibility is the ability to run a process back and forth (backwards and forwards) infinitely withOUT Losses
Money analogy: Currency Conversion• NO service fee (reversible):
$100 113000₩, and one hour later at the same place, 113000₩ $100
• WITH service fees (IRreversible: $100 68€, and one hour later at the same place, 68€ $90 (5% fee both ways)
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt6
Bruce Mayer, PE Engineering-10: Intro to Engineering
Reversibility and Energy
Electric Current
Motor Generator
Voltage
Turbine Pump
Fluid Flow
Pressure
If IRreversibilities were ELIMINATED, these systems would run FOREVER.• These Systems would then be
Perpetual Motion Machines
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Example: Popping at Ballon
Not reversible unless energy is expended
X
A “reversible process” can go in either direction, but these processes are rare
Generally, the irreversibility shows up as waste heat
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Sources of Irreversibilities
Friction (force drops) Voltage (electrical
resistance) drops Pressure drops Temperature drops Concentration drops Magnetic Hysteresis
(H Drops)
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Irreversibility Example It’s EASY To Mix the
Cream Into the Coffee
It’s extremely difficult to UNmix (separate) the Cream from the Mixed Coffee• It takes a LOT of
Effort, or WORK, to separate
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt10
Bruce Mayer, PE Engineering-10: Intro to Engineering
First Law of ThermoDynamics
One form of work may be converted into Another,
Or, work may be converted to heat, Or, heat may be converted to work, But, ALWAYS
FINAL energy = INITIAL energy
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Bruce Mayer, PE Engineering-10: Intro to Engineering
11
2nd Law of Thermodynamics
We intuitively know that heat flows from higher to lower temperatures and NOT the other direction.• i.e., heat flows “DownHill”; just like water
WHY don’t we see Water flow UpHill, or Heat move Cold→Hot on Occasion?
Water & Heat Flow ONE-WAY Because These processes, which “down-flow-hill”, are inherently IRreversible.
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt12
Bruce Mayer, PE Engineering-10: Intro to Engineering
Heat↔Work Conversions
Heat transfer is inherently irreversible. • This places LIMITS on the amount of work
that can be produced from heat.
Heat can be converted to work using heat engines; e.g.,• Jet engines (planes), • Steam engines (Old Locomotives)• Steam Turbines (Nuclear PowerPlants), • Internal combustion engines (automobiles)
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt13
Bruce Mayer, PE Engineering-10: Intro to Engineering
Heat into Work (Power Plant)
A heat engine takes in an amount of heat, Qhot, and produces work, W, and waste heat Qcold Qhot = W + Qcold
Nicolas Sadi Carnot (kar nō) derived the LIMITS of converting heat into work
High-temperatureSource, Thot
Low-temperatureSink, Tcold
HeatEngine
W
Qhot Qcold(e.g. flame) (e.g. cooling pond)• W = Mechanical Work • Q = Heat
coldhot QWQ
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Carnot Equation: Efficiency
Given the heat ENGINE on the previous slide, the maximum work that can be produced is governed by:
hot
cold
hot
max
T
T
Q
W1
• where the temperatures are absolute (e.g. Kelvins)
Thus, as Thot Tcold, Wmax 0
This ratio is also called the Thermal Efficiency, η
N.L.S
. Carn
ot
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Example: PowerPlant
A BWR Nuclear PowerPlant Boiler Runs at about 1000 °F
The “Heat Sink” is the cold Pacific Ocean at 52 °F
What is ηmax ?
1000 °F = 1460 °R
52 °F =
512 °R
%9.641460
51211max
hot
cold
T
T
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Moving Energy Cold→Hot
Not USING Heat, Just Moving it Around Moving Heat UPhill requires WORK The CoEfficient of Performance, CoP,
informs about the effectiveness of AirConditioners and HeatPumps
High-temperatureSink, Thot
Low-temperatureSource, Tcold
HeatEngine
W
Qhot Qcold(e.g. OutSide Air) (e.g. InSide AC)
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt17
Bruce Mayer, PE Engineering-10: Intro to Engineering
Carnot Equation: CoP
Given the heat PUMP on the previous slide, the Minimum Work needed to move heat UpHill is governed by: 1
1
coldhotmin
cold
TTW
Q
• where the temperatures are absolute (e.g. ºRankine)
Thus, as Thot Tcold, Wmin 0
This ratio is also called the CoEfficient of Performance, CoP
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Example: Air Conditioner
It’s REALLY Hot Outside, 105 °F
A “Cold Blooded” person Keeps the house at 65 °F
What is CoPmax?
