Self-Sustaining Street Light L.C. Smith College of Engineering and Computer Science Syracuse University Reid Berdanier Karen Hernandez Christopher Horvath Laura Graham Chuck Raye MEE 472 Spring 2010
Mar 16, 2016
Self-Sustaining Street Light
L.C. Smith College of Engineering and Computer Science
Syracuse University
Reid Berdanier
Karen Hernandez
Christopher Horvath
Laura Graham
Chuck Raye
MEE 472
Spring 2010
Table of Contents Self-Sustaining Street Light
2
Abstract ......................................................................................................................................4
Acknowledgements.....................................................................................................................5
Chapter 1: Introduction ...............................................................................................................6
Chapter 2: Ethical Implications ...................................................................................................8
Chapter 3: Stress Analysis.........................................................................................................12
Chapter 4: Wind Turbine...........................................................................................................23
Chapter 5: Off-The-Shelf Components ......................................................................................35
Chapter 6: Manufacturing..........................................................................................................38
Chapter 7: Conclusions and Recommendations .........................................................................45
Appendices
Appendix A: Gantt Charts
Figure A-1. Original Gantt Chart .................................................................................47
Figure A-2. Final Gantt Chart ......................................................................................48
Appendix B: Graphs
Figure B-1. Rotor performance using published data for CP. ........................................49
Figure B-2. Predicted power performance utilizing CFD data. .....................................49
Figure B-3. Predicted power performance utilizing CFD data with extrapolated
generator data...........................................................................................50
Appendix C: Engineering Drawings
Figure C-1. McMaster-Carr parts list order ..................................................................51
Figure C-2. Long truss rod...........................................................................................52
Figure C-3. Short truss rod...........................................................................................52
Figure C-4. Truss plate ................................................................................................53
Figure C-5. Short solar panel bracket ...........................................................................53
Figure C-6. Long solar panel bracket ...........................................................................54
Figure C-7. Rotor.........................................................................................................54
Figure C-8. Top and bottom housing sections ..............................................................55
Figure C-9. Middle housing sections............................................................................55
Appendix D: CFD Results
Figure D-1. Sample calculation grid for 15 degree converging angle............................56
Figure D-2. Torque fluctuations for λ=1.0....................................................................56
Figure D-3. CFD results for Cm as a function of time showing velocity independence
of turbulence model..................................................................................57
Table of Contents Self-Sustaining Street Light
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Figure D-4. CFD results for CP as a function of tip-speed ratio showing velocity
independence of turbulence model ...........................................................57
Figure D-5. CFD results for Cm as a function of tip-speed ratio for various
converging angles ....................................................................................58
Figure D-6. CFD results for CP as a function of tip-speed ratio for various
converging angles ....................................................................................58
Appendix E: Wind Speed Data Analysis
Figure E-1. Histogram for Skytop area anemometer data (11/13/2009 – 4/22/2010).....59
Figure E-2. Histogram for Standart lot anemometer data (11/13/2009 – 4/22/2010) .....59
Appendix F: MATLAB Code ..............................................................................................60
Abstract Self-Sustaining Street Light
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ABSTRACT
In continuation of the project to design a self-sustaining street light, the main efforts of
this project were focused on the manufacturing and construction of a prototype. This included
acquiring the individual components, designing appropriate interconnections between parts, and
drafting engineering drawings for various parts. In order to complete the prototype in a feasible
and timely manner, the design was scaled down by a factor which would ease the assembly
requirements. Through cooperation of the team members and faculty advisors, the problems
encountered in the design for manufacturing were creatively approached and solved. In the end,
the prototype was assembled and verified to function correctly. Within this report, ethical
implications are also discussed.
Note to the reader: This report serves as a continuation of the companion report presented for fall
semester 2009.
Acknowledgements Self-Sustaining Street Light
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ACKNOWLEDGEMENTS
Our deepest gratitude goes to everyone who continued to support our project this
semester. We would like to thank Professor Thong Dang and Professor Michael Pelken once
again for their help and weekly advice. We would also like to thank Professor Frederick Carranti,
for his continued support and encouragement. A special thank goes to MAE graduate students
Nhan Huu Phan and Premkumar Siddarth for performing further finite element analysis on our
lightpost to analyze wind speed amplification effect and stress applied on the street light
assembly. We also sincerely thank Debbie Brown and the MAE purchasing department for
taking care of all purchasing orders for our prototype. We express a deep thanks to Ryan Dygert,
for assisting us in the setup of our generator testing, and advice on manufacturing procedure of
lightpost housing. To Jeff Ellison and the SU Physical plant team for helping us install
anemometers and collect data, as well as manufacture components for our prototype. To the
Engineering Machine Shop for constructing components for our prototype and Physics
Department machine shop for assembling the rotor. Finally, special thanks go to Tim Hatlee
(team member from fall 2009), Evan Beckerman, Denis Pradhan, Jakub Walczak, and all other
undergraduate students who took time away from their own projects to assist in the production of
this project.
Chapter 1: Introduction Self-Sustaining Street Light
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CHAPTER 1: INTRODUCTION
Last semester, our senior design group designed and developed a “Self-sustaining Street
Light” device powered by a vertical-axis wind turbine and solar photovoltaic panels. The rotor
design, energy storage system, and sizing calculations were a few of the aspects analyzed. Our
goal this semester was to assemble a working prototype of the “Self-sustaining Street Light,”
utilizing off-the-shelf components, to further investigate its performance. This semester, our
team improved previous semester’s Computer Aided Design (CAD) drawings to give to machine
shops. In this report, ethical implications for patent pending design of Self-sustaining Street
Light are also taken into account, and discussed.
Our team collaborated with following multi-disciplinary teams: an advertising team,
MAE graduate students, and an industrial design team (COLAB). The advertising team
investigated a target market and came up with an advertising campaign for our product. This
campaign was presented to our team by the end of the semester.
A simulation of wind velocity amplification effect and stress analysis was carried out by
two MAE graduate students. Computational Fluid Dynamics (CFD) was used to analyze the
wind amplification effect and the optimal converging angle for the housing section. ANSYS
software was utilized by a graduate student to perform stress analysis on the street light and pole
assembly. Results obtained were then compared with basic handmade calculations for stress
applied to the pole. In addition, the industrial design group, COLAB, implemented our design to
their plans of an environmentally friendly service station.
In addition to multi-disciplinary collaborations, and manufacturing of working prototype,
our group submitted an abstract and paper to participate in the 7th international conference on
Indoor Air Quality, Ventilation and Energy Conservation in Buildings (IAQVEC) 2010 at
Chapter 1: Introduction Self-Sustaining Street Light
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Syracuse University to be held August 15-18, 2010. This conference is hosted by Syracuse
University, Syracuse Center of Excellence, National Research Council Canada, and the United
States Environmental Protection Agency (EPA).
Chapter 2: Ethical Implications Self-Sustaining Street Light
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CHAPTER 2: ETHICAL IMPLICATIONS
This section will seek to explain the important points of this design that deal with more
qualitative issues of the project, such as liability risks, manufacturing methods, environmental
concerns and responsibility, and the handling of intellectual property. From the beginning, the
original concept for the design came from the collaboration of Professors Michael Pelken and
Thong Q. Dang. While the technical aspects of the converging section involved Dr. Dang, the
aesthetic properties of the design originated from Professor Pelken. The original patent filed by
these two is owned by the University. Recently, rights for sole production of this patent has
been extended to a company with whom they will continue collaboration. This exciting
collaboration and sharing of intellectual property will provide a means of funding and further
development of the idea and prototype into a manufactured product. This means that the project
started here by this interdisciplinary team has the potential to eventually expand into a profitable
market, making the research and prototype development a worthwhile investment.
