VAWT Report

EFFECT OF LIFT TO DRAG RATIO, MASS AND NUMBER OF

BLADES ON OVERALL EFFICIENCY IN A VERTICAL AXIS

WIND TURBINE

by

Yousif Alsarraf

John Benavides

Michael Lagalle

Nicholas Lippis

Husam Zawati

2015

UCF

EFFECT OF LIFT TO DRAG RATIO, MASS AND NUMBER OF BLADES ON OVERALL EFFICIENCY IN A VERTICAL AXIS WIND TURBINE

by

Yousif Alsarraf John Benavides Michael Lagalle Nicholas Lippis Husam Zawati

A final report submitted in partial fulfillment of the requirements for the degree of Bachelor’s of Science

in the Department of Mechanical and Aerospace Engineering in the College of Engineering and Computer Science

at the University of Central Florida Orlando, Florida

Fall Term 2015

Major Advisors: Mr. Kurt Stresau Dr. Bijay Sultanian

© 2015 Team Anemoi

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ABSTRACT

The purpose of the project is to apply mechanical engineering concepts to

reverse engineer and improve an existing state-of-the-art VAWT that is commercially

available in the market. After extensive analyzing of governing equations, researching

relevant topics in aerodynamics, manufacturing and electricity, equation parameters

were taken into consideration to study the factors that were affecting the efficiency of

the turbine. The existing turbine was initially tested to check its functionality and its

overall efficiency (𝜂𝜂) was calculated to be between 0.12 and 7.28 % at wind speeds of

6.5 and 24.5 𝑚𝑚 𝑠𝑠⁄ , respectively. Selection of material and the increase in lift to drag

ratio as well as decreasing the number of blades for the prototype were proven to have

the highest impact on the calculated efficiency. To make this a fair comparison, it has

been decided that the prototype wind turbine will have the same dimensions when it

comes to the swept area (𝐴𝐴𝑇𝑇). After optimizations, the prototype was a 3-bladed system

with a mass reduction of 30%, and an overall maximum efficiency (𝜂𝜂) ranging between

0.5 and 19.28 % at wind speeds of 6.2 and 11 𝑚𝑚 𝑠𝑠⁄ . The overall average increase in

efficiency for the prototype was 67%.

ii

This final report is first and foremost dedicated to our parents, and those who influenced and

supported us throughout the years in college

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ACKNOWLEDGMENTS

Team Anemoi wishes to express heartfelt gratitude to Mr. Kurt Stresau for his

continuous assistance throughout Senior Design 1 and 2. Sharing some of his personal

experiences and thoughtful ideas helped us shape the way we perceive team spirit.

We also would like to be particularly thankful to Dr. Bijay Sultanian, who

provided us with the necessary advice and guidance that built the pillars for this

project.

Special thanks to our sponsors: Duke Energy for their generous financial

support, Ms. Morgan Hamel from re:3D who introduced us to Mr. Darrel Barnette, our

mentor for 3D printing and Mr. Chuck Sackett for his donation of services . Thanks to

our sponsor Aphnic Inc., who made the visual content that were used during the final

presentation and symposium day.

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v

ETHIC STATEMENT

To whom it may concern:

As primary investigators of this project, we are aware that we are in a position

of responsibility and trust. We realize that this work involves conducting tests and

looking up information from different sources that will help us achieve our desired

goal. We are also responsible for the generous amount of funding granted by Duke

Energy, by spending on project completion and approved purchases.

Except to where it is specified as citations and/or published and unpublished

sources, the team is aware that any uncited incorporation of material included within

this project is considered plagiarism, and is subject to the U.S. laws of publishing. All

of the external sources used are indicated in the references within this report.

None of the data was altered or modified for the sake of improving the overall

look and/or the final achieved efficiency of our Vertical Axis Wind Turbine. The team

as a whole follows the American Society of Mechanical Engineer’s code of ethics. We

abide the ten fundamental canons of the Code of Ethics for Engineers. All our

knowledge and skills were used for the enhancement of human welfare. We will

always strive to increase the competence and prestige of the engineering profession

throughout our careers.

__________________________

p.p. Team Anemoi

vi

vii

CONTENTS

Abstract ........................................................................................................................................... ii

Acknowledgments.......................................................................................................................... iv

Ethic Statement .............................................................................................................................. vi

Contents .......................................................................................................................................... 1

List of Tables .................................................................................................................................. 4

List of Figures ................................................................................................................................. 5

List of Abbreviations ...................................................................................................................... 7

Nomenclature .................................................................................................................................. 7

Greek Letters ............................................................................................................................... 7

Chapter 1: Background ................................................................................................................... 9

1.1 Introduction .................................................................................................................... 12

1.2 Design Requirement ....................................................................................................... 13

1.2.1 Customer Requirement ........................................................................................... 13

1.2.2 Constraints .............................................................................................................. 15

1.2.3 Meeting the Requirement ........................................................................................ 16

1.2.4 Existing Issues ........................................................................................................ 18

1.3 Idea Development and Design Phase ............................................................................. 18

1.3.1 Concept Design ....................................................................................................... 19

1.3.2 Configuration Design .............................................................................................. 22

1.3.3 Parametric Design ................................................................................................... 24

1.3.4 Detail Design .......................................................................................................... 26

Chapter 2: Product Design, Developments, and Prototyping ....................................................... 29

2.1 Development of the Final Solution to the Design Problem ........................................... 29

2.1.1 Design Modifications .............................................................................................. 29

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2.1.2 Analyses and Simulations ....................................................................................... 32

2.1.3 Optimization ........................................................................................................... 35

2.2 Parts Descriptions ........................................................................................................... 36

2.2.1 List of Parts Used .................................................................................................... 38

2.2.2 Part Drawings and Schematics ................................................................................ 40

2.3 Manufacturing and Assembly ........................................................................................ 41

2.3.1 Description of Manufacturing Processes and Techniques ...................................... 41

2.3.2 Manufacturing Schematics ...................................................................................... 44

2.3.3 Manufacturing Instruction ...................................................................................... 45

2.3.4 Assembly Drawing .................................................................................................. 47

2.3.5 Assembly Instruction .............................................................................................. 48

2.4 Test and Evaluation ........................................................................................................ 48

2.4.1 Test Method and Procedures ................................................................................... 48

2.4.2 Testing Results and Performance Analyses ............................................................ 51

2.5 User Manual ..................................................................................................................... 1

2.5.1 Safety Precautions ..................................................................................................... 3

2.5.2 Introduction ............................................................................................................... 4

2.5.3 Specifications ............................................................................................................ 5

2.5.4 Package Contents ...................................................................................................... 5

2.5.5 Tools required for assembly...................................................................................... 5

2.5.6 Assembly Instructions ............................................................................................... 6

2.5.7 Maintenance .............................................................................................................. 9

2.5.8 Troubleshooting ...................................................................................................... 10

2.5.9 Warranty ................................................................................................................. 11

Chapter 3: Project Management.................................................................................................... 68

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3.1 Work breakdown structure ............................................................................................. 68

3.2 Organization Chart ......................................................................................................... 69

3.3 Individual responsibilities .............................................................................................. 70

3.3.1 Action Log for Fall 2015 Semester ......................................................................... 70

3.4 Project Period and Budget summary .............................................................................. 72

3.5 Finalized Gantt Chart ..................................................................................................... 78

Chapter 4: Lessons Learned .......................................................................................................... 79

4.1 Discussion ...................................................................................................................... 79

4.2 Contribution in Relation to Customer’s Need ................................................................ 81

4.3 Team Design Experience and Lessons Learned ............................................................. 81

Chapter 5: Conclusions and Recommendation ............................................................................. 84

5.1 VAWT: A Deeper Insight .............................................................................................. 84

5.2 Conclusion ...................................................................................................................... 85

References ..................................................................................................................................... 86

Appendices .................................................................................................................................... 87

3D Printed Airfoil ................................................................................................................. 88

Engineering Drawings .......................................................................................................... 89

Relevant Material .................................................................................................................. 94

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LIST OF TABLES

Table 1: List of parts used ............................................................................................................. 38

Table 2: Weight differentials in systems ...................................................................................... 55

Table 3: Parametric changes ......................................................................................................... 55

Table 4: Troubleshooting of Anemoi VAWT ............................................................................... 10

Table 5: Action log ....................................................................................................................... 70

Table 6: Summary of budgeting ................................................................................................... 72

Table 7-Blade material decision matrix ........................................................................................ 95

Table 8-Airfol decision matrix ...................................................................................................... 96

Table 9-Component decision matrix ............................................................................................. 96

Table 10-Other factors decision matrix ........................................................................................ 96

Table 11-Key to decision matrix ................................................................................................... 97

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LIST OF FIGURES

Figure 1: Types of VAWT .............................................................................................................. 9

Figure 2: Savonius and Darrieus VAWTs .................................................................................... 10

Figure 3: Efficiency and Betz's Law limit (Thermodynamics book by Cengel) .......................... 11

Figure 4: Wind forces on a single blade ....................................................................................... 20

Figure 5: 3 and 5 bladed Darrieus VAWTs .................................................................................. 20

Figure 6: GOE 481 airfoil ............................................................................................................. 21

Figure 7: Base model Eppler 541 airfoil ....................................................................................... 21

Figure 8: GOE 481 and Eppler 541 airfoils .................................................................................. 21

Figure 9: Connection of rod-to-shaft ............................................................................................ 22

Figure 10: Connection of sleeve-to-shaft ...................................................................................... 23

Figure 11: Connection of blade-to-arm ......................................................................................... 24

Figure 12: CAD of rotor arms ....................................................................................................... 26

Figure 13: Acrylic shaft ................................................................................................................ 27

Figure 14: Aluminum shaft ........................................................................................................... 27

Figure 15: Testing rig.................................................................................................................... 28

Figure 16: PLA printed airfoil ...................................................................................................... 30

Figure 17: Blemish on PLA airfoil ............................................................................................... 30

Figure 18: Different shapes of rotor arms ..................................................................................... 32

Figure 19: Von Mises stress analysis ............................................................................................ 33

Figure 20: Displacement analysis ................................................................................................. 33

Figure 21: CFD of pressure distribution on airfoil ....................................................................... 34

Figure 22: Pressure distribution on the system ............................................................................. 34

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Figure 23: Different infills of 3D printed plastic .......................................................................... 35

Figure 24: Cut-in-half rotor arms .................................................................................................. 36

Figure 25: Alignment of rotor arms .............................................................................................. 37

Figure 26: Airfoil drawing ............................................................................................................ 40

Figure 27: Rotor arm drawing ....................................................................................................... 40

Figure 28: Surface preparation of rotor arm ................................................................................. 42

Figure 29: CAD of main shaft ...................................................................................................... 44

Figure 30: CAD of generator ........................................................................................................ 44

Figure 31: CAD of half a rotor arm .............................................................................................. 46

Figure 32: Generator shaft manufacturing .................................................................................... 46

Figure 33: Drawing of assembly ................................................................................................... 47

Figure 34: Calibration graph for prototype ................................................................................... 49

Figure 35: Manometer reading vs. RPM....................................................................................... 51

Figure 36: Voltage generated vs. RPM ......................................................................................... 52

Figure 37: Voltage vs. wind speed ................................................................................................ 52

Figure 38: Comparison of power vs. wind speed ......................................................................... 53

Figure 39: Power vs. wind and car speeds .................................................................................... 54

Figure 40: Comparison of power vs. speed of impact .................................................................. 54

Figure 41: Work breakdown structure .......................................................................................... 68

Figure 42: Organization chart ....................................................................................................... 69

Figure 43: Gantt chart ................................................................................................................... 78