105 °F = 565 °R
65 °F = 525 °R
1.131525565
1
1
1max
coldhot TTCoP
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Nicolas Léonard Sadi Carnot
Founder of the Science of ThermoDynamics
BORN: Paris, France,June 1 1796
DIED: Paris, France,August 24 1832
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Bruce Mayer, PE Engineering-10: Intro to Engineering
“Water Powered” Hydrogen Car A “Hydrogen” car is the
SAME THING as any Other “Electric Car”
In BOTH Cases an Electric Motor turns the Wheels• In an “Electric Car” The
Energy is stored in traditional Batteries
• In an H2 car the energy is stored in Hydrogen Tanks– Sometimes at 5,000 psi
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt21
Bruce Mayer, PE Engineering-10: Intro to Engineering
“Water Powered” Car
It’s Easy Just get some H2O,
split it into H2 & O2
Store the H2 in Big Tanks in your Car,
Run it thru a “Fuel Cell” to turn an Electric Motor• Could also burn the H2 in
a Heat Engine
Off you go
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt22
Bruce Mayer, PE Engineering-10: Intro to Engineering
“Water Powered” Car – Not so Fast
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy & Humans
James Watt and His Predecessors (e.g., Savery & Newcomen) FREED Human-Kind From Muscle Power
The Heat Engine Was One of the Great Advances in Human History• Enabled the “Industrial Age”
The Generation & Application of Energy Multiplies The Capabilities of EVERY Person
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Watt’s EngineWatt, James (1736-1819)
Scottish inventor and mechanical engineer, renowned for his improvements of the steam engine. Watt was born on January 19, 1736, in Greenock, Scotland. He worked as a mathematical-instrument maker from the age of 19 and soon became interested in improving the steam engines, invented by the English engineers Thomas Savery and Thomas Newcomen, which were used at the time to pump water from mines.
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt25
Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources
Let’s LIST Real And Potential Energy Sources OTHER Than Fossil Fuels
1. ?
2. ?
3. ?
4. ?
5. ?
6. ?
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Bruce Mayer, PE Engineering-10: Intro to Engineering
44.52%
23.35%
20.25%
6.93%
1.87%
1.38%
0.99%
0.38%
0.30%
0.02%
0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50%
Coal
NaturalGas
Nuclear
Hydro
Wind
Wood &BioMass
Fuel Oil
GeoThermal
Other
Solar
Fraction of Total Electrical Generation
Ele
ctri
cal P
ow
er S
ou
rce
USA Electricity Production Mix - 2009
USA_Electricity_Mix_1010.xls
Source = USA Energy Information Adminsistration * http://www.eia.gov/cneaf/electricity/epa/epates.html
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy Wind Power
• Wind Turbines Are VERY Attractive– Energy Input to Produce is Low– Incremental Added Capacity– NO Emissions of Any Kind
• Limitations– Low Energy Density
Must Cover Large Areas to Produce Much EnergyLimited Viable Sites
– Balance of System Costs (AC→AC Freq Converter)– Danger to WildLife; Particularly Birds (Raptors)
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
Split Wood, Not Atoms → BioMass• Burning Garbage or Plant Matter
is Attractive– Simultaneous Solution to Energy
and Solid-Waste Problems – “Renewable” Resource– Low Energy Input to Produce
• Limitation: Emission Stream is VERY Unpleasant– Scrubbing Wood-Smoke is MUCH Harder than
Cleaning Gasoline Combustion ByProducts
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Glen Canyon Dam – Page, AZ Electrical Power Generation
• River: Colorado River• Plant Type: Conventional• Powerhouse Type: Above Gnd• Turbine Type: Francis• Original Nameplate Capacity:
950,000 kW (950 MWe)• Installed Capacity:1,304 MWe• Year of Initial Operation:1964• Net Generation (FY 2005):
3,208,591,407 kWh• Rated Head:510 feet
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Glen
Can
yon
Dam
Aerial V
iewGenerators
Tran
smis
sio
n
Tow
ers
Transformer
Switch
Yard
Visito
r Cen
ter
Bridge
Lawn
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Glen Canyon Dam – Page, AZ
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Glen Canyon Dam – Power Gen
150 rpm48
Poles
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Glen Canyon Dam – Power Gen
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Glen Canyon Dam – Power Gen
Set-UP Transformers
13.8kV 230kVor
13.8kV 345kV
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Fran
cis Turb
ine
Gen
erator S
ystem
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt36
Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
Hydroelectric Power • Fancy: Can Provide for Future Growth• Fact: Almost ALL Viable Hydro Sites
Have Been USED– Damming More Rivers is a Political Issue
Ethanol as AutoMobile Fuel• Fancy: Ethanol Can Replace Oil As a
Source for Automobile Fuel• Fact: Making Ethanol from Corn May Use
MORE Energy than It Produces
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
Ethanol Continued• DISTILLATION of Ethanol from Fermented
Corn Requires Large Amounts of Energy– Usually Provided by Burning Fossil Fuels at the
Distillation Site, or at the Electrical Power Plant
Solar PhotoVoltaics (solar cells) Can Supply Future Energy Needs • Photovoltaic Solar-Electric Cells Have
Many Advantages – Remote Siting, Incremental Expansion
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
Solar Cells Continued• BUT Making a Solar Cell Requires
Large Amounts of Energy– Silicon Cells are Made by, in the
Beginning, MELTING SAND– Production Processes Can be
Energy Intensive as Well
• Connecting to the Existing Electric Grid Includes a Great Deal of “Balance of System” Components– DC→AC “Inverters”, Special Electrical boxes
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
Solar Cells Continued• Solar Radiation has a
Very Low “Energy Density”– Requires LARGE Areas to Collect
Significant Amounts of EnergyCan Crowd-Out Other Uses:
Solar-Farm vs. Tomato-Farm
Hydrogen Fuel Cells• Based on Chemical Reaction
OHOH 2222
Proton Exchange
Membrane (PEM) FC
http://fuelcells.si.edu/
basics.htm
See also http://www.olympusmicro.com/primer/java/fuelcell/
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Solar-Farm vs. Orange Orchard
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
Hydrogen Fuel Cells Continued• The Fuel Cell Reaction Looks Very Good
– NO VOCs/HydroCarbon Emissions– NO NOx emission
– NO Greenhouse Gases (CO2)
• But WHERE Do We Get the HYDROGEN?– There are NO Hydrogen WELLS or MINES
• The Viable Sources of Massive Amounts of Hydrogen themselves Require Large Energy or Carbon Inputs
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
In Apr04 Gov. Arnold Schwarzenegger has proposed an ambitious network of hydrogen filling stations by 2010
See also http://www.hydrogenhighway.ca.gov/
But How can we MAKE all the Hydrogen needed to Replace Gasoline?