As with any engineering product developed, there is a certain amount of risk of injury
associated; this is why safety factors are usually included and why stress analyses are done.
Hopefully, the stress analysis will provide a useful understanding of the limitations of this
technology and the recommendations will be followed in further development and manufacturing
of the product to ensure that civilians and users will be safe from harm. With many products,
services, and machines, there is a way in which the consumer could be hurt in its use. However,
with this particular product, it is particularly static in that it is not intended to be interactive, and
should not cause harm in this way. In maintenance, the technician will need to interact, and
therefore certain design elements should be included to ensure his safety. This would include a
Chapter 2: Ethical Implications Self-Sustaining Street Light
9
shutoff of electricity from the base, as well as a shutoff for the rotor, to exclude the possibility of
injury from moving parts or from electricity.
When originally considering the possibility to proceed with the production of this project,
the motivation was to provide a solution for lighting in several situations. The idea was to
produce a product that was sustainable, environmentally responsible, and applicable for regions
without established electric infrastructure. As such, utilizing renewable sources of energy was
an ideal solution. By taking advantage of solar and wind resources, this lightpost achieves these
goals; it produces free energy as necessary, produces no greenhouse gases, and can be put into a
place that require lighting without the need for expensive trenching or access to an existing
electric grid. Since this product could be put into place in a variety of locations, the payback
period would vary depending on how far the location is from standard infrastructure.
Nonetheless, it will provide a service that has more value than its monetary component. Without
contributing to the ever-increasing global warming trend, this product will also serve as a
consistent reminder to those who see it in use, to change their individual habits towards a
sustainable and responsible lifestyle.
With the future manufacturing of the product, it is desirable to employ methods which are
sustainable and environmentally friendly, keeping in conjunction with the goals of this project.
This would include manufacturing methods which use machines that produce the least amount of
waste materials. Accordingly, it may be best to use methods of casting to produce the rotor and
housing parts rather than using costly machining methods.
It is possible that in the future the rotor will be made out of a non-metal material which is
lighter and non-reflective, so as to provide for non-distracting, easier rotation. It also may be
Chapter 2: Ethical Implications Self-Sustaining Street Light
10
more cost-effective to use a cheaper material such as a plastic through a type of mold casting.
The casting method would also imply a greater production, and much less material waste.
For greater efficiency of the system, the individual electrical components would be
designed and manufactured by the company, rather than bought off the shelf to closely match the
product’s purposes. The generator and the LED drivers when custom designed would especially
provide great increases in the overall efficiency. It would allow the generator to meet the exact
range for which the rotor will function to avoid losses in production. It would also eliminate the
losses in converting DC to AC to DC for the electricity leaving the batteries to power the LED
lights at the necessary current and voltage.
If the poles would like to be custom built, it is likely that the most cost-effective method
would be to make these within the company as well. This will provide the ability to create a
method of manufacturing the quantity necessary for production. Producing all of these
components and pieces of the product also means that there is no need to ship items – a process
which adds both cost and a carbon footprint to the product.
In conjunction with the responsibility in manufacturing of the product, it is just as
important to consider the end of the product’s life. While the lifespan is currently uncertain, it is
estimated that it should last as long as typical VAWTs with the occasional maintenance as
deemed necessary. This should ensure at least 10-15 years of safe usage, and can be better
determined as the product is further developed and tested for durability and function. The cost
of the life-span will be built into the overhead considered for the cost analysis of the company.
This includes the dismantling of the product at the end of its life, and the recycling and
processing of the materials. The metals and plastics used in the rotor and housing will be
salvaged within the company, melted down for reuse in the manufacturing processes. The
Chapter 2: Ethical Implications Self-Sustaining Street Light
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batteries will be forwarded to a recycling plant where they will be properly disposed of, rather
than adding to a typical landfill where they could leak heavy metals and corrosive acids into the
earth. The electrical components will be assessed and inspected carefully for damage and
reused where appropriate. It will obviously be more costly to do this processing, but it will most
definitely provide for a more responsible product, also making it a more legitimately green and
marketable technology. In such a way, it will easily end up paying for itself.
As a sustainable solution, this project aims to meet three important criteria that make it
exactly that – sustainable: to develop a product that is environmentally responsible, meets a need
of society, and is financially plausible. In view of these ethical implications, this project meets
the criteria for sustainability, and hopefully as the product continues in development, it will be
financially feasible while meeting this important criteria.
Chapter 3: Stress Analysis Self-Sustaining Street Light
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CHAPTER 3: STRESS ANALYSIS
1.1 Static Stress Analysis
As the design of the rotor and housing have changed, so has the way that the load will be
distributed upon the pole which supports the weight and other forces involved with the
lightpost’s function. Therefore, it is important to analyze these forces and determine whether a
typical pole would be suitable for this function, or whether it would be prudent to have a custom
built pole that would suit the particular needs of this project.
Figure 3.1. Diagram demonstrating weight distribution for determination of compressive stress.
The first stress that was investigated was the compressive force due to the structure’s
weight. The total weight, estimated at 140 pounds, was divided into the rotor and the housing,
which were estimated to be 45 and 90 pounds respectively. With the weight of the rotor applied
C
D
WRotor
WHousing
Supports
weight of
Rotor
Supports
weight of
Housing
Support
Pole
Chapter 3: Stress Analysis Self-Sustaining Street Light
13
at point C, and the weight of the housing at point D, the total compressive force was found to be
59 KPa, with more detail given below in Table 3.2. These important geometries of the pole and
rotor are displayed in Figure 3.1.
The value of the compressive stress is well within the acceptable loads for both Steel and
Aluminum, whose important material properties are summarized in Table 3.3. The given strain
values due to this compression are also given below.
Measurement Metric English
Units
Rotor Height (Total) 0.889 M 35 in
Rotor Diameter 0.610 M 24 in
Rotor Radius 0.305 M 12 in
Rotor W 200.2 N 45 lbs
Housing W 400.3 N 90 lbs
a 0.076 M 3 in
b 0.076 M 3 in
c 0.266 M 10.5 in
d 0.596 M 23.5 in
x 0.254 M 10 in
Pole Outer Radius 0.076 M 3 in
Pole Inner Radius 0.051 M 2 in
CS Area of Pole 0.010 M^2
J 0.005 M^2
I 2.12E-05 M^2
L (pole height) 7.62 M 25 ft Table 3.1. Important geometrical values of rotor, housing, and pole.
][/)(/ PaAreaWhWrAP +==σ (3.1)
][/ mAEPL Dc δδδ +== (3.2)
Table 3.2. Determination of compressive stress due to weight.
Value Steel Pole Aluminum Pole
σ [Pa] 59255.8 59255.8
δc [m] 0.000753 0.002184
δd [m] 0.001455 0.004223
δtotal [m] 0.002207 0.006408
Chapter 3: Stress Analysis Self-Sustaining Street Light
14
After finding the compressive stress, the torsional stress due to the wind on the rotor was
also investigated. The force due to the wind was estimated by assuming a static situation of the
rotor. The analysis is as follows, and results in a moment around the z-axis of the rotor, with
values that increase with the change in the wind speed. The values of the moment and the stress
are given in Table 3.4 found later in this section.
