Must hybrid power generation station {wind turbine(hawt)&solar (pv)}
1. 1
Misr University for Science & Technology
Faculty of Engineering
Mechanical Engineering Department
Graduation project (2017/2018)
Must Hybrid Power Generation System
{Wind turbine (HAWT) & Solar (PV)}
Project Students
Ahmed Ayman Gelany 52287
Ahmed El–Montasser Saad 46484
Amr Mohsen Galal 46591
Mohammed Ahmed Ramadan 51640
Under Supervision
Dr/Mohamed Ahmed Aziz
General Supervision
Prof/Mohamed M.M. El–Refaee
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Contents
Chapter 1 Renewable Energy 18
1.1 Different Source Of Renewable Energy 19
1.1.1 Solar Energy 19
1.1.2 Wind Energy 23
1.1.3 Hybrid Power Generation System 29
1.1.4 Design Of Hybrid Energy System 35
Chapter 2 Hawt Preliminary Design 40
2.1 Introduction 41
2.2 Blade Element Method (Bem) 42
2.2.1 Rotor Design 43
2.3 Airfoil Selection 46
2.3.1 Aerodynamic Properties 49
2.4 Blade Element Method (Bme) Results53
2.4.1 Modified Chord And Twist Angle Distribution 54
2.5 Final Design55
2.6 Generator 60
2.6.1 Types Of Generators 61
2.6.2 Induction Generator 61
2.6.3 Doubly Fed Induction Generator 62
2.6.4 Permanent Magnet Generator 63
2.6.5 Why Choosing Induction Generator In Our Project? 65
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2.7 Wind Farm Design66
2.7.1 Design Steps Of A Wind Farm 66
2.7.2 500 Kwatt Wind Farm 69
2.8 Tower Design 69
2.8.1 Wind Speed Of The Site Station 71
2.8.2 10mtubular Steel Tower 72
Chapter 3 Rotor Performance And Computational Fluid Dynamics (Cfd) 73
3.1 Introduction 74
3.2 Rotor Performance75
3.3 Rotor Performance Analysis With Cfd Software 79
3.3.1 2d Nrel S-835 Airfoil Simulation 79
3.3.2 Model Description And Geometry 80
3.3.3 Mesh 81
3.3.4 Fluent83
3.3.5 Results 84
3.4 Estimate A Cl & Cd In 5kwatt Hawt Blade With A Different Chord 87
Chapter 4 Design Of 600kwalt Photovoltaic (Pv) Plant 94
4.1 Introduction 95
4.1.1 The Main Advantages Of Photovoltaic (Pv) Plants:95
4.1.2 The Main Disadvantages Of Photovoltaic (Pv) Plant: 96
4.2 The Annual Electrical Power Output Of Photovoltaic (Pv) Plant Depends On
Different Factors 96
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4.3 How Photovoltaic (Pv) Works? 97
4.4 Types Of Solar Photovoltaic (Pv) System 98
4.4.1 On Grid System Or (Grid-Tied)99
4.4.2 Off Grid System Or (Stand-Alone) 101
4.5 Design Of 600kwalt Photovoltaic (Pv) Plant By (Pv Syst Software) 103
Chapter 5 Model Construction 108
5.1 Introduction 109
5.2 Design Requirement 109
5.3 Design Constrain Of Hybrid System 110
5.4 Wind Turbine Design And Performance 110
5.4.1 Main Principles Of Wind Turbines 110
5.4.2 Wind Turbine Solid Works Drawing 111
5.5 Design Construction Of Hybrid System 114
5.5.1 20 Hawt 114
5.5.2 Control System 1 116
5.5.3 Grid 116
5.5.4 Generator 120
5.5.5 20 Hawt Manufacturing Using 3d Printing 121
5.5.6 Pv System 121
5.5.7 System Bunch 124
5.5.8 Box And Control System 2 125
5.5.9 Final System 126
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Chapter 6 Augmented Diffuser And Its Effects Of 5kwatt Hawt 127
6.1 Introduction 128
6.2 Basic Working Principle Of Wind Turbines 129
6.3 Advantages Of Wind Energy 130
6.4 Design Principals 132
6.4.1 Diffuser-Augmented Wind Turbine (Dawt) 133
6.4.2 Mechanics 133
6.4.3 Wind Lens 134
6.5 Limitations Of Traditional Turbines 134
6.5.1 Manufacturing 135
6.5.2 Betz's Law 135
6.6 Diffuser Angle 135
6.7 Diffuser Augmentation Ration (Dar) 136
6.8 Calculations And Results Of The Diffuser Design 138
6.9 Final Design Diffuser 142
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LIST OF FIGURES
Fig. 1.1 Different Source Of Renewable Energy
Fig. 1.2ASample Of Photovoltaic Cells
Fig. 1.3 Different Types Of Solar Thermal Power Technology
Fig.1.4 Kuraymat Egypt First Solar Thermal Station
Fig.1.5 Hawt Wind Turbine
Fig.1.6 Vawt Wind Turbine
Fig. 1.7 Site Layout For Zafarana Wind Farms
Fig. 1.8 Hybrid Power Generation System
Fig. 1.9 Pv Solar System
Fig. 1.10 Wind Power Generation
Fig.1.11 Hybrid System Component
Fig. 1.12 Must Hybrid Power Generation Station Site
Fig. 1.13 Global Solar Irradiation In World
Fig. 1.14 Global Solar Irradiation In Egypt
Fig. 1.15 WindAtlas Of Egypt
Fig. 2.1 Hawt
Fig. 2.2 Blade Element Model
Fig. 2.3 - Curve Of The Rotor [Ref. 1]
Fig. 2.4 Number Of BladesAnd Design Tip Speed Ratio [Ref. 1]
Fig. 2.5An Infinitesimal Element Of The Rotor Blade
Fig. 2.6 NRELl's S835Airfoil
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Fig. 2.7 Relation Between ClAnd CDAndAlpha Curve
Fig. 2.8 Relation Between CL AndAlpha Curve
Fig. 2.9 Relation Between CL/CDAnd ? CD Curve
Fig. 2.10 Relation Between CL/CDAndAlpha Curve
Fig. 2.11 Relation Between CMAndAlpha Curve
Fig 2.12 5kwatt Hawt Blade
Fig. 2.13 5kwatt Hawt
Fig. 2.14 Relation Between R/RAnd FlowAngle F
Fig. 2.15 Relation Between R/RAndAngle OfAttackA
Fig. 2.16 Relation Between R/RAnd TwistAngle ß
Fig. 2.17 Relation Between R/RAnd C
Fig. 2.18 Relation Between R/RAnd Lift Coefficient Cl
Fig. 2.19 Relation Between R/RAnd Drag Coefficient Cd
Fig. 2.20 Relation Between VelocityAnd Power
Fig. 2.21 Inside Generator Of Wind Turbine
Fig. 2.22 Fig Induction Generator Construction
Fig. 2.23 Doubly Fed Induction Generator
Fig. 2.24 Permanent Magnet Generator
Fig. 2.25 Fig Induction Generator
Fig. 2.26 Must Hybrid Power Generation Station Site
Fig. 2.27 Wind Stream
Fig. 2.28 500 Kwatt Wind Farm
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Fig. 2.29 Effect Of Tower Height On The VelocityAt Hub Height [Ref. 1]
Fig. 2.30 Velocity Ratio With Respect To 10 M For Different Roughness Heights
Fig. 2.31 10mTubular Steel Tower
Fig. 3.1 Low Speed Wind Tunnel
Fig. 3.2 Relation Between RpmAnd Power In Different Speed
Fig. 3.3 Relation Between - 4m/Sec
Fig. 3.4 Relation Between - 6m/Sec
Fig. 3.5 Relation Between - 8m/Sec
Fig. 3.6 Relation Between - 10m/Sec
Fig. 3.7 S-835airfoil Geometry
Fig. 3.8 C-Type Geometry
Fig. 3.9 C-Type Structured Grid
Fig. 3.10 Partial GridAround The Wall ForAirfoil
Fig. 3.11 C-Type Structured MeshAround The ModifiedAirfoil With The Boundary Conditions
Fig. 3.12 Velocity ContourAroundAirfoilAtAngle OfAttackA=5.25°
Fig. 3.13 Turbulence ContourAroundAirfoilAtAngle OfAttackA=5.25°
Fig. 3.14 Total Pressure ContourAroundAirfoilAtAngle OfAttackA=5.25°
Fig. 3.15 Relation Between IterationAnd Lift Coefficient
Fig. 3.16 Relation Between IterationAnd Drag Coefficient
Fig. 3.17 Velocity ContourAroundAirfoilAt Length =0.728mAndA=34.8535
Fig 3.18 Velocity ContourAroundAirfoilAt Length =0.62mAndA=21.8277
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Fig. 3.19 Velocity ContourAroundAirfoilAt Length =0.516mAndA=10.8407
Fig. 3.20 Velocity ContourAroundAirfoilAt Length =0.436mAndA=5.1197
Fig. 3.21 Velocity ContourAroundAirfoilAt Length =0.376mAndA=5.1390
Fig. 3.22 Velocity ContourAroundAirfoilAt Length =0.328mAndA=5.1545
Fig. 3.23 Velocity ContourAroundAirfoilAt Length =0.288mAndA=5.1659
Fig. 3.24 Velocity ContourAroundAirfoilAt Length =0.26mAndA=5.1753?
