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Wind Energy is the energy contained in the force

of the winds blowing across the earth¶s surface.

Wind is created when air that has been warmed

over sun heated land rises, leaving a vacuum in

the space it once occupied.

Cooler surrounding air then rushes in to fill the

vacuum. This movement of rushing air is whatwe know as wind.

What is wind energy?



WIND TURBINE



i) Horizontal Axis Windmills

(a) Multi blade type windmill (b) Sail type

windmill (c) Propeller type windmill.

ii) Vertical Axis Windmills

(a) Savonius type windmill (b) Darrieus type

windmill.

TYPES OF WINDMILLS



Following factors should be considered while locating Wind

Energy Conversion Systems (WECS).

i. Wind energy conversion machines should be installed at sites

where winds are strong and persistent. The most suitable sitesfor wind turbines would be found where the annual average

wind speeds are known to be moderately high. It is desirable to

have average wind speed of about 3.5 -4.5 m/sec, which is the

lower limit at which WECS generators start turning. An ideal

site will be one where a smooth steady wind flows all the time.

ii. It is desirable to install WECS at higher altitudes because the

winds tend to have higher velocities at higher altitudes.

SITE SELECTION FOR WIND MILL



iii. The ground conditions at the site should be such that

the foundations for WECS are secured. The land costshould be low.

iv. Icing problem, salt spray or blowing dust should not

be present at the site as they affect aero turbing

blades.

v. The site selected should be near to the users of

generated electric energy.

vi. The site should be near to the road or railwayfacilities. The best sites for wind energy systems are

found off shore and the seacoast and at mountains.



The wind electric plants should make use of wind energy in the best

possible method. The overall efficiency of an aero-generator is calculated

as follows:

= A. g. e Gen

= overall conversion efficiency of an aero-generator.

g = Efficiency of gearinge = efficiency of coupling

Gen = efficiency of generator

A = efficiency of aerotubine

Useful shaft power output = Cp

Wind power input

Where Cp = coefficient of performance

PERFORMANCE OF WIND MACHINES



Single blade type windmill Multi blade type windmill



Darrieus type windmill Drag Type Vertical Windmill



MULTI BLADE TYPE WINDMILL



The wind blows day and night, which allows windmills to produce

electricity throughout the day. (Faster during the day)

Energy output from a wind turbine will vary as the wind varies,

although the most rapid variations will to some extent be

compensated for by the inertia of the wind turbine rotor. Wind energy is a domestic, renewable source of energy that

generates no pollution and has little environmental impact. Up to 95

percent of land used for wind farms can also be used for other

profitable activities including ranching, farming and forestry.

The decreasing cost of wind power and the growing interest inrenewable energy sources should ensure that wind power will

become a viable energy source in the United States and worldwide.

Advantages of Wind Power



� Tide is periodic rise and fall of water level of the sea. In

about 24 hours there are two high tides and two low tides.

� The difference between high and low water levels is

called the range of the tide.

� Tides occur due to the attraction of seawater by themoon.

� These tides can be used to produce electrical power

which is called tidal power.

� World¶s first tidal power plant was commissioned at

Rance in France. This plant is 1240 MW capacity.

TIDAL POWER



The tidal range at the desired location should be adequate throughout the year.

The site selected for tidal power plant should

be free from the wave attack of sea.

There should be no appreciable change in tidal

pattern at the proposed site.

The site at which tidal power plant is to be

located should not have excessive sediment

load.

SELECTION OF LOCATION OF TIDAL POWER PLANT



� Tidal power plants are classified on the basis of number of

basin used for the power generation. They are further

subdivided as one way or two way system as per the cycle of

operation for power generation. Various types of power plants

are as follows:

� i. Single basin systema) One way system

b) Two way system

c) Two way with pump storage.

� ii. Double basin system

a) Simple double basin system

b) Double basin with pumpling.

CLASSIFICATION



SINGLE BASIN TWO WAY DOUBLE BASIN ONEWAY



Single basin system Two way system



� It is free from pollution.

� It is inexhaustible and does not depend on rain.

� Tidal power plants do not require large area of

valuable land because they are located on seashore.

� Tidal power has a unique capacity to meet peak

power demand effectively when it works in

combination with hydropower plant or thermal power plant

Advantages



� The output varies because of variation in tidal range.

� The power transmission cost is high because the tidal power

plants are located away from load centers.

� Sedimentation of basins are the problems associated with tidal power plants.

� The turbines have to work on a wide range of variable head

because of variable tidal range.

�Capital cost of the plant is high.

Disadvantages



Geothermal energy



� Geothermal energy is heat transported from the interior of theearth.

� It is recoverable in some form such as steam or hot water.

� The earth is said to have been created as a mass of liquids and

gases, 5 to 10 percent of which was steam.

� As the fluids cooled, by losing heat at the surface, an outer

sold crust formed and the steam condensed to form oceans and

lakes in depressions of that curst.

� The crust now averages about 20 mi (32 km) in thickness.

Below that crust, the molten mass, called magma, is still in the process of cooling.

Geothermal energy



1. Hydrothermal convective systems:

These are again sub-classified as:

i) Vapour -dominated or dry steam fields.

ii) Liquid-dominated system or wet steam fields, andiii) Hot-water fields.

2. Geo pressure resources.

3. Petro-thermal or Hot dry rocks (HDR).

4. Magma resources.

5. Volcanoes.

GEOTHERMAL SOURCES



� Geothermal sources are therefore of three basic kinds

(1) hydrothermal,

(2) geopressured,

(3) petrothermal.

Hyper-Thermal Fields

1. Wet fields. Where the water is pressurized and temperatures are above

1000C. when they are led to the surface a fraction will be splashed into

steam and a major part remains as the boiling water.

2. Dry fields. They produce dry saturated steam or superheated steam at

pressure above atmospheric.

(b) Semi-Thermal Fields

These are capable of producing hot water at temperature above 1000C.

Geothermal sources



Resources in high-pressure steam fields

Dry steam power plantSingle flash steam power plant

Double flash power plant

Binary cycle power plant

Technologies for geothermal

resource exploitation



It is common practice to reinject the spent fluid, to

prevent the falling fluid

pressures and make theresource more sustainable

Dry steam plant is thesimplest. Most common andmost commercially attractive

Dry steam power plant



TEMPERATURE Vs ENTROPY



Single flash steam power plant

Geothermal fluid reaching the

surface may be wet steam

A separator is installed simply to

protect the turbine from a

massive influx of water

Avoid flashing in the well that

lead to a rapid build-up of scale

deposits as minerals dissolved inthe fluid come out of solution,



Geo pressure resources



� Biomass, a renewable energy source, is biological

material derived from living, or recently living

organisms, such as wood, waste, and alcohol fuels.

�Biomass energy is derived from three distinctenergy sources: wood, waste, and alcohol fuels.

� Biomass can be converted to other usable forms of

energy like methane gas or transportation fuels like

ethanol and biodiesel.

BIOMASS



Thermal conversion( Combustion, Pyrolysis, Gasification)

Biochemical conversion

(aerobic digestion ,anaerobic digestion, fermentation)

Chemical conversion

Biomass conversion



� Biomass gasifiers are devices performingthermo chemical conversion of biomass

through the process of oxidation and reduction

under sub stochiometric conditions.

� These, as sources of combustible gas for

energizing internal combustion engines, have

been in existence for nearly half a century.

� Gasifiers are broadly classified into updraft,

downdraft and cross draft types depending

on the direction of airflow.

BIOMASS GASIFIER



R aw Materials for Gasification



UPDR AFTGASIFIER DOWNDR AFTGASIFIER



CR OSSDR AFT GASIFIER



ADVANTAGES

�Suitable for biomass gasification� Low Tar Yield

� High Carbon Conversion

� Low Ash Carry Over

�Simple Construction and Operation

DISADVANTAGES

� High

Gas Exit Temperature

� Uniformly Sized Feed Stock

� Limited Moisture Content of Feed (H2O<30%)

THROAT TYPE DOWNDRAFT GASIFIER



TECHNICAL SPECIFICATIONSTECHNICAL SPECIFICATIONS

OF THE DOWNDRAFT GASIFIEROF THE DOWNDRAFT GASIFIER



BIOGAS

� Biogas is produced by the decomposition of animal wastes,

plant wastes and human wastes.

� It is produced by digestion, pyrolysis or hydro-gasification.

� Digestion is a biological process that takes place in the

absence of oxygen and in the presence of aerobic organisms at

ambient pressure an temperature of 35-700C.

� The container used for digestion process is called digester.

� There are two significant temperature zones in an aerobic

digestion.

� It is observed that two types of micro-organisms mesophilic

and thermophilic are responsible for digestion at the twotemperature ranges.

� The optimum mesophilic temperature is around 350C while

optimum thermophilic temperature is about 550C.



CLASSIFICATIONOF BIO-GAS PLANTS

� Various types of biogas plants are as follows

i) Continuous and batch type

ii) The dome and drum type

Continuous and batch type

�The continuous process may be completed in a single stage or separated into two stages.

� In the digester the entire process of conversion of complex

organic compounds into biogas is completed in a single

chamber.

� This chamber is regularly fed with raw materials while the

spend residue keeps moving out.



Bio Gas Composition

Particulars Rice Husk Wood Biomass

CO 15-20% 15-20%

H 2 10-15% 15-20%

CH 4 Upto 4% Upto 3%

N 2 45-55% 45-50%

CO2 8-12% 8-12%

Gas C.V. (kcal/Nm3

) Above 1050 Above 1100 Gas generated in

Nm3 /kg of biomass

2 2.5



K VIC Digester for Gobar Gas Generator



K VIC Digester forGobarGas Generator

Construction of the gas plant can be understood broadly from fig.(7). It mainly

consists of two main parts:

1. Digester or pet,

2. The gas holder or the gas collector.

Digester

� Also called as the fermentation plant, it is sort of well of masonry work,

dug and built below the ground level.

� The depth of this well varies from 3.5 meters to 6 meters, and diameter

from 1.35 meters to 6 meters, depending upon the gas generating capacity

and the quality of raw material fed each day.

� The digested well is divided vertically into two semi-cylindrical

compartments by means of a partition wall in the centre.

� The partition wall is lower than the level of the digester rim and hence it is

submerged in slurry when the digester¶ full.

� Two slanting cement pipes reach the bottom of the well on either of the

partition wall.



� One pipe serves as the inlet and the other a outlet. An inlet

chamber near the digester at surface level serves for mixing

dung and water which is done mechanically or manually.� The mixture of dung and water in proportion of 4:5 by volume,

called slurry flows down the inlet pipe to the bottom of the

primary compartment of the digester. The digester is designed

to hold 60 days raw materials.

� This ensures enough stay time of the input material for

complete digestion. The outlet chamber is again at surface

level, just a few cms below the level of the inlet chamber.

� If both compartments of the digester are full an if more slurry

is added from the inlet, then an equivalent the digester are fulland if more slurry is added from the inlet, then an equivalent

amount of fermented slurry out of the outlet and discharged

into composite pit.



Gas Holder

� It is a drum constructed of mild steel, sheet, cylindrical in

shape with a conical top and radial supports at the bottom.

� It fits into the digester like a stopper. It sinks into the slurrydue to its own weight and rests upon the ring constructed for

this purpose.

� The gas is generated the holder rises and floats freely on the

surface of the slurry. As pipe is provided at the top of theholder for flow of gas for usage.

� To prevent the holder from tilting a central guide pipe is fitted

to frame and is fixed at the bottom in the masonary work.

� The pressure under which the gas is generated in this

arrangement varies between 7-9 cms of water column. The

holder also acts as a seal for the gas.

� The cost of the holder constitutes almost 40 per cent of the

digester.



CHINESE DIGESTER (JANTA BIOGAS PLANTS)

Chi Di (J Bi Pl )



Chinese Digester (Janta Biogas Plants)

� Chinese have mainly gone into biogas technology for the sake of fertilizer

with biogas as by product. When about 5,00,000 biogas plants exists in

India, China has gone very much ahead with more than about 20 million

plant (1988 data).

� The Chinese design is quite different from that of K VIC.

� The Chinese design contains a fixed dome for the collection of the gas and

hence the gas availability is at variable pressures.

� The cost of the design is very much low and the construction is easier.

� As an illustration, it can be said that 2 cu m plant of Chinese type can be

constructed at a cost of about Rs.3,000, where the K VIC may cost around

Rs.6,000 for the same capacity.

� The difference in cost may vary for different capacities but yet the Chinese

type is cheaper.

� The fixed dome is made of masonry and this replaces the floating drum of

K VIC digester. Generally, the pressure of the gas that exists in K VIC

plants is about 15 cm of water while a pressure of even 70 cm, of water in

Chinese type of design is not uncommon.



FIXED DOME

ANAEROBICDIGESTER FIXED DOME



ANAER OBICDIGESTER FIXED DOME

The fixed dome is made of masonry structure.

� The digestion takes places in the masonry well.

� The gas generated is taken out from the top. A removable man hole cover

sealed with clay is provided.

� The generation of gas in biogas plants depends upon the following factors:

i) pH or Hydrogen ion concentration.

ii) Temperature.

iii) Loading rate.

iv) Seeding

v) Solid content of the feed material.

vi) Type of feed stocks.

vii) Nutrients.viii) Pressure.

ix) Stirring and mixing of the contents of the digester.

x) Acid forming and methane forming bacteria.

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