Figure 3.2. Determination of torsion moment and stress.
heightDiameterPW VY **5.*= (3.3)
][**5. NmRadiusWM YZ = (3.4)
]/[* 2mN
J
cM
Pole
Z=τ (3.5)
)(*5.0;22
ioPolerrJRadiusc −== π (3.6)
In a similar way, the forces and stresses on the pole were found by means of a similar
assumption; a static situation was considered and the rotor was assumed as a flat plate, with the
two rotors parallel to each other, rather than orthogonal. Such an analysis results in an
MZ
[Nm] WY [N]
PV [Pa]
D [m]
H
[m]
Chapter 3: Stress Analysis Self-Sustaining Street Light
15
over-estimation of the forces and, in a way, provides a factor of safety in the analysis. The
forces are then translated to the pole as displayed in Figure 3.3 and Figure 3.4.
Figure 3.3. Dynamic pressure to linear force along axis of rotor and housing.
DiameterPWV
*= (3.7)
heightWWX
*= (3.8)
Figure 3.4. Determination of forces on rotor bearings.
W [N/m]
WX [N]
PV [Pa]
D [m]
H
[m]
W [N/m]
Ax [N]
WX [N/m]
Bx [N]
Bearings
a [m]
b [m]
Chapter 3: Stress Analysis Self-Sustaining Street Light
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;)(*)2
(*0;;0 hbaAbh
WMWBAFXxBxxxX
++−+==Σ=+=Σ
;)(/)2
(* hbabh
WAxx
+++= (3.8)
xxX
AWB −= (3.9)
There are two bearings which translate the forces from the rotor to the rest of the
structure. In accordance with Figure 3.1, the bearing at point A translates part of the force to the
housing, while the bearing at point B within the pipe below the rotor translates the force to the
coupling that is attached to the pole. These are shown in the diagram, with the eventual result as
shown in the diagram of the pole. The main points of force are given at points C and D, with
moments at the same points due to the translation from the point at which the original force is
applied.
Figure 3.5. Determination of forces on housing collar and on rotor/generator collar.
xxX
AWB −= (3.9)
;)(*;;0 dhaAMDAF XDXXX ++===Σ (3.10)
DX
AX
MD
d
Bearing Pipe
Pole Collar
Generator
BX
CX
c
MC
Chapter 3: Stress Analysis Self-Sustaining Street Light
17
;*;;0 cBMCBF XDXXX ===Σ (3.11)
The bottom of the pole, point G, shows the connection of the pole to the ground, and
shows the point of greatest shear stress and torque. This was determined by the method of
moment and shear diagrams. As a result this is the point that was investigated for the point of
failure of the pole. The value of stress due to the forces and moments at the top of the pole are
indicated in Table 3.4.
;cbdX −−=
XXXXDCGF +==Σ ;0
DCXXGMMxLDLCMM −−−+== )(**;0 (3.8)
StressShearPaI
cMG
−= ][;*
σ (3.9)
)(*25.44
iorrI −= π (3.10)
Figure 3.6. Determination of forces on housing collar and on rotor/generator collar.
It is important to see the values of this stress and find where it reaches the shearing yield
point for a given material. For the Steel investigated – ASTM–A36 – with dimensions of
diameter 6 inches, and thickness of 2 inches, even at high wind speeds of 60 m/s or 134 mph the
shearing stress at the bottom only reaches about 1.8 MPa; this is well below the expected
x
GX MG
L
CX
MC
DX
MD
Chapter 3: Stress Analysis Self-Sustaining Street Light
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yielding point of Steel due to shearing, which is around 145 MPa. Even the aluminum pole, for
6063-T1, it is equally well below its yielding point (about 97 MPa). It seems that the structure
would fare quite well on a typical pole, of either Aluminum or Steel, at the given height.
Apparently, it seems to require even more of a force to cause the pole to yield, although perhaps
with cyclical loading, this may occur easier. Property values for these materials are shown below
in Table 3.3, while the values of stress as they vary with wind speed are shown in Table 3.4.
Table 3.3. Material properties.
Wind Speed (m/s)
Dynamic Pressure (Pa)
W - (N/m)
Wx - (N)
Mz (Nm)
Torque σ [Pa]
Ax [N]
Bx [N]
Mc (Nm)
Md (Nm)
Mg (Nm)
Gx [N]
Shear σ [Pa]
1 0.6 0.4 0.3 0.03 0.38 0.2 0.2 0.0 0.1 0.1 0.3 460.6664
4 9.8 6.0 5.3 0.41 6.11 2.7 2.7 0.7 2.0 2.1 5.3 7370.663
7 30.1 18.4 16.3 1.24 18.71 8.2 8.2 2.2 6.1 6.3 16.3 22572.65
10 61.5 37.5 33.3 2.54 38.19 16.7 16.7 4.4 12.5 12.8 33.3 46066.64
13 103.9 63.4 56.3 4.29 64.54 28.2 28.2 7.5 21.1 21.7 56.3 77852.62
16 157.4 96.0 85.3 6.50 97.77 42.7 42.7 11.4 31.9 32.9 85.3 117930.6
19 222.0 135.3 120.3 9.17 137.87 60.2 60.2 16.0 45.0 46.4 120.3 166300.6
22 297.7 181.5 161.3 12.29 184.85 80.7 80.7 21.5 60.4 62.2 161.3 222962.5
25 384.4 234.3 208.3 15.87 238.70 104.2 104.2 27.7 78.0 80.3 208.3 287916.5
28 482.2 293.9 261.3 19.91 299.43 130.6 130.6 34.8 97.8 100.7 261.3 361162.5
31 591.0 360.3 320.3 24.41 367.03 160.1 160.1 42.6 119.9 123.5 320.3 442700.4
34 710.9 433.4 385.3 29.36 441.50 192.6 192.6 51.3 144.2 148.5 385.3 532530.4
37 841.9 513.2 456.3 34.77 522.85 228.1 228.1 60.7 170.8 175.9 456.3 630652.3
40 984.0 599.8 533.3 40.63 611.07 266.6 266.6 70.9 199.6 205.5 533.3 737066.3
43 1137.1 693.2 616.3 46.96 706.17 308.1 308.1 82.0 230.7 237.5 616.3 851772.2
46 1301.3 793.3 705.2 53.74 808.15 352.6 352.6 93.8 264.0 271.8 705.2 974770.1
49 1476.6 900.1 800.2 60.98 916.99 400.1 400.1 106.5 299.6 308.4 800.2 1106060
52 1663.0 1013.7 901.2 68.67 1032.72 450.6 450.6 119.9 337.4 347.4 901.2 1245642
55 1860.4 1134.1 1008.2 76.82 1155.31 504.1 504.1 134.1 377.4 388.6 1008.2 1393516
58 2068.9 1261.2 1121.2 85.43 1284.78 560.6 560.6 149.2 419.7 432.1 1121.2 1549682
61 2288.4 1395.0 1240.2 94.50 1421.13 620.1 620.1 165.0 464.2 478.0 1240.2 1714140
Table 3.4. Resultant forces and stresses.
Property Steel Aluminum Unit
E (modulus of Elasticity) 200 68.9 Gpa
Compressive Yield 152 152 MPa
Ultimate Tensile Stress 400 400 MPa
Yield Shear 145 96.5 MPa
Chapter 3: Stress Analysis Self-Sustaining Street Light
19
1.2 Conclusions and Recommendations
Considering these findings, a few recommendations can be made. While this analysis
makes a few assumptions that results in a lower wind speed for the material’s yield point, this
can be seen as an appropriate safety factor for the design point. Therefore, these values should
be interpreted appropriately. If there is still worry regarding the strength of the pole, then a
custom pole could be built from a stronger Steel alloy, with a wider radius, or with a thicker
cross section. Such a procedure would work to strengthen the pole and would likely result in a
smaller value of strain at the top of the pole.