There are 3 Viable Alternatives
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt43
Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
1. Use WIND or NUCLEAR Power to generate Electricity which, in Turn, would be Used to Electrolize WATER
• Electrolosis applies Electrical current to water and splits it into oxygen and hydrogen, which are then separated…
• The Chemical Reaction
222 22 OHOH EnergyElectrical This is a Very Energy Intensive Process;
about 75% efficient
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt44
Bruce Mayer, PE Engineering-10: Intro to Engineering
Electric Cars: H2 vs ElectroChemUlf Bossel, “Does a Hydrogen Economy Make Sense?”, Proceedings
of the IEEE | Vol. 94, No. 10, October 2006, pp 1826-1837
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
2. Steam reforming of natural gas • If you take methane, the main component
of natural gas, and expose it to steam, the final products are primarily carbon dioxide and hydrogen. Chemically
• This is already a Large-Volume Industrial Process, but it produces a LOT of CO2 – a GreenHouse Gas
• Natural Gas Supplies seem ample
2224 42 COHOHCH
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Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
3. Coal gasification • hydrogen could be produced at
centralized plants, compressed and most likely transported in trucks.
• Coal is mostly carbon & hydrogen, but also contains some sulfur. Exposed to water at high temperature and high pressure, it chemically reacts to yield carbon monoxide (CO) and hydrogen.
– But CO is Poisonous to Humans
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt47
Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy Sources Fact & Fancy
3. Coal gasification, cont.• Oxygen from additional water vapor turns
carbon monoxide into carbon dioxide. So the end products are primarily carbon dioxide and hydrogen gas. Chemically
• We have LOTS of Coal, but still need to clean up the CO2 and H2S
SwHzCOyHOxHSCH 2222005080 ..
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Bruce Mayer, PE Engineering-10: Intro to Engineering
US
A P
rimary E
nerg
y P
rod
uctio
n b
y So
urce
http://www.eia.doe.gov/aer/overview.html * 2009
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Bruce Mayer, PE Engineering-10: Intro to Engineering
USA Energy Production Mix - 2008
Coal, 32.36%
Natural Gas, 28.69%
Crude Oil, 14.27%
NGPL, 3.28%
Nuclear, 11.47%
Hydro, 3.33%
Geothermal, 0.49%
Solar/PV, 0.12%
Wind, 0.70%
BioMass, 5.29%
Energy Information Administration / Annual Energy Review 2008
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt50
Bruce Mayer, PE Engineering-10: Intro to Engineering
Energy BackWork Ratio
The BIG QUESTION for Any Energy Src • For Every Unit of Energy OUTput, How Much
Energy was INput for the ENTIRE Production Stream?– In Electrical Power Generation, for the Steady-State
Condition, this is called the “BackWork Ratio”
Plant theofOutput Power
Plant Run the Power toBWR
Many Energy Sources Fail This Question• e.g., Many Solar-Electric Systems will NOT
Return the Energy Required to Make Them
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt51
Bruce Mayer, PE Engineering-10: Intro to Engineering
All Done for Today
California’sHydrogenHighWay
There were 143 H2 vehicles in
2007
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Bruce Mayer, PE Engineering-10: Intro to Engineering
A Potential Energy Scenario
[email protected] • ENGR-10_Lec-09_Chp6_Population_Energy.ppt53
Bruce Mayer, PE Engineering-10: Intro to Engineering
48.13%
21.69%
19.54%
6.18%
1.34%
1.33%
1.12%
0.36%
0.28%
0.02%
0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55%
Coal
NaturalGas
Nuclear
Hydro
Wind
Wood & BioMass
Fuel Oil
GeoThermal
Other
Solar
Fraction of Total Electrical Generation
Ele
ctr
ica
l Po
we
r So
urc
eUSA Electricity Production Mix - 2008
USA_Electricity_Mix_0810.xls
Total = 4 125 675GWhe
Source = USA Energy Information Adminsistration * http://www.eia.doe.gov/cneaf /electricity/epa/epates.html