Transcript Slide 1

An engineering example for
unsustainable development
Prof. R. Shanthini
Nov 12, 2012
1
How is electricity
generated from
non-renewable energy
sources (oil, coal or
natural gas)?
Diesel
Generator
Gas Turbine
(GT)
Prof. R. Shanthini
Nov 12, 2012
Combined
Power Plant
(GT & ST)
Steam Turbine
(ST)
2
Electric Generator
Prof. R. Shanthini
Nov 12, 2012
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Electric Generator
We need a
rotating shaft?
Electrical
output
N
Rotating
wire loop
Magnet
S
How to rotate the
wire loop?
Prof. R. Shanthini
Nov 12, 2012
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http://electron9.phys.utk.edu/phys136d/modules/m8/images/gen.gif
Wind turbine gives a rotating shaft
Prof. R. Shanthini
Nov 12, 2012
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http://www.electricityforum.com/images/motor-eout.gif
Water turbine could also give a rotating shaft
Prof. R. Shanthini
Nov 12, 2012
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Diesel generator
It is a diesel engine coupled to a electric generator.
Diesel engine provides the rotating shaft.
Prof. R. Shanthini
Nov 12, 2012
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http://www.rkm.com.au/animations/animation-diesel-engine.html
Diesel generator
It is a diesel engine coupled to a electric generator.
Diesel engine provides the rotating shaft.
Prof. R. Shanthini
Nov 12, 2012
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http://www.rkm.com.au/animations/animation-diesel-engine.html
Diesel generator
Prof. R. Shanthini
Nov 12, 2012
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http://www.myrctoys.com/engines/ottomotor_e.swf
Gas Turbine Power Plant
fuel
compressed
air
Compressor
Combustion
Chamber
hot
gases
Gas
Turbine
Gen
fresh
air
Prof. R. Shanthini
Nov 12, 2012
gases
to the
stack
10
Gas turbine to produce electricity
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Nov 12, 2012
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Gas turbine driving a jet engine
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Nov 12, 2012
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Gas Turbine Power Plant
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Nov 12, 2012
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Gas Turbine Power Plant
(QCC)
in
fuel
compressed
air
Combustion
Chamber
Compressor
hot
gases
(WGT)
out
Gas
Turbine
(WC)
in
fresh
air
Prof. R. Shanthini
Nov 12, 2012
Gen
gases
to the
stack
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Gas Turbine Power Plant
(QCC)
in
fuel
compressed
air
Combustion
Chamber
hot
gases
Compressor
(WGT)
out
Gas
Turbine
(WC)
in
fresh
air
Prof. R. Shanthini
Nov 12, 2012
Useful work output = ?
Total heat input = ?
Total energy loss = ?
Gen
gases
to the
stack
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Gas Turbine Power Plant
Useful work output = (WGT)
(WC)
in
out
Total heat input = (QCC)
goes to
electricity
generation
in
comes with the fuel
Thermal efficiency of the GT power plant
ηthermal =
Prof. R. Shanthini
Nov 12, 2012
(WGT)
out
- (WC)
(QCC)
in
in
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Gas Turbine Power Plant
ηthermal =
(WGT)
out
(QCC)
Energy wasted:
= (QCC)
- (WC)
in
-
in
= 22 – 28%
in
[ (W
GT)
out
- (WC) in
]
= 72 – 78% of heat released by the fuel
Prof. R. Shanthini
Nov 12, 2012
for 50 to 100 MW plant
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Heat engine converts heat into work
Hot reservoir at TH K
Qin
Wout
Qout
ηthermal
Wout
=
Qin
ηCarnot = 1 -
TC
TH
ηthermal < ηCarnot
Cold reservoir at TC K
Prof. R. Shanthini
Nov 12, 2012
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Gas Turbine Power Plant
Carnot efficiency of the GT power plant
ηCarnot = 1 -
TC
TH
Lowest temperature
(exhaust gas temperature)
Highest temperature
(combustion chamber temperature)
ηCarnot =
Maximum possible work output
Total heat input
Maximum possible work output =
Prof. R. Shanthini
Nov 12, 2012
ηCarnot (QCC)
in
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Gas Turbine Power Plant
Second-law efficiency of GT power plant
=
Useful work output
Maximum possible work output
ηthermal (QCC)
=
ηCarnot (QCC)
in
ηthermal
= η
Carnot
Prof. R. Shanthini
Nov 12, 2012
in
<1
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Steam turbine
Prof. R. Shanthini
Nov 12, 2012
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http://www.bizaims.com/files/generator.JPG
Steam Turbine Power Plant
Steam
Turbine
Gen
Prof. R. Shanthini
Nov 12, 2012
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Steam Turbine Power Plant
hot gases
compressed Steam Generator
water
superheated
steam
Steam
Turbine
Pump
C
Gen
Condenser
saturated
water
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Nov 12, 2012
cooling water
saturated
steam
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Steam turbine to produce electricity
Oil could be used
instead of coal.
R. Shanthini
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Aug
Prof.