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LIST OF ABBREVIATIONS

𝐴𝐴𝐴𝐴 Alternating current, V

𝐴𝐴𝐶𝐶2 Carbon Dioxide

𝐷𝐷𝐴𝐴 Direct current, 𝑉𝑉

𝐺𝐺𝐶𝐶𝐺𝐺 # Göttingen airfoil

𝐻𝐻𝐴𝐴𝐻𝐻𝐻𝐻 Horizontal Axis Wind Turbine

𝑅𝑅𝑅𝑅𝑅𝑅 Revolutions per minute

𝐻𝐻𝑇𝑇𝑅𝑅,𝑋𝑋 Tip-speed ratio

𝑉𝑉𝐴𝐴𝐻𝐻𝐻𝐻 Vertical Axis Wind Turbine

NOMENCLATURE

𝐴𝐴𝑇𝑇 Swept area, 𝑚𝑚2

𝑐𝑐 Local blade cord, 𝑚𝑚

𝐴𝐴𝐷𝐷,0 Initial value of the drag coefficient

𝐴𝐴𝐿𝐿 Coefficient of lift

𝐴𝐴𝑃𝑃 Coefficient of power

𝐷𝐷 Diameter of VAWT, 𝑚𝑚

𝐻𝐻 Height, 𝑚𝑚

𝐿𝐿 Length of blade, 𝑚𝑚

𝑁𝑁 Number of rotor blades

𝑅𝑅 Power delivered, 𝐻𝐻

𝑅𝑅 Blade radius, 𝑚𝑚

𝑉𝑉0 Wind speed, 𝑚𝑚 𝑠𝑠⁄

𝑉𝑉𝑡𝑡𝑡𝑡𝑡𝑡 Tip speed, 𝑚𝑚 𝑠𝑠⁄

𝐻𝐻 Width, 𝑚𝑚

𝐻𝐻 Power, Watts

𝑤𝑤 Angular velocity of rotor, 𝑟𝑟𝑟𝑟𝑟𝑟 𝑠𝑠

𝑥𝑥 1.5∗TSR

° Degrees

Greek Letters

𝜃𝜃 Azimuth angle of blade, °

𝜌𝜌 Density of air, 𝑘𝑘𝑘𝑘 𝑚𝑚3

𝜇𝜇 Total efficiency

𝜂𝜂 Overall efficiency

𝜔𝜔 Rotational blade speed, 𝑟𝑟𝑟𝑟𝑟𝑟 𝑠𝑠

7

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CHAPTER 1: BACKGROUND

A wind turbine is a device that harnesses the energy of the wind to convert it

into electrical power. The energy of the wind is captured by the blades of the turbine to

achieve rotation that will be used in rotating a generator. The generator will then

produce power (𝐻𝐻) that will be collected in a battery or connected to a grid.

This project was focused on a Vertical Axis Wind Turbine (VAWT) (figure 1),

which is a different design in comparison to a Horizontal Axis Wind Turbine (HAWT).

A VAWT is designed to capture the energy of the wind from whichever direction the

wind strikes the turbine. However, force for rotation is only harnessed from one blade,

while the others are not affected by the lift forces. A HAWT is designed to capture the

wind energy from one direction, which requires the turbine to identify the direction of

the wind and reposition its blades for wind energy capturing. The benefit is that each

blade is used to harness energy, instead of one like in the VAWT. The VAWT is

classified into two designs, the Darrieus and the Savonius, (figure 2). The Darrieus

design is based on lift, which is the design that the team has chosen since it is a more

Figure 1: Types of VAWT

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efficient design in terms of using wind energy more effectively, while the Savonius is a

drag based design.

Figure 2: Savonius and Darrieus VAWTs

The intent of this senior design project is to build a superior vertical axis wind

turbine than what is generally available in today’s market. To be more precise, the

base-line model that is being challenged is the ALEKO 30 W VAWT. The ALEKO

bench mark that the team is currently in the process of surpassing is its efficiency,

which was claimed to be 15%.

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Figure 3: Efficiency and Betz's Law limit (Thermodynamics book by Cengel)

In order to achieve the goal the team has set, an in-depth understanding of

turbine efficiency had to be understood. Detailed literature, along with online review

papers that study wind turbines and their associated efficiency have been researched

and read to understand how to approach the higher efficiency goal. These books have

all similarly stated efficiency is determined by the tip speed ratio (𝐻𝐻𝑇𝑇𝑅𝑅) (equation 1),

and torque force (𝜏𝜏) generated. In terms of gathering usable wind energy it was

learned, according to Betz limit, no turbine can capture more than 59.3% of the wind’s

kinetic energy, (figure 3). On top of that, no VAWT on the market has an efficiency of

even 40%, regardless of the type of technology used for lift maximization and drag

minimization.

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𝑋𝑋 = 𝑉𝑉𝑡𝑡𝑡𝑡𝑡𝑡𝑉𝑉0

(1)

Where 𝑉𝑉𝑡𝑡𝑡𝑡𝑡𝑡 = 𝜔𝜔×2×𝜋𝜋×𝑅𝑅60

(2)

1.1 Introduction

Existing power generating sources which are implemented on a world wide

scale are typically involved in the consumption of natural resources such as oil. Such

consumptions produce a byproduct that goes along with the energy production, such as

greenhouse gases, 𝐴𝐴𝐶𝐶2. To minimize the production of such gases, an alternative to

such energy sources have been explored.

Of the many ways of generating power, some have the capability of producing

power without the harmful byproducts. This power has to come from an energy source

that is naturally occurring, whether it being the heat of the sun, the motion of the ocean,

or the force of the wind.

Wind turbines are a device that this project entitled both in terms of theory and

practice. The wind turbines harness the kinetic energy of the wind, and through

induced rotation, convert the kinetic energy of the wind into power, provided that the

induced rotation is also rotating an 𝐴𝐴𝐴𝐴 − 𝐷𝐷𝐴𝐴 generator.

Unfortunately, there are some drawbacks to a wind turbine which will cause

design problems. These drawbacks are the need of adequate wind speed, as well as the

low efficiency that wind turbines poses. To produce a successful wind turbine, such

drawbacks must be minimized or maximized where appropriate.

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The need of adequate wind speed is due to the necessity of inducing rotation.

The wind speed is an uncontrollable parameter, however, weight and friction are

controllable. To allow greater rotation while being exposed to the same wind speed, the

turbine must be constructed from light material, and have a lesser friction points.

As for efficiency 𝜂𝜂, the process is more challenging. To increase the efficiency

of a wind turbine, a complete understanding of the wind turbine and the parameters that

affect the efficiency have to be explored, and only then should there be an attempt for

increasing the efficiency.

𝜇𝜇𝑇𝑇𝑇𝑇𝑇𝑇 = 𝐴𝐴𝑃𝑃 × 𝜇𝜇𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔 × 𝜇𝜇𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑔𝑡𝑡𝑔𝑔𝑔𝑔 (3)

The team spent a large amount of time on research to understand how a wind

turbine works and what affects its efficiency, and from there, the controlling and

affecting parameters were optimized to fit the projects application requirements,

budget, and goals.

1.2 Design Requirement

1.2.1 Customer Requirement

As a senior design project that has been handed down from the department, the

customer by default was our technical advisor Dr. Sultanian, who unfortunately has left

the department. This project has been handed over to Mr. Stresau, who is considered

the new customer. The latter customer has not changed the requirements set by the

former.

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The customer requirements of this project were to provide a superior product

than what is readily available on the market. To create a bench mark for such a

requirement, a wind turbine from the manufacturer ALEKO was chosen to be the

bench mark, as well as the direct competitor. The areas of improvement that the team

focused on improving are safety, weight, versatility, cost, power production, and

efficiency.

Safety is the most important issue that most customers focus on, whether it

would be personal safety, or fear of liability. Whatever the reason may be, safety must

be at the top of the list when discussing requirements.

The second requirement involved the weight of the turbine. The turbine over all

weight was decided to be kept and reduced to a minimum. This is due to the research

that indicated that wind turbines produce more power once placed on elevated grounds;

which brings in the discussion of transportation. If the wind turbine is needed to be

transported to higher grounds, it will be beneficial to have such a turbine to be light

weight as well.

Weight also ties in to one of the constraints that the turbine must uphold. The

lighter the turbine is at the blade and shaft section, the faster the blades will rotate

causing more power generation. A lighter turbine also provides a safer product, if the

turbine is to be blown away or fall of its high rise support.

Versatility is also a requirement of the customer. The customer decided that the

turbine must have the ability to be placed on most existing structures, which will

ensure that the product will have a larger market.

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Minimizing the cost was also another requirement of the customer. The

customer required that the product not cost more than what is available on the market.

The team decided to go above and beyond, and decided that the product should cost

less than what is available on the market.

Earlier in the semester the power output was not specified in terms of a certain

amount, it was indicated that the power output should be reasonable to power a

household applicant. After extensive research and crunching in of numbers, it was

indicated that the power output of a turbine that the team was limited and would not

produce enough power instantaneously to run a household applicant for 24 hours. Thus

the customer revisited the requirement list and made some changes due to the new

discoveries. Power output requirement was removed and efficiency became the new

focus. The customer required that the efficiency be larger than other models, but left

the exact percentage of increase to be determined by the team. The team decided

unanimously that the increase in efficiency should be as high as possible with a

minimum goal of 10%.

1.2.2 Constraints

Safety is a very important constraint; this product had to be safe to function

within populated areas. A scenario where safety becomes a big factor is when the

turbine might need to be removed or collapsed while rotating at a high 𝑅𝑅𝑅𝑅𝑅𝑅 rate.

Weight is one of the constraints that the turbine must uphold. The lighter the

turbine at the blade and shaft section, the faster the blades will rotate causing more

power generation and higher efficiency. A lighter turbine also provides a safer product,

15

if the turbine is to be blown away or fall off its high rise support. As a solution to this

constraint, lightweight materials were considered for the design.

Cost is a default constraint, and this was apparent early on when each team had

to present an estimated budget of how much funding the project might require. The

budget does not mirror the exact cost of what the product might cost if it is offered in

the market. It is the cost of creating a prototype, as well as all the equipment that are

needed to be purchased to facilitate testing and manufacturing.

As previously stated, wind turbines require an initial wind velocity to induce

rotation. Therefore, the wind turbine is subject to an operational constraint so that an

output of power generation can be achieved. Such wind speeds might not always be

available, especially in the sun shine state, but placing the turbine in optimum locations

helps the turbine generate as much power as environmentally available.

One of the most important constraints for such a project are codes and

regulations. Placing any device on top of residential or commercial establishments

requires that it follows codes and regulations. As a solution to this problem, the team

decided to create a product that would be universally acceptable in all states, since

every state had its own codes and regulations that differed from other states.

1.2.3 Meeting the Requirement

As safety being the most important requirement, a decision was made to

implement a breaking system that could stop the turbine when it is rotating at a high

𝑅𝑅𝑅𝑅𝑅𝑅. This should be achieved without damaging the components and the turbine

itself, as well as the operator. For such a situation, a solution that the team has come up

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with is a circuit which has the capability of working as a breaking system when

polarity of the current are switched. This causes the turbine to rapidly slow down and

eventually stop.

The second requirement was reduction of weight. The turbine was viewed as a

whole to see where exactly can weight be reduced without compromising the structural

integrity of the turbine. To reduce the weight, light materials were chosen for the

various components of the turbine. Instead of steal for the blades and rotor arms, 3D

printed plastic was used. For the main shaft, the steel was replaced by aluminum and

acrylic.

To tackle the requirement of versatility, the team decided that the dimensions of

the turbine resemble what is readily on the market of its class. This will ensure that the

mounting area needed of this turbine will not be extremely large, thus providing

versatility in mounting.

In minimizing the cost, several routes were taken. From a manufacturing stand

point, the parts would not be labor intensive, and of hard geometry. The simple

geometry causes the cost to be reduced. And the components that are not readily

available, such as the blades, the parts can be manufactured by using plastic injection

molding for mass production, 3D printing for the prototype. The only cost that is

significant enough that would need major funding would be the creation of the mold

for the plastic injection molding process.

