An experimental study in using natural admixture as an alternative for chemic...
Unit iv wind energy
1. UNIT IV
Wind Energy
syllabus
WIND ENERGY
Sources and potentials
Horizontal and vertical axis wind mills
Performance characteristics
Betz criteria
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2. Syllabus(contd)
BIOMASS
Principles of bio conversion
Anaerobic/aerobic digestion
Types of bio gas digesters
Gas yield
Combustion characteristics of bio gas
Utilization for cooking
I.C engine operation
Economic aspects
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3. Sources and potentials of wind
energy
Wind energy is an indirect form of solar
energy
One percentage of solar radiation is
converted into wind energy
Wind resource potential in India is 34,043
MW for power generation according to
recent assessment.
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4. Installed capacity as on march 2018
State Total capacity (MW)
TAMIL NADU 8197
GUJARATH 5613
MAHARASTRA 4784
KARNATAKA 4509
RAJASTHAN 4298
ANDHRA PRADESH 3963
MADHYA PRADESH 2520
TELENGANA 101
KERELA 53
OTHERS 04
TOTAL 34043
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5. Sources and potentials of wind
energy(contd)
Wind energy in india may be considered cost
effective alternative to conventional sources of
electrical power.
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6. Wind turbines (OR) Wind mills
Wind turbines are machines that generate electricity
from the kinetic energy of the wind.
Today, turbines can be used to generate large amounts
of electrical energy in wind farms both onshore and
offshore
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7. Factors involved in site selection
for wind mills
The availability of wind with sufficient kinetic
energy
The magnitude of wind velocity should be high
The wind availability should be throughout the
year
The site should be free from obstacles
Availability of vast open land at a lower land cost
The construction materials should be available
and cheaper
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8. Factors involved in site
selection for wind mills(contd)
Availability of skilled workers
Away from the populated places but not away
from load centre.
No possibility of storms, floods, earthquakes,
volcanoes, etc.
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9. Advantages of wind mills
Free of energy cost,
No pollution,
No water required,
low operating costs etc
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10. Disadvantages of wind mills
Fluctuation in wind speed,
occupies more land,
Noisy
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11. Types of wind mills
BASED ON NO. OF ROTOR BLADES:
Single blade
Multi-blade rotors
BASED ON AXIS OF ROTATION :
Horizontal Axis wind mills (or) turbine (HAWT)
Vertical Axis wind mills (or) turbine (VAWT)
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13. Parts of wind turbine
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14. Horizontal axis wind turbine
More popular
The axis of the rotor's rotation is parallel to the wind
stream and the ground.
Most HAWTs today are two- or three-bladed,
though some may have fewer or more blades.
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15. Horizontal axis wind turbine
There are two kinds of Horizontal Axis Wind Turbines:
1. Upwind wind turbine
2. Downwind wind turbine.
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16. Advantages of Horizontal axis wind
turbine
Higher stability
The turbine collects the maximum amount of wind
energy
The ability to pitch the rotor blades in a storm so that
damage is minimized
The tall tower allows the access to stronger wind
Self-starting
Cheaper because of higher production volume
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17. Disadvantages of Horizontal
axis wind turbine
It has difficulties operating near the ground
The tall towers and long blades
Hard to transport from one place to another
They need a special installation procedure
They can cause a navigation problem when placed
offshore
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20. Vertical axis wind turbine
The vertical axis wind turbine is an old technology,
dating back to almost 4,000 years ago.
The rotor of the VAWT rotates vertically around its
axis
This is not as efficient as a HAWT,
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21. Vertical axis wind turbine
This does offer benefits in low wind situations wherein
HAWTs have a hard time operating.
It tends to be easier and safer to build,
This can be mounted close to the ground and handle
turbulence better than the HAWT.
its maximum efficiency is only 30%,
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23. Comparison between HAWT and
VAWT
HAWT VAWT
Higher cost Lower cost
Less noisy More noisy
More power from wind Less power from wind
Technology fully developed Technology under developed
More efficient Less efficient
Smooth output Fluctuating output
Low starting torque High starting torque
Operates moderate wind speed Operates even in low wind speeds
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24. Terms Used In Wind Energy
1.Wind speed:
The speed at which the wind is flowing.