Fig. 3.25 Velocity ContourAroundAirfoilAt Length =0.236mAndA=5.1829
Fig. 3.26 Velocity ContourAroundAirfoilAt Length =0.2196mAndA=5.1892
Fig. 4.1 Basic Solar Cell Construction The Sandwich Of Semiconductor Materials Produces
Electricity Directly From The Sunlight WithoutAny Moving Parts
Fig 4.3 Photovoltaic Cells, ModulesAndArrays The Building Blocks Of Solar ElectricityAre
Modular In Nature,Allowing Great Flexibility InApplications
Fig. 4.3 Types Of Pv System
Fig. 4.4 On Grid SystemAnd Components
Fig. 4.5 Off Grid SystemAnd Components
Fig. 4.6 600kwalt Photovoltaic (Pv) Plant
Fig. 5.1 Blade Solid Works Drawing
Fig. 5.2 Hub Solid Works Drawing
Fig. 5.3 Nut Solid Works Drawing
Fig. 5.4 Wind Turbine Solid WorksAssemble
Fig. 5.5 The Framework OfActivities
Fig. 5.6 The Layout Of Hawt Simulation System
Fig. 5.7 The DuctAnd Fan Parts Before Installing
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Fig. 5.8 The DuctAnd Fan PartsAfter Installing
Fig. 5.9 Varying Speed Control System
Fig. 5.10 The GridAfter Manufacturing
Fig. 5.11 Generator
Fig. 5.12 BladeAfter 3d Printing
Fig. 5.13 Pv Panel
Fig. 5.14 Battery
Fig. 5.15 Charger Controller
Fig. 5.16 Solar Tracker
Fig. 5.17 Bunch
Fig. 5.18 BoxAnd Control System 2
Fig. 5.19 40watt Hybrid System
Fig. 6.1 Two Types Of Hollow Structures
Fig. 6.2 FlowsAround NozzleAndAround Diffuser Type Models. The Smoke Flows From Left
To Right Nozzle Type Model Diffuser Type Model
Fig. 6.3 FlowAroundACircular-Diffuser Model WithABrim
Fig. 6.4 FlowAroundAWind Turbine With Brimmed-Diffuser (Wind Lens)
Fig. 6.5 Wind Lens Diffuser
Fig. 6.6 Betz's Law
Fig 6.7 Basic FactorsAffecting Dawt Evaluation
Fig. 6.8 Theoretical Peak DawtAugmentation Ratio Vs DawtAugmentationArea
Fig. 6.9 Relation Between V& Delta P
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LIST OFTABLES
Table 1:AdvantagesAnd Disadvantages Of HawtAnd Vawt
Table 2:AdvantagesAnd Disadvantage Of Hybrid System
Table 3: Must Consumption
Table 4 : NrelAirfoil Families [Ref.2]
Table 5 : EstimatedAnnual Energy Improvements From NrelAirfoil Families [Ref.2]
Table 6: Initial Design 7.5 Kwatt
Table 7: Final Design 5.3 Kwatt
Table 8: Bem Initial Design Versus Modified Design
Table 9: Wind Speed MeasurementsAt 10m Height
Table 10: Rotor Performance With Different SpeedAnd R.P.M
Table 11: The Cp- Relationship Of The Rotor
Table12: Fluent Model
Table13: Comparison Between Cfd DateAnd Xfoil Date
Table14: Cfd Results
Table 15: Design Constrain Parameter
Table 16: Wind Turbine Design Parameter
Table 17: Design ParameterAt Different Wind Turbine Speed
Table 18: 20 Hawt
Table 19: Grid LossesAt Different Shape
Table 20:Air Speed Measured ByAnemometerAt Different Points On The Grid
Table 21: StudyAndAchieve The Numbers Measured ByAnemometer
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Table 22: FinalAir Velocity On The Grid, Which Was Studied By CalculationsAnd Previous
Laws
Table 23: Pv Components
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FREQUENTLY USED SYMBOLS
Design power coefficient of the rotor
Drive train efficiency
Generator efficiency
VD Design wind velocity
Angular velocity
R Radius of rotor
V Wind speed
Flow angle
Setting angle
Angle of attack
B Number of blade
R Radius of element
Dr Ratio between radius and number of elements
dF Element force of the blade
dT Element Torque of the blade
C Chord length of the blade
Speed ratio of the blade at each element
P Power generate from design turbine
Design lift coefficient
Design drag coefficient
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ACKNOWLEDGMENT
In the name of Allah, the Most Gracious, the Most Merciful
First and foremost, countless thanks go to Allah for endowing me with health, patience,
and knowledge to complete this work.
At the beginnings, we want to say that there is a fact that our days in the University
comes to an end, During our last five years we were glad to know a lot of Professors,
Teacher Assistants, Long life Friends, University Managers and workers, which we felt
there as a big one family No words could describe our thanks and greetings to all of you
for what you did to us Thank you Misr University for Science and Technology especially
our mechanical engineering department under the supervision of Prof /Hamdy Ashour
and Eng/ Tarek shaker A great thanks to all of you Teaching stuff , University president
and Chancellor for the great studying conditions inside the university .
We acknowledge, with deep gratitude and appreciation, the inspiration, encouragement,
valuable time and guidance given to me by my supervisor Dr/Mohamed Ahmed Aziz
We are proud of working under his supervision, And the most influential person in our
life. We are considering him as my spiritual father in the scientific field and we are really
proud of being one of his students
All of my appreciation and respect is dedicated to my supervisor
Prof/Mohamed M.M. El–Refaee I am proud of working under his supervision.
Warm greetings to one of the most Successful professor all over the country and Arab
world, Prof/Ahmed Fayez El-sayed helal who has many researches, books and great
experience, Thank you sir for your visit and we are glad and honor to stand in front of
your excellence to present our project, Thank you Sir and we hope that our project gets
your appreciate and respect
Special thanks to Eng /Mohammed Medhat who helped me in the early stage of our
work, we are really grateful for their valuable suggestions and help.
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Special thanks to Eng / Mohamed Ibrahim who helped me in Experimental model
construction of our work, we appreciate that work.
Special thanks to Eng / Eslam Allam and TAQA Academy, who helped me in PVsyst
simulation and Experimental model construction of our work, we appreciate that work.
Special thanks to Eng / Fawzy abdelaziz who helped me in CFD simulation of our work,
We appreciate that work.
Special thanks to Eng / Mahmoud Elgohary who helped me in Experimental model
construction of our work, we appreciate that work.
Special thanks to Mr /Abdulrahman Ramadan and Mr / Ramadan Abdulrahman
who helped me in Experimental model construction of our work, we appreciate that
work.
Finally, our sincere gratitude goes to our parents, our brothers and our sisters for their
Encouragement, support and motivation. Also, deeply thanks go to our friends and
colleagues for their concern throughout the whole work.
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CHAPTER ONE
ENEWABLE ENERGY
Renewable energy is energy that is generated from natural processes that are
continuously replenished. This includes sunlight, geothermal heat, wind, tides, water, and
various forms of biomass. This energy cannot be exhausted and is constantly renewed.
Such as solar energy, wind energy, hydropower, bioenergy and geothermal energy
Fig. 1.1 Different source of renewable energy
1.1 Different source of renewable energy
1.1.1 Solar energy
The sun is probably the most important source of renewable energy available today.
Traditionally, the sun has provided energy for practically all living creatures on earth,
through the process of photosynthesis, in which plants absorb solar radiation and convert
it into stored energy for growth and development. Scientists and engineers today seek to
utilize solar radiation directly by converting it into useful heat or electricity. Two main
types of solar energy systems are in use today:
Solar photovoltaic.
Solar thermal.
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1.1.1.1 Solar Photovoltaic
Photovoltaic systems convert solar radiation to electricity via a variety of methods. The
most common approach is to use silicon panels, which generate an electrical current
when light shines upon it. Solar photovoltaic are especially valuable for remote rural
applications where it would be prohibitively expensive to supply electricity from a utility
line.
Fig. 1.2 a sample of Photovoltaic cells
Solar photovoltaic in Africa1.1.1.1.1
Declining solar equipment costs are expected to significantly increase solar installations
in Africa with an industry projection forecasting that the continent's annual PV market
will expand to 2.2 GW by 2018.Future installations for harvesting solar energy in Africa
will tend not to be found within the equatorial and subequatorial climate zones, that are
located in the western part of Central Africa usually near the equator but that extend as
far north and south as the 8th or 9th parallel in both hemispheres, since they are
systematically linked with almost permanent cloud cover and only intermittent bright
sunshine. Therefore, countries that entirely lie in this wet-humid zone such as the
Republic of the Congo, Equatorial Guinea, Gabon, Rwanda, Uganda, Burundi, Liberia
and Sierra Leone are by far the least favoured in solar power of all the continent and
except for these eight quoted nations, each other African country experiences over 2,700
hours of bright sunshine on at least a part of its territory. Many perpetually sunny African
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nations like Egypt, Libya, Algeria, Niger, Sudan, South Africa and Namibia for instance
could rely on developing their tremendous solar resources on a large scale thanks to the
immense surface of their territory and at reduced prices. For example
A 50 MW photovoltaic power plant is planned for Garissa in Kenya, a city located
at the equator where the sun is said to shine for about 3,144 hours each year on
average, and it is expected to produce approximately 76,473 MWh/year.
A 155 MW photovoltaic power plant is planned for Ghana, and is expected to be
completed in 2015.
A 75 MW solar power plant started production on September 13, 2013 in Kalkbult,
in South Africa's Northern Cape (implemented by Scatec). Two other PV plants
will be completed by the same company in 2014. These are located at Linde in the
Northern Cape and Dreunberg in the Eastern Cape, both sun-drenched regions
boasting some of the best conditions for solar power in the world. Altogether, these
3 plants will provide power for around 90,000 South African households.
There are also many small-scale modular solar power installations being implemented
across the continent at the village and household levels.
1.1.1.2 Solar thermal
Solar Thermal Systems seek to store heat from the sun that can be used for a variety of
purposes. Many different approaches can be employed here, including active systems,
such as solar hot water heaters, and passive systems, in which careful engineering design
results in a building that automatically stores and utilizes solar energy. Greenhouses are a
prime candidate for passive solar design, in which they collect solar energy on sunny
days in winter and utilize it to keep the house warm at night.
The main advantages of solar energy are that it is clean, able to operate independently or
in conjunction with traditional energy sources, and is remarkably renewable. The main
disadvantages are that it is currently more expensive than traditional energy, and the
availability of solar radiation varies from day to day, and from season to season., there is
still opportunity for using solar energy effectively.
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Types of solar thermal (concentrated solar power C.S.P)1.1.1.2.1
Parabolic through.
Central receiver (solar tower).
Parabolic dish.
Linear Fresnel reflector.
Fig. 1.3 Different types of solar thermal power technology
Solar thermal in Africa1.1.1.2.2
Africa is the sunniest continent on Earth, especially as there are many perpetually sunny
areas like the huge Sahara Desert. It has much greater solar resources than any other
continent. Desert regions stand up as the most sunshiny while rainforests are considerably
cloudier but still get a good global solar irradiation because of the proximity with the
equator.
The distribution of solar resources across Africa is fairly uniform, with more than 85% of
the continent's landscape receiving at least 2,000 kWh/(m² year). A recent study indicates
that a solar generating facility covering just 0.3% of the area comprising North Africa
could supply all of the energy.
Solar thermal in Egypt1.1.1.2.3
Due to its location, topography and climate, Egypt has an average level of solar radiation
of between 2,000 to 3,200kWh per square meter a year, giving it significant potential for
utilizing this form of renewable energy. To date, however, uptake of solar projects has
been slow due to high capital costs. In 2010, Egypt‘s only major solar power project was
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commissioned in Kuraymat. The plant is a 140MW solar thermal combined cycle power
plant of which 20MW is from solar energy.