The efficiency was where most of the effort was distributed. If the efficiency

increased to the set goal, then most of the requirements would have been achieved as a

17

byproduct of the efficiency. By reducing the weight of the components, and using three

blades in the design, as well as using a blade with a higher lift to drag ratio.

1.2.4 Existing Issues

A requirement that has been partially fulfilled for the project was the

collapsibility of the turbine. One of the characteristics that were envisioned for the

turbine is that it would be collapsible, so the turbine can be taken apart and have its

components placed back together without the use of tools. That goal was partially

achieved, the turbine is still collapsible, and can be taken apart, but tools are required to

do so.

1.3 Idea Development and Design Phase

The final design of the turbine is different than the initial concept. At first a

new concept design was planned. Debate initiated on how to examine if the new design

is actually something that would achieve the requirements and goals.

During the initial meeting with the technical advisor, the team shifted the focus

from a new concept to the various wind turbines that are well researched and had

numerous journals and research papers that would greatly benefit the team.

A better understanding of how wind turbines are classified and their difference

were fully grasped. Vertical Axis Wind Turbines VAWT, as well as Horizontal Axis

Wind Turbines HAWT becomes more familiar in terms of functionality, advantages

and disadvantages, and operating conditions.

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Once the differences were fully understood, a VAWT design that was based on

lift, the Darrius, was preferred over the VAWT design that was based on drag,

Savonius, and this is due to the higher efficiency that the Darrius exhibits, thus power

generation of the Darrius design is higher.

Research was conducted to understand what the parameters are that causes a

Darrius design to be more efficient, and how those parameters can be manipulated to

produce the best results.

The parameters were then manipulated to fit the requirements of the customer,

as well as the existing constraints, such as wind speed in the State of Florida. The

materials as well as manufacturing techniques were chosen for both the prototype as

well as for mass production.

1.3.1 Concept Design

In designing the conceptual design, following research papers and journals, as

well as online resources seemed to be the most rational plan. The research indicated

that the number of blades on a VAWT have an effect on efficiency thus power output.

As well increasing the number of blades does not necessarily mean more power

generated. The designs for the VAWT indicated testing of 2 to 7 bladed systems. The

majority of the designs either supported 3 or 5 blades. The optimum number of blades

was discovered to be 3, since only one blade at a time can induce rotation, while the

rest are spinning along (figure 4). Having one blade induce rotation while 2 instead of

4 or more blades as extra weight during the rotation was decided to be the more logical

approach. Figure 5 shows 3 and 5 bladed systems.

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Figure 4: Wind forces on a single blade

Figure 5: 3 and 5 bladed Darrieus VAWTs

Since the VAWT is based on lift, a blade with a high lift to drag ratio was

selected for optimization. The blade chosen was the (GOE 481) (figure 6). This blade

proved to have a higher lift to drag ratio than the base model blade (figure 7).

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Figure 6: GOE 481 airfoil

Figure 7: Base model Eppler 541 airfoil

Figure 8: GOE 481 and Eppler 541 airfoils

In choosing the materials, the material that fell within the domain of the

requirements and the constraints were selected and then narrowed down to what best fit

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the design. Customer can choose between an aluminum and an acrylic shaft, which has

an advantage of being clear and thus, better looking.

1.3.2 Configuration Design

The configuration was decided to be as consistent as possible. Since the initial

goal of having the turbine fully collapsible without the use of tools did not occur, the

attachment method would be designed so that one tool can be used to separate and

connect all the components.

The main shaft was chosen to be larger in diameter with a very small tolerance

so that it can slide on to the shaft of the generator. A 5mm bolt would be placed

through the two rods to create a connection (figure 9).

Figure 9: Connection of rod-to-shaft

22

The rotors were designed as a sleeve that has a larger inner diameter than the

main shaft, with a small tolerance. Once the rotor arms are in place, (2) 5mm bolts

were placed through the rotor sleeve and through the main shaft to create the

connection (figure 10).

Figure 10: Connection of sleeve-to-shaft

The blades were designed to connect directly to the rotor arms with no excess

material on the outside of the blade, so that drag can be reduced. To achieve this direct

connection, a 5mm screw is screwed through the blade and into the rotor arms (figure

11).

23

Figure 11: Connection of blade-to-arm

1.3.3 Parametric Design

In order to understand how a wind turbine’s efficiency is optimized, various

parameters have to be related. The parameters are the Tip Speed Ratio 𝐻𝐻𝑇𝑇𝑅𝑅, the Power

Coefficient (𝐴𝐴𝑡𝑡), which is also referred to as the turbines efficiency, as well as the

power delivered.

𝐻𝐻𝑇𝑇𝑇𝑇 𝑇𝑇𝑇𝑇𝑆𝑆𝑆𝑆𝑟𝑟 𝑅𝑅𝑟𝑟𝑅𝑅𝑇𝑇𝑅𝑅: 𝑋𝑋 = 𝑉𝑉𝑡𝑡𝑡𝑡𝑡𝑡𝑉𝑉0

(4)

𝐻𝐻𝑇𝑇𝑇𝑇 𝑇𝑇𝑇𝑇𝑆𝑆𝑆𝑆𝑟𝑟: 𝑉𝑉𝑡𝑡𝑡𝑡𝑡𝑡 = 𝜔𝜔×2×𝜋𝜋×𝑅𝑅60

(5)

𝑅𝑅𝑅𝑅𝑤𝑤𝑆𝑆𝑟𝑟 𝐴𝐴𝑅𝑅𝑆𝑆𝐶𝐶𝐶𝐶𝑇𝑇𝑐𝑐𝑇𝑇𝑆𝑆𝐶𝐶𝑅𝑅: 𝐴𝐴𝑡𝑡 = 𝑁𝑁𝑐𝑐2𝑅𝑅 (𝑋𝑋𝜔𝜔)[𝐴𝐴𝐿𝐿 sin(𝜃𝜃) − 𝐴𝐴𝐷𝐷,0 + 𝐶𝐶𝐿𝐿

2

𝜋𝜋𝜋𝜋𝑅𝑅 (𝑥𝑥 + cos(𝜃𝜃)] (6)

(𝐻𝐻𝑇𝑇𝑅𝑅) Is directly influenced by the wind velocity (𝑉𝑉0), the distance from the

rotating shaft to the blade (𝑅𝑅), as well as the angular velocity in RPM (𝜔𝜔). For a

Darrius design, the optimal value for the (𝐻𝐻𝑇𝑇𝑅𝑅), which relate to the greatest Power

Coefficient (𝐴𝐴𝑡𝑡) of (0.42) is about (4) (figure 3). This gives the designers a desired

24

output to achieve in order to increase the efficiency and produce the greatest amount of

power. After the (𝐴𝐴𝑃𝑃) has been determined from the (𝐻𝐻𝑇𝑇𝑅𝑅), the power delivered to the

generator (𝑅𝑅) can be determined by

𝑅𝑅𝑅𝑅𝑤𝑤𝑆𝑆𝑟𝑟 𝐷𝐷𝑆𝑆𝐷𝐷𝑇𝑇𝐷𝐷𝑆𝑆𝑟𝑟𝑆𝑆𝑟𝑟: 𝑅𝑅 = (𝐴𝐴𝑡𝑡)(12𝜌𝜌𝐴𝐴𝑇𝑇𝑉𝑉03) (7)

The variables effecting the power delivered (𝑅𝑅), are the density of air present at

the turbine location (𝜌𝜌), the area of the wind that is being swept by the turbine blades

(𝐴𝐴𝑇𝑇), the available wind velocity that the turbine is experiencing (𝑉𝑉0), as well as the

Power Coefficient (𝐴𝐴𝑡𝑡), which can also be referred to as the efficiency of the turbine.

There are other parameters that will affect the turbines efficiency beyond this

point that are not controlled by the design of the turbine itself, rather by the equipment.

Such equipment that will further effect the turbines efficiency are the generator and the

gear box. The decision was made against the use of a gear box since the wind speed is

relatively low, and the torque needed to achieve any rotation would increase

significantly, thus decreasing the turbines power output and efficiency. As for the

generator, it was decided that if the team’s goal is to achieve a higher efficiency than

the base model by improving on the design of the turbine, then the original generator

should be used for the new turbine, so that to display that the higher efficiency was

achieved purely from the altercation of the design and not from any exterior influences,

such as a more efficient generator.

25

1.3.4 Detail Design

For the prototype, a decision was made to 3D print the blades as well as the

rotor arms. First a CAD was made of the blade and the rotor arms (figure 12), and then

they were 3D printed. Other manufacturing processes were considered, such as carbon

fiber, but later dismissed because of the complex shape of the blades and the

inconsistencies that blades might possess, due to the fact that several blades were

needed and they all had to be greatly similar.

Figure 12: CAD of rotor arms

To acquire the 3D printed blades, a specific distributor for a 3D printing

machine that can tolerate the dimensions of the blades was contacted. In the process,

several providers were referred and contact was established. After ordering the first

batch of blades, and having them not be to satisfaction, another provider was contacted.

The new contact seemed to have greater knowledge of the 3D printing process and

26

gave insightful information. Once the team finalized final decisions, the new provider

was asked to print the blades as well as the rotor arms.

Acquiring the shafts was the next activity on the list. The shafts had to match

the generator that would be used in the prototype. Once the generator was chosen, the

shafts with close dimensional resemblance were chosen.

2 shafts were acquired, acrylic (figure 13), as well as aluminum (figure 14). The

acrylic was machined so that it can slide on top of the generator shaft. Both shafts were

machined as well so that the bolts for the rotor arms and the generator can be bolted

through.

The generator shaft was machined so that the aluminum and acrylic shaft can

slide over, and then the bolt can go through both. A rig was constructed so that the

Figure 13: Acrylic shaft Figure 14: Aluminum shaft

27

generator could be mounted on top. This rig was later placed on top of a moving car to

test the turbine (figure 15).

Figure 15: Testing rig

28

CHAPTER 2: PRODUCT DESIGN, DEVELOPMENTS, AND PROTOTYPING

2.1 Development of the Final Solution to the Design Problem

The design problem was to create a VAWT that was in an improvement on the

efficiency of a current VAWT on the market. The VAWT on the market constructed

with heavy material and total of 5 airfoils. The model had a very inefficient method of

connecting the airfoils, the airfoils were to slide in. However the majority of the time

the airfoils had to be shoved into the rotors, actually scratching the airfoils. Our

solution is creating a VAWT out of lighter materials, reducing the number of airfoils to

3. As well as simplifying the airfoil to rotor connection.

2.1.1 Design Modifications

There were a few design modifications on the airfoils, generator, and rotor

design. The airfoils had two iterations created. They both were the same profile and

had the same dimensions. However the material and printing orientation was changed.

The first iteration of the airfoils were printed on its trailing edge, with small supports

designed to hold the model upright during the printing process (figure 16). This

iteration was also made with PLA plastic. Upon receiving the airfoils, the team was not

satisfied. They were heavier than intended, the supports did not snap of as easy as

intended, and left blemishes (figure 17). The material of PLA was not the team’s first

choice either, as it does not hold up well being left out in the heat.

29

Figure 16: PLA printed airfoil

Figure 17: Blemish on PLA airfoil

The second iteration of the airfoils as mentioned earlier had the exact same

geometry as the first. However the model was positioned to be printed standing straight

up. This allowed the filaments to line up in a way that followed the direction of the

flow of wind. This was a precaution as to not create a point where turbulence could be

created. This iteration was also made with PETG, this plastic is not only lighter than

PLA, but it also holds up in the heat.

Grain direction

30

In the beginning of the design phase, a generator was selected. There was to be

a simple direct to shaft connections. Upon receiving the generator, the team came to the

conclusion that it was heavy, and required too much torque to rotate. Overall the

generator was not the generator for the project. As an alternative, the team took the

market’s VAWT’s generator and modify it to fit our needs. This included cutting down

the generators shaft length, shaving off existing threads, and drilling a hole for a

connection point.

