Ieee-rwep Vertical Axis Wind t Summary Lect

8/13/2019 Ieee-rwep Vertical Axis Wind t Summary Lect

http://slidepdf.com/reader/full/ieee-rwep-vertical-axis-wind-t-summary-lect 1/20

VERTICAL AXIS WIND TURBINE (VAWT)FOR MICRO-ENERGY GENERATION:

SPINNING STUDENTS’ MINDS Summary Lecture

Authors:

Betina Baère Campos Neves, MSc [1] & Pedro Barbosa Guedes, MSc [2]

[1] ProfessorDepartment of Electrical EngineeringInstitute of Engineering of Porto – Polytechnic Institute of Porto (ISEP - IPP); Portugal

[2] ProfessorDepartment of MathematicsInstitute of Engineering of Porto – Polytechnic Institute of Porto (ISEP - IPP); Portugal



OBJECTIVES

Proposition of a hands-on, team-based projectaddressed at first-year students that:

• Will encourage student learning throughparticipation

• Increase student retention through satisfaction

• Improve student confidence throughachievement

• Having meaningful basic context. This meansthat those possessing the correspondentknowledge will have a positive impact on society& environment while acting as engineering

agents

DIY VAWT 52 W, 12.5 mph



OBJECTIVES

To focus on energy generation where it is most needed, using differentapproaches and locations, respecting the environment and contributingsignificantly to the well-being of society.

Microgeneration technologies, especially the onesbased on renewables, have the potential to reducebuilt environment related CO 2 emissions coupledwith reductions in consumers’ electricity costs.

Kazekamome Remote Hybrid StreetLamp by Hybridyne Power Systems,Canada

In a best case scenario Small (<100 kW) and Micro(<10 kW) Wind electricity generation in a builtenvironment could be equivalent to about 4% ofthe domestic electrical demand (UK estimates foryear 2000 consumption reference numbers andactual wind resource category).



OBJECTIVES

• Small VAWTs – A GOOD POSSIBILITY

• Urban renewable generation – THE NEXT BEST THING

• Engineering spirit – THE KEY TO THE PROBLEM• Fun but requiring knowledge – CHALLENGES BRINGOUT THE BEST IN EVERYONE

• “Doing is learning” – LEARNING BY DOING SPARKLESCREATIVITY AND YOU FEEL GOOD ABOUT IT



FIRST STEPS

Equations and laws are extremely helpful!They mean less trial and error

and better results!

Existing types of VAWTsHow do they work…

- from an amateur point of view- from an engineer’s point of view Low-cost Savonius turbine by

EMAT Ltd, England



FIRST STEPS

But still…there is always trial and error. VAWTs built:Savonius

- covered- uncovered

Giromill

- 3, 4 and 6 blades using quarter-cylinder shaped blades- 3 and 6 airfoil shaped blades



FIRST STEPS

THE ONES THAT WORKEDSavonius works just fine and has

better performance if covered.

Is self-starting, even at very lowspeeds.Tall models tend to require a

stabilization point on top,otherwise they will oscillate

far too much.These models can be good prime

movers for high torque pmstepper motors if madetaller/bigger…

Our Savonius model, with top and bottomcovers, spinning for testing purposes!



FIRST STEPS

Giromill VAWTs Airfoil shaped blades work just fine. Other types tried in

the process did not.

It is advisable to build these VAWTs with an uneven

number of blades.

They may sometimes need a push to start if done in abigger scale

Rotation is faster than for Savonius but torque is muchsmaller

A simple way of doing an airfoil shaped blade is by foldinga piece of PETG or polycarbonate, aligning and holding it,using a small adjustable workbench structure and, finally,riveting it underneath the workbench! Loosening thesupport system we have a nice symmetrical airfoil blade!



FIRST STEPS

Since Giromill modelswere hard to self-startan hybrid model was

tried out, addingsomething new…

It simply got a smallSavonius structureright in the middle…and things didimprove!



WHAT CAN BE LEARNED FROMTHIS EXPERIENCE

BUILDING: not easy nor immediate but rewarding.

Learned quite some new vocabulary and now I know how bearings andcouplings work. I’ll be able to choose them on my own if I need to.