2. Cut-in speed:
The minimum speed of turbine at which the
turbine starts developing power. e.g. 5 m/s
3. Cut-off (Furling) speed:
The maximum speed of turbine at which the
turbine stops developing power. e.g. 30 m/s .Its for
safe operation of wind turbine.
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25. Terms Used In Wind Energy
4. Power of wind,
P = 0.5 ρ A V3.
Where A – Swept area of rotors,
V-Velocity of wind ,
ρ– Density of air
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26. Terms Used In Wind Energy
5. Betz’ limit or law:
The theoretical maximum possible power can be
extracted from the wind energy.
Its value is 59.3% of power available in the wind.
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27. Terms Used In Wind Energy
6. Power co-efficient
Power co-efficient is the ratio of power output of
the turbine to the power available in the wind.
Power co-efficient = Power output of the
turbine/power available in
the wind
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33. Performance
characteristics(contd.,)
The ideal efficiency of 59.3% is based on Betz’s
limit.
The single rotor, Darrius rotor, multi-blade rotors
etc are given in the graph
The range of speed ratio with the power co-eff is
compared.
The three blade rotor machine performs better in
the speed ratio as well as power developed.
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35. Factors Affecting Performance of wind
turbine
various factors such as
1. location,
2. geographical factors,
3. mechanics,
4. rotor shape/ size, etc
Output can be regulated by
1. constant or variable rotational speed,
2. adjustable and non-adjustable blades.
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36. Power equation and Betz criteria
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37. Power equation and Betz criteria(contd.,)
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38. Power equation and Betz criteria(contd.,)
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39. Power equation and Betz criteria(contd.,)
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40. Power equation and Betz criteria(contd.,)
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41. Power equation and Betz criteria(contd.,)
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42. Power equation and Betz criteria(contd.,)
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43. Power equation and Betz criteria(contd.,)
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44. Power equation and Betz criteria(contd.,)
A German physicist Albert Betz
concluded in 1919 that no wind turbine
can convert more than 16/27 (59.3%) of
the kinetic energy of the wind into
mechanical energy turning a rotor.
This is known as the Betz Limit or Betz'
Law.
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45. BIOMASS
Principles of bio conversion
Anaerobic/aerobic digestion
Types of bio gas digesters
Gas yield
Combustion characteristics of bio gas
Utilization for cooking
I.C engine operation
Economic aspects
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46. Introduction
Bioenergy is the general term for
energy derived from materials such as
wood, straw or animal wastes
Bioenergy can be converted into the
following
1.biofuels
2.charcoal
3.biodiesel
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50. Biomass sources
Tropical crops wastes
1.Bagasse
2.Rise husks
Animal wastes
1.Animal manure
2.Sewage sludge
3.Poultry litter
Municipal solid waste
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51. Principles of bio conversion
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52. Principles of bio conversion
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53. Thermo-chemical conversion
Energy is produces by applying heat and chemical
processes.
1. Combustion process
2. Pyrolysis Process
3. Gasification process
4. Liquefaction process
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55. Combustion process(contd,.)
Combustion is an exothermic chemical reaction,
in which biomass is burned in the presence of air.
The chemical energy which is stored in the
biomass is converted in the mechanical and
electrical energies.
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57. Pyrolysis Process( contd,.)
It is the process of conversion of
biomass to liquid (bio-oil), solid
(charcoal) and gaseous (fuel gases)
products by heating in the absence
of air at 500 °C.
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58. Gasification process
In biomass gasification, charcoal,
wood chips, energy crops, forestry
residues, agricultural waste and
other wastes are transformed into
flammable gases at high
temperature (800-1000°C).
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60. Gasification process
The Fischer–Tropsch reactor
process is a collection of chemical
reactions that converts a mixture
of CO and H2 into
liquid Hydrocarbons
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61. Liquefaction process
It is the process in which
biomass is converted into liquid
phase at low temperatures (250-
350 °C) and high pressures (100-
200 bar).