The rotor design had the majority of modifications. The initial design was a

thick sleeve with a circular arm. During the design phase, the team wanted to try and

make the rotors themselves into a type of airfoil. On the project's scale that was just not

feasible. When the selected profiles were scaled to fit the sleeve they were extremely

thin, and could not support an airfoil. So the shape of an oval was selected to make the

rotors more aerodynamic (figure 18).

The final iteration sleeve was trimmed down significantly, reducing the cost of

the overall print job by $100. The final iteration had one last design modification. In

order for the model to be printable without a tremendous amount of excess support

material, the model needed to be cut down the middle. This allowed each half to print

face down flat on the bed, requiring to almost no support material. Since the halves

31

would half to be affixed to each other with an adhesive, a key slot was designed in the

flat face of each half. The key slot allowed the halves to be attached symmetrically.

2.1.2 Analyses and Simulations

The main concern of failure was the rotors. If there were to be any type of

deformation it would first occur on the rotors. The rotors were then submitted to a

stress simulation using SOLIDWORKS. The sleeve was assigned to be considered

fixed geometry, and a load of 150 N was applied to each arm of the rotor. The arms

were designed to support the airfoils which is a load less than 150 N. However that

does not mean that the arms are to be extremely weak, as a slight load on it causes

deformation. Hence the reason the simulation was done with the value of 150 N. The

results are displayed below, (figures 19, 20).

Figure 18: Different shapes of rotor arms

32

Figure 19: Von Mises stress analysis

Figure 20: Displacement analysis

The results displays that the highest point of stress is located at the fillet of that

connects the arms to the sleeve. The results displayed a max von Mises of 2.433e+5

𝑅𝑅𝑟𝑟. The yield strength of ABS plastic is 4.8263e+7 𝑅𝑅𝑟𝑟. The stress falls well into

tolerable amount provided by the material. The simulation also shows the max

displacement to be 3.956e-1 mm. This values also falls into the tolerable displacement

range.

The airfoil was submitted to a flow simulation in SOLIDWORKS. The

simulation was used to understand the flow of air of the airfoil, and how the pressure

changed with that flow. The results of that simulation is shown below, (figures 21, 22).

33

Figure 21: CFD of pressure distribution on airfoil

Figure 22: Pressure distribution on the system

34

2.1.3 Optimization

Optimization was briefly touched on in Design Modifications. As it was a key

reason into the design changes. The airfoils were optimized through material selection,

printer settings, and printing orientation. The desired material was ABS, however the

first supplier did not have that available. So the selection of PLA was made. PLA has a

higher density than ABS and does not do as well in high heat environments, PLA tends

to warp. The first supplier also printed on its trailing edge, where the filaments lined up

perpendicular to the flow of wind. This could be a scenario that trips turbulence.

Optimizing the design, a second provider was found. This provider had ABS, and had

more options available when printing settings were involved. To reduce weight even

more, a density infill of 15% was chosen with a single filament layer thick shell,

(figure 23).

Figure 23: Different infills of 3D printed plastic

The airfoils were also positioned to allow for the filaments to line up following

the flow of wind. However, during the printing process ABS was failing, so PETG was

35

selected, which has density even smaller than ABS. The rotors were also optimized.

They were initially designed with a thick sleeve to increase support and strength.

However, after some consideration and simulations it was determined that that excess

material was not necessary therefore it was eliminated reducing the printing time, and

overall cost of the part.

2.2 Parts Descriptions

The airfoils were 3D printed by Mr. Darrel Barnette, with the exact geometry as

a GOE 481 airfoil. It was made out of PETG and has a length of 52 𝑐𝑐𝑚𝑚. PETG was

used after the first airfoil made from ABS could not withstand the printing process and

warped when printed due to the length of the blade themselves. The rotor arms were

made out of ABS and had a length of 27𝑐𝑐𝑚𝑚. The arms had a standard symmetrical

airfoil shape in order to reduce the drag profile while the turbine was spinning thus

increasing the efficiency. However the profile was too thin, so a thin elliptical shape

was selected. The arms had to be made in two different halves to simplify and save cost

on the 3D printing process. These halves were subsequently fused together with ABS

slurry, a glue like substance when mixing ABS and acetone together (figures 24, 25).

Figure 24: Cut-in-half rotor arms

36

Figure 25: Alignment of rotor arms

Two different shafts where purchased for the project. An aluminum shaft was

used as the testing shaft while the acrylic shaft will be used for the presentation and

final design. The aluminum was used for testing as it can withstand impact forces

better than the acrylic shaft. During testing wanted to ensure the safety of the entire

prototype so the aluminum shaft was use as it could withstand our experiment better

than the acrylic shaft as the acrylic shaft chips easier than the aluminum shaft. The

team used the generator from the base ALEKO turbine and made modifications to the

generator to fit the team's needs, with the significant modification was to cut of the

generator shaft and do a complete drill through in order to attach our aluminum/acrylic

shafts to the generator. This manufacturing was donated by Charles Sackett Repairs as

a contribution to the UCF College of Engineering and Computer Science.

The airfoil to arms, arms to shaft, and shaft to generator connection all required

screws/bolts and washers to ensure a perfect connection. The airfoils had two pre-

manufactured screw holes that would align with the end of the rotor arms. The arms

had two sets of be manufactured holes that would light up with the through hole along

the shaft and connected with a bolt and washer combination. Finally the shaft slide

37

over the connection of the generator and was connected with a bolt and washer

combination. Finally an acrylic base was designed to hold the entire turbine up. This

base would be in a shape of a box that can hold the circuitry and wiring to the battery

and keeping these components safe from the outdoor elements. The generator will be

attached directly to the base with the top portion of the acrylic box having holes in it

that will allow the generator to sit and be attached to the box.

2.2.1 List of Parts Used

Table 1: List of parts used

Description Manufacturer Vendor Information Cost

McMaster-Carr Acrylic Shaft McMaster-Carr http://www.mcmaster.com $23.37

Aluminum Shaft McMaster-Carr http://www.mcmaster.com $53.27

Rotor Arms (Darrel Barnette) Darrel Barnette Darrel Barnette 512-565-7463 $211.62

Airfoils X 4 (Darrel Barnette) Darrel Barnette Darrel Barnette 512-565-7463 $261.66

Wooden Dowel Creatology http://www.michaels.com $3.20

McMaster-Carr Nylon Screws McMaster-Carr http://www.mcmaster.com $13.99

Machining the Shaft's (Donation)

Charles Sackett Repairs

5500 Old Winter Garden Road(407) 298 5540 0

Jam Nut Zinc 5/16"-18 Home Depot Home Depot (321) 235-3600 $2.36

Jam Nut Zinc 1/4"-20 Home Depot Home Depot (321) 235-3600 $2.36

Metric Screw 10.9 M6X20MM Zinc Home Depot Home Depot (321) 235-3600 $2.70

38

Metric Screw 10.9 M6X30MM Zinc Home Depot Home Depot (321) 235-3600 $3.30

METRIC NUT P/1.0 6 ZINC Home Depot Home Depot (321) 235-3600 $4.14

Tartan Electrical Tape 1615 60FT Home Depot Home Depot (321) 235-3600 $0.79

Blue Standard Wire Connectors Home Depot Home Depot (321) 235-3600 $2.18

#4-6X7/8" Plastic Ribbed Anchor Home Depot Home Depot (321) 235-3600 $1.98

Sheet Metal Screws Zinc #8X2" Home Depot Home Depot (321) 235-3600 $1.18

Sheet Metal Screws Zinc 6X1-1/2 Home Depot Home Depot (321) 235-3600 $2.36

DREMEL 1/32" Tool Chuck Dremel www.dremel.com/ $10.90

#4-8X7/8 Plastic Anchor + screws Home Depot Home Depot (321) 235-3600 $12.46

5mm-.8 X 40 mm Bolt Home Depot Home Depot (321) 235-3600 $1.88

.8 mm 5 X 50 mm Bolt Home Depot Home Depot (321) 235-3600 $2.72

8 mm 1/4 Drive Home Depot Home Depot (321) 235-3600 $1.68

Metric Lock Washer Home Depot Home Depot (321) 235-3600 $1.71

Metric Flat Washer Home Depot Home Depot (321) 235-3600 $0.47

Metric Nt .8 Home Depot Home Depot (321) 235-3600 $0.86

Lock Nut Nylon Home Depot Home Depot (321) 235-3600 $0.82

Acrylic Sheets X 3 Skycraft Skycraft Parts & Surplus (407) 628-5634 $71.25

39

2.2.2 Part Drawings and Schematics

Figure 26: Airfoil drawing

Figure 27: Rotor arm drawing

40

2.3 Manufacturing and Assembly

2.3.1 Description of Manufacturing Processes and Techniques

During the progression of the project, the material was heavily debated due to

what to be considered as a requirements for Senior Design 1, deemed unrelated to our

actual prototype design. Meaning the material, and therefore manufacturing process,

planned for mass production would be different from how the prototype is constructed,

aside from the mass production side of things. For a variety of reasons, 3D printing was

used for the majority of the manufacturing process. While the aesthetics and ease of

specific part material selection are benefits for picking 3D printing, these are not the

main factors which influenced the team's decision on this means of fabrication.

With the information compiled earlier in the year, the team concluded on

several key design barriers; a high percentage of these issues had to do with the process

of fabrication. The base turbine had aluminum blades which was a viable option but the

drawbacks included the rigorous machining necessary and the cost to go with it;

making the dye itself would cost more than purchasing a multiple of turbines. Carbon

fiber/fiberglass was the ideal option based on chosen characteristics however this also

proved to be an issue when it came to cost and fabrication. Since the only way it could

be made with our resources was to make either a female or male mold of our airfoil

(with a hot wire foam cutter or some other means) and lay the cloth on it with the resin

applied, to later melt away the foam with a solution once dried. It would not have been

the safest option with the lack of technique and skill dealing with such a process.

Unlike 3D printing; which had a well-rounded score from the team’s Decision Matrix

(table 7). This option allows for various attachment methods to be used.

41

Our design engineer was able to model the blade to rotor arm connection which

was decided to be a singular bolt fed through a bored hole in the sleeve and shaft.

These parts could be printed within 8 hours each without the need for additional parts

to machine together. While machining each part on the other hand would be more

costly and possibly more time consuming than necessary. All together the total printing

process would take around two days for the two rotor arms and four blades. Although it

appeared to be simply a proper CAD designing and printing, a constraint came with

this process. This was the printing bed. The model was required to be positioned in a

particular way to get our desired results. Otherwise the plastic would have flowed

where it was not intended, ultimately either ruining the desired outcome or making it

more difficult to smoothen after the print. Faced with two options, of splitting the arms

in half on the printing bed to be later bound together or support beams under the fail

zones (figure 28). Based on the parts printed by Darling, the team decided it did not

want the support beams. The particular position that was mentioned would be a

symmetrical cut, down the x-axis. Allowing the models to be printed with the widest

Figure 28: Surface preparation of rotor arm

42

portion on the bottom for the rotor arms. Simply put, the model’s centerline is split in

two halves to be printed separately which will later be glued together to form a

complete rotor arm.

The blades were oriented on the printing bed so that the plastic (ABS) grains

are parallel to the wind stream. In regards to the connection from the shaft to the

generator a hollow aluminum shaft and an acrylic shaft is machined. The aluminum

used for testing, while the acrylic used for the presentation/symposium. They are bored

out as to slide into the shaft on the base turbine, which has a smaller diameter. The

steel shaft from the generator was also machined to remove the threading, and decrease

the diameter to approximately 6/10 inches (converted from metric to imperial). This

secured it in the x and y-planes. Z-plane translational movement was halted by a bolt

through the shafts, acting as a pin connection. From here the rotor arms were “glued”

together with ABS Slurry, and attached to the shaft with two bolts on each rotor arm

sleeve. The blades were then attached to the rotor arms with a screw as previously

mentioned.