Fig.1.4 Kuraymat Egypt First Solar thermal station
1.1.2 Wind Energy
The energy of wind converted into useful form is called wind energy. The first use of
wind power was to sail ships in the Nile some 5000 yr. ago. Many civilizations used wind
power for transportation and other purposes: The Europeans used it to grind grains and
pump water in the 1700s and 1800s. The first windmill to generate electricity in the rural
U.S. was installed in 1890. An experimental grid- connected turbine with as large a
capacity as 2 MW was installed in 1979 on Howard Knob Mountain near Boone, NC, and
a 3-MW turbine was installed in 1988 on Berger Hill in Orkney, Scotland. Today, even
larger wind turbines are routinely installed, commercially competing with electric utilities
in supplying economical, clean power in many parts of the world. Two main types of
wind turbines are used:
Horizontal Axis Wind Turbines (HAWT)
Vertical Axis Wind Turbines (VAWT)
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1.1.2.1 Horizontal Axis Wind Turbines (HAWT)
Horizontal axis wind turbines, also shortened to HAWT, are the common style that most
of us think of when we think of a wind turbine. A HAWT has a similar design to a wind
mill, it has blades that look like a propeller that spin on the horizontal axis.
Horizontal axis wind turbines have the main rotor shaft and electrical generator at the top
of a tower, and they must be pointed into the wind. Small turbines are pointed by a
simple wind vane placed square with the rotor (blades), while large turbines generally use
a wind sensor coupled with a servo motor to turn the turbine into the wind. Most large
wind turbines have a gearbox, which turns the slow rotation of the rotor into a faster
rotation that is more suitable to drive an electrical generator.
Since a tower produces turbulence behind it, the turbine is usually pointed upwind of the
tower. Wind turbine blades are made stiff to prevent the blades from being pushed into
the tower by high winds. Additionally, the blades are placed a considerable distance in
front of the tower and are sometimes tilted up a small amount.
Downwind machines have been built, despite the problem of turbulence, because they
don't need an additional mechanism for keeping them in line with the wind. Additionally,
in high winds the blades can be allowed to bend which reduces their swept area and thus
their wind resistance. Since turbulence leads to fatigue failures, and reliability is so
important, most HAWTs are upwind machines.
Fig.1.5 HAWT wind Turbine
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1.1.2.2 Vertical Axis Wind Turbines (VAWT)
Vertical axis wind turbines, as shortened to VAWTs, have the main rotor shaft arranged
vertically. The main advantage of this arrangement is that the wind turbine does not need
to be pointed into the wind. This is an advantage on sites where the wind direction is
highly variable or has turbulent winds.
With a vertical axis, the generator and other primary components can be placed near the
ground, so the tower does not need to support it, also makes maintenance easier. The
main drawback of a VAWT generally creates drag when rotating into the wind.
It is difficult to mount vertical-axis turbines on towers, meaning they are often installed
nearer to the base on which they rest, such as the ground or a building rooftop. The wind
speed is slower at a lower altitude, so less wind energy is available for a given size
turbine. Air flow near the ground and other objects can create turbulent flow, which can
introduce issues of vibration, including noise and bearing wear which may increase the
maintenance or shorten its service life. However, when a turbine is mounted on a rooftop,
the building generally redirects wind over the roof and these can double the wind speed at
the turbine. If the height of the rooftop mounted turbine tower is approximately 50% of
the building height, this is near the optimum for maximum wind energy and minimum
wind turbulence.
Fig.1.6 VAWT wind Turbine
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Table 1: Advantages and disadvantages of HAWT and VAWT
HAWT VAWT
Advantage
1- The tall tower base allows access to
stronger wind in sites with wind shear. In
some wind shear sites, every ten meters
up the wind speed can increase by 20%
and the power output by 34%.
1. No yaw mechanisms are needed.
2- Can be located nearer the ground, making it
easier to maintain the moving parts.
3- Have lower wind startup speeds than the typical
the HAWTs.
2- High efficiency, since the blades
always move perpendicularly to the
wind, receiving power through the
whole rotation. In contrast, all vertical
axis wind turbines, and most proposed
airborne wind turbine designs, involve
various types of reciprocating actions,
requiring airfoil surfaces to backtrack
against the wind for part of the cycle.
Backtracking against the wind leads to
inherently lower efficiency
4- May be built at locations where taller structures
are prohibited.
5- Situated close to the ground can take advantage
of locations where rooftops, mesas, hilltops,
ridgelines, and passes funnel the wind and
increase wind velocity.
Disadvantage
1- Massive tower construction is required to
support the heavy blades, gearbox, and
generator.
2- Components of a horizontal axis wind
turbine (gearbox, rotor shaft and brake
assembly) being lifted into position.
3- Their height makes them obtrusively
visible across large areas, disrupting the
appearance of the landscape and
sometimes creating local opposition.
4- Downwind variants suffer from fatigue
and structural failure caused by
turbulence when a blade passes through
the tower's wind shadow (for this reason,
the majority of HAWTs use an upwind
design, with the rotor facing the wind in
front of the tower).
5- HAWTs require an additional yaw
control mechanism to turn the blades
toward the wind.
6- HAWTs generally require a braking or
yawing device in high winds to stop the
turbine from spinning and destroying or
damaging itself.
1- Most VAWTs have a average decreased
efficiency from a common HAWT, mainly
because of the additional drag that they have as
their blades rotate into the wind. Versions that
reduce drag produce more energy, especially
those that funnel wind into the collector area.
2- Having rotors located close to the ground
where wind speeds are lower and do not take
advantage of higher wind speeds above.
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1.1.2.3 Wind energy in Africa
Wind installed capacity in Africa is not only small – both in absolute terms measured by
installed capacity, and relative terms as measured by its contribution to the energy mix –
but has also been highly concentrated with 3 countries (Egypt, Morocco and Tunisia)
holding about 96% of total installed capacity as at end-2011.
wind energy development in Africa to provide stylized facts on the industry and its
funding sources, then analyze the market‘s outlook. Inevitably, there is a strong focus on
market leaders including analyses of specific policies, strategies and financing
instruments adopted in these countries to develop the market. We use a hand collected
sample of 94 wind energy projects.
1.1.2.4 Wind Energy in Egypt
Egypt enjoys an excellent wind regime, particularly in the Suez Gulf, where average
wind speeds reach over 10 m/second.
The Egyptian wind energy market increased from just 5 MW in 2001 to 310 MW at the
end of 2007, and 80 MW of new capacity were added in 2007 to the Zafarana wind farm.
Over 3,000 MW are earmarked for wind power developments in the near future on the
Gulf of Suez coast.
In April 2007, Egypt‘s Supreme Council of Energy announced an ambitious plan to
generate 20 per cent of the country‘s electricity from renewable sources by 2020,
including a 12 per cent contribution from wind energy, translating into 7,200 MW of
grid-connected wind farms. This plan will provide investor security and stimulate private
investment in wind energy.
Moreover, a new draft energy act has recently been submitted to the Egyptian Parliament
to encourage renewable energy deployment and private sector involvement. In addition to
guaranteeing third-party access, power generation from renewable energy would enjoy
priority grid access under this law.
With the Zafarana project, Egypt has moved on from limited experimental projects to
large-scale grid-connected wind farms. Overall, 305 MW has been installed in different
stages: 63 MW in 2001, 77 MW in 2003/2004, 85 MW in July 2006 and 80 MW in
December 2007. The electricity production from the Zafarana farm is over 1,000 GWh
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per year at an average capacity factor of 40.6 per cent. A further 240 MW extension of
the wind farm is currently being put into place.
In addition to this, an area of 656 km2 has been earmarked to host a 3,000 MW wind
farm at Gulf of El-Zayt on the Gulf of Suez coast. Studies are being conducted to assess
the site potential to host large scale grid connected wind farms of 200 MW capacity in
cooperation with Germany, 220 MW (in cooperation with Japan) and 400 MW as (a
private-sector project).
Zafarana wind farm1.1.2.4.1
The first large-scale wind farm was built in Egypt in 2000-2001. The wind farm is
erected in one of the windiest sites in this part of the world, where the average wind
speed rises above 9m/sec. The wind farm is located in a stony desert near the seacoast.
Fig 1.7 Site layout for zafarana wind farms
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1.1.3 Hybrid Power Generation System
Hybrid energy system is the combination of two energy sources for giving power to the
load. In other word it can defined as ―Energy system which is fabricated or designed to
extract power by using two energy sources is called as the hybrid energy system.‖
Hybrid energy system has good reliability, efficiency, less emission, and lower cost. In
this proposed system solar and wind power is used for generating power. Solar and wind
has good advantages than other than any other non-conventional energy sources. Both the
energy sources have greater availability in all areas. It needs lower cost. There is no need
to find special location to install this system.
There is a growing need for energy throughout the world. This insatiable demand is being
driven from an ever expanding growth from the middle class of people in emerging
economies looking to avail themselves of conveniences and tools that are normally taken
for granted. Additionally, the worldwide explosion of technologies of all types, including
personal electronics, mobile devices, and ―quality of life‖ conveniences, place a greater
demand or strain on traditional grid or utility supplied energy sources.
Hybrid systems that use renewable energy sources, such as solar and wind resource, may
be feasible and an alternative to supply electricity to remote or isolated areas from the
national grid and help in reducing the use of fossil fuels, dependence on costly fuel, and
reduce the emission of greenhouse gases.
there are problems in utilizing the solar as well as wind energy efficiently. In order to
overcome these problems, concept of ‗hybrid power plant‘ is introduced. In this both
solar and wind power plants are used so that their disadvantages are reduced to a
considerable amount.
As we know that sun is available in the day only, energy is not available during night
from sun whereas wind energy is available throughout the day and its capacity increases
in the nights. Here when sun is not available wind energy comes to play and vice-versa.
Thus hybrid power plants are more useful than individual ones and therefore they are
extensively used nowadays.
33. 33
Fig 1.8 Hybrid Power Generation System
1.1.3.1 Hybrid Power Generation System component
PV system1.1.3.1.1
Fig 1.9 PV solar system
35. 35
Table 2: advantages and disadvantage of hybrid system
ADVANTAGES DISADVANTAGES
The advantages covered by the propose
system are listed as,
1- Overcoming disadvantages of standalone
renewable electrical energy generation
system.
2- Producing much more efficiency as two
or more renewable energy generation
system working together in the terms of
electrical energy generation.
3- Since, the system doesn‘t have
microcontroller or microprocessor the
complexity of system testing and
understanding became easy in terms of
difficulties.
4- System maintains is remarkably reduced
and becomes easy.
5- Renewable energy sources like, sun,
wind,. Are utilized so, no waste
production.
6- Producing clean, friendly to
environment, renewable energy.