Another method of reinforced restraint would involve cables that anchor the housing of
the lightpost, and help to secure it from swaying in the wind while dispersing the stress from the
pole. If these two procedures were used in conjunction, it would ensure that the prototype is safe
for use while in testing. Additionally, the lightpost could be secured by wrapping some sort of
netting or webbing to the housing, and attached to the anchor cables, catching the housing in case
it falls from the pole. This is very important, because if the proper precautions are not followed,
there is the possibility that the lightpost could fall due to failure and possibly injure a bystander.
In order to avoid cyclical loading on the structure from high winds, a better method of
safety precautions could be implemented in future design of the lightpost when manufactured for
actual production. The best thing to do would be to include a control system that senses when
the wind speed is at a point that is too great for energy harvesting, and would automatically
disconnect the shaft from the rotor to the generator. This would allow for a free-spinning
situation of the rotor. This is different than the safety procedure for Horizontal-Axis Wind
Turbines in which they move to stall position in high winds and storms, but should provide an
appropriate. The free spinning situation would allow the wind to pass through the structure
Chapter 3: Stress Analysis Self-Sustaining Street Light
20
without translating its full force to the structure and the pole. This would, however, result in a
high rpm of the structure, and it should be investigated as to whether it could eventually reach a
rotational speed that creates resonance for the structure. While this implementation is beyond
the scope of this project, it could easily be developed for future manufacturing purposes.
The way it currently stands, when the battery is full or the wind speed is too great, the
generator simply applies a load so great that the rotor is unable to spin, resulting in a static
situation as was investigated above. That is why this additional recommendation would provide
better safety than the current prototype. Another possible safety recommendation involves a
method that would result in a stall position, while dispersing the force of the wind on the
structure. Such a method could involve a similar control system that would cover or enclose the
rotor within a cylindrical or other smooth surface that would move the air around the housing
and not move the rotor – it could be a system that has moving doors. However, this has several
negatives. Notably, it introduces additional moving parts and also adds additional weight to the
structure. The additional weight could be easily supported, as the compression forces were well
within a reasonable range, but the additional moving parts means that there would be a greater
need for maintenance of the structure.
1.3 Dynamic/Harmonic Analysis
In view of the function of this lightpost, it was desirable to do a harmonic analysis in
order to determine the safety of functioning within the desired design range of wind speeds. In
cooperation with a graduate student, Siddharth Premkumar, the program ANSYS was utilized to
analyze a simple model of the structure, using the diagrams below which estimate the function of
the structure.
Chapter 3: Stress Analysis Self-Sustaining Street Light
21
Figure 3.7. Simplified lightpost housing.
Figure 3.8. Simplified lightpost rotor.
17.5”
41.25” 6.25”
24”
0.125”
50.2”
42”
4.8”
2” .5”
18”
24
6
Chapter 3: Stress Analysis Self-Sustaining Street Light
22
The first attempt was to build the rotor and housing separately in ANSYS, and then
analyze them together in a dynamic analysis. However, this method was unable to produce
results, because the number of nodes produced from the meshing exceeded the allowable number
for analysis in the program. The meshing was not able to be simplified and still keep the desired
shape of the structure. Instead, a second method was to analyze the parts separately, to find the
critical wind speed and corresponding rotational speed for the rotor, and then find the associated
stresses on the housing. Unfortunately, because of the low rotational speed and the complexity
of the model, it was explained that the critical speed was not able to be found from the analysis.
It was qualitatively explained by Siddharth that the structure would not reach an
rotational speed at which it would fail, because of the design range. Due to time constraints and
responsibilities outside of this project, Siddharth was unable to provide additional services in
pursuit of quantitative dynamic analysis results. Therefore, the dynamic analysis of this lightpost
structure will need to be investigated further at a later time in order to determine the range within
which the lightpost can safely operate.
Chapter 4: Wind Turbine Self-Sustaining Street Light
23
CHAPTER 4: WIND TURBINE
4.1 Generator Selection:
Significant research was conducted last semester to determine an appropriate permanent
magnet generator/alternator (PMG/PMA – both terms will be used interchangeably in this report)
for the vertical-axis wind turbine (VAWT) in this project. Those investigations showed that the
Ginlong GL-PMG-500A PMG was an appropriate match for this light source design. Upon
beginning preparations for prototyping, however, it was determined that the current size was far
too large to produce effectively, inexpensively, and quickly – all necessities for this specific
prototype. As a result, the power production capabilities of the rotor were cut in half; this led to
a reduction in all sizing parameters by a factor of 2 . Understandably, this would, in turn, also
effectively reduce the light-on time of the LED luminaire by approximately a factor of two.
Nonetheless, this handicap was accepted by the project team after determining that the primary
goal of the prototyping phase is to prove the efficacy of the design – a proof of concept. After
deciding that a size reduction was appropriate for the prototype production, though, a new
generator was also necessary.
New investigations into available PMG products showed that few, if any, off-the-shelf
products were available to appropriately match the rotor size and, accordingly, power output of
this light source. Specifically, all products from last semester were readdressed for plausible
inclusion, including: Ginlong GL-PMG-500A, Ginlong GL-PMG-1000, WindBlue DC-520,
WindBlue DC-540. In addition, new products were also considered: Wind Turbine
Technologies’ Cat 3 and Cat 4 PMAs. However, new power curves exposed the unfortunate fact
that the same issue from last semester – the requirement of low power at relatively high
Chapter 4: Wind Turbine Self-Sustaining Street Light
24
rotational speeds – was amplified by the prototype size reduction. This observation can be
explained by the relation for tip-speed ratio, λ:
U
d
2
ωλ = (4.1)
defined for diameter, d, rotational speed, ω, and effective wind speed, U. From (4.1), it can be
deduced that, for a given wind speed, the tip-speed ratio (the independent variable when
comparing non-dimensional relations to power coefficient, CP) shows an inverse relationship
between diameter and rotational speed. As a result, the reduction in diameter discussed earlier
appropriately led to an increase in rotational speed by the same factor of 2 at all wind speeds.
From this increase in rotational speed, none of the generators of interest showed adequate rotor
matching behavior.
Nonetheless, the search for a generator was not abandoned and a product was discovered
from a domestic distributor, Georgia Generator. Specifically, the product was described as a
PMA rated for 100W of output at a rotational speed of 450 rev/min. Unfortunately, though, the
industry-standard power curves showing performance at all rotational speeds provided by most
manufacturers and distributors were not available for this product. Despite this fact, an
approximation for power characteristics according to the observations of all other generators
listed above showed that this Georgia Generator product would, in fact, match nearly perfectly
with this rotor design if it behaved in the same manner as other generators. As the only true
option, the decision was made to purchase the product and physically test its performance at
other rotational speeds.
Chapter 4: Wind Turbine Self-Sustaining Street Light
25
4.2 Generator Testing:
In order to determine the power output characteristics of the purchased generator, the
generator needed to be tested. Various methods for accomplishing this goal were considered,
including the measurement of voltage and output from the generator explicitly. However, the
three-phase AC output of the generator creates considerable issues when considering such an
undertaking and, as a result, the experimental setup in Figure 4.1 was designed implementing a
torque meter (TM) and a DC drive motor. A variable frequency drive (VFD) was connected to
the motor, allowing for rotational speed control output from the motor. The three-phase AC
output from the generator was connected to the appropriate inputs on the charge controller
purchased for use with the prototype and, finally, a 12V car battery was connected to the charge
controller as the sink for the power.