Acrylic sheets were also used as a housing for the turbine components. It is

opaque and resilient as a plastic in terms of hardness. ⅜ inch sheets were purchased to

be laser cut into a base 6” wide and 13” long with faces that were screwed together to

more easily access the circuit and wires.

43

2.3.2 Manufacturing Schematics

Figure 29: CAD of main shaft

Figure 30: CAD of generator

44

2.3.3 Manufacturing Instruction

Manufacturing began with 3D models for all parts. The airfoils began with

selecting a profile (figure 6) based on the decision matrix (table 7), imported into the

3D CAD program to generate the curve. The curve was then scaled to the desired

measurements and extruded to the desired height. The bolt holes were predefined in the

model and then sent off to a 3D printer. Material was selected as well as the printer

settings. Since the airfoils are desired to be light, a small infill of 15% was selected, to

further improve weight reduction, the exterior layer was set to be a single continuous

thread of filament. To allow for a smooth surface for the air to flow over, the airfoils

are sanded with low grain to remove the rough finish followed by a high grain

sandpaper to smooth it out further.

The rotor arms were designed the same way. Several iterations were created

using a 3D software (SOLIDWORKS), and working closely with a 3D printer’s

restrictions they were made to be printable models that had enough support and would

not collapse during the process. Bolts holes and key slots were predesigned in the

model. The rotors were desired to be stronger and stiffer than the airfoils. So for the 3D

printing the setting of 30% infill and a layer thickness of the 3 was selected. The rotors

were also designed to be printed in half, split down the middle horizontally (figure 31).

This was to ensure they had a flat surface for the printer bed. This design choice also

meant the reduction of supporting material. Which meant for faster production, as well

as cheaper manufacturing cost.

45

Two shafts were be manufactured. One was manufactured from an acrylic rod,

the second was manufactured from a hollow aluminum rod. The desired shaft was the

acrylic rod, but if that proves to be faulty the aluminum will be brought in as a backup.

They were both designed according to the same schematics. There were 5 thru holes

bored along the centerline of the rods. Then at the base a hole was bored to the

specified distance, with the specified diameter.

Figure 31: CAD of half a rotor arm

Figure 32: Generator shaft manufacturing

46

The existing generator shaft had modifications made, as shown in the schematic

(figure 32). The shaft was shortened by cutting it down to the specified height. The

existing thread was shaved off to have a uniform diameter along the base of the shaft.

Then a thru hole was bored at the specified height along the centerline of the shaft, and

it has the specified diameter.

2.3.4 Assembly Drawing

Figure 33: Drawing of assembly

47

2.3.5 Assembly Instruction

The rotor arms were assembled by placing a key in the key slots of the bottom

halves. In this case, the keys were wooden dowels approximately ⅛ in. in diameter.

These keys would allow for the proper alignment of top and bottom halves, with the

bonus of extra reinforcement. There is a bonding agent (Acetone and ABS mixture)

that placed on the top of the bottom half. The top half was then applied to the bottom

half and fastened together with vice grips while the bonding agent cures. Once the

halves were solidified, they were sanded to remove any excess bonding agent and to

smooth the surface of the printed model. They were then bolted into their respective

positions along the acrylic/aluminum shaft. After the rotors were affixed to the shaft,

the airfoils were then bolted with metallic bolts to the rotors. The bolts were affixed

into anchors that were place in the rotor.

The assembly of the shaft connection was made simple, the generator shaft was

slid into the bored hole of the acrylic/aluminum rod. It would then be secured with a

single through bolt that is fastened with a nut on the opposite side.

2.4 Test and Evaluation

2.4.1 Test Method and Procedures

2.4.1.1 Introduction

A calibration graph of wind speed and car speed was obtained by taking the test

vehicle for a dry run on the testing road (figure 34). This assured the consistency

in obtaining data points and a more dependable results, which can be inaccurate

due to the boundary layers on top of the vehicle and where the turbines will be

48

securely mounted. As expected, the graphs showed that the measured wind

speeds were slightly higher than the car speed due to the direction of wind on

testing days and the velocity boundary layers. The turbines were then mounted

on the car, and RPM as well as voltage were taken at the specified wind speed

range of (3m/s – 14 m/s). During later analyses, the efficiency and other wind

turbine related calculations were done.

Figure 34: Calibration graph for prototype

2.4.1.2 Testing of prototype turbine

After the complete assembly of the turbine that includes bonding of rotor arms,

bolting blades in place, connecting the permanent magnet generator to the 3-phase AC

wires to the rectifier circuit, the DC output from this same circuit has to be measured in

order to see the effectiveness of the entire system and calculate the total efficiency of

the system.

y = 0.9374x + 0.5714R² = 0.9768

02468

10121416

0 2 4 6 8 10 12 14 16Man

omet

er R

eadi

ng (m

/s)

Wind Speed (m/s)

Calibration Data

Manometer Reading 1 Reading 2

Reading 3 Linear (Manometer Reading 1)

49

2.4.1.3 Method

The system was securely mounted on top of a moving vehicle at known speeds,

which was fixed using the vehicle’s feedback -cruise control- system, that way an

approximated velocity of the wind is known in m/s depending on how fast the car is

going in a wide road, straight line. The blades will start spinning and generate AC that

will be converted and regulated to DC output, which will be stored in a deep cycle

battery with a projected capacity of 9AH. An actual battery was not charging nor

connected for safety reasons until the system was static and fully stationary to prevent

risks of fire or hazard, and to assure full attention remains on the test run.

2.4.1.4 On the Road

The tests took place around noon time, for it would allow the team to assemble

and assure readiness of system to be mobile on the road during the morning time. The

roads in mind included Old Lockwood Rd in Oviedo, Florida and east of McCulloch

Rd in Orlando, Florida or any of the northern parallel roads to it, Faun Run, Red Ember

Rd since those roads had two things in common: long enough with low traffic.

Inside the vehicle, there was one driver maintaining a constant speed on the

road, other was reading voltage output off of the multimeter connected to the 2-phase

DC output from the rectifier circuit, one person recording data on an Excel sheet and

another assuring consistency of test flow and recording RPMs. This data was saved for

later analyses.

2.4.1.5 Battery Charging

To charge up the battery, the output direct current coming out of the system had

not to exceed that of the battery specifications. For example, if the battery was rated at

50

12V, the system needed to be producing about 13.5V for the battery to start charging

up. The delta in voltage would compensate for the losses in efficiency as heat

dissipated in wiring and rectifier circuit. The system would be spun manually using a

constant RPM to generate DC voltage while stationary, and the capacity of the battery

would be read after a fixed time to insure proper charging.

2.4.2 Testing Results and Performance Analyses

2.4.2.1 Data Analysis

The excel sheets from both models can were used to plot two graphs of wind

speed, obtained from the vehicle’s speedometer, with an expected uncertainty of 7%,

vs. the voltage output from the two phase DC voltage output from the rectifier circuit

(figure 37). The deltas on the graphs show how much of improvement the new

prototype achieved.

Figure 35: Manometer reading vs. RPM

y = 24.632x - 93.741R² = 0.851

y = 38.877x - 242.88R² = 0.6088 y = 14.175x - 28.136

R² = 0.6004

-50.0

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

0 2 4 6 8 10 12 14

RPM

Mano reading (m/s)

Manometer Vs. RPM (Prototype)

Readings 1

Readings 2

Readings 3

Readings 4

Linear (Readings 1)

Linear (Readings 2)

Linear (Readings 3)

Linear (Readings 4)

51

Figure 36: Voltage generated vs. RPM

Figure 37: Voltage vs. wind speed

y = 0.0605x + 0.3882R² = 0.8207

y = 0.0815x - 0.5088R² = 0.9897

y = 0.0482x + 0.8143R² = 0.5907

0

5

10

15

20

25

30

0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0

Volta

ge

RPM

Voltage Vs. RPM (Prototype)

RPM Vs. Voltage

Reading 2

Reading 3

Linear (RPM Vs. Voltage)

Linear (RPM Vs. Voltage)

Linear (Reading 2)

Linear (Reading 3)

y = 0.0274e0.6304x

R² = 0.9216

y = 0.025e0.6727x

R² = 0.9442

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

2 4 6 8 10 12

Volta

ge (V

)

Wind Speed (m/s)

Voltage Vs. Wind Speed (Prototype)

Power Vs. Wind Speed Car speed Vs. Power

Expon. (Power Vs. Wind Speed) Expon. (Power Vs. Wind Speed)

Expon. (Car speed Vs. Power)

52

The same process was used to calculate peremiters for ALEKO turbine, and

then the results were compiled together, and combined to calculate the efficiency. The

electrical circuit had a resistance of 12.5 (Ω). Power was determined from (equation 8),

and (figure 38) below was produced for the prototype, and the combination was

plotted.

𝑅𝑅 = 𝑉𝑉2𝑅𝑅 (8)

Figure 38: Comparison of power vs. wind speed

y = 0.0314e0.6197x

R² = 0.9097

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 2 4 6 8 10 12 14

Pow

er (w

)

Speed of impact (m/s)

Aleko (Blue) Vs. Prototype (Orange)

Power Vs. Wind (ALEKO) Power Vs. Wind (Prototype) Expon. (Power Vs. Wind (Prototype))

53

Figure 39: Power vs. wind and car speeds

2.4.2.2 Base Model Comparison

The same procedure above was done to compare ALEKO model to our existing

prototype and data were obtained for further analyses and comparisons.

Figure 40: Comparison of power vs. speed of impact

-5.00.05.0

10.015.020.025.030.035.040.0

0 2 4 6 8 10 12 14 16 18

Pow

er (W

)

Speed (m/s)

Power Vs. Speed

Power Vs. Wind Power Vs. Car

y = 0.0314e0.6197x

R² = 0.9097

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 2 4 6 8 10 12 14

POW

ER (W

)

SPEED OF IMPACT (M/S)

Aleko (Blue) Vs. Prototype (Orange)

Power Vs. Wind (ALEKO)

Power Vs. Wind (Prototype)

Expon. (Power Vs. Wind(Prototype))

54

As noticed from the (figure 40) above, the prototype model had higher,

exponential growing trend line with an equation of 𝑦𝑦 = 0.0314 ∗ 𝑆𝑆(0.6179𝑥𝑥). Whereas,

the prototype model started generating above 7W at wind speeds of approximately 7

m/s.

2.4.2.3 Efficiency Calculation

According to the equation of maximum energy obtained from wind (equation

7), the actual vs. the theoretical, and the ratio of both would be the total system

efficiency; that includes mechanical, and electrical combined. As the prototype is much

lighter, has three blades instead of five, ellipsed rotor arms, and the airfoils had rather

higher lift to drag ratio, the total efficiency is expected to be on a higher magnitude.

(Table 2) includes differences in parameters and percentage of weight reduction.

Table 2: Weight differentials in systems

ALEKO Prototype Δ (g) % Difference Arms 1182 330 852 72.1 Blade 1510 681 829 54.9

Shaft + Generator 3196 3167 29 0.9 Total (g) 5888 4178 1710 29.0

Table 3: Parametric changes

Perimeter ALEKO Prototype Difference (%)

# of Blades 5 3 -66.6%

Blade Eppler 541 GOE 481 N/A

Lift at Maximum L2D 1.032 1.451 +40.6%

Mass of System (kg) 5.89 4.18 -29%

Average Efficiency 3.04 5.07 66.8%

55

56

2.5 User Manual

ANEMOI VAWT

Installation and Operation Instructions

Anemoi Vertical Axis Wind Turbine

CONTENTS

2.5.1 Safety Precautions ................................................................. 3

2.5.2 Introduction ........................................................................... 4

2.5.3 Specifications ........................................................................ 5

2.5.4 Package Contents .................................................................. 5

2.5.5 Tools required for assembly.................................................. 5

2.5.6 Assembly Instructions ........................................................... 6

2.5.7 Maintenance .......................................................................... 9

2.5.8 Troubleshooting .................................................................. 10

2.5.9 Warranty ............................................................................. 11

2

2.5.1 Safety Precautions

Safety must ALWAYS be your primary concern during the assembly, installation

and operation of your turbine. Always be aware of the risk involved with the

components during installment. If in doubt about any issue regarding construction or

maintenance, please seek further assistance.