7- Once the system is designed and
developed or manufactured, the
installation of system is easy.
8- Within certain time period the
installation cost gets covered.
9- If the system gets damaged in case, no
need of changing entire system or
subsystem. Just, changing a damage
component will work out.
There‘s no system without having a
disadvantage. So as, the system have
disadvantages as follow:
1- The first time installation cost is huge
in terms of finance.
2- The circuit designing complexity is
more as there in no micro-computer
for controlling action.
36. 36
1.1.3.2 MUST Hybrid power generation system
The purpose of this project is to design a low cost power system that combines both wind
electric and solar electric technologies. This hybrid system will be designed to deliver
1.1MWatts of continuous power of Misr University For Science and Technology
(MUST) which is enough to power a wide range of appliances and medical equipment,
To cover the electricity consumption for Misr University for Science and Technology
(MUST) , this station must be designed to give 1.5 MWatt, but we designed it to give
1.1MWatt because of the site station area capacity.
The system is composed of a wind generator, a solar panel, a charge controller, a battery
and an inverter. The solar panel and wind turbine work in tandem to charge a battery via
a controller. After, an inverter will be used to convert DC power from the battery into AC
power suitable for domestic use. The system will have a battery bank large enough to
supply electric load for two days.
The main objective of this project is to provide an alternative power solution for Misr
University for Science and Technology. Also the system can be used as a temporary
power solution for locations affected by natural disasters. In order to reach these
objectives the product must be low cost and easy to manufacture.
Table 3: Must Consumption
Date Total month
consumption(MWH)
Average day
consumption(MWH)
Consumption
Per hour (MWH)
January 761.1 25.4 1.06
July 889.5 29.7 1.3
August 1047.6 34.9 1.5
38. 38
1.1.4 DESIGN OF HYBRID ENERGY SYSTEM
For design of the hybrid energy system we need to find the data as follows
1.1.4.1Data required for Solar System:
1. Annual mean daily duration of Sunshine hours = 6 hr.
2. Daily Solar Radiation horizontal (KWH/m2/day) = 2200KWH/m2/day.
Fig. 1.13 Global Solar irradiation in world
Fig. 1.14 Global Solar irradiation in Egypt
39. 39
1.1.4.2Data required for Wind System:
Mean Annual Hourly Wind Speed (m/sec) = 6m/sec
Fig. 1.15 Wind Atlas of Egypt
1.1.4.3Procedure of MUST hybrid power generation system design
The hybrid unit contains two complete generating plants, a PV solar cell plant and a
wind-turbine system. These sources are connected in parallel to a 220V AC line. The
procedure of MUST hybrid power generation system design is given below:
1. Determine the power required.
2. Determine the percentage of power can be generate from wind and solar system
such as (45% generate from wind and 55% generate from solar system).
3. Determine the specification of solar system (PV selection).
4. The solar system installing.
5. Panel output is connected to a DC to AC inverter and is then supplied from the
inverter‘s output to a single-phase, 220 VAC load.
40. 40
6. Design the wind turbine for give the power requirement.
7. Make CFD model for simulation of wind turbine.
8. Change in the turbine parameter for getting the high power.
9. Manufacture of turbine blade and other parts.
10.Design the tower of turbine.
11.Installing the wind farm.
12.Create a link between solar and wind system.
1.1.4.4Wind-Solar Hybrid System Design Impact
Using sustainable and free energy sources like wind and sun is good for the environment
and helps promote energy independence. A wind-solar hybrid system lets you take
advantage of the best that the two technologies independently offer. By knowing the
disadvantages of wind-solar hybrid systems, you can make an educated decision about
the type of renewable energy setup that‘s best for you.
Property Requirements1.1.4.4.1
To install a wind-solar hybrid system, your property must have the ideal layout for a
residential wind turbine and a solar array. If your site doesn‘t receive an adequate amount
of wind or sun, there‘s no point in installing a hybrid system. The U.S. Department of
Energy recommends that an energy expert consult a wind resource map or use a wind
measurement system to determine whether or not a home receives enough wind. To
qualify for solar panels, your roof needs to be in good condition, use strong materials for
shingles, lack tree coverage and be no more than 10 years old. If you plan to install the
solar panels on the ground instead of a roof, you must have enough flat, unshaded terrain
on your property.
Aesthetics and Building Codes1.1.4.4.2
A wind-solar hybrid system will change the way your site looks. Instead of shingles,
passersby will see a row of solar panels on your roof. In addition to trees, guests will see
a large turbine in your landscaping. In some cases, contractors install small turbines and
solar panels on the roof. While the renewable energy sources may increase the value of
your home, the way they look may reduce your home‘s curb appeal. Your city and
homeowners association may care about the aesthetics of your home, as well. Some cities
or neighborhoods have restrictions regarding the height of structures in residential zones.
A city or neighborhood association may also have problems with the noise that turbines
make as they spin.
41. 41
High Costs1.1.4.4.3
Despite the tax credits offered, hybrid wind and solar electric systems are not inexpensive
to install and maintain. They have the potential to cost tens of thousands of dollars,
depending on the system that you choose. In addition to the cost of labor, the solar panels
will make up a generous portion of the initial cost of a solar hybrid system because of the
crystalline silicone in them. Additional costs may include the wind turbine, wiring,
permits, fees, power inverters and batteries. While solar panels don‘t need much
maintenance other than cleaning, wind turbines require regular maintenance to inspect the
blades.
Energy Generation and Storage Considerations1.1.4.4.4
When installing a wind-solar hybrid system, you need to decide if you want the system to
tap into the local power grid or use batteries. If you are able to connect the system to the
power grid, you may be able to sell the extra electricity that it generates to the power
company. With this method, you can use electricity generated from the grid until your
hybrid system is able to generate energy again. Batteries may be a good option if you live
in a remote area and aren‘t already connected to the power grid or if you don‘t want to
connect to the power grid at all. The batteries store the extra energy that the hybrid
system generates. However, if the batteries are full and the system continues to generate
electricity, the extra power created gets wasted. On the other hand, if there‘s a period
when the skies are grey and calm, the batteries will only supply power to your home for a
limited time.
Fig.1.16 loud of wind turbine effect
42. 42
1.1.4.5Scope of Feasibility Study on Use of Hybrid System (PV&Wind)
Feasibility on scope of application of an energy system would need to identify
quantitatively the resource potential of them which mainly decides the economy.
In case of solar PV:
Measurement of solar irradiance at site concerned and studies on availability of
sunlit hours at site
The scope of area availability for placement is the three data which are to be
availed. They can be availed either from actual site study and/or search from
meteorological department data of the concerned zone. Thereafter based on
equations can be decided number of PV module requirement, which decides the
economy, being more than 80% contributing factor of the total cost.
Measurement of wind speed using anemometer at the concerned site and Studies
on period/ hours that the cut in wind speed is available at the concerned site and
Convert the said wind speed at the hub height from the measurement made at
anemometer height using logarithmic relationship shown in equation 4 and
knowing the terrain data (surface roughness index)
Determining the swept area from the diameter of the blades of wind turbine being
used.
Thereby can be determined the value electricity availability/sq. m. of the concerned
zone using equations.
It may be added that the turbine cost together with the gridline connecting cost
constitute 80% of the total cost of a land based wind farm. In case of off-shore
wind farm turbine cost together with gridline cable cost constitutes 70% of the total
cost plus foundation cost constitutes 20% of the total cost.
44. 44
CHAPTER TWO
HAWT PRELIMINARY DESIGN
2.1 Introduction
Wind turbines work by turning the kinetic energy of the wind into torque (a force) that
causes the wind turbine to turn and drives an electrical generator. The wind is made up of
real matter with mass, when mass is moving it has kinetic energy. As the wind causes the
wind turbine to turn, we are reducing the energy in the wind. The energy that is removed
from the wind is converted into mechanical energy that is used to drive an electrical
generator.The electric generator uses the turning motion to spin a magnetic rotor inside
the generator housing that is surrounded by loops of copper wire (often wrapped around
iron cores). As the rotor spins around the inside of the core it excites "electromagnetic
induction" through the wire that generates an electrical current. The efficiency of the
wind turbine blade determines the power performance of the wind turbine rotor. Wind
turbine blade design optimization is generally a heuristic process, which cannot be
finished in one single step. Iterations are needed for most cases. For the design
optimization of a wind turbine blade, an aerodynamic criterion, such as maximum power
coefficient, maximum annual energy production or minimum cost of energy is often
considered as the objective. Until an optimal blade is obtained according to the criterion,
the blade aerodynamic design task is finished. In wind turbine aerodynamics, it was
reported by many researchers that the Blade Element Momentum (BEM) method is the
most widely used and acceptably efficient approach for wind turbine blade design and
analysis.
Fig. 2.1 HAWT
45. 45
2.2 Blade element method (BEM)
Blade Element Momentum (BEM) Theory is a calculation method that is commonly used
to determine the performance of a wind turbine. It provides a good estimate of power
generated by a HAWT of a given diameter and number of blades for a given wind speed.
The BEM theory combines two methods to describe the aerodynamic behavior of a wind
turbine. The first method is based on the Momentum Theory which uses momentum
balance on a rotating annular stream tube passing through an actuator disc model of a
wine turbine. The second method is based on the Blade Element Theory which evaluates
the forces generated at various sections along the blades. By equating the force and
torque relations derived separately from momentum and blade element theory, the
induced velocities and induction factors at the actuator disk can be predicted. Once
induced velocities are modeled accurately, the power and thrust of a wind turbine can be
determined.
Fig. 2.2 Blade element model
46. 46
2.2.1 Rotor design
For design rotor to develop 5KWatt using (BEM) method some parameter estimated and
other parameter assumed such as:
Power coefficient may be in the range of 0.4 to 0.5 (Cp).
The combined efficiency (Generator efficiency and drive train) may be taken as
0.9.
The radius of the rotor can be estimated as:
[ ]
Design tip speed ratio depends on the application for which the turbine is being
developed. For example, when we design the rotor for a wind pump which require high
starting torque, low tip speed ratio is chosen. On the other hand, if our intention is to
generate electricity, we require a fast running rotor and hence high tip speed ratio. we
may go for higher . For aero generator s may be higher than 5.
The relationship between and at all the wind velocities converges to a single
curve. This non-dimensional relationship can represent the performance of any
dimensionally similar rotor irrespective its size. Fig. 2.3 gives a guideline for choosing
the tip speed ratio based on the power coefficient.