Figure 4.1. Generator testing rig setup.
The benefit of such an arrangement over other recommendations to explicitly measure
voltage and current output from the generator is the simulation of the true system load
experienced by the generator during operation. Therefore, the data created by this test was the
most accurate representation of generator performance with the prototype model; in fact, the
information achieved from this test is more reliable than performance data received from
manufacturers for the other generators which were considered.
DC Motor
TM
Gen
erato
r
VFD
Chapter 4: Wind Turbine Self-Sustaining Street Light
26
By adjusting the VFD, the output from the motor changed, leading to a change in system
torque. By reading real-time data from the torque meter and recording rotational speed of the
system shaft via a laser tachometer, the performance data in Table 4.1 was created.
Unfortunately, though, the load on the system would not permit the motor to operate at rotational
speeds higher than approximately 200 rev/min. As a control for comparison, the same test was
performed while having the battery disconnected. These results are reported in Table 4.2.
VFD Setting N (rev/min) Torque (N-m)
10.0 95 0.20
14.5 115 0.55
18.0 133 0.99
19.0 160 1.46
21.0 191 1.87
VFD Setting N (rev/min) Torque (N-m)
12.0 100 0.18
14.0 165 0.20
15.0 186 0.21
16.0 242 0.22
18.0 322 0.24
Table 4.1. Loaded generator performance. Table 4.2. Unloaded generator performance
From Table 4.1, a torque value of 0.2 N-m was the point at which the generator began to
turn freely – indicative of the startup torque. This observation is appropriately congruent with
the published value for the product of 2.0≤ N-m, making the generator a good match by
creating a low cut-in speed for our wind turbine. Similar to the process for plotting the
performance for the other generators, these results were plotted against the power output from
the rotor at various wind speeds.
4.3 Power Analyses:
By plotting the predicted power output of the rotor with the performance characteristics
of the generator, operating conditions can be determined for varying wind speeds. Last semester,
generator curves were plotted against rotor performance assuming CP characteristics observed by
Modi and Fernando [1]. Due to the similarity of the rotor cross section for this project to the one
Chapter 4: Wind Turbine Self-Sustaining Street Light
27
used by Modi and Fernando, the same assumptions were made at this point in the design stage
and these data were plotted against the generator performance from Table 4.1 – see Figure 4.2.
Figure 4.2. Rotor performance using published data for CP.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
λ
Cp
No Surrounding Disk 0 Degree Disk 5 Degree Disk 15 Degree Disk 22 Degree Disk 30 Degree Disk
Figure 4.3. CFD results for CP as a function of tip-speed ratio.
Chapter 4: Wind Turbine Self-Sustaining Street Light
28
Alternatively, though, further advancements were made utilizing computational fluid
dynamics (CFD), incorporating the converging effect from the outer housing – one of the
fundamental aspects of this design. Figure 4.3 presents the results of these investigations,
showing the relative increases which can be achieved for corresponding increases in the angle of
convergence for the housing.
By processing the results from Figure 4.3 corresponding to the prototype housing angle
of 15 degrees, the performance data presented in Figure 4.4 is acquired. Comparing the results
of Figure 4.4 with those of Figure 4.2, the beneficial contributions of the converging section are
apparent. It should be noted, however, that the data of Figure 4.4 are accounting for a traditional
Savonius rotor cross-section, whereas the data from Figure 4.2 implement a Bach-type cross
section similar to the one implemented for this design. Based on the comparison results between
Savonius- and Bach-type rotor cross sections, it is assumed that the data of Figure 4.4 will
improve further yet, particularly as Reynolds number increases with higher wind speeds. This
effect can likely be attributed to the lift effects which contribute with the Bach-type cross
section.
From Figure 4.4, however, it can be seen that the predicted rotor performance at 6.76 m/s
extends beyond the observed generator performance data. As a result, Figure 4.5 presents the
predicted rotor performance (utilizing CFD data for CP) across the entire range of wind speeds
observed at Skytop. It should be noted that the generator performance beyond the five points
recorded in Table 4.1 is extrapolated by a curve-fit of known data.
Chapter 4: Wind Turbine Self-Sustaining Street Light
29
Figure 4.4. Predicted power performance utilizing CFD data.
Figure 4.5. Predicted power performance utilizing CFD data
with extrapolated generator data.
Chapter 4: Wind Turbine Self-Sustaining Street Light
30
The data of Figures 4.2-4.5 tell an important story. Notably, this information can provide
a good estimation of the cut-in speed of the VAWT. Combining the cut-in information observed
during the generator test with the data in these figures and similar reproductions, it can be
determined that the cut-in speed of the VAWT is approximately 2.50 m/s – a number that is
extremely encouraging for the productivity of this system.
However, further analysis can lead to a calculation of rated power for the wind turbine
system. As with last semester, two anemometers have been collecting and continue to collect
wind speed data for this project. Continued studies of these data through histogram plots has
given an even greater idea of wind speed spreads at the two locations of interest – Standart
parking lot and Skytop parking lot. These histogram results are presented in Figure 4.6 and
Figure 4.7 corresponding to data recorded between November 12, 2009 and April 22, 2010. On
April 22, 2010, the anemometer recording data at Standart parking lot was moved to a location
near the Syracuse University Warehouse in downtown Syracuse, NY to measure wind speeds as
part a potential coordination with the Connective Corridor project.
Chapter 4: Wind Turbine Self-Sustaining Street Light
31
Figure 4.6. Histogram plot of wind data at Standart parking lot.
Figure 4.7. Histogram plot of wind data at Skytop parking lot.
Chapter 4: Wind Turbine Self-Sustaining Street Light
32
The results from these histograms can then be applied to calculate the rated power:
∑
∑=
total
i
ii
n
Pn
RP (4.2)
for n time intervals producing power, P, for all velocity bins, i. The important observation in
(4.2) comes from the fact that the denominator takes into account the total number of time
intervals, ntotal, thus incorporating the amount of time during which the wind speed is lower than
the cut-in speed of the turbine. Understandably, in the limit, ∞→i , this equation becomes
increasingly accurate.
The operating points utilized for calculating rated power of this wind turbine system from
the Skytop lot histogram of Figure 4.7 are shown in Table 4.3 (calculated over the same data
collection period presented in Figure 4.7). The anemometers used for this project average wind
speeds over 10-minute intervals, which provides the time intervals for calculating n in (4.2).
Assuming the cut-in speed discussed earlier of 2.50 m/s, (4.2) was applied for these data.
Although the anemometers observed wind speeds as high as 11 m/s, the extrapolated data
prediction for generator performance shows the generator staying within its 150W peak limit for
wind speeds up to 9.75 m/s. As a result, the power output of the rotor at any wind speed higher
than 9.75 m/s can be essentially considered to be zero. Ultimately, this calculation process yields
a resulting rated power value of 6.541 Watts.