Aligning the structure: not easy but extremely important to have a smoothand light rotation. 3 bearings (in 2 levels), to minimize contact andfriction, solved the puzzle. Other solutions didn’t work as good.

IGUS plastic

plain bearing.Not as good as3 bearings…

The reflector for speedmeasurements with anoptical digital tachometer

3 bearings: 2 fixed andone adjustable, by rotatingthe metal bar holding it,against the axis. A smallscrew holds it in place.




“Creative engineered solution”:

A small screw (not very visible…)prevents the garden hose fromrotating inside the shaft.

A small hole in the hose, along withmarkings helps inserting, aligning withshaft hole and fastening with screw.

HOW ABOUT ATTACHING THE MOTOR/ GENERATOR TOTHE SHAFT WITHOUT UNBALANCING THE TURBINE?

FLEXIBLE COUPLING!

Standard (expensive) solutionfor flexible precision couplings




MEASURINGEquipments: Multimeter, Oscilloscope, Tachometer,

Anemometer… now I know how to use them, what theyare for and have an idea on how they work (I’ll needsome more knowledge to explore them)

Units: Some old ones…some new ones… Engineers speaka “standard” language!

That’s very useful! [1]

[2]

[3]

[4][4]

[1]: Digital oscilloscope, 2 channels;[2]: Digital multimeter;[3]: Digital optical tachometer

[4]: Digital hand-held anemometer[1]




Maybe not easy while you don’t grasp it… Easy once you start leaning about it.

Addictive once you see your first generator working!It can only become better from this point onwards!

ELECTROMECHANICAL ENERGY CONVERSION

[1] [2] [3]

[1][3] Details on the two LED’s that served as electrical (very visible!) charge. The PMmotor [2] working as generator has 6 wires. Each group of 3 represents one winding,

Example: yellow / green – 1 “full” winding; The orange wire is the “middle point”. Weused 1 “full” winding per LED. The other winding: black / brown; red = middle




THE GENERATORWE USED A PM MOTOR AS GENERATOR… With another schedule and more knowledge

it would be possible to build a generator forthe turbine.In a real-world application, as far as smalland medium size wind turbines are

concerned, it is usual to have a direct drivepm generator built exclusively for thatturbine.

[1]

[2]

[3]

[1] Coil arrangement for a DIY PM axial flux generator for wind turbines

[2] STAMFORD radial flux PM generator – Wuxi Huaxiang, Ltd. China

[3] PM direct drive axial flux generator assembly by PacWind




NOTIONS AND FORMULÆWhat is windDrag and lift – what makes turbines go roundHow to evaluate a turbine

CpCt

TSR or λ Basic electromagnetics in action




From the obtained data it ispossible to estimate theturbine’s Tip -Speed Ratio R D

TSR = = =V 2V

Graphics summarize some of the observations and datacollected

Step Motor no load

1

1,5

2

2,5

3

3,5

4

4,5

5

0 25 50 75 100 125 150 175 200

Speed (r.p.m.)

V r m s Fan_speed1

Fan_speed2

Fan_speed3

Step Motor with 2 leds load

1

1,5

2

2,5

3

3,5

4

4,5

5

0 25 50 75 100 125 150 175 200

Speed (r.p.m.)

V r m s ( h a l f w

a v e

)

Fan_speed1

Fan_speed2

Fan_speed3

Step Motor no load

1

1,5

2

2,5

3

3,5

4

4,5

5

0 25 50 75 100 125 150 175 200

Speed (r.p.m.)

V r m s Fan_speed1

Fan_speed2

Fan_speed3

Step Motor with 2 leds load

1

1,5

2

2,5

3

3,5

4

4,5

5

0 25 50 75 100 125 150 175 200

Speed (r.p.m.)

V r m s

( h a

l f w a v e )

Fan_speed1

Fan_speed2

Fan_speed3




LOOKING CAREFULLY AT VISUAL DATAThere is more to it than the eye can meet… In the next months, years, it will all be unveiled …



CONCLUSIONS

This ends the 15 day first experience withengineering.

This lecture only shows a fraction of all thelearning and experimental processesbehind the project.

The great adventure of engineering hasalready started.

May you all fully enjoy it!

Thank you!

Ieee-rwep Vertical Axis Wind t Summary Lect

Documents

Transcript of Ieee-rwep Vertical Axis Wind t Summary Lect