47. 47
Fig. 2.3 - Curve of the rotor [Ref. 1]
Number of blades in a rotor is directly related to the design tip speed ratio. The higher the
tip speed ratio, the lower would be the number of blades. Fig. 3.3 gives a guideline for
choosing the tip speed ratio based on the number of blades
Fig. 2.4 Number of blades and design tip speed ratio [Ref. 1]
48. 48
Using the angular velocity for estimate the rotor speed (N[ ]) by:
The flow angle can be estimated as:
( )
The setting angle can be estimated as:
The angle of attack ( ) is constant value depend on the selected airfoil chosen so that
Is the design lift coefficient and is the design drag coefficient It may be constant
for all elements.
Fig. 2.5 An infinitesimal element of the rotor blade
The Chord length of the blade can be estimated as:
49. 49
The speed ratio of the blade at each element can be estimated as:
The element force of the blade can be estimated as:
[ ]
The element Torque of the blade can be estimated as:
[ ]
Finally from above analysis of turbine blade can be estimate the power generate from
design turbine
∑
2.3 Airfoil selection
The team is choice National Renewable Energy Laboratory Airfoils (NREL). NREL
started the development on airfoils that were specially made for horizontal-axis wind
turbines in 1984. Since then NREL has come up with nine airfoil families that have been
designed for different rotor sizes. The families consist of twenty-five airfoils with their
designation starting at S801 and ending with S828. The designations represent the
numerical order, which the airfoils were designed during 1984-1995. After this period
there have been some modifications to the airfoils. Some of the airfoils have been
improved after wind tunnel testing and other have undergone more comprehensive testing
at the Technical University of Delft (TUDelft), in their low-turbulence wind tunnel. All
these airfoils, except the early blade-root airfoils (S804, S807, S808, S811), are designed
to have a CL max which is relatively insensitive to roughness effects.17 This is
accomplished by ensuring that the transition point from laminar to turbulent flow is near
the leading edge on the suction side of the airfoil, just prior to reaching CL max . At its
clean condition, the airfoil achieves low drag through the extensive laminar flow. The tip-
region airfoils have close to 50 % laminar flow on the suction surface and over 60%
laminar flow on the pressure surface. The pitching moment coefficient (Cm) is mostly
50. 50
proportional to CL max for the NREL airfoils. Therefore, the tip region airfoils with its
low CL max exhibits lower Cm than other modern aft-cambered aircraft airfoils. The
NREL airfoils are also designed to have a soft-stall characteristic, which is a result from
the progressive separation at the trailing edge. This helps the blade in turbulent wind
conditions, by mitigating power and load fluctuation.
Seven airfoil families consisting of 23 airfoils have been designed for various size rotors
since 1984. The appropriate blade length and generator size for each airfoil family along
with the corresponding airfoils comprising each family from blade root to tip are shown
in Table 3. The airfoil designations starting with the S801 and ending with the S823
represent the numerical order in which the airfoils were designed between 1984 and
1993. The "A" designation stands for an improved version of an airfoil based on wind-
tunnel test results for a similar airfoil. The three airfoils having underlined bold lettering
have undergone comprehensive tests in the Delft University low-turbulence wind tunnel.
Table 4 : NREL Airfoil Families [Ref.2]
Five of the airfoil families are designated "thick" (16% to 21%) to indicate that the tip-
region airfoils are thick enough to accommodate over speed-control aerodynamic devices
and to reduce the blade weight.
51. 51
These "thick" airfoil families lend themselves to stall-regulated wind turbines. The two
airfoil families labeled "thin" (11 % to 15%) are more suited to variable-pitch or variable-
rpm turbines that use full-span blade pitch. Greater thickness is desired for the blade-root
airfoils to accommodate structural and dynamic considerations. The blade-root airfoil
thickness falls in the range of 18% to 24%. Thicknesses greater than 26% were found to
result in unacceptable performance characteristics shown in table 4
Table 5 : Estimated Annual Energy Improvements from NREL Airfoil Families [Ref.2]
The step number 1 to blade design must be selecting the correct Airfoil. Our team is
choice S835 Airfoil and the airfoil has the following characteristics:
1. Reynolds number effects
The section characteristics of the S835 airfoil Using the previously described criterion,
the maximum lift coefficient for the design Reynolds number of 0.25 x lo6 is estimated to
be 1.04, which does not meet the design objective of CL max = 1.20, primarily because the
objective is incompatible with the other requirements, especially the combination of large
airfoil thickness and low Reynolds number. The stall characteristics are expected to be
docile, which meets the design goal. Low drag coefficients are predicted over the range
of lift coefficients from below 0 to 0.94. Thus, the lower limit of the low-drag range is
below the design objective of CL = 0.40, although the upper limit is also below the
design objective of CL = 1.00, primarily to meet other, more important goals. The zero-
lift pitching-moment coefficient is predicted to be -0.14, which satisfies the design
constraint. The actual zero-lift pitching-moment coefficient should be about -0.12.
52. 52
2. Effect of roughness
The effect of roughness on the section characteristics of the S835 airfoil. The maximum
lift coefficient for the design Reynolds number of 0.25 x 1 o6 with transition fixed is
estimated to be 1.00, a reduction of 4 percent from that with transition free. For the rough
condition, the maximum lift coefficient for the design Reynolds number is estimated to
be 1.03, a reduction of 1 percent from that with transition free. Thus, the design
requirement has been satisfied. The effect of roughness on the maximum lift coefficient is
nearly constant with Reynolds number. The drag coefficients are, of course, adversely
affected by the roughness.
A family of quiet, thick, natural-laminar-flow airfoils, the S833, S834, and S835, for 1- to
3-meter-diameter, variable-speed/variable-pitch, horizontal-axis wind turbines has been
designed and analyzed theoretically. The two primary objectives of high maximum lift
coefficients, relatively insensitive to leading-edge roughness, and low profile-drag
coefficients have generally been achieved. The airfoils should exhibit docile stall
characteristics, which meets the design goal. The constraints on the zero-lift pitching-
moment coefficient and the airfoil thicknesses have been satisfied.
Fig. 2.6 NREL's S835 airfoil
2.3.1 Aerodynamic Properties
During the rotor analysis the Reynold number consdered to be equal 106
and CL/CD max
at
53. 53
Fig. 2.7 relation between and and Alpha Curve
Fig. 2.8 Relation between and Alpha Curve
54. 54
Fig. 2.9 relation between and Curve
Fig. 2.10 relation between and Alpha Curve
62. 62
Curve fitting Equation {P = (4.1*10^0.2*2V)-(2.4*10^3*V) + (4.6*10^3)}
Fig. 2.20 relation between Velocity and Power
63. 63
2.6 Generator
The generator is the core of a wind turbine. It converts the rotational energy of the rotor, driven by
the kinetic energy of the wind, and converts it into electrical energy. Inside this component, coils
of wire are rotated in a magnetic field to produce electricity, Different generator designs produce
either alternating current (AC) or direct current (DC), and they are available in a large range of
output power ratings, the generator's rating, or size, is dependent on the length of the wind
turbine's blades because more energy is captured by longer blades. On large wind turbines
(above 100-150 kW) the voltage (tension) generated by the turbine is usually 690 V
three-phase alternating current (AC). The current is subsequently sent through a
transformer next to the wind turbine (or inside the tower) to raise the voltage to
somewhere between 10,000 and 30,000 volts, depending on the standard in the local
electrical grid. Large manufacturers will supply both 50 Hz wind turbine models (for the
electrical grids in most of the world) and 60 Hz models (for the electrical grid in
America).Generators need cooling while they work. On most turbines this is accomplished by
encapsulating the generator in a duct, using a large fan for air cooling, but a few manufacturers use
water cooled generators. Water cooled generators may be built more compactly, which also gives
some electrical efficiency advantages, but they require a radiator in the nacelle to get rid of the
heat from the liquid cooling system. If you connected (or disconnected) a large wind turbine
generator to the grid by flicking an ordinary switch, you would be quite likely to damage both the
generator, the gearbox and the current in the grid in the neighborhood. Wind turbines may be
designed with either synchronous or asynchronous generators, and with various forms of
direct or indirect grid connection of the generator. Direct grid connection mean that the
generator is connected directly to the (usually 3-phase) alternating current grid. Indirect
grid connection means that the current from the turbine passes through a series of electric
devices which adjust the current to match that of the grid. With an asynchronous
generator this occurs automatically.
Fig. 2.21 inside generator of wind turbine
64. 64
2.6.1 Types of generators
Asynchronous generator
Induction Generator
Doubly fed induction generator
Synchronous generator
Electrically Excited Generator
Permanent Magnet Generator
2.6.2 Induction generator
The curious thing about this type of generator is that it was really originally designed as
an electric motor. In fact, one third of the world's electricity consumption is used for
running induction motors driving machinery in factories, pumps, fans, compressors,
elevators, and other applications where you need to convert electrical energy to
mechanical energy.
One reason for choosing this type of generator is that it is very reliable, and tends to be
comparatively inexpensive. The generator also has some mechanical properties which
are useful for wind turbines.
Fig. 2.22 Fig Induction Generator Construction
65. 65
2.6.3 Doubly Fed Induction Generator
Are electric motors or electric generators where both the field magnet windings and
armature windings are separately connected to equipment outside the machine. By
feeding adjustable frequency ac power to the field windings, the magnetic field can be
made to rotate, allowing variation in motor or generator speed. This is useful, for
instance, for generators used in wind turbines, similar to AC electrical generators, but
have additional features which allow them to run at speeds slightly above or below their
natural synchronous speed. This is useful for large variable speed wind turbines, because
wind speed can change suddenly. When a gust of wind hits a wind turbine, the blades try
to speed up, but a synchronous generator is locked to the speed of the power grid and
cannot speed up. So large forces are developed in the hub, gearbox, and generator as the
power grid pushes back. This causes wear and damage to the mechanism. If the turbine is
allowed to speed up immediately when hit by a wind gust, the stresses are lower and the
power from the wind gust is converted to useful electricity.
One approach to allowing wind turbine speed to vary is to accept whatever frequency the
generator produces, convert it to DC, and then convert it to AC at the desired output
frequency using an inverter. This is common for small house and farm wind turbines. But
the inverters required for megawatt-scale wind turbines are large and expensive.
Doubly fed generators are one solution to this problem. Instead of the usual field winding
fed with DC, and an armature winding where the generated electricity comes out, there
are two three-phase windings, one stationary and one rotating, both separately connected
to equipment outside the generator. Thus the term "doubly fed".
One winding is directly connected to the output, and produces 3-phase AC power at the
desired grid frequency. The other winding (traditionally called the field, but here both
windings can be outputs) is connected to 3-phase AC power at variable frequency. This
66. 66
input power is adjusted in frequency and phase to compensate for changes in speed of the
turbine.