Chapter 4: Wind Turbine Self-Sustaining Street Light
33
Wind Speed (m/s) RPM Power (W) Torque (N-m) # of 10-min intervals W-(10 min)
2.50 96.0 2.3 0.23 1371 3153.3
2.75 100.0 3.1 0.30 902 2796.2
3.00 103.5 4.0 0.37 1287 5148.0
3.25 108.5 5.1 0.45 847 4319.7
3.50 113.5 6.3 0.53 1163 7326.9
3.75 117.5 7.7 0.63 722 5559.4
4.00 121.5 9.2 0.72 992 9126.4
4.25 126.0 11.0 0.83 610 6710.0
4.50 130.8 12.8 0.93 811 10380.8
4.75 136.3 15.1 1.06 431 6508.1
5.00 142.5 17.5 1.17 580 10150.0
5.25 149.5 20.3 1.30 321 6516.3
5.50 157.0 23.3 1.42 409 9529.7
5.75 165.8 26.8 1.54 219 5869.2
6.00 175.0 30.7 1.68 288 8841.6
6.25 185.0 34.8 1.80 110 3828.0
6.50 195.0 39.2 1.92 175 6860.0
6.75 204.0 44.2 2.07 86 3801.2
7.00 215.0 49.5 2.20 124 6138.0
7.25 225.3 55.2 2.34 58 3201.6
7.50 236.0 61.2 2.48 68 4161.6
7.75 248.0 68.0 2.62 40 2720.0
8.00 259.5 75.0 2.76 61 4575.0
8.25 272.0 82.6 2.90 26 2147.6
8.50 284.3 90.7 3.05 25 2267.5
8.75 297.0 99.2 3.19 23 2281.6
9.00 309.3 107.9 3.33 27 2913.3
9.25 322.1 117.0 3.47 8 936.0
9.50 335.0 126.7 3.61 15 1900.5
9.75 348.2 136.8 3.75 8 1094.4
not running 11241 0.0
sum 23048 150761.9
Rated Power (W) 6.541
Table 4.3. Rated power data.
4.4 Rotor Production:
In partnership with the Syracuse University Physics Machine Shop staff, the two VAWTs
for this project were produced. A cross-sectional drawing of the prototype rotor is shown in
Figure 4.8 with all dimensions in inches. Parallel with the design considerations discussed last
semester, the cross-section maintains a Bach-type shape, leading to increases in power output
and a slight shift of peak power output toward a higher value of tip-speed ratio, as discussed
Chapter 4: Wind Turbine Self-Sustaining Street Light
34
earlier. It is assumed, though, that the effect of shifting the power curves up and to the right will
replace them near peak operating points on the generator curve of Figure 4.4 and Figure 4.5.
The material used to produce the generator was selected to be aluminum alloy 5052,
according to recommendations from the machine shop staff. The blades were produced by a
rolling technique with 0.080” thick sheets and the circular endplates were cut by a computer-
controlled mill from 0.125” thick sheets. Holes were appropriately added (not shown in Figure
4.8) for the middle connection of the two rotor sections and the attachment of shaft collars.
Finally the two blade sections and the two end plates were mechanically fastened for use.
Figure 4.8. Prototype rotor cross-sectional drawing.
References:
[1] Modi, V.J. and M.S.U.K Fernando. “On the performance of the Savonius wind turbine.”
Journal of Solar Energy Engineering. 111 (1989): 71-81.
135º
R4.00
0.080
Chapter 5: Off-The-Shelf Components Self-Sustaining Street Light
35
CHAPTER 5: OFF-THE-SHELF COMPONENTS
For the purpose of the prototype of the design, it was easiest to order some key
components from vendors as opposed to constructing or assembling these components ourselves.
These components consisted of the charge controller, the solar panel, the LED streetlight, the
batteries and the generator.
5.1 Charge Controller
The charge controller is a Windmax Wind Turbine/Wind Generator Charge Controller.
The charge controller was purchased from Applied Magnets in Plano, Texas. The charge
controller was purchased last semester, and arrived timely and with no problems. The charge
controller is used to connect and safely control input and output of electricity to every electrical
component of the light post.
5.2 Solar Panel
The solar panel is a Kyocera KC65T, 65 W 12 V Nominal Solar Panel. This solar panel
was purchased from Affordable Solar Group, LLC in Albuquerque, New Mexico. The solar
panel arrived timely and with no problems, ready to be assembled into our design. The only
assembly required with the solar panel is to hook up wires from the solar panel down to the
charge controller. The solar panel will be held up by small rectangular aluminum rods attached to
the truss of the housing.
Chapter 5: Off-The-Shelf Components Self-Sustaining Street Light
36
5.3 LED streetlight
The LED streetlight is a Beta LED streetlight, type 4, 30 LED light fixture. This
streetlight was purchased through a local vendor, Ferrini-Konarski Associates in Baldwinsville,
NY. The vendor had attended a weekly meeting of our group in early October 2009, and brought
a light fixture that was similar to the light we were interested in. After deciding the exact light
we would need, we ordered the light from him in early February. Unfortunately, the vendor did
not seem to be very helpful in ordering the light and seemed a little confused on the process of
ordering through the University. This caused a significant amount of problems and the light was
in the process of being ordered until late April. Debbie Brown in the Mechanical and Aerospace
office was very helpful in this process and was persistent in trying to get the light. The team
contacted the vendor company and contacted the parent company to try to get the situation sorted
out, and the team was about to give up and find a new plan for the light when the light arrived.
The light is very simple to assemble into the design. The light only needs a power source
which will be taken from the batteries connected to the charge controller. The light fixture can be
placed outside of the assembly, or could be directly integrated into the housing of the light post.
The LED light ordered has three panels that contain 10 LEDs that can be easily removed from
the light housing and arranged in any pattern in our own housing. The wires and driver are easily
removed from the housing allowing the placement into our design to be simple.
Figure 5.1. LED light panel of 10 LEDs (three of these total).
Chapter 5: Off-The-Shelf Components Self-Sustaining Street Light
37
Figure 5.2. Entire light fixture.
5.4 Batteries
The batteries for this design are picked out, but not yet ordered. The batteries are two 6
volt Sun Xtender deep cycle cell batteries. The reason these batteries have not been purchased
yet is to wait until the light post is fully assembled, when the batteries are completely necessary.
Luckily, the Link Hall Machine shop has been helpful in providing a 12 volt car battery to our
group when performing tests on the generator, and when testing our light post before completion
of the project.
Chapter 6: Manufacturing Self-Sustaining Street Light
38
CHAPTER 6: MANUFACTURING
The wind turbine structure was designed so that our group would be able to assemble it
fairly easily once all of the parts were ordered. Using SolidWorks helped with dimensioning and
the order of assembly for the entire structure. First, the drawings for the disks were sent to a local
metal spinning company by the end of March so that the company would have enough time to
make them. With that order in, a work order was filled out for the physics machine shop to build
three individual rotors. Two rotors would be used for our prototype as shown before (two rotors
offset 90 degrees and approximately three feet tall), while the third rotor will be used in future
wind tunnel testing. The three struts with a T-cross section needed to be rolled and this was given
to the Physical Plant machine shop. Those three components were the main pieces of the puzzle
that needed to be outsourced and could not be made in the engineering machine shop. The rest of
the parts were done with help from the engineering machine shop.
The physics building machine shop finished our three rotors and they came out very
nicely. The team wanted to have the two plates welded to the top and bottom of each rotor but
the aluminum was too thin and it was easier to fasten each rotor together with screws and an
adapter, as seen below in Figure 6.1 and Figure 6.2.
Figure 6.1. Wind tunnel test rotor. Figure 6.2. Mechanical fastener for rotor blades.