• SAVE THESE INSTRUCTIONS. This manual contains important instructions

that must be followed during assembly, installation, and maintenance.

• Ensure the turbine and the platform it rests on are installed in a suitable position

where nobody can approach or interfere with the path of the turbine rotor blades.

• Ensure the turbine is located in a position where it cannot cause any damage to

buildings, neighboring properties, or nearby utility lines.

• Do NOT install on a windy day.

• During assembly and installation properly tighten all fasteners, be careful not to

apply an excess pressure due to risk damaging the machine.

• If unusual noise or operation is experienced, turn off machine using brake on

circuit and contact service personnel.

• When performing routine inspection or maintenance, always stop the turbine by

activating the braking system.

• Make sure the turbine is not in motion when connecting the wires to the

circuit/battery.

• Consult manual for chosen battery for additional safety measures.

• Read, understand and respect all warnings.

3

2.5.2 Introduction

Please read this manual before attempting to assemble and install your Anemoi turbine

to ensure optimum safety and performance.

This kit has been designed for use with a marine deep cycle battery to store

power built up over a course of a multitude of windy periods. With an approximately

half a meter diameter its ability to harness wind is dependent on the speed of the wind. It

is recommended to be used on windy days that do not exceed 18 m/s (40mph) due to the

excessive forces on the machine.

It is possible to install the Anemoi turbine with two people in a very short time.

Only a ratchet, a screwdriver, and pliers are necessary. Aside from these tools all other

parts are included in this package, battery not included.

The life expectancy of the turbine is rated to be between 4-5 years depending on the

typical wind speed in your area and wear and tear of components.

PLEASE READ THIS MANUAL THOROUGHLY BEFORE CONTINUING

WITH THE INSTALLATION OF YOUR ANEMOI TURBINE.

4

2.5.3 Specifications

Product Name: Anemoi vertical axis wind turbine

Maximum height: 1 meter Materials: 3D printed – ABS rotor arms, PETG blades, Acrylic Shaft and electrical housing, and steel screws Wires: 2mm three split copper wire Foot Print: 0.229 m2 Turbine Diameter: 0.54 m

2.5.4 Package Contents

• 6 – 1” flathead #6 screws • 5 – 1.5” bolts, and 5 corresponding nuts • 1 – 10mm nut • 3 blades, 1 extra • 2 sets of rotor arms • An acrylic shaft • An acrylic component housing/base of turbine • 3 phase circuit • Assembled generator • Corresponding wires for power transfer

2.5.5 Tools required for assembly

• Screwdriver / power drill with Philips head bit • 6mm wrench / socket and ratchet • 10mm wrench • Pliers • gloves

5

2.5.6 Assembly Instructions

1) Remove parts from packaging, excluding the extra (fourth) blade

2) Place the pre-made base in a secure area

3) Attach generator by setting it on the base, feeding the threading through the pre-

cut hole. Screw on 10mm nut

4) Slide shaft onto the generator, use first bolt to secure connection

Manual 1 : Parts included

6

5) Slide on sleeves to shaft, use four remaining bolts to secure connection

Manual 2: Connecting rotors onto shaft

6) Using a hand-drill or Philips screwdriver, screw in 1” screws through each blade

hole onto the rotor arm

7) Repeat step 6. Two more times for remaining blades

7

Manual 3: Attaching blades

8) Connect wires to circuit, leaving the middle phase open (this will act as the

brake when needed)

8

Manual 4: Circuit connection

2.5.7 Maintenance

Please follow the preventive maintenance listed below. This will ensure that the Anemoi

turbine operates safely and at full performance

ALWAYS SHUT DOWN THE TURBINE BEFORE ATTEMPTING TO CARRY OUT

MAINTENANCE

• Perform monthly checks on the following: o The blade condition; check for warping, cracks, deep discoloration o Check for any warping or damage that might be in the arms or shaft o Tighten fittings o Examine generator for any debris; gently wipe with damp cloth o Check wires for any abnormalities, replace if necessary o Ensure tilt is proper

9

2.5.8 Troubleshooting

Table 4: Troubleshooting of Anemoi VAWT

Problems Causes Solutions

Abnormal noise

1. Fastened parts are getting loose

2. Connection between the bearing of the generator and the base is getting loose

3. The bearing of the generator has been damaged

4. Mill rubs with other parts 5. Rotor and stator rubs with

each other

1. Check the loose parts and fasten again

2. Find out the exact point and fix it

3. Change the bearing 4. Inspect and fix it 5. Repair the rubbing points

Rotating speed of the mill is decreasing

1. Rotor and stator rubs with each other

2. Short circuit occurred in rotor winding

3. The Switch is in the Off position

1. Disassemble the generator to restore the specification data in the magnet

2. Find out the point with short circuit to peel off and insulate

3. Put the switch into On

Output voltage is low

1. Rotating speed of generator is low

2. Permanent magnet rotor is demagnetized

3. Short circuit exists in the stator winding

4. Slip ring in power transfer and joints of output wires are not conducted

5. Low voltage power line too long, wire too slim

1. Find the causes to restore the normal speed

2. Change the rotor 3. Find out the point, and paint

it to insulate 4. Clean the slip ring and

joints to decrease contact ring brush

5. Shorten the wire or enlarge the wire diameter to decrease lost in transferring

No output from the generator

1. Output wire is broken 2. Stator winding burned and

caused broken

1. Find out the point and reconnect

2. Disassemble and fix

System generating AC

but not DC

1. DC safety belt broken 2. Output wire is broken 3. Rectifier is damaged

1. Change the safety belt 2. Find out the point and

reconnect 3. Change the rectifier

10

2.5.9 Warranty

Your Anemoi turbine carries a one-year warranty from the original purchase date.

During the warranty period, any component found to be defective in material or

workmanship will, at the discretion of Anemoi will be replaced at no charge.

For minor component failures, replacements may be sent directly to the

customer/dealer for replacement or repair. In call cases Anemoi will take reasonable

action to ensure customer satisfaction.

Your Anemoi turbine must be installed and operated in accordance with this

guide and local codes. Failure to do so will result in this warranty becoming null and

void. Any unauthorized modifications to the design will void the warranty and may

compromise the safety of the mount.

What is not covered by your warranty:

• Damage caused by the neglect of periodic maintenance in the manner recommended by this manual.

• Damage caused by repair or maintenance performed using methods not specified by this manual or by non-authorized dealers.

• Damage caused by the use of non-genuine parts. • Damage caused by operating in conditions outside those specified in this guide. • Damage caused by improper storage or transport. • Damage caused by lightning strikes. • Damage due to extremely high winds and storm conditions (50 mph+). • Damage caused by flying debris.

If you should experience an issue, your first ‘port-of-call’ should be the reseller or

installer from whom you purchased the product. They will be able to resolve the

problem quickly and effectively. If you are unable to contact the original reseller, then

please contact us directly.

11

67

CHAPTER 3: PROJECT MANAGEMENT

3.1 Work breakdown structure

Vertical Axis Wind Turbine

Vertical Support

Material Selection

Airfoil

Material Selection

Geometry

CAD

Manufacturing

Bearing Electrical Component

Battery

Wiring

Power Components

Generator

Circuit

Braking System

Automatic Braking System

Figure 41: Work breakdown structure

68

3.2 Organization Chart

Helical Power System

Vertical Axis Wind Turbine

Technical/Faculty Advisor

Kurt Stresau

Operations Manager

John Benavides

Design Engineer

Michael Lagalle

Program Manager

Husam Zawati

Process Engineer

Yousif Alsarraf

Tooling Engineer

Nicholas Lippis

Figure 42: Organization chart

69

3.3 Individual responsibilities

3.3.1 Action Log for Fall 2015 Semester

Table 5: Action log

Task Agreed Date Start Due

Date Submitted

Responsibility

Order Airfoils From DR Andrew Darling

8/27/2014 8/27/2015 9/14/2015 9/14/2015 John

Obtain DAQ and Measurements Lab Equipment

8/31/2015 9/1/2015 9/1/2015 9/1/2015 Husam

Research on Alternator 8/28/2015 8/28/2015 8/31/2015 8/31/2015 Yousif

Order Alternator 9/1/2015 9/1/2015 9/1/2015 9/1/2015 John

Research on Acrylic 9/1/2015 9/2/2015 9/2/2015 9/2/2015 Yousif

Research if Airfoil is better or Oval. 9/2/2015 9/3/2015 9/8/2015 9/14/2015 Yousif

Gearbox Research 9/2/2015 9/3/2015 9/7/2015 9/11/2015 Yousif

Research Bearings 9/14/2015 9/14/2015 9/16/2015 9/17/2015 Nick

Re-Design Rotor 9/17/2015 9/17/2015 9/19/2015 9/19/2015 Michael

Research the circuit 9/25/2015 9/26/2015 10/5/2015 10/5/2015 Husam

Research new generator 9/25/2015 9/26/2015 10/5/2015 10/5/2015 Husam

Return old generator 9/25/2015 9/26/2015 9/29/2015 10/1/2015 John

Return Old shaft 9/25/2015 9/26/2015 9/30/2015 9/30/2015 John

Check the Budget 9/25/2015 9/26/2015 9/30/2015 9/30/2015 Husam

Contact Outside Machine Shops 10/1/2015 10/2/2015 10/7/2015 10/7/2015 Yousif

Re-Design Sketches for Machine Shop 10/1/2015 10/1/2015 10/5/2015 10/5/2015 Michael