Adjusting the frequency and phase requires an AC to DC to AC converter. This is usually
constructed from very large IGBT semiconductors. The converter is bidirectional, and
can pass power in either direction. Power can flow from this winding as well as from the
output winding.
Fig. 2.23 Doubly Fed Induction Generator
2.6.4 Permanent Magnet Generator
Is a generator where the excitation field is provided by a permanent magnet instead of a
coil. The term synchronous refers here to the fact that the rotor and magnetic field rotate
with the same speed, because the magnetic field is generated through a shaft mounted
permanent magnet mechanism and current is induced into the stationary armature.
Synchronous generators are the majority source of commercial electrical energy. They
are commonly used to convert the mechanical power output of steam turbines, gas
turbines, reciprocating engines and hydro turbines into electrical power for the grid.
Some designs of wind turbines also use this generator type.
67. 67
In the majority of designs the rotating assembly in the center of the generator—the
"rotor"—contains the magnet, and the "stator" is the stationary armature that is
electrically connected to a load. As shown in the diagram, the perpendicular component
of the stator field affects the torque while the parallel component affects the voltage. The
load supplied by the generator determines the voltage. If the load is inductive, then the
angle between the rotor and stator fields will be greater than 90 degrees which
corresponds to an increased generator voltage. This is known as an overexcited generator.
The opposite is true for a generator supplying a capacitive load which is known as an
underexcited generator. A set of three conductors make up the armature winding in
standard utility equipment, constituting three phases of a power circuit—that correspond
to the three wires we are accustomed to see on transmission lines. The phases are wound
such that they are 120 degrees apart spatially on the stator, providing for a uniform force
or torque on the generator rotor. The uniformity of the torque arises because the magnetic
fields resulting from the induced currents in the three conductors of the armature winding
combine spatially in such a way as to resemble the magnetic field of a single, rotating
magnet. This stator magnetic field or "stator field" appears as a steady rotating field and
spins at the same frequency as the rotor when the rotor contains a single dipole magnetic
field. The two fields move in "synchronicity" and maintain a fixed position relative to
each other as they spin.
They are known as synchronous generators because f, the frequency of the induced
voltage in the stator (armature conductors) conventionally measured in hertz, is directly
proportional to rpm, the rotation rate of the rotor usually given in revolutions per minute
(or angular speed). If the rotor windings are arranged in such a way as to produce the
effect of more than two magnetic poles, then each physical revolution of the rotor results
in more magnetic poles moving past the armature windings.
68. 68
Fig. 2.24 Permanent Magnet Generator
2.6.5 Why choosing induction generator in our project?
Most wind turbines in the world use a so-called three phase asynchronous generator, also
called an induction generator to generate alternating current.
This type of generator is not widely used outside the wind turbine industry, and in small
hydropower units, but the world has a lot of experience in dealing with it anyway.
Fig. 2.25 Fig induction Generator
69. 69
2.7 Wind farm design
Wind farm is a collection of specially designed wind turbines positioned across the
landscape in our case or ocean in other cases, where the winds are steady and strong.
Building a wind farm is a big project that requires teams of specialists to handle the many
aspects of the project, from conception to planning to implementation. From selecting the
proper location and assessing the risk to wildlife to acquiring the proper permits and
implementing and testing the turbines themselves, a lot of planning goes behind building
this special type of energy generator. First, make sure to choose a location that has
enough wind resources. The best sites for commercial wind farms have wind speeds of 6
meters/second or more .Too much wind can actually strain equipment and make the
project more expensive.
2.7.1 Design steps of a wind farm
1. Preliminary site identification.
2. detailed technical and economic analysis.
3. Environment, social and legal appraisal.
4. micro-siting and construction.
The first step in the development of a wind farm is to identify a suitable location, having
reasonably high wind velocity. Once the broad geographical region for the development
of the proposed wind farm is identified, it may be possible to locate several sites which
could be used for constructing the wind farm. Wind data available from local weather
stations, airports etc. or published documents like wind maps may be used for this
purpose. A candidate site must usually have a minimum annual average wind speed of 5
m/s.our location and site identification have reasonably wind velocity 6 m/s .Once such
sites available in the region are identified, computer models are used for estimating the
energy potential of these sites in different time frames.
70. 70
Fig. 2.26 Must Hybrid power generation station site
In the first stage we relied on existing information to rate the potentiality of the sites. In
the next stage, more rigorous analysis is required. The nature of the wind spectra
available at the sites is to be thoroughly understood for the detailed technical analysis.
For this, wind speed has to be measured at the hub height of the proposed turbines.
Anemometers installed on guyed masts are used for wind measurement. Installed at
different locations, are preferred for accurate analysis. Wind speed at the site has to be
monitored at least for six months. If time and resources permit, the duration may further
be increased to one year or even more Apart from the sites wind potential, other factors
like access to the grid, roads and highways, existing infrastructure for power transmission
and ground condition at the site are also to be critically analyzed while choosing the site.
In our case the land has accessibility to the road and The local electricity distribution
system at these sites should be examined to ensure that minimum infrastructures are
additionally required for feeding the power to the grid Similarly, accessibility to major
highways and roads is also an important factor, as we have to transport the turbine and its
components to the site. Availability and cost of land for the wind farm development is
another major consideration. If our intention is to sell the generated power, an
understanding on the prevailing energy market is also essential. The physical condition of
the site should be thoroughly examined at this stage. This will give us an idea about the
cost of foundation and other related constructions. The size (power rating) and number of
turbines required for the project can be decided. Cost of the turbines and its accessories
71. 71
As well as the mode of maintenance may be negotiated with the manufacturer or local
suppliers. Once all these issues are examined and costs involved are estimated, we can
further workout the economics of wind energy generation at the sites it should be
environmentally acceptable. The major concerns are visual effects, avian interaction,
noise emission and ecological factors. Local survey and consultation with the local
planning authority would be helpful in determining the environmental acceptability of the
project. It should also be ensured that the proposed project is acceptable to the local
residents. The developer should discuss the proposed project with the local community
for avoiding any possible hassles in a later stage. It should be ensured that the project
comply with the statutory requirements prevailing in the region. Finally, the site
satisfying all these requirements-technical, economic, environmental, legal and social-in
the best possible way can be selected for the wind farm development. Next step is to
formulate a detailed proposal for the project. Suitability of the site in all the above aspects
should be described in the proposal. The proposal may then be submitted to the
appropriate body (for example, the local planning authority) for further processing and
approval. As development of wind farm is a capital intensive affair (approximately
costing $ 1 million per MW of installed capacity), possible funding for the project also
should be located side by side. Once the proposal for the project is approved by the
competent authority, then we can proceed further with the micro sitting. Micro siting
involves laying out the turbine and its accessories at optimum locations at the selected
site. Turbines are placed in rows with the direction of incoming wind perpendicular to it,
when several turbines are installed in clusters, the turbulence due to the rotation of blades
of one turbine may affect the nearby turbines. In order to minimize the effect of this rotor
induced turbulence, a spacing of 3 DT to 4 DT is provided within the rows, where DT is
the rotor diameter. Similarly, the spacing between the rows may be around 10 DT, so that
the wind stream passing through one turbine is restored before it interacts with the next
turbine. These spacing may be further increased for better performance, but may be
expensive as we require more land and other resources for farther spacing.
72. 72
Fig. 2.27 Wind stream
2.7.2 500 KWatt wind farm
Consists of 100 turbines each turbine has an output 5kwatt.
Fig. 2.28 500 KWatt wind farm
2.8 Tower design
It is a usual practice to leave a clearance of (hT + DT) from the roads, where hT is the
hub height of the turbine. Leaving this clearance on both sides, the row width available at
a given site can be calculated. If not constrained by other factors, the number of turbines
per row (NTR) may be estimated as
73. 73
Where LR is the row length and SR is the row spacing. If PF is the total capacity of the
wind farm and PT is the rated power of a turbine, then
Where NT is the total number of turbines in the farm. Hence the total number of rows is
obviously
the final placement of individual turbines at a given site depends on several factors like
the shape and size of the available land, existing electrical network etc. Turbines may be
relocated due to environmental factors also-for example we may violate the above norms
to locate turbine at a point which is less prominent from a visually critical spot.
Fig. 2.29 Effect of tower height on the velocity at hub height [Ref. 1]
74. 74
2.8.1 Wind speed of the site station
Table 9: wind speed measurements at 10m Height
From table8 and fig 2.30 we choose tower height to be 10 meter and to be from
Tubular steel towers. These towers are fabricated by joining tubular sections of 10 to 20
m length. The complete tower can be assembled at the site within 2 or 3 days. The
tubular tower, with its circular cross-section, can offer optimum bending resistance in all
directions. These towers are aesthetically acceptable and pose less danger to the avian
population. (Shown Fig. 2.31)
75. 75
Fig. 2.30 Velocity ratio with respect to 10 m for different roughness heights
2.8.2 10mTubular steel tower
Fig. 2.31 10m Tubular steel tower
77. 77
CHAPTER 3
ROTOR PERFORMANCEAND COMPUTATIONALFLUID
DYNAMICS (CFD)
3.1 Introduction
Theoretical study of fluid dynamics of wind turbines could be described by mainly two
approaches: analytical and numerical solution. Analytical method, which is well known
as the blade element momentum (BEM) theory, has significant advantages in
computational speed, robustness and minimal computing capacity requirements. The
basic idea of BEM theory is coupling the results of momentum theory with blade element
theory, therefore it is able to calculate the steady loads and power for different settings of
wind speed, rotational speed and pitch angle. Codes that depend on BEM require
tabulated data for the lift, drag and moment versus the angle of attack to calculate the
blade aerodynamic loads. Furthermore, empirical corrections are necessary to account for
turbulent wake state and blade tip losses. It is difficult to accurately predict the turbine
power output using BEM at realistic operating conditions. Also it is difficult to study the
effect of tip vortices using BEM method due to the nature of two dimensionality of BEM
theory. To overcome limitations of the BEM method, numerical methods can, in
principle, provide a full description of the flow field. Nowadays, full CFD simulations
have been performed on wind turbines. CFD techniques are robust and provide more
detailed results than experimental methods such as tip vortex analysis. In the present
study, both methods are compared with the available experimental data of a Horizontal
Axis Wind Turbine (HAWT). The validated CFD model will be used in a second part of
the study for investigating new modifications of turbine blades to improve turbine
performance. The study of aerodynamic performance of horizontal axis wind turbines has
attracted many researchers in recent years because of potential applications in the
production of electricity based on wind kinetic energy that falls into the category of clean
renewable energy to the environment. This study is based on CFD simulation
(Computation Fluid Dynamic) using the software ANSYS/Fluent that solves the
equations of fluid mechanics in 2D and 3D flows, incorporating highly advanced
turbulence models. This software uses the finite element method, appropriate digital
techniques and features a mesh adapted to very complex configurations.