Chapter 6: Manufacturing Self-Sustaining Street Light
39
Once the rotor was finished, it could be put together in the orientation for which it was
designed. Aluminum pipe was used for the spacing between the two rotors and ran four seven-
inch screws through the pipe to hold the rotors together. This also made the pipe spacers
essentially a solid rod connecting the rotors. The collars were attached to the top and bottom of
the rotors as well – see Figure 6.3 and Figure 6.4.
Figure 6.3. Dual rotors with spacers and one shaft collar. Figure 6.4. Close-up of rotor shaft collar.
Figure 6.5. Generator shaft enclosure with pressed thrust bearing and
attached rotor shaft coupling.
Chapter 6: Manufacturing Self-Sustaining Street Light
40
With the two rotors connected the base of the turbine could be assembled with bearings,
bearing fittings, shafts and shaft collars. The bearing was pressed into an aluminum pipe with a
fitting which was made in the LCS machine shop – see Figure 6.5.
The bearing is a tapered thrust bearing that is rated up to 1000 pounds of axial loading,
which is well over the weight of the turbine. The pipe was screwed into a flange that rests on top
of the generator. The mounting screws for the generator are extended through the flange to the
mounting base, which is a four foot square piece of plywood that the entire structure sits on – see
Figure 6.6. With the rotor completely assembled and the base with the generator assembled, the
two components were connected via the shaft and bottom collar on the rotor – see Figure 6.7.
Figure 6.6. Base plate with generator assembly attached. Figure 6.7. Dual rotors attached to base plate.
Once the rotor was assembled, the outer housing could be assembled and be slid over the
rotor. The funneling disks were made by Hy-Grade Metal in Syracuse, NY and they came out
beautifully. The middle housing disks were each 42 inches in diameter and the top and bottom
disks were 38 inches in diameter. This change in diameters adds an aesthetically pleasing
curvature to the entire structure. One of the spun disks is shown in Figure 6.8.
Chapter 6: Manufacturing Self-Sustaining Street Light
41
There are 3 curved pieces of steel that line the inner radius of each spun disk to stability.
These rings were cut in the LCS machine shop and they were clamped inside of each ring so that
holes could be drilled through both the spun parts and the rings, so they can attach to the struts.
Once the holes were drilled, screws were placed in them to hold it in place – see Figure 6.9.
Figure 6.8. Spun disks (middle disks). Figure 6.9. Bottom spun disk with support rings temporarily bolted on.
With the metal disks and inner rings all drilled and ready to go, the struts could be
attached. The struts had to be rolled in the Physical Plant machine shop so they could attach to
all of the disks. The struts were bolted to the outside of each disk with the inner race of rings on
all of the disks – see Figure 6.10.
While attaching the struts to the disks and inner rings, the top and bottom trusses were
assembled so they could be attached to the top and bottom housing pieces. On the top, the truss is
used to hold the top bearing and also hold the solar panel. On the bottom the truss would be able
to hold the light fixture that would go onto an actual structure. For the presentation, though, the
light will be held on a small five foot PVC pole and the truss will be there for stability. Both of
the trusses add stability to the entire structure – see Figure 6.10 and Figure 6.11.
Chapter 6: Manufacturing Self-Sustaining Street Light
42
Figure 6.10. Top housing attached to top truss and struts. Figure 6.11. Bottom truss assembly.
Figure 6.12. Full assembly of rotor and housing attached to wooden base.
Before the rotor was attached to the base, the bottom truss was slid over the base because
the middle part of the truss would not be able to slide over the rotor. With the entire housing
assembled, it was slid over the rotor and rests at the right height with the assistance of some
wooden blocks secured to the wooden base – see Figure 6.12.
Chapter 6: Manufacturing Self-Sustaining Street Light
43
With the housing secure around the rotor, the alignment of everything was checked and
any necessary adjustments were made. Then, the top bearing was placed on the top shaft and the
corresponding mounting holes were marked on the top bearing plate of the top truss. The bearing
was then attached to the plate and secured to the rotor. This secured the rotor from the top and
the bottom and completed the wind turbine structure.
Figure 6.13. Solar panel attached to full assembly. Figure 6.14. LED luminaire attached to pole.
After everything was secure the solar panel was mounted to the top of the truss with the
solar panel brackets that were made in the LCS machine shop – see Figure 6.13.
As stated before, the light was not mounted to the bottom of the turbine housing for our
presentation. Instead, we made a pole out of PVC pipe and mounted the light to the top of that
with a switch so we can turn the light on/off as we pleased. This pole was attached to a piece of
Chapter 6: Manufacturing Self-Sustaining Street Light
44
wood and a secured so that it would not fall over. The light will also be angled so that it is
perpendicular to the solar panel and would power the solar panel when on – see Figure 6.14.
All of the electrical components were mounted to the wood base and the wires were all
attached as necessary. The final structure came out very well and the group worked very hard
assembling everything. Everyone working with the team was very pleased with the final product
and is excited to see how it performs and consider some of the improvements that can be done to
create a better product.
Chapter 7: Conclusions and Recommendations Self-Sustaining Street Light
45
CHAPTER 7: CONCLUSIONS AND RECOMMENDATIONS
As a result of this senior design project, our group successfully developed an off-the-grid
lighting solution that will be powered by a vertical axis wind turbine and a solar PV panel, to
power a LED streetlight. This semester, our group built a working prototype for our “Self-
sustaining Street Light”. The size of the product considered last semester was decreased by ½,
with a swept area of 0.545m² and rated power output of 7 Watts in the Syracuse area. However,
the PV solar panel size did not change. Material chosen to build prototype was mostly aluminum,
for its light weight compared to steel. Components that need to resist more strength were made
of steel. A different generator from last semester was obtained and tested to ensure its
performance would match our rotor size.
Finite element analysis and computational fluid dynamics simulations showed that a
converging angle of 15 degrees would provide sufficient improvements upon power output,
although larger converging angles could likely be implemented; future wind tunnel testing will
provide more qualitative results. Stress analysis showed that the device is indeed safe enough to
resist high wind speeds of even 60 m/s, with a maximum shear stress of 1.65 MPa. In future
testing of the prototype, anchor lines and safety net around housing are recommended. In
production, it is recommended to adapt a freely rotating mechanism for safety reasons.
The following is the final cost of our working prototype. Understandably, estimated
production cost of the streetlight should be significantly lower due to the fact that most
components utilized for this working prototype are off-the-shelf components.
Chapter 7: Conclusions and Recommendations Self-Sustaining Street Light
46
Bill of Materials:
Appendix A: Gantt Charts Self-Sustaining Street Light
47
APPENDIX A: GANTT CHARTS
Figure A-1. Original Gantt Chart.
Appendix A: Gantt Charts Self-Sustaining Street Light
48
Figure D-2. Final Gantt Chart.
Appendix B: Graphs Self-Sustaining Street Light
49
APPENDIX B: GRAPHS
Figure B-1. Rotor performance using published data for CP.
Figure B-2. Predicted power performance utilizing CFD data.
Appendix B: Graphs Self-Sustaining Street Light
50
Figure B-3. Predicted power performance utilizing CFD data with extrapolated generator data.
Appendix C: Engineering Drawings Self-Sustaining Street Light
51
APPENDIX C: ENGINEERING DRAWINGS
Figure C-1. McMaster-Carr parts list order.
Appendix C: Engineering Drawings Self-Sustaining Street Light
52
Figure C-2. Long truss rod.
Figure C-3. Short truss rod.
Appendix C: Engineering Drawings Self-Sustaining Street Light
53
Figure C-4. Truss plate.