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63. Liquefaction process(contd,.)
Fermentation is a
metabolic process that produces
chemical changes in organic
substrates through the action of
enzymes
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64. Bio-Chemical conversion
Biochemical conversion makes use of
the enzymes of bacteria and other living
organisms to break down biomass and
convert it into fuels.
1.Anaerobic digestion process
2. fermentation
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66. Anaerobic digestion process
This is a process in which organic
material directly converted to a gas
which is termed as biogas.
It is mixture of methane, carbon dioxide
and other gases like hydrogen sulphide
in small quantities.
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67. Anaerobic digestion process
Biomass is converted in anaerobic
environment by bacteria,
which produces a gas having an energy
of 20-40% of lower heating value of the
feedstock.
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69. Fermentation process
Fermentation is an anaerobic process
that breaks down the glucose within
organic materials.
It is a series of chemical reactions that
convert sugars to ethanol.
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70. Fermentation process
The basic fermentation process involves
the conversion of a plant’s glucose (or
carbohydrate) into an alcohol or acid.
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71. Biogas
The biogas is used for cooking, domestic
lighting and heating, run I.C. Engines
and generation of electricity for use in
agriculture and rural industry.
Family biogas plants usually of 2-3 m^3
capacity.
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72. Biogas
Biogas contains
55-65% methane,
30-40% carbon dioxide
The rest being H2,H2S and some N2
Biogas can be produced from the
decomposition of animal, plant and human
waste.
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73. Raw materials
Cow dung
Sewage
Crop residues
Vegetable wastes
Water hyacinth
Poultry droppings
Pig manure
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74. Advantages
The initial investment is low for the
construction of biogas plant.
The technology is very suitable for rural areas.
Biogas is locally generated and can be easily
distributed for domestic use.
Biogas reduces the rural poor from
dependence on traditional fuel sources, which
lead to deforestation
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75. Advantages
The use of biogas in village helps in improving
the sanitary condition and checks
environmental pollution.
The by-products like nitrogen rich manure
can be used with advantage.
Biogas reduces the drudgery of women and
lowers incidence of eye and lung diseases
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76. Biogas generation
Digestion is biological process that occurs in
the absence of oxygen and in the presence of
anaerobic organisms at temperatures (35-70ºc)
and atmospheric pressure.
The container in which, this process takes
place is known as digester.
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77. Biogas generation
Most organic materials undergo a natural
anaerobic digestion in the presence of moisture
and absence of oxygen and produce biogas.
The biogas so obtained is a mixture of methane
(CH4): 55-65% and Carbon dioxide (CO2): 30-40%.
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78. Anaerobic digestion:
The treatment of any slurry or sludge
containing a large amount of organic
matter utilizing bacteria and other
organisms under anaerobic condition is
commonly referred as anaerobic
digestion or digestion.
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79. Anaerobic digestion(phases)
The three stages are
(i). The enzymatic hydrolysis,
(ii). Acid formation and
(iii). Methane formation.
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80. The enzymatic hydrolysis
Where the fats, starches and proteins contained
in cellulosic biomass are broken down into simple
compounds
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81. Acid formation
The micro organisms of facultative and anaerobic
group collectively called as acid farmers,hydrolyse
and ferment, are broken to simple compounds
into acids
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82. Methane formation
Where organic acids are converted into
methane(CH4) and carbon dioxide(CO2).
(C6H10O5)n + nH2O ==== 3nCO2+3nCH4
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83. Advantages of anaerobic digestion
1.Calorific value of gas
2.New sludge production
3.Stable sludge
4.Low running cost
5.Low odour
6.Stability
7.Value of sludge
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84. Classification of biogas plants
1. Continuous and batch types
2. The dome and drum types
3. Different variations in the drum type
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85. Continuous and batch types
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95. Types of biogas plants(digesters)
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96. Utilization of biogas
1. House hold cooking
2. Lighting
3. Operating small engines
4. Utilizing power for pumping water
5. Grinding flour
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97. IC ENGINE OPERATION USING BIOGAS
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