78. 78
3.2 Rotor performance
Once a wind turbine rotor is designed for a specific application, its performance
characteristics are to be brought out before we fabricate the prototype. Dimension- ally
similar scaled down models of the proposed design are tested under wind tunnels for this
purpose. Low speed wind tunnels working at a very low Mach number are used for these
experiments. Details of such a tunnel used for testing a wind turbine are shown in Fig4.1.
The actual field conditions under which a wind turbine operates can be simulated inside
the tunnel. Model wind turbine to be tested is fixed at the throat or working section.
There are provisions to vary wind velocity as well as the load on the rotor shaft. A
complete set of instrumentation with transducers and data loggers‘ sense and record
information like wind velocity, rotor torque and speed. The rotor is tested for different
wind velocities and shaft loads. Power-speed and torque-speed characteristics of the
rotor, at different wind velocities, can be generated from the test results. This is further
used to estimate the CP- relation- ship of the rotor. Starting behavior of the rotor can
also be found out.
Fig. 3.1 low speed wind tunnel
The power coefficient of the model rotor can be estimated from the relationship:
The tip speed ratio may be calculated as:
And the corresponding for the rotor, at different wind velocities and loads, are
calculated using the above expressions.
79. 79
But in the case using (BEM) calculated Power at different wind velocities show in table
10, 11.
Table 10: Rotor performance with different speed and r.p.m
Fig. 3.2 Relation between RPM and Power in different speed
80. 80
Table 11: the CP- relationship of the rotor
Fig. 3.3 Relation between CP-λ in 4m/sec
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 2 4 6 8 10 12
Cp
λ
4 m/sec
82. 82
Fig. 3.6 Relation between CP-λ in 10m/sec
3.3 Rotor performance analysis with CFD software
3.3.1 2D NREL S-835 Airfoil simulation
The analysis of the two dimensional subsonic flow over a National Renewable Energy
laboratory (NERL) S-835 airfoil at various angles of attack and operating at a Reynolds
number of 0.5×106
.The flow was obtained by solving the steady-state governing
equations of continuity and momentum conservation combined with one of Viscous
turbulence models [Spalart-Allmaras, Vorticity Based].The aim of the work was to show
the behavior of the airfoil at these conditions and to establish a verified solution method.
The computational domain was composed of 20000 cells emerged in a structured way,
taking care of the refinement of the grid near the airfoil in order to enclose the boundary
layer approach. Calculations were done for constant air velocity altering only the angle of
attack for every turbulence model tested.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
4 6 8 10
Cp
λ
10 m/esc
83. 83
3.3.2 Model description and Geometry
NREL's S835 Airfoil - NREL HAWT airfoil S835 at Length Chord 1m
Fig. 3.7 S-835Airfoil geometry
Fig. 3.8 C-Type geometry
84. 84
3.3.3 Mesh
The first step in performing a CFD simulation should be to investigate the effect of the
mesh size on the solution results. Generally, a numerical solution becomes more accurate
as more nodes are used, but using additional nodes also increases the required computer
memory and computational time. The appropriate number of nodes can be determined by
increasing the number of nodes until the mesh is sufficiently fine so that further
refinement does not change the results. A grid is structured C-Type mesh consist of
20400 Nodes and 20000 Elements.
Fig. 3.9 C-type structured grid
85. 85
Fig. 3.10 Partial grid around the wall for airfoil
Fig. 3.11 C-type structured mesh around the modified airfoil with the boundary conditions
86. 86
3.3.4 Fluent
In this work, flow solver was performed Using Ansys Software to Solve a Reynolds-
averaged Navier–Stokes (RANS) equations.
Table12: Fluent model
General Pressure-Based , Absolute , Steady ,planar
Model Viscous , Spalart-Allmaras , Vorticity-Based
Materials Fluid , Air
Boundary
Conditions
Inlet
Velocity Specification Method (Components)
Wind speed = 6m/sec
Angle of Attack ( ) = 5.25
Vx = 5.97 m/sec
Vy = 0.55 m/sec
Initial Gauge Pressure = 0 Pascal
Turbulence (Intensity and Hydraulic Diameter)
Turbulent Intensity(%) = 5%
Hydraulic Diameter = 1m
Outlet
Gauge Pressure = 0 Pascal
Turbulence (Intensity and Hydraulic Diameter)
Turbulent Intensity(%) = 5%
Hydraulic Diameter = 1m
87. 87
Solution
Methods
Pressure –Velocity Coupling
Scheme (coupled)
Spatial Discretization
Gradient (least squares cell Based)
Pressure (standard)
Density (Second order up wind)
Momentum (Second order up wind)
Modified (Second order up wind)
Energy (Second order up wind)
3.3.5 Results
Fig. 3.12 Velocity contour around airfoil at angle of attack α=5.25°
88. 88
Fig. 3.13 Turbulence contour around airfoil at angle of attack α=5.25°
Fig. 3.14 Total Pressure contour around airfoil at angle of attack α=5.25°
89. 89
Fig. 3.15 Relation between Iteration and lift coefficient
Fig. 3.16 Relation between Iteration and Drag coefficient
90. 90
Table13: Comparison between CFD Date and Xfoil Date
CFD Date Xfoil date
CL = 0.7808 CL = 0.8146
CD = 0.03914 CD = 0.01052
3.4 Estimate a CL & CD in 5Kwatt HAWT blade with a different chord
Fig 3.16 5Kwatt HAWT blade with a different chord (m)
The same S-835 Airfoil and Boundary Conditions but a velocity inlet is a relative
velocity and our team assumed a Reynolds number of 1×106
it had to be operated
Reynolds number of 0.5×106
because estimate a power developed at Low wind speed.
91. 91
Fig. 3.17 Velocity contour around airfoil at Length =0.728m and α=34.8535
Fig. 3.18 Velocity contour around airfoil at Length =0.62m and α=21.8277
92. 92
Fig. 3.19 Velocity contour around airfoil at Length =0.516m and α=10.8407
Fig. 3.20 Velocity contour around airfoil at Length =0.436m and α=5.1197
93. 93
Fig. 3.21 Velocity contour around airfoil at Length =0.376m and α=5.1390
Fig. 3.22 Velocity contour around airfoil at Length =0.328m and α=5.1545☉
94. 94
Fig. 3.23 Velocity contour around airfoil at Length =0.288m and α=5.1659
Fig. 3.24 Velocity contour around airfoil at Length =0.26m and α=5.1753
95. 95
Fig. 3.25 Velocity contour around airfoil at Length =0.236m and α=5.1829
Fig. 3.26 Velocity contour around airfoil at Length =0.2196m and α=5.1892
98. 98
CHAPTER FOUR
DESIGN OF 600KWALT PHOTOVOLTAIC (PV) PLANT
4.1 Introduction
Photovoltaic is the process of converting sunlight directly into electricity
using solar cells. Today it is a rapidly growing and increasingly important
renewable alternative to conventional fossil fuel electricity generation, but
compared to other electricity generating technologies, it is a relative
newcomer. Photovoltaic offer consumers the ability to generate electricity in a
clean, quiet and reliable way. Photovoltaic systems are comprised of
photovoltaic cells, devices that convert light energy directly into electricity.
Because the source of light is usually the sun, they are often called solar cells.
The word photovoltaic comes from ―photo,‖ meaning light, and ―voltaic,‖
which refers to producing electricity. Therefore, the photovoltaic process is
―producing electricity directly from sunlight.‖ Photovoltaic are often referred
to as PV.
4.1.1 s o l ne (s eh loT eo a ehesemh na da n am ehT:
Electricity produced by solar cells is clean and silent. Because they do not
use fuel other than sunshine, PV systems do not release any harmful air or
water pollution into the environment, deplete natural resources, or endanger
animal or human health.
Photovoltaic systems are quiet and visually unobtrusive.
Small-scale solar plants can take advantage of unused space on rooftops of
existing buildings.
PV cells were originally developed for use in space, where repair is
extremely expensive, if not impossible. PV still powers nearly every
satellite circling the earth because it operates reliably for long periods of
time with virtually no maintenance.
Solar energy is a locally available renewable resource. It does not need to
be imported from other regions of the country or across the world. This
99. 99
reduces environmental impacts associated with transportation and also
reduces our dependence on imported oil. And, unlike fuels that are mined
and harvested, when we use solar energy to produce electricity we do not
deplete or alter the resource.
Reliability of the plants since they do not have moving parts (useful life 20
years).
Reduced operating and maintenance costs.
4.1.2 The main Disadvantages of Photovoltaic (PV) plant:
Some toxic chemicals, like cadmium and arsenic, are used in the PV
production process. These environmental impacts are minor and can be
easily controlled through recycling and proper disposal.
Solar energy is somewhat more expensive to produce than conventional
sources of energy due in part to the cost of manufacturing PV devices and
in part to the conversion efficiencies of the equipment. As the conversion
efficiencies continue to increase and the manufacturing costs continue to
come down, PV will become increasingly cost competitive with
conventional fuels.
Solar power is a variable energy source, with energy production dependent
on the sun. Solar facilities may produce no power at all some of the time,
which could lead to an energy shortage if too much of a region's power
come from solar power.
4.2 The Annual Electrical Power output of Photovoltaic (PV) plant depends
on different factors:
Solar radiation incident on the installation site.
Inclination and orientation of the panels.
Presence or not of shading.
Technical performances of the plant components (mainly modules and
inverters).
100. 100
4.3 How Photovoltaic (PV) Works?
PV cells convert sunlight directly into electricity without creating any air or
water pollution and are made of at least two layers of semi- conductor
material. One layer has a positive charge, the other negative. When light
enters the cell, some of the photons from the light are absorbed by the
semiconductor atoms, freeing electrons from the cell‘s negative layer to flow
through an external circuit and back into the positive layer. This flow of
electrons produces electric current.
Fig. 4.1 Basic solar cell construction the sandwich of semiconductor materials produces
electricity directly from the sunlight without any moving parts
To increase their utility, dozens of individual PV cells are interconnected
together in a sealed, weatherproof package called a module. When two
modules are wired together in series, their voltage is doubled while the current
stays constant. When two modules are wired in parallel, their current is
doubled while the voltage stays constant. To achieve the desired voltage and
current, modules are wired in series and parallel into what is called a PV
array. The flexibility of the modular PV system allows designers to create
solar power systems that can meet a wide variety of electrical needs, no matter
how large or small.