R.2010
Shanthini
Nov 12, 2012
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Steam engines are also used to power the train.
(QSG)
Steam Turbine Power Plant
in
hot gases
compressed Steam Generator
water
Pump
C
WP
in
superheated
steam
(WST)
out
Steam
Turbine
Gen
Condenser
saturated
water
Prof. R. Shanthini
Nov 12, 2012
cooling water
saturated
steam
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Steam Turbine Power Plant
ηthermal =
(WST)
out
(QSG)
- (WP)
in
= 30 – 40%
in
Energy wasted:
= (QSG) in-
[ (W
ST)
out
- (WP)
in
]
= 60 – 70% of heat released by the fuel
Prof. R. Shanthini
Nov 12, 2012
for 200 to 800 MW plant
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Combined Power Plant
fuel
GT
atmospheric
air
hot gases
gases
to the
stack
ST
C
cooling water
Prof. R. Shanthini
Nov 12, 2012
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Combined Power Plant
fuel
GT
atmospheric
air
hot gases
gases
to the
Stack ST
ST
C
cooling water
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Nov 12, 2012
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Combined Power Plant
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Nov 12, 2012
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Combined Power Plant
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Nov 12, 2012
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Combined Power Plant
ηthermal = Useful work output at GT & ST
Heat released by fuel
= 36 – 50%
Energy wasted:
= 50 – 64% of heat released by the fuel
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Nov 12, 2012
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for 300 to 600 MW plant
Containment
CORE
Pressurized water
C
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Nov 12, 2012
Nuclear Power Plant
Control
rods
PWR
ST
cooling water
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Nuclear power plant to produce electricity
R. Shanthini
15
Aug
Prof.
R.2010
Shanthini
Nov 12, 2012
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Nuclear Power Plant
ηthermal =
Useful work output at ST
Heat released by fuel
= 31 – 34%
Energy wasted:
= 66 – 69% of heat released by the fuel
Prof. R. Shanthini
Nov 12, 2012
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for 500 to 1100 MW plant
According to the
2nd Law of Thermodynamics
when heat is converted into work,
part of the heat energy must be wasted
Power generation
type
Diesel engine
Unit size
(MW)
Energy Wasted
(MW)
10 - 30
7 – 22
Gas Turbine
50 - 100
36 – 78
Steam Turbine
200 - 800
120 – 560
Combined (ST & GT)
300 - 600
150 – 380
Nuclear (BWR & PWR)
500 - 1100
330 – 760
Prof. R. Shanthini
Nov 12, 2012
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50% - 70% lost
in producing
electricity
2% - 20% lost
in transmitting
electricity
Prof. R. Shanthini
Nov 12, 2012
Generation, transmission
and end-use losses
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Electric
power sector
Typical energy losses in an
industrialised country
70% energy losses
Transportation
sector
80% energy losses
Residential
& Commercial
sector
25% energy losses
Industrial
sector
20% energy losses
Prof. R. Shanthini
Nov 12, 2012
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A user of a car always asks for some
minimum requirements while using a car.
- The drive should be smooth and easy
- The car should maintain a good speed so as
to cope up with other cars in traffic
- Easy and fast refuelling of cars
- A good mileage
- Less pollution
Prof. R. Shanthini
Nov 12, 2012
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Vehicles mostly uses Internal Combustion Engines
EffCarnot = 1 - TC
TH
TH
TC
= Flame temperature (800oC)
= Exhaust Temperature (40oC)
313 K
EffCarnot = 1 1073 K
≈ 71%
Prof. R. Shanthini
Nov 12, 2012
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A Typical Car:
63 kJ
Fuel
Energy
Engine losses in fuel energy conversion,
In engine cooling and with exhaust gases
6 kJ
Driveline losses
18 kJ
100 kJ
2.5 kJ
Aerodynamic
drags
4 kJ
Rolling
resistance
5.5 kJ
Braking
12 kJ
17 kJ
2 kJ
Prof. R. Shanthini
Nov 12, 2012
Urban Driving
Standby Idle
Energy for
accessories
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Source: http://www.fueleconomy.gov/feg/atv.shtml
A Typical Car:
69 kJ
Fuel
Energy
Engine losses in fuel energy conversion,
In engine cooling and with exhaust gases
5 kJ
Driveline losses
25 kJ
100 kJ
11 kJ
Aerodynamic
drags
7 kJ
Rolling
resistance
2 kJ
Braking
20 kJ
4 kJ
2 kJ
Prof. R. Shanthini
Nov 12, 2012
Highway Driving
Standby Idle
Energy for
accessories
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Source: http://www.fueleconomy.gov/feg/atv.shtml
Discussion Point 4:
Is there a problem in burning oil and
coal to make electricity and to drive
automobiles in such an inefficient
manner?
Take 10 mins.
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Nov 12, 2012
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March
of the
Penguins
Fossil
fuel
use
Erin Brockovich
CarbonThe
dioxide
Big Ask
Global
warming
The Story
of Stuff
more….
Climateand
change
Kyoto protocol
etc.
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Nov 12, 2012
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