Upload
rudolf-whitehead
View
220
Download
3
Tags:
Embed Size (px)
Citation preview
Prof. R. Shanthini Nov 12, 2012
1
An engineering example for unsustainable development
Prof. R. Shanthini Nov 12, 2012
2
How is electricity generated from
non-renewable energy sources (oil, coal or
natural gas)?
Diesel Generator
Gas Turbine (GT) Steam Turbine
(ST)
Combined Power Plant
(GT & ST)
Prof. R. Shanthini Nov 12, 2012
3
Electric Generator
Prof. R. Shanthini Nov 12, 2012
4
http://electron9.phys.utk.edu/phys136d/modules/m8/images/gen.gif
Magnet
Rotating wire loop
Electrical output
S
N
How to rotate the wire loop?
Electric Generator
We need a rotating shaft?
Prof. R. Shanthini Nov 12, 2012
5
http://www.electricityforum.com/images/motor-eout.gif
Wind turbine gives a rotating shaft
Prof. R. Shanthini Nov 12, 2012
6
Water turbine could also give a rotating shaft
Prof. R. Shanthini Nov 12, 2012
7
Diesel generator
It is a diesel engine coupled to a electric generator.
Diesel engine provides the rotating shaft.
http://www.rkm.com.au/animations/animation-diesel-engine.html
Prof. R. Shanthini Nov 12, 2012
8
Diesel generator
It is a diesel engine coupled to a electric generator.
Diesel engine provides the rotating shaft.
http://www.rkm.com.au/animations/animation-diesel-engine.html
Prof. R. Shanthini Nov 12, 2012
9
Diesel generator
http://www.myrctoys.com/engines/ottomotor_e.swf
Prof. R. Shanthini Nov 12, 2012
10
Comp-ressor
fresh air
Combustion Chamber
fuel
GasTurbine
gasesto the stack
Gen
compressed air
hot gases
Gas Turbine Power Plant
Prof. R. Shanthini Nov 12, 2012
11
Gas turbine to produce electricity
Prof. R. Shanthini Nov 12, 2012
12
Gas turbine driving a jet engine
Prof. R. Shanthini Nov 12, 2012
13
Gas Turbine Power Plant
Prof. R. Shanthini Nov 12, 2012
14
Comp-ressor
fresh air
Combustion Chamber
fuel
GasTurbine
gasesto the stack
Gen
compressed air
hot gases
Gas Turbine Power Plant
(WGT)out
(WC)in
(QCC)in
Prof. R. Shanthini Nov 12, 2012
15
Comp-ressor
fresh air
Combustion Chamber
fuel
GasTurbine
gasesto the stack
Gen
compressed air
hot gases
Gas Turbine Power Plant
(WGT)out
(WC)in
(QCC)in
Useful work output = ?
Total heat input = ?
Total energy loss = ?
Prof. R. Shanthini Nov 12, 2012
16
Gas Turbine Power Plant
Useful work output =
Total heat input =
Thermal efficiency of the GT power plant
(WGT)out
(WC)in
(QCC)in
-
(QCC)in
(WGT)out
(WC)in
-ηthermal =
goes to electricity generation
comes with the fuel
Prof. R. Shanthini Nov 12, 2012
17
= = 22 – 28%
Energy wasted:
- [ ]=
=
72 – 78% of heat released by the fuel
for 50 to 100 MW plant
(QCC)in
(WGT)out
(WC)in
-
(QCC)in
(WGT)out
(WC)in
-
ηthermal
Gas Turbine Power Plant
Prof. R. Shanthini Nov 12, 2012
18
= TC
1 - TH
Hot reservoir at TH K
Heat engine converts heat into work
Cold reservoir at TC K
ηthermal = Wout
Qin
Wout
Qin
Qout
< ηthermal
ηCarnot
ηCarnot
Prof. R. Shanthini Nov 12, 2012
19
ηCarnot =
Carnot efficiency of the GT power plant
Gas Turbine Power Plant
TC
TH
1 -Lowest temperature(exhaust gas temperature)
Highest temperature(combustion chamber temperature)
ηCarnot =
= (QCC)in
Maximum possible work output
Total heat input
Maximum possible work output ηCarnot
Prof. R. Shanthini Nov 12, 2012
20
Gas Turbine Power Plant
Second-law efficiency of GT power plant
(QCC)in
ηCarnot
= Maximum possible work output
Useful work output
= (QCC)
inηthermal
ηCarnot
= ηthermal
< 1
Prof. R. Shanthini Nov 12, 2012
21
Steam turbine
http://www.bizaims.com/files/generator.JPG
Prof. R. Shanthini Nov 12, 2012
22
SteamTurbine
Gen
Steam Turbine Power Plant
Prof. R. Shanthini Nov 12, 2012
23
C
saturated water
hot gases
SteamTurbine
Gen
compressed water
superheated steam
Condenser
Pump
cooling watersaturatedsteam
Steam Generator
Steam Turbine Power Plant
Prof. R. Shanthini Nov 12, 2012
24
R. Shanthini 15 Aug 2010
Steam turbine to produce electricity
Oil could be used instead of coal.