Research Outside Machine Shops 10/1/2015 10/1/2015 10/5/2015 10/7/2015 Yousif

Submit Midterm Report to Husam 10/5/2015 10/5/2015 10/10/2015

10/10/2015 John

Submit Midterm Report to Husam 10/5/2015 10/5/2015 10/10/2015

10/10/2015 Michael

70

Submit Midterm Report to Husam 10/5/2015 10/5/2015 10/10/2015

10/10/2015 Nick

Submit Midterm Report to Husam 10/5/2015 10/5/2015 10/10/2015

10/10/2015 Yousif

Put in UCF Machine Shop Request 10/5/2015 10/5/2015 10/5/2015 10/5/2015 John

Sanding parts 10/9/2015 10/9/2015 10/31/2015 10/31/2015 Nick

Drop off Shaft/Generator from Machine shop outside UCF

10/14/2015 10/14/2015

10/14/2015

10/14/2015 John

Pick up Shaft/Generator from Machine shop outside UCF 10/16/2015

10/16/2015

10/16/2015 10/16/2015 John

Test Original and Prototype Turbine 10/24/2015 10/24/2015

11/15/2015 11/15/2015 Everyone

Analyze Data from Test 10/31/2015 10/31/2015

11/2/2015 11/2/2015 Husam

CFD Analysis 11/5/2015 11/5/2015 11/8/2015 11/8/2015 Michael

Skycfart: purchase Motor 11/15/2015 11/15/2015

11/15/2015

11/15/2015 Husam

Purchase Acrylic Sheets 11/16/2015 11/16/2015

11/17/2015

11/16/2015 John

Design Base for Acrylic to get cut out 11/16/2015 11/16/201

5 11/18/2015

11/20/2015 Michael

Buy Acrylic Sheets cut for Base 11/18/2015 11/18/2015

11/18/2015

11/18/2015 Michael

Submit Final Report Section 11/16/2015 11/16/2015

11/20/2015

11/20/2015 Everyone

Test Motor For Symposium 11/16/2015 11/16/2015

11/23/2015

11/23/2015 Husam

Design Poster For Symposium 11/16/2015 11/16/2015

11/23/2015

11/23/2015 Husam

Practice For Symposium/Final Presentation 11/30/2015

11/30/2015 12/2/2015 12/2/2015

Everyone

71

3.4 Project Period and Budget summary

Table 6: Summary of budgeting

Description Vendor Cost Paid Received Form

#

Initial Budget Duke $3,232.28

Aleko Turbine Aleko $269.00 2/27/2015 3/2/2015 1

Digital Tachometer CyberTech $19.52 3/28/2015 3/30/2015 1

Anemometer Ambient Weather $25.99 3/28/2015 3/30/2015 1

Digital Multimeter INNOVA $19.60 3/28/2015 3/30/2015 1

50 Ft-Outdoor Cord (Lowes) Intertek $31.32 3/27/2015 3/27/2015 1

Fiberglass Cloth (Lowes) Lowes $3.18 3/27/2015 3/27/2015 1

DC Low Wind Alternator (Returned) WindBlue Power $18.82 9/1/2015 9/9/2015 NA

The Spot (Return Generator) $19.09 10/1/2015 2

Airfoils X 4 Daring Research $227.90 8/27/2015 9/4/2015 2

Sandpaper 120 Grit Imperial & Wetordry $4.98 9/9/2015 9/9/2015 2

Sandpaper 2000 Grit Imperial & Wetordry $5.97 9/9/2015 9/9/2015 2

Socket Adaptor Dewalt $3.47 9/9/2015 9/9/2015 2

3/8 Bit Socket Dewalt $3.04 9/9/2015 9/9/2015 2

McMaster-Carr Acrylic Shaft McMaster-Carr $23.37 9/22/2015 9/24/2015 2

UPS (Return Steel Shafts) $16.81 9/30/2015 2

McMaster-Carr Aluminum Shaft McMaster-Carr $53.27 9/28/2015 10/1/2015 3

72

McMaster-Carr Shaft Coupler (Returned 10/15/15) McMaster-Carr

41.82-41.82 9/28/2015 10/1/2015 3

Rotor Arms (Darrel Barnette) Darrel Barnette $211.62 10/1/2015 10/8/2015 3

Airfoils X 4 (Darrel Barnette) Darrel Barnette $261.66 10/1/2015 10/8/2015 3

Aleko turbine Aleko $269.00 10/5/2015 10/13/2015 3

Wooden Dowel Creatology $3.20 10/7/2015 10/7/2015 3

Acetone W.M. Barr and Co $6.88 10/7/2015 10/7/2015 3

Latex Gloves Big Time Products $5.18 10/7/2015 10/7/2015 3

Goggles 3M, Constructions $3.47 10/7/2015 10/7/2015 3

Protective Masks Wal-Mart $2.20 10/7/2015 10/7/2015 3

Brush Wal-Mart $1.00 10/7/2015 10/7/2015 3

McMaster-Carr Nylon Screws McMaster-Carr $13.99 10/8/2015 10/9/2015 3

JOBY GripTight GorillaPod Stand Joby $16.99 10/9/2015 10/13/2015 4

Digital Multifunction Scale Ozeri $11.79 10/9/2015 10/13/2015 4

DWT Series Carbon Steel Tap Set Drill America $9.38 10/9/2015 10/13/2015 4

Cordless Dremel Dremel $42.92 10/9/2015 10/13/2015 4

Machining the Shaft's (Donation) Charles Sackett Repairs 0

10/15/2015

10/16/2015

UPS (Return Shaft Coupler) $11.02 10/15/2015 4

73

Angle Grinder Porter -Cable $31.93 10/20/2015

10/22/2015 4

Angle Grinder Blade DeWalt 4-1/2 Dewalt $9.42 10/20/2015

10/22/2015 4

Dremel Sand Wheel Dremel $7.55 10/14/2015

10/14/2015 4

Dremel Diamond Wheel Dremel $17.70 10/14/2015

10/14/2015 4

16 ft. x 1-1/4 in. Small Ratchet X2 Cargo Boss $16.96 10/14/2015

10/14/2015 4

16OZ Gaps & cracks Home Depot $3.98 10/18/2015

10/18/2015 4

18-2 T-Stat/Bell Wire 1' Home Depot $1.32 10/18/2015

10/18/2015 4

Jam Nut Zinc 5/16"-18 Home Depot $2.36 10/18/2015

10/18/2015 4

Jam Nut Zinc 1/4"-20 Home Depot $2.36 10/18/2015

10/18/2015 4

Metric Screw 10.9 M6X20MM Zinc Home Depot $2.70 10/18/2015

10/18/2015 4

Metric Screw 10.9 M6X30MM Zinc Home Depot $3.30 10/18/2015

10/18/2015 4

METRIC NUT P/1.0 6 ZINC Home Depot $4.14 10/18/2015

10/18/2015 4

Tartan Electrical Tape 1615 60FT Home Depot $0.79 10/18/2015

10/18/2015 4

Blue Standard Wire Connectors 35PK Home Depot $2.18 10/18/2015

10/18/2015 4

6" Wire Stripper/Cutters Home Depot $8.98 10/18/2015

10/18/2015 4

74

#4-6X7/8" Plastic Ribbed Anchor Home Depot $1.98 10/18/2015

10/18/2015 4

Plastic Wood- Natural 1.87OZ. Home Depot $4.48 10/18/2015

10/18/2015 4

Loctite 2OZ. Universal Epoxy Putty Home Depot $5.97 10/18/2015

10/18/2015 4

10MM Ratcheting Wrench Home Depot $5.97 10/18/2015

10/18/2015 4

Rod, Threaded_5/16-18 X 12"_Zinc Home Depot $8.80 10/18/2015

10/18/2015 4

Black Duct Tape Lowe's $3.73 9/13/2015 9/13/2015 4

1X12-10FT Wood Common Board Home Depot $24.25 10/22/2015

10/22/2015 5

Sheet Metal Screws Zinc #8X2" Home Depot $1.18 10/22/2015

10/22/2015 5

Sheet Metal Screws Zinc 6X1-1/2 Home Depot $2.36 10/22/2015

10/22/2015 5

DREMEL 1/32" Tool Chuck Dremel $10.90 10/22/2015

10/22/2015 5

Dremel Diamond Tile Cutting Wheel Dremel $24.97 10/22/2015

10/22/2015 5

Dremel Flap wheel 3/8" 120 GRIT Dremel $7.60 10/22/2015

10/22/2015 5

#4-8X7/8 Plastic Anchor + screws Home Depot $12.46 10/22/2015

10/22/2015 5

Dremel EZ402 4-5/32" EZ lock mandrel Dremel $9.95 10/22/2015

10/22/2015 5

3M PGP 9X11 Sandpaper 150 Grit 4PK Home Depot $3.97 10/22/2015

10/22/2015 5

75

Corded DREMEL 3000 Dremel $73.49 10/23/2015

10/23/2015 5

5/16 Speed Cutter Dremel Head Dremel $9.97 10/23/2015

10/23/2015 5

Grinder Metal Cutting Wheel Avanti Pro $3.39 10/23/2015

10/23/2015 5

3/16 X 1 Screw Home Depot $1.18 10/26/2015

10/26/2015 5

#6 X 1 Screw Home Depot $1.18 10/26/2015

10/26/2015 5

5mm-.8 X 40 mm Bolt Home Depot $1.88 10/26/2015

10/26/2015 5

.8 mm 5 X 50 mm Bolt Home Depot $2.72 10/26/2015

10/26/2015 5

8 mm 1/4 Drive Home Depot $1.68 10/26/2015

10/26/2015 5

Metric Lock Washer Home Depot $1.71 10/26/2015

10/26/2015 5

Metric Flat Washer Home Depot $0.47 10/26/2015

10/26/2015 5

Metric Nt .8 Home Depot $0.86 10/26/2015

10/26/2015 5

Lock Nut Nylon Home Depot $0.82 10/26/2015

10/26/2015 5

PYLE PLT 26 Digital Tachometer PYLE $27.96 10/21/2015

10/23/2015 5

Cordless Drill Gun Black & Decker $59.99 10/9/2015 10/11/2015 5

Assorted Bungee Cords Master Lock $30.17 10/9/2015 10/11/2015 5

76

19 mm Wrench Duralast $11.09 10/31/2015

10/31/2015 6

Permatex Threadlocker 02 Oz Permatex $6.99 10/31/2015

10/31/2015 6

1 X 18 X 72 Pine Board Home Depot $18.65 11/1/2015 11/1/2015 6

12 X 1/4 X 20 Zinc Rod (4) Home Depot $3.60 11/1/2015 11/1/2015 6

1/4 Drill Bit Milwaukee $6.98 11/1/2015 11/1/2015 6

HEX Nut 1/4-20 Home Depot $1.18 11/1/2015 11/1/2015 6

Metric Flat Washer 8 Zinc (2) Home Depot $3.15 11/1/2015 11/1/2015 6

PST AC Motor Skycraft $12.50 11/14/2015

11/14/2015 6

PST Label X 8 Skycraft $2.00 11/14/2015

11/14/2015 6

AC 12 V 500 ma Adaptor Skycraft $5.00 11/14/2015

11/14/2015 6

DC Motor Speed Control 8 Amp Skycraft $22.51 11/14 11/14 6

Acrylic Sheets X 3 Skycraft $71.25 11/16 11/16 6

Cable Wire Skycraft $4.95 11/17 11/17 6

12 V DC Power Supply Skycraft $19.44 11/17 11/17 6

6 V LEAD Durcell Battery Batteries Plus $11.66 11/18 11/18 6

Final Report (Print and Bounded) UCF $120.00 6

Poster (symposium) $130.00 NA

Cotton Paper Staples $31.02 11/23/2015

11/23/2015

77

3.5 Finalized Gantt Chart

Figure 43: Gantt chart

78

CHAPTER 4: LESSONS LEARNED

4.1 Discussion

There were many lessons learned in the design and fabrication phase. During

design, learning how to model a product with the intent of 3D printing was a

completely new experience. The first lesson would be that each fabricator has a

different methodology when it comes to the actual fabrication of the designed part. It is

very important to talk to the fabricator to find out their methodology. Accomplishing

this allows for a design that they can realistically fabricate. As well as guaranteeing the

part is fabricated in the most efficient manner. During the design phase the team

worked with two different 3D printers. One insisted on supports being added to the

airfoil to allow it to print on its trailing edge. The second suggested the supports were

unnecessary and it could be printed standing on its side. Both valid options, however

both required adjusting the designs.

A second lesson is when designing, always be mindful of what you are relating

your dimensions to. As mentioned earlier the first fabricator required supports. So the

supports were incorporated into the model, the model then continued to be developed

and pre-designed bolt holes were created. The mistake of relating these bolts holes to

the supports was made. When the second fabricator request the supports to be removed,

what should have been a 10 minute job became longer since the holes were no longer

related to anything the model was broken. The important lesson of not relating

permanent modifications to temporary modifications was learned.

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The lesson of having bolts selected before design was also learned. Something

as a small as a bolt can completely impede the design process. The assumption of being

able to find the bolt that fit just right was made, and the design was made without a

clear bolt in mind. This lead to several problems in fabrication. That only compounded

with 3D printing shrinkage and tolerance misconceptions. When the bolts were

selected they were too tight in the 3D printed sleeve, but too loose in the machined

shaft. So a bigger bolt had to be found which to find the right size proved difficult, and

the sleeve bolt holes had to be expanded, which increased fabrication time. This lesson

also taught the lesson of verifying tolerance values. As well as when 3D printing make

sure to account for shrinkage as the plastic cools, the pre-designed holes will also

shrink. This will leave you will a hole smaller than designed and add to fabrication

time and cost.

For our project, when the decision to switch from producing the airfoils from fiber

glass cloth to 3D printing was made, our manufacturing process changed with it and

which created a greater array for options and issues. Options being the variety of

design options was vaster since complex shapes could be more easily produced, the

issues however involved finding a printer to suit this design. It took out team over a

month to find out first contractor who would be willing to print our airfoils and later

on, our rotor arms. The team could not use a standard printer as our airfoils and rotor

arms were too large to fit in a standard printer. If the team was unable to find a printer

large enough for our design, not only would the team be spending time that it could not

have recovered, but we would have had to revert back to our original fiberglass cloth

concept. In the end our team was fortunate to find a contractor that not only printed our

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parts for senior design, but also taught us some basic concepts and 3D printing process

to help insure a better print design. For this reason it is better to look at the

manufacturing process first, then design the project around the manufacturing process

in senior design.

4.2 Contribution in Relation to Customer’s Need

Initially, the customer had an unrealistic expectation of the performance that would be

seen from the turbine. The scope being that it could be attached to the top of the house

in Florida and generate power to run an appliance, ultimately saving on the electric bill.

However this contribution was beyond what was actually possible. The customer

changed their need in lieu of this to get comparable results, rather than an unrealistic

expectation of an application. Improving the efficiency of the commercial ALEKO

24V turbine was a new set goal the customer now expected. Rather, instead of

improving the ALEKO turbine, the prototype built by team Anemoi would be an

improvement on efficiency for most commercial VAWTs in the market. Such a feat

would mean the applications for such devices would also see an improvement. With

regards to power generation, functionality, intent of use, and weight reduction.

4.3 Team Design Experience and Lessons Learned

From the first day it was clear collaboration and unity were desirable for the team to

have. It was taken slow initially, trying to understand the project's scope; what was

possible with our limitations, new goals had to be set and the concepts to be

understood. The team was not completely on the same page, trying to grasp what was

being asked of us for the class which became a setback. Team Anemoi designed the

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turbine for mass production purposes during the spring semester, neglecting to find out

how the prototype will be built, what materials to be used, etc. Leading to a new

selection of desirable traits, materials, and all together a new design. What remained

the same was the idea for three blades and airfoil selection. This of course

demonstrated a failure to properly eliminate our options due to limitations that were

already known, had to be found out, or had to inquire from credible sources and

researched. Proper research was and is something that still needs to be learned. It is

obvious we learned about vertical axis turbines, horizontal axis turbines was additional

information that was gladly explored. Wind turbines are dependent on only a few

factors, mainly tip speed ratio and torque. There is also swept area, and wind speed that

influence power generation but these are things that don’t involve in depth study to

improve upon. Tip speed ratio and torque impact the efficiency greatly, which is what

this whole project is about, improving efficiency. As it stands, no wind turbine can

reach 100%, not even near that due to the Betz’s limit which states the max efficiency a

wind turbine can obtain is 59.3%.

Material selection was a huge factor in developing a working prototype. The

limitations on this were vast, with most plastic, and metal options being instantly

removed from our choices due to manufacturing costs that greatly exceed our budget.

The different processes to fabricate the parts necessary were explored and questioned

until the team came to what was the thought to be the ideal decision.

When designing the prototype, it is important to ensure that all connection points have

the same diameter size hole to ensure a proper alignment and connection point. Even

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though a particular design concept is by far the best design for the project, it is

important to see how the manufacturing process will take place.

Team chemistry and bonding is the number one key to maintain a healthy relationship

of the team during senior design. This project is not like any other class as the time

commitment is equivalent to having a part time job. This project is an extremely

stressful process that shows the true engineering skills of the team. Just like any team

we had our moments where some members would argue or strongly disagree with the

decision made on the project, but one of the best things this team did was to let water

under the bridge and not take anything personal. If there is a real concern, the opinions

of all members should be heard, but nothing should be made personal which is easier

said than done. Once things become personal, that is where the team can fall apart. A

team torn apart can never have a successful senior design project. Although it is

difficult with all members having completely different schedules, it is important to

enjoy the major milestones with the team and bond outside of senior design doing

proactive activities to reduce built up tension.

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CHAPTER 5: CONCLUSIONS AND RECOMMENDATION

5.1 VAWT: A Deeper Insight

The greater understanding of the various types and classes of turbines, allowed the team to make

precise decisions that would achieve their required goals. By understanding the parameters that

dictate the Darrius's efficiency, the team was able to increase the efficiency of the turbine by an

average of 67% above its direct competitor. In achieving the highest requirement placed on the

team, the members have immerged victorious at the end of the project, with a great and an in depth

knowledge of designing, implementing, manufacturing, and testing, of a wind turbine that is

capable of generating energy without harming the environment.

Blades were 3D printed, which made the process of manufacturing significantly easier. In the

future if the team would have more time, the blades should be manufactured by the team members.

This will not only save on cost, but also add a skillset to the team.

Another skillset that the team could have benefited from is the manufacturing of the circuit board,

as well as the generator. This will give the team a skill in electrical components, which most

mechanical engineers lack.

Instead of outsourcing the manufacturing or placing an order for machining in the manufacturing

lab, the team members could have taken the initiative to learn how to machine components, if time

and resources permitted.

Last but not least, the availability of a wind tunnel would have been extremely beneficial. A wind

tunnel could have provided better testing results since the wind direction and speed could be

controlled with accuracy.

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5.2 Conclusion

The harnessing of power and increasing the efficiency of the less popular Vertical Axis Wind

Turbine VAWT, can be achieved using a Darrius design. Such results can be achieved by the

manipulation of various parameters to obtain desired results. The various VAWT designs were

researched and their differences were grasped. The Darrius was chosen as the prime candidate

because of it exhibiting higher efficiency in theory. A base model Darrius was obtained from an

online store, and used as a direct competitor to which improvements on the efficiency of the new

prototype would be compared. On average, an increase of 67% was achieved. The increase in

efficiency proved to be obtainable by manipulating the affecting parameters, as well as the

selection of the suitable materials.

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REFERENCES

1. Patel, B., & Kevat, V. (2013). PERFORMANCE PREDICTION OF STRAIGHT BLADED DARRIEUS WIND TURBINE BY SINGLE STREAMTUBE MODEL. Address for Correspondence.

2. Jha, A. R. Wind Turbine Technology. Boca Raton, FL: CRC, 2011. Print 3. Scott, Jeff. "Aerospaceweb.org | Ask Us - Gottingen Airfoils." Aerospaceweb.org | Ask

Us - Gottingen Airfoils. Aerospaceweb, 10 Oct. 2004. Web. 19 Mar. 2015. 4. Freeman, Janine. Reference Manual for the System Advisor Model's Wind Power

Performance Model. 1st ed. Golden, CO: National Laboratory of the U.S. Department of Energy, 2014. Web. 19 Mar. 2015.

5. Ragheb, Maghdi, and Adam Ragheb. Ratio of Blade Tip-Speed to Wind Speed. Digital image. InTech - Open Science Open Minds | InTechOpen. N.p., n.d. Web. 20 Mar. 2015.

6. Wizelius, Tore. Developing Wind Power Projects: Theory and Practice. London: Earthscan, 2007. Print.

7. Hansen, Martin O. L. Aerodynamics of Wind Turbines, 2nd edition. Routledge, December 2007

8. Wortman, Andrze J. Introduction to Wind Turbine Engineering Butterworth-Heinemann, September 1983

9. "Airfoil Investigation Database - Welcome." Airfoil Investigation Database - Welcome. N.p., n.d. Web.

10. "Turbine Calculator." Turbine Calculator. N.p., n.d. Web. 11. "REUK.co.uk - The Renewable Energy Website." Calculate KWh Generated by Wind

Turbine. N.p., n.d. Web. 12. "MakeItFrom.com :: Material Properties Database." MakeItFrom.com :: Material

Properties Database. N.p., n.d. Web. 13. "Materials Chart." - ABS, Polystyrene, CAB (Butyrate), PVDF, UHMWPE, HDPE,

LDPE, LLDPE, PVC Flexible Polycarbonate, Polyurethane, Nylon, TPEs. N.p., n.d. Web.

14. "Introducing the 4N-55 Vertical Axis Wind Turbine." 4 NAVITAS Vertical Axis Wind Turbines. N.p., n.d.

15. "Statutes & Constitution: View Statutes: Online Sunshine." Statutes & Constitution: View Statutes: Online Sunshine. N.p.

16. "Windspire Vertical Wind Turbine Applications and Uses." Windspire Vertical Wind Turbine Applications and Uses. N.p., n.d.

17. "ALEKO | WGV45W 30W Nominal 45W Maximum 12V Residential Vertical Wind Turbine Generator." AlekoGreenEnergy.com. N.p., n.d.

18. "Applications of Vertical Axis Wind Turbines for Remote Areas." Applications of Vertical Axis Wind Turbines for Remote Areas. N.p., n.d.

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APPENDICES

87

3D Printed Airfoil

88

Engineering Drawings

89

90

91

92

93

Relevant Material

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Table 7-Blade material decision matrix

BLADE

MATERIAL CRITERIA COST MNFCTRING WT. STRENGTH TOTAL

Importance

Weight % 0.20 0.25 0.35 0.20 1.00

COMPOSITE

PLASTIC Rating 5.25 6.00 4.50 5.67

Weighted

Rating 1.05 1.50 1.58 4.13

CARBON

FIBER Rating 2.75 3.75 9.67 10.00

Weighted

Rating 0.55 0.94 3.38 4.87

FIBER GLASS

(CLOTH) Rating 7.25 6.50 7.25 7.67

Weighted

Rating 1.45 0.23 2.54 4.22

METAL

(ALUM,

TITANIUM,

ETC.)

Rating 3.00 5.75 6.50 9.00

Weighted

Rating 0.60 1.44 2.28 4.31

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Table 8-Airfol decision matrix

AIRFOILS CRITERIA GEOMETRY SIZE ANGLE OF

ATTACK

LIFT TO

DRAG TOTAL

Importance Weight % 0.50 0.05 0.05 0.40 1.00

GOE 462 Rating 1.00 5.67 6.67 10.00

Weighted Rating 0.50 0.28 0.33 4.00 5.12

Importance Weight % 0.50 0.05 0.05 0.40

GOE 481 Rating 6.00 5.00 7.33 9.00

Weighted Rating 3.00 0.25 0.37 3.60 7.22

Table 9-Component decision matrix

ADDITIONAL

COMPONENTS COST

IMPORTANT

WEIGHT %

TALL/

THIN

WIDE/S

HORT

EQUAL

HXW

TWISTED

BLADE

TAPERED

BLADE

COICIDENT

EDGE BLADE

GEARBOX 7 0.50 1.00 6.40 6.00 4.80 4.20 5.80

BRAKING SYSTEM 9 0.50 8.00 6.20 6.40 5.80 5.80 5.80

Table 10-Other factors decision matrix

Other Factors cost Tall/skinny Wide/s

hort

Equal

H*W

Twisted

blade Tapered Blade

Coincident Edge

blade

Ease of

Manufacturing NA 6.25 6.25 6.25 3.75 7.25 8.25

Tip-Speed Ratio NA 9.25 4.00 6.50 4.25 6.00 6.50

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RPM NA 9.50 4.25 6.50 7.75 7.75 6.50

Torque NA 5.00 9.25 6.75 5.00 5.00 5.50

Lift to Drag

Ratio NA 4.50 6.00 6.50 6.75 5.75 5.00

Angle of Attack NA 4.75 4.50 5.00 5.25 5.50 5.50

Maintenance NA 4.50 5.25 4.25 5.75 4.50 3.75

Table 11-Key to decision matrix

KEY

1 TO 3 Low/Horrible

4 TO 6 Moderate/Neutral

7 TO 9 High/Great

10.00 Must Have/Perfect

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