Figure C-5. Short solar panel bracket.
Appendix C: Engineering Drawings Self-Sustaining Street Light
54
Figure C-6. Long solar panel bracket.
Figure C-7. Rotor.
Appendix C: Engineering Drawings Self-Sustaining Street Light
55
Figure C-8. Top and bottom housing sections.
Figure C-9. Middle housing sections.
Appendix D: CFD Results Self-Sustaining Street Light
56
APPENDIX D: CFD RESULTS
(All CFD results compliments of Nhan Huu Phan)
Figure D-1. Sample calculation grid for 15 degree converging angle.
Figure D-2. Torque fluctuations for λ=1.0.
Appendix D: CFD Results Self-Sustaining Street Light
57
Figure D-3. CFD results for Cm as a function of time showing velocity independence of turbulence model.
Figure D-4. CFD results for CP as a function of tip-speed ratio showing velocity independence of turbulence model.
Appendix D: CFD Results Self-Sustaining Street Light
58
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
λ
Cm
No Surrounding Disk 0 Degree Disk 5 Degree Disk 15 Degree Disk 22 Degree Disk 30 Degree Disk
Figure D-5. CFD results for Cm as a function of tip-speed ratio for various converging angles.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
λ
Cp
No Surrounding Disk 0 Degree Disk 5 Degree Disk 15 Degree Disk 22 Degree Disk 30 Degree Disk
Figure D-6. CFD results for CP as a function of tip-speed ratio for various converging angles.
Appendix E: Wind Speed Data Self-Sustaining Street Light
59
APPENDIX E: WIND SPEED DATA
Figure E-1. Histogram for Skytop area anemometer data (11/13/2009 – 4/22/2010).
Figure E-2. Histogram for Standart lot anemometer data (11/13/2009 – 4/22/2010).
Appendix F: MATLAB Code Self-Sustaining Street Light
60
APPENDIX F: MATLAB Code
%% MEE 472 Lightpost Project
%% Reid Berdanier
%% Rotor-Generator Matching
clc
clear all
close all
%% Generator Performance %%
N_gen = [95, 115, 133, 160, 191]; %tested rpm of generator (rpm)
T_gen = [0.2, 0.55, 0.99, 1.46, 1.87]; %tested torque of generator at
N_gen rpm (N-m)
P_gen = N_gen .* T_gen .* 2 .* pi ./ 60; %power generated from N_gen &
T_gen (W)
N_gen(6:13) = [200, 225, 250, 275, 300, 325, 350, 360];
P_gen(6:13) = [42.085, 54.9825, 69.13, 84.5275, 101.175, 119.0725, 138.22,
146.229]; %extrapolated power from curve fit of N_gen and T_gen data
%% Designed Rotor Performance %%
lambda = [0.2:0.1:1.4];
Dft = 24.5/12; %rotor diameter, ft
Dm = Dft*12/39.37; %rotor diameter, m
Hft = 17.25/12; %rotor height, ft
Hm = Hft*12/39.37; %rotor height, m
rho = 1.204; %air density at 20 deg C, kg/m^3
Cp = [0.124; 0.183; 0.24; 0.29; 0.333; 0.371; 0.4; 0.423; 0.44; 0.451;
0.4488; 0.4368; 0.42];
U = [4.40 5.70 6.76 7.5 8.5 9.5]; %wind speed, m/s
for j=(1:1:length(U))
omega(:,j) = 2 .* lambda .* U(j) ./ Dm;
end
N = omega .* 60 ./ (2.*pi);
for j=(1:1:length(U))
R_power(:,j) = Cp(:,1) .* (1/2) .* rho .* 2 .* (Dm .* Hm) .* U(j) .^3;
%calculated rotor output power, W
end
%% Plot
figure(1);
hold on
plot(N(:,1), R_power(:,1), '-b', 'Linewidth', 1.5)
plot(N(:,2), R_power(:,2), '-g', 'Linewidth', 1.5)
plot(N(:,3), R_power(:,3), '-c', 'Linewidth', 1.5)
plot(N(:,4), R_power(:,4), '-m', 'Linewidth', 1.5)
plot(N(:,5), R_power(:,5), '-y', 'Linewidth', 1.5)
plot(N(:,6), R_power(:,6), '-r', 'Linewidth', 1.5)
plot(N_gen(1:5), P_gen(1:5),'sk-', 'Markersize', 9,
'MarkerEdgeColor','k', 'MarkerFaceColor','y')
plot(N_gen(5:13), P_gen(5:13), 'k:', 'Linewidth', 1.5)
title({['Power vs. Rotational Speed'];['15 Degrees']})
xlabel('Rotational Speed (rpm)')
Appendix F: MATLAB Code Self-Sustaining Street Light
61
ylabel('Power (W)')
grid on
legend('U = 4.40 m/s','U = 5.70 m/s','U = 6.76 m/s','U = 7.50 m/s', 'U =
8.50 m/s', 'U = 9.50 m/s',...
'Generator','Extrapolated Generator','Location','Northwest')
% axis([50,300,0,40])
hold off
figure(2);
hold on
for j=(1:1:length(U))
plot(N(:,j), R_power(:,j),'Linewidth',1.5)
end
plot(N_gen, P_gen,'k-','Linewidth',1.5)
title({['Power vs. Rotational Speed'];['15 Degrees']})
xlabel('Rotational Speed (rpm)')
ylabel('Power (W)')
grid on
% legend('U = 4.40 m/s','U = 5.70 m/s','U = 6.76
m/s','Generator','Location','Northwest')
hold off
Appendix F: MATLAB Code Self-Sustaining Street Light
62
%% MEE 472 Lightpost Project
%% Reid Berdanier
%% Skytop Wind Speed Analysis
clc
clear all
close all
%% Data Input %%
data = load('C:\Documents and Settings\Reid Berdanier\My Documents\8 - 10 SU
Spring\MEE 472\Anemometer Data\Skytop_Done_20100202_fix.txt');
index= data(:,1); %original data point
indices
V_ms = data(:,2); %wind speed, m/s
V_avg = mean(V_ms); %average wind speed, m/s
points= length(index);
hours = points/6;
hours_round = round(hours);
%% Histogram %%
bins1 = [0:1:11];
n1 = hist(V_ms, bins1);
figure(1);
bar(bins1, n1)
title({['Histogram of Wind Speed at Skytop'];['Average Wind Speed =
',num2str(V_avg),' m/s']})
xlabel('Wind Speed, (m/s)')
ylabel({['Frequency, (# of 10-minute intervals over
',num2str(hours_round),' hours)']})
axis([-1,12,0,3500])
bins2 = [0:0.1:11];
n2 = hist(V_ms, bins2);
figure(2);
bar(bins2, n2)
title({['Histogram of Wind Speed at Skytop'];['Average Wind Speed =
',num2str(V_avg),' m/s']})
xlabel('Wind Speed, (m/s)')
ylabel({['Frequency, (# of 10-minute intervals over
',num2str(hours_round),' hours)']})
axis([-0.1,11.1,0,400])
bins3 = [0:0.25:11];
n3 = hist(V_ms, bins3);
figure(3);
bar(bins3, n3)
title({['Histogram of Wind Speed at Skytop Lot'];['Average Wind Speed =
',num2str(V_avg),' m/s']})
xlabel('Wind Speed, (m/s)')
ylabel({['Frequency, (# of 10-minute intervals over
',num2str(hours_round),' hours)']})
axis([-0.25,11.5,0,2500])