John Wloch

Wind-Aid

Critical Design Review4/22/2008

Andy Crutchfield James Gates

Keri Macaulay David Rupp

Wind-AidProblem Statement

• Design a compact, portable and robust wind energy system to extract wind energy and convert it to storable, electric energy.

• Able to extract enough energy from a wind that is nominally 15 mph (wind speed can vary over a 24 hr. period from 0 to 30 mph).

• Power an emergency communication system with a 20 watt load at 12 volts DC continuous performance requirement.

Wind-AidCustomers

• People in emergency situation (primary)

• Relief organizations

Pros Cons

Batteries(40 lb car battery)

High reliability, easy set up

Uneasy to charge, toxic to the environment, performance dependence on operating environment

Solar energy sources(SunLinq)

Lightweight, compact, easily assembled

Only effective during a clear day, risks damage or being broken

Other portable wind systems(Air 403)

Lightweight, adequate power

Insufficient packaging, 7 mph cut in speed

Competition

FEMA Red Cross

Wind-AidKey Features

• Portability– Compact– Weight requirement

• Ease of assembly– Number of people– Tools to assemble

• Energy storage capabilities– Regulator– Batteries

• Safety– brake

• Continuous power– Batteries– Tail

Design Requirements

Wind-AidDecision• Horizontal axis turbine

•Operates well at high speeds•More documentation and analysis

• “Box” base•House all of the components•Could add more weight if necessary

• Three lift-type blades• Stability issues with fewer blades•Least amount without problems•Lift blades are more efficient in higher wind speeds

• Telescoping pole•Portability•Compact

Wind-Aid

PrototypeFinal Product

Wind-Aid

Trade Studies

Wind Turbine BaseEstimate drag force generated on blades (CD = 1):

F= 10.3 lbs @ 30 mph

Filling base halfway with material : Achieve 53 lbs with poplar wood or 375 lbs with dense stone

Wind-Aid

Trade Studies

Wind Turbine Tower

Estimate tower stresses:

Maximum stress is 19 MPa.

Tower material: Yield strength Density

Al 2014 97 MPa 2800 kg/m^3

Steel 350 MPa 7850 kg/m^3

I =

Wind-Aid

Trade Studies

Wind Turbine Generator

Shaft speed is proportional to voltage output.

Wind-Aid

Trade Studies

Wind Turbine Blades

Wind speed = 12 mph

FX63-137 28 inch twisted airfoil carbon fiber epoxy blades designed

Wind-AidPrototype - Base

•Folding Design•All Components Fit Inside•Material - Wood

Wind-AidPrototype - Tower

•Coupling Design•Material – Aluminum•Wires Through Center

Wind-AidPrototype – Nacelle

•Sleeve Bearing•Generