Power Generation Thermodynamics

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Power Generation

Thermal Power Pants and their working CyclesHydal Power Plants, run of river, accumulation type, turbines &

stations

Necular Power Plants, reactors, radiation damages.

Thermo Electric, MHD

PV Generators, working principles, Design Specifications

Fuel Cells, working principles

Wind Power Generation


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Power Generation

Recommended Books

Principles of Energy Conversion by Arche W. Culp, Latest Edition

Power Plant Technology by M.M Wakel, Latest Edition


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Power Generation

Quizzes 5

Assignments/ Reports 5

Lab Work/ Experiments

Every student have to pick a topic (Given) and write up a 4-5 pages

comprehensive report at the end of semester+ Presentation of 5-6

Slides.


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Power Generation Thermodynamics

Energy & Life

All Living on Planet Earth Needs Energy.

Food, Sun Radiations,

Modern civilization can only thrive if existing sources

can meet the rising change.

Energy exist in many forms from Atoms of matters to

Radiations of Sun.

Many Sources of Energy known Un known,Transform of Energy fro One form to Other


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Energy

Chemical Energy of Combustion ofFossil Fuels (Oil, Gas, Coal)

Waste (Agriculture, Domestic, Commercial)

Used to produce heat which in turns produce Mechanical Energy in

Turbines or Pumps.Advantages & Disadvantage

Potential Energy of Water is converted into Mechanical Energy on

Run ofRiver or Storage Dams.

Uranium Atoms are bombarded asunder & Nuclear Energy is

Released as heat


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Power Generation ThermodynamicsEnergy

Kinetic Energy of Air is harnessed by Wind Mills to produceElectricity.

Energy of Waves of See is Converted into Electrical Energy byfloating turbines.

Geo Thermal Energy under Earth crest s used to roduce ElecricalEnergy.

Immense Radiations of Sun are tapped to produce heat well asElectricity.

Power Kites are Seeming successful poducing MW Generation.


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Power Generation ThermodynamicsNew Energy Horizon

To Cop With upcoming Energy Crises &R

isisng Energy Demandsfollowing fields are currently under devolpement are migh be stateof the art in upcoming Decades.

Geo Magnets

Gravity EnergyCold Fusion

Photon fired power plats

Photosynthesis

Hydrogen Devolvement


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Applied Thermodynamics

Science Deals With Heat, Work & Properties of SystemIt is concerned with means necessary to convert heat from

available sources (Fossil fuels) into Mechanical Energy.

Heat

Form of Energy, transformable from one body to other.Thermal Equilibrium.

System

Collection of matter with Identifiable boundaries.

e.g cylinder of engine during Expansion Stroke


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Close System

Heat Engine

Open System

Fluid in turbine

Pressure

The pressure of system is the force on unit area f its boundries

Pascal 1Pa= 1N/m2

1 bar = 105 N/m2 = 105 Pa


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Multiples and sub multiples

Multiplying Factor Prefix Symbol

1012 Tera T

109 Giga G

106 Mega M

103 Kilo K

10-3 mili m

10-6 micro u

10-9 nano n

10-12 pico p


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1st Law of Thermodynamics

When a system goes into complete cycle net heat supplied + network input is zero.

Q+ W=0

2nd Law of Thermodynamics

In any Complete cycle the gross heat supplied + net work input

must be grater than zero.

Q1 > -W


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Forward Heat Engine

First Law of Thermodynamics

Q1+Q2+W=0

Second Law of Thermodynamics

Q1 > -W

100 unit > -30 Units

Cycle Efficiency

= -W/ Q1

= 30/100 = 0.3


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Reversed Heat Engine

First Law of Thermodynamics

Q1+Q2+W=0

Second Law of Thermodynamics

It is impossible to construct a device

that

operating in cycle will produce no effect

Other than the transfer of heat from a cooler body to hotter

body.


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Conventional Power Plant:

Receiving fuel energy (F)Producing Work (W)

Rejecting Heat (QA)

Basic Power Plant


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Objectives:

Least fuel Input for Given outputEconomically beneficial

Minimizing fuel cost

Key Objective

Capital Cost of Achieving High efficiency has to be accessed

And balanced against resulting saving in fuel costs.


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Conventional Power Plant

Closed Cyclic Power Plant (Heat Engines)

Open Circuit Power Plants

Discussion is restricted to plants in which flow is steady


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Power Generation ThermodynamicsClosed Cyclic Power Plant (Heat Engines):

Fluid passes continuously round a closed circuit

Through a thermodynamic cycle

Heat QB is received from source at THigh

Heat QA is Rejected to sink at Tlow

Work (W) output


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Fig. 2 Closed Circuit gas turbine Power Plant


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Dotted Chain Control Surface Y surrounds

Cyclic Gas turbine

Compressor

Heater

Cooler

Power to Generator

Dotted Chain Control Surface Z surrounds

Open Control Surface

Combustion Chamber

Air fuel Mixture

Exhaust Gases


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Air fuel input

Heat is produced in Combustion Chamber

Heat QB is transferred from Z to Y

Exhaust gases


Cyclic Gas turbine

Compressor

Heater

Cooler

Power to Generator


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Air fuel input

Heat is produced in Combustion Chamber

Heat QB is transferred from Z to Y

Exhaust gases


Cyclic Gas turbine

Compressor

Heater

Cooler

Power to Generator

Turbine


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Open Circuit Gas Turbine Plant

Usually Gas Turbine Operate n Open Circuit with Internal Combustion

Burning n Combustion Chamber

Turbine done work

Compressor is al being run by Turbine

Exhaust Gases.

Performance is accessed by treating it as equivalent to closed cyclic power

plant but with most care


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The Joule-Brayton (JB) Constant Pressure

The Constant Pressure Closed cycle is the basis of the cyclic gas

turbine power plant, with steady flow of air(or gas) through a

compressor, heater, turbine, cooler, within closed circuit.

Heat is supplied at constant pressure and rejected at constant

pressure.


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Combined Plants

UpperTapping Thermodynamic cycle

Produces power, but part of all its heat

Rejected Is used in supplying heat to

bottom cycle.

The Upper is Open Circuit Gas Turbine

Lower is closed Gas Tubine

Togater they form

Combind cycle gas turbine (CCGT) plant.


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Combined Plants

The objective of combining two power

plants in this way is to obtain greater

Work output for a given supply of heat

or fuel energy.

This is achieved by converting some of

the heat rejected by the upper plant into extra work in thelower plant.


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Power Generation ThermodynamicsCombined Heat & Power Plants (CHP)

The term cogeneration is sometimes used

to describe a combined power plant,

but itis better used for a

combined hear and power (CHP)plant.

Now the fuel energy is converted

partly into (electrical) work (W)

and partly into useful heat (Qu)t a low

temperature, But higher than ambient.The non-useful heat rejected is Qw.


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Power Generation ThermodynamicsCriteria for the performance of power plants

Closed Cycle Power Plant

For a cyclic gas turbine plant in which fluid

is circulated continuously within the plant

(e.g. the plant enclosed within the

control surface Y).

one criterion ofperformance is simply

the thermal or cycle efficiency.

= W/ QB

W= net workQB is heat supplied,

W & QBis may be measured for a Mass of

Fluid M


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Closed Cycle Power Plant

The heat supply to the cyclic gas turbine

power plant, comes from the control

surface Z.

Within this second control surface,

a steady-flow heating device is supplied

With reactants (fuel and air) and it

discharges the products of combustion.

We may define a second efficiency for the 'heating device'(or boiler) efficiency;

= QB/ F = QB/Mf [CV]o


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[CV], is its calorific value per unit mass of fuel for the

ambient temperature (To at which

the reactants enter.

Mf[CV] = [-AH0] = HR0 Hpo, Change in Enthapy


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Overall Efficiency

0= W/ F =(W/ QB)(QB/ F)


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Power Generation ThermodynamicsEfficiency of an Open Circuit Gas Turbine Plant

For an open circuit (non-cyclic) gas turbine plant a different criterion

of performance is sometimes used-the rational efficiency (m)

This is defined as the ratio of

the actual work output to the maximum work output that can be

achieved between the reactants, each at pressure (po) and

temperature (To) of the environment, and products each at the same

po, To. Thus

R= W/ Wmax


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Power Generation ThermodynamicsIdeal Carnot Power Plant

The second law of thermodynamics may be used to show that a cyclic

heat power plant (or cyclic heat engine) achieves maximum efficiencyby operating on a reversible cycle

called the Carnot cycle for a given (maximum) temperature of supply

(T-) and given minimum) temperature of heat rejection (Tmin).Such a

Carnot power plant receives all itsheat (QB) at the maximum temperature @.e. TB = Tmin) and rejects all

its heat(QA) at the minimum temperature (i.e. TA = Tmin); the other

processes are reversible and adiabatic

CAR= W/ QB =(QB- QA / QB)=(QB- QA / QB)

(Tmax-Tmin)/Tmax


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Power Generation ThermodynamicsIdeal Carnot Power Plant

The Carnot engine (or cyclic power plant) is a useful

hypothetical device in the study of the thermodynamics of

gas turbine cycles, for it provides a measure of the best

performance that can be achieved under the given

boundary conditions of temperature.

In his search for high efficiency,

the designer of a

gas turbine power plant will attempt

to emulate these features of the Carnot cycle.

Power Generation Thermodynamics

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