The Turby concept - Karadimov

The Turby concept

The necessity for renewable energy– Large wind turbines - public issues– Photo- Voltaïcs - not economical– Small wind turbines - attractive, but need height– Height essential - but expensive

Use available height BUILDINGS

Urban Turbines

Design criteria

Safety

Good price / performance ratio• Good efficiency• Low cost of manufacturing• Low additional costs for transport and erection• Maintenance free

No impacts• vibrations • noise • flickering / shade

Fundamental choicesAXIS: Horizontal (HAWT) or Vertical (VAWT) ?• VAWT mechanically simpler• aerodynamically more complex

ROTOR: Impulse type or aerodynamic ?Impulse type (Savonius)- extracts energy in the direction of the flow- ɖ theoretical < 19 %

Aerodynamic (lift) type rotor- extracts energy perpendicular to the flow- ɖ theoretical < 59 %

Turby is an aerodynamic VAWT

VAWT: Basic principle

• Angle of attack [Ŭ] :– Blade speed (rotational speed x radius) & Wind speed– Ŭ < 150 : ENERGY; Ŭ > 150 STALL

• To prevent stall: Blade speed > 3-4 x wind speed

Blade speed

Wind

Angle of attackApparent wind

Rotating rotor "sees" a rotating wind

The best known VAWT: Darrieus

• Rotational speed same over length of axis

• Radius varies• Blade speeds varies

• Near shaft: STALL vibrations• In middle Ŭ å 00 noise• In between: lift energy

• Little effective use of rotor surface

Turby’s solution

• Constant radius

• Uneven number of blades

• Blades twisted to smoothen the effects change of wind direction

Turby meets design goalsSafety

Survival wind speed > 55 m/sKevlar inlay - blades may crack but will not shatter2 independent brake systems / vibration control

Price / performanceGood efficiency Few systemsEasy transportation and installationMaintenance free

ImpactsNearly vibration freeNoise level 70 dB(A) at 5 m distanceSmall blades matte finish

Yield

Available wind energy• Macro average wind speed in the area• Micro roughness of the terrain

• height• increase in wind speed over obstacles• undisturbed wind flow from all directions

Properties of the windturbine• Efficiency• Suitability for local conditions

• turbulence• temperatures• snow and icing

Yield II• Effect of

averagewindspeed

• Effect of height

Annual yield - average windspeed

0

12

3

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7

8

4 4,5 5 5,5 6 6,5 7

v wind average [m/s]

MW

h

Annual yield - height

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1000

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7000

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9000

0 10 20 30 40 50 60 70 80

height of tower

kWh

Yield varies with area and heightAnnual yield - height and roughness length for the Netherlands

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1000

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9000

0 10 20 30 40 50 60 70 80

height of tower [m]

yiel

d [k

Wh]

Each of these 100 linesrepresents a 1% area of the Netherlands

Wind speed range

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500

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2500

3000

0 5 10 15 20

wind speed

h / W

0

50

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150

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kWh

wind speed distributionpower curveenergy production [kWh]

Effect of direction

0%

2%

4%

6%

8%

10%

12%

14%

0 t/m 4 m/s5 t/m 12 m/s> 12 m/stotaal

A free flow from all sides is important

Wind over buildings

• above the roof.• near centre of roof• undisturbed flow from all sides

• Wind speeds 1,2 – 1,4 x higher! > 2 x more energy

Local conditions

0

4

8

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28

-15 -10 -5 0 5 10 15 20 25 30 35

Temperature [C]

Win

d sp

eed

[m/s

]

De BiltEeldeVlissingen

Status• Turby concept August 2000• Windtunnel tests 2001• Full scale prototype March 2002• Testing – engineering 2002 / 2003• Final prototype January2004• Prototype series 24 units 7 installed 2004

Experience:• No breakdowns, no safety issues• No adverse impacts

Preparing for commercialization:• Fine tuning the software• System dynamics roof – pole - turbine

A very early adapter

Number ONE

Ÿ Ŷ

On the roof

Other installations

A computer representation