Steam engines are also used to power the train.
Prof. R. Shanthini Nov 12, 2012
25
Steam Turbine Power Plant
C
saturated water
Gen
compressed water
superheated steam
cooling water
(WST)out
Pump
SteamTurbine
Condenser
Steam Generator
saturatedsteam
(QSG)in
hot gases
WPin
Prof. R. Shanthini Nov 12, 2012
26
ηthermal = (WST)
out (WP)
in
(QSG)in
-= 30 – 40%
Energy wasted:
(QSG)in
- [ (WST)out
- (WP)in]
=
=
60 – 70% of heat released by the fuel
for 200 to 800 MW plant
Steam Turbine Power Plant
Prof. R. Shanthini Nov 12, 2012
27
atmosphericair
fuel
GT
gasesto the stack
C
hot gases
ST
cooling water
Combined Power Plant
Prof. R. Shanthini Nov 12, 2012
28
atmosphericair
fuel
GT
gasesto the Stack ST
C
hot gases
ST
cooling water
Combined Power Plant
Prof. R. Shanthini Nov 12, 2012
29
Combined Power Plant
Prof. R. Shanthini Nov 12, 2012
30
Combined Power Plant
Prof. R. Shanthini Nov 12, 2012
31
ηthermal = Heat released by fuel
Useful work output at GT & ST
= 36 – 50%
Energy wasted:
= 50 – 64% of heat released by the fuel
for 300 to 600 MW plant
Combined Power Plant
Prof. R. Shanthini Nov 12, 2012
32
Nuclear Power Plant
C
Pressurized water
ST
cooling water
CORE Control rods
Containment
PWR
Prof. R. Shanthini Nov 12, 2012
33
R. Shanthini 15 Aug 2010
Nuclear power plant to produce electricity
Prof. R. Shanthini Nov 12, 2012
34
= 31 – 34%
Energy wasted:
= 66 – 69% of heat released by the fuel
for 500 to 1100 MW plant
Nuclear Power Plant
ηthermal = Heat released by fuel
Useful work output at ST
Prof. R. Shanthini Nov 12, 2012
35
According to the 2nd Law of Thermodynamics
when heat is converted into work, part of the heat energy must be wasted
Power generation
type
Unit size (MW)
Energy Wasted (MW)
Diesel engine 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
36
50% - 70% lost in producing
electricity
2% - 20% lost in transmitting
electricity
Generation, transmission and end-use losses
Prof. R. Shanthini Nov 12, 2012
37
Electric power sector 70% energy losses
Transportationsector
Industrialsector
Residential & Commercial
sector
80% energy losses
25% energy losses
20% energy losses
Typical energy losses in an industrialised country
Prof. R. Shanthini Nov 12, 2012
38
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
39
EffCarnot =
TC 1 -
TH
TC
TH = Flame temperature (800oC)
= Exhaust Temperature (40oC)
EffCarnot =
313 K1 -
1073 K
71%≈
Vehicles mostly uses Internal Combustion Engines
Prof. R. Shanthini Nov 12, 2012
40
A Typical Car:
100 kJ
63 kJ
18 kJ
17 kJ
2 kJ
Engine losses in fuel energy conversion, In engine cooling and with exhaust gases
Energy for accessories
Standby Idle
Fuel Energy
6 kJ
12 kJ
Driveline losses
2.5 kJ
4 kJ
5.5 kJ
Aerodynamic drags
Rolling resistance
Braking
Source: http://www.fueleconomy.gov/feg/atv.shtml
Urban Driving
Prof. R. Shanthini Nov 12, 2012
41
A Typical Car:
100 kJ
69 kJ
25 kJ
4 kJ
2 kJ
Engine losses in fuel energy conversion, In engine cooling and with exhaust gases
Energy for accessories
Standby Idle
Fuel Energy
5 kJ
20 kJ
Driveline losses
11 kJ
7 kJ
2 kJ
Aerodynamic drags
Rolling resistance
Braking
Source: http://www.fueleconomy.gov/feg/atv.shtml
Highway Driving
Prof. R. Shanthini Nov 12, 2012
42
Take 10 mins.
Discussion Point 4:
Is there a problem in burning oil and coal to make electricity and to drive automobiles in such an inefficient manner?
Prof. R. Shanthini Nov 12, 2012
43
Carbon dioxideCarbon dioxide
Global warmingGlobal warming
Climate changeClimate change
Kyoto protocolKyoto protocoletc.etc.
Fossil fuel use Fossil fuel use
March of the Penguins March of the Penguins
Erin BrockovichErin Brockovich
The Big Ask The Big Ask
The Story of StuffThe Story of Stuff
and more…. and more….
should be watched under parental care
should be watched under parental care