Base contact
Top electrical contact
P-Type material
(boran-doped silicon)
P/N junction
External circuit
Encapsulate seal
Sunlight
(photons)
101. 101
Fig. 4.3 Photovoltaic cells, modules and arrays the building blocks of solar
electricity are modular in nature, allowing great flexibility in applications
4.4 Types of Solar Photovoltaic (PV) System
Solar PV systems can be classified based on the end-use application of the
technology.
There are two main types of solar PV systems:
ON grid system or (grid-tied).
OFF grid system or (stand-alone).
102. 102
Fig. 4.3 Types of PV system
4.4.1 ON grid system or (grid-tied)
Grid-tied or grid connected solar is a solar electricity system without
batteries. Your home is hooked up to both the national grid and your Power
Smart solar electricity system, so you will always have electricity available at
the flick of a switch; even at night, or if it is cloudy. You can install a solar
electricity system of any size and you will only ever be billed if your power
consumption is in excess of the amount you are generating.
The electricity grid acts as a 100% efficient and maintenance free battery
while also providing unlimited ‗on demand‘ energy. This is what makes grid
connected solar electricity so attractive. It has all the benefits of being
attached to the electricity grid but with a portion of your electricity bill never
increasing in price.
However we do offer grid-connect solar power systems with back-up for
customers with special requirements.
103. 103
Fig. 4.4 on grid system and components
4.4.1.1 Operation
Residential grid-connected which have a capacity more than 10 kilowatts can
meet the load of most consumers. They can feed excess power to the grid
where it is consumed by other users. The feedback is done through a meter to
monitor power transferred. Photovoltaic wattage may be less than average
consumption, in which case the consumer will continue to purchase grid
energy, but a lesser amount than previously. If photovoltaic wattage
substantially exceeds average consumption, the energy produced by the panels
will be much in excess of the demand. In this case, the excess power can yield
revenue by selling it to the grid. Depending on their agreement with their local
grid energy company, the consumer only needs to pay the cost of electricity
consumed less the value of electricity generated. This will be a negative
number if more electricity is generated than consumed. Additionally, in some
cases, cash incentives are paid from the grid operator to the consumer.
Connection of the photovoltaic power system can be done only through an
interconnection agreement between the consumer and the utility Company.
104. 104
The agreement details the various safety standards to be followed during the
connection.
4.4.2 OFF grid system or (stand-alone)
Off-grid connected solar is a solar electricity system with battery backup.
During the day the sun shines and charges the batteries as well as supplies
power to your home. During the evening or on rainy days when the sun isn‘t
shining you use the power stored in the batteries. Your house is not connected
to the national grid hence the name: off-grid. Although there have been large
price reductions in the cost of panels and inverters, batteries are generally
quite expensive and require regular maintenance. Generally the idea of being
off the grid is quite appealing but it does require more investment. Most of the
time it is more cost efficient to connect to the grid and offset your electricity
consumption with a grid-connect solar PV system than to go off-grid.
However if you are building a new house or holiday home in a remote
location off-grid solar can work out to be a lot cheaper than paying to be
connected to the grid. There is no absolute standard off-grid system and it
should be designed to suit your specific electrical loads and use patterns. At
Power Smart we have designed systems that run whole pacific nations. We
love off-grid systems and would love to help design yours.
105. 105
Fig. 4.5 off grid system and components
4.4.2.1 Major system components
Solar PV system includes different components that should be selected according to your system type,
site location and applications. The major components for solar PV system are solar charge controller,
inverter, battery bank, auxiliary energy sources and loads (appliances).
PV module – converts sunlight into DC electricity.
Solar charge controller – regulates the voltage and current coming from the PV
panels going to battery and prevents battery overcharging and prolongs the battery
life.
Inverter – converts DC output of PV panels or wind turbine into a clean AC current
for AC appliances or fed back into grid line.
Battery – stores energy for supplying to electrical appliances when there is a
demand.
Load – is electrical appliances that connected to solar PV system such as
lights, radio, TV, computer, refrigerator, etc.
106. 106
4.5 Design of 600kWalt Photovoltaic (PV) plant by (PV syst Software)
Fig. 4.6 600kWalt Photovoltaic (PV) plant
112. 112
CHAPTER 5
MODELCONSTRUCTION
5.1 Introduction
The purpose of this project is to design a portable and low-cost power system that
combines both wind electric and solar electric technologies. This hybrid system will be
designed to deliver 40Watt of continuous power. The system is composed of a wind
generator, a solar panel, a charge controller, a battery and an inverter. The solar panel and
wind turbine work in tandem to charge a battery via a controller. After, an inverter will be
used to convert DC power from the battery into AC power suitable for domestic use. The
system will have a battery bank large enough to supply electric load for two days.
To install a wind-solar hybrid system, your property must have the ideal layout for a
residential wind turbine and a solar array. If your site doesn‘t receive an adequate amount
of wind or sun, there‘s no point in installing a hybrid system. The U.S. Department of
Energy recommends that an energy expert consult a wind resource map or use a wind
measurement system to determine whether or not a home receives enough wind. To
qualify for solar panels, your roof needs to be in good condition, use strong materials for
shingles, lack tree coverage and be no more than 10 years old. If you plan to install the
solar panels on the ground instead of a roof, you must have enough flat, unshaded terrain
on your property.
5.2 Design Requirement
To install a wind-solar hybrid system, your property must have the ideal layout for a
residential wind turbine and a solar array. If your site doesn‘t receive an adequate amount
of wind or sun, there‘s no point in installing a hybrid system. The U.S. Department of
Energy recommends that an energy expert consult a wind resource map or use a wind
measurement system to determine whether or not a home receives enough wind. To
qualify for solar panels, your roof needs to be in good condition, use strong materials for
shingles, lack tree coverage and be no more than 10 years old. If you plan to install the
solar panels on the ground instead of a roof, you must have enough flat, unshaved terrain
on your property. The power produced from system equal 40 watt divided into two
systems (PV solar system and wind turbine system). The solar system produces 20 watt
and wind turbine system produce 20watt.
113. 113
5.3 Design constrain of hybrid system
The increasing energy demand and environmental concerns aroused considerable interest
in hybrid renewable energy systems and its subsequent development.
The design of wind turbine depends on some parameter such tip speed ratio and wind
speed. In the MUST design wind turbine parameters taken see Table12
Table 15: design constrain parameter
Parameter symbol value
Tip speed ratio 5.5
Wind speed U Varying from
4 to10(m/s)
5.4 Wind turbine design and performance
5.4.1 Main Principles of Wind Turbines
When a force is transferred from an air stream to a solid object, it is very different than
the force which is transferred between solid objects. Moreover, when an object
experiences a force from an air stream, it can be distinguished in two equivalent
components. In the first component the force is acting in the direction of the flow and is
known as drag force while in the second one the force is acting perpendicular to the flow
and is known as the lift force. Lift and drag forces are proportional to the energy of the
wind.The drag force can be resolved in two more components; pressure drag and friction
drag. Pressure drug acts on the front side of the object, pushes the object along with the
flow and the more perpendicular this pressure drag is, the bigger is the drag force
experienced on the object. On the other hand, friction drug acts when the fluid is in line
with the front side of the object and as it becomes more parallel, the drag force which
occurs on the object becomes less. Objects are designed to reduce the drag forces as
much as they can, and they are described as streamlined objects, lines which follow a
smooth stream. These kinds of shapes can be found in sharks, airships and the aero foils
(the shape of a wing or blade). A body which is designed to produce large quantities of
lift is an airfoil. By using design equation can get the all wind turbine deign parameter.
The wind turbine performance parameter summarized in Table 14 and Table 17.
114. 114
Table 16: wind turbine design parameter
No r/R U C W dF dT
1 0.02 0.55 3.3 61.1892 35 26.1892 0.0606 0 0 6.8476 0 0
2 0.04 1.1 6.6 42.2737 22 20.2737 0.0516 0 0 8.9196 0 0
3 0.06 1.65 9.9 31.2184 11 20.2184 0.043 1.552 0.022 11.5763 0.2116 0.0074
4 0.08 2.2 13.2 24.444 5.25 19.194 0.0363 1.0518 0.00813 14.4997 0.2695 0.0096
5 0.1 2.75 16.5 19.9831 5.25 14.7331 0.0313 1.0518 0.00813 17.557 0.3515 0.0125
6 0.12 3.3 19.8 16.8584 5.25 11.6084 0.0273 1.0518 0.00813 20.6891 0.4333 0.0153
7 0.14 3.85 23.1 14.5603 5.25 9.3103 0.024 1.0518 0.00813 23.8665 0.5125 0.018
8 0.16 4.4 26.4 12.8043 5.25 7.5543 0.0216 1.0518 0.00813 27.0732 0.5978 0.021
9 0.18 4.95 29.7 11.4212 5.25 6.1712 0.0196 1.0518 0.00813 30.3 0.6828 0.0238
10 0.2 5.5 33 10.3048 5.25 5.0548 0.0183 1.0518 0.00813 33.541 0.784 0.0273
Table 17: design parameter at different wind turbine speed
5.4.2 Wind Turbine solid works drawing
By using design parameter for drawing the turbine that is the first step for manufacturing.
For drawing the wind turbine more flexible must be drawing each part individually such
as blades, hub and nut using solid works parts drawing and after finishing all parts
drawing used solid works assemble show in table 18.
115. 115
Table 18: 20 HAWT
Fig. 5.1 blade solid works drawing
Fig. 5.2 hub solid works drawing
116. 116
Fig. 5.3 nut solid works drawing
Fig. 5.4 Wind turbine solid works assemble
117. 117
5.5 Design construction of hybrid system
The generation of both wind power and solar power is very dependent on the weather
conditions. Thus, no single source of energy can supply cost-effective and reliable power.
The combined use of multiple power resources can be a viable way to achieve trade-off
solutions. With combine of the renewable systems, it is possible that power fluctuations
will be incurred. To mitigate or even cancel out the fluctuations, energy storage
technologies, such as storage batteries (SBs) can be employed.
The proper size of storage system is site specific and depends on the amount of
renewable generation and the load. The needed storage capacity can be reduced to a
minimum when a proper combination of wind and solar generation is used for a given
site.The hybrid system is shown in Fig.5.5. In the following sections, the model of
components is discussed.
Fig. 5.5 The framework of activities
5.5.1 20 HAWT
Choosing a suitable model is very important for wind turbine power output. The most
simplified model to simulate the power output of a wind turbine could be calculated from
its power-speed curve at different wind speed.
The simulation of wind speed is considered using fan and duct (Shown Fig 5.6). It has a
rated capacity of 20W as output). The power of fan is described in terms voltage and
current.
118. 118
Fig. 5.6 the layout of HAWT simulation system
Fig. 5.7 the Duct and fan parts before installing
Fig. 5.8 the Duct and fan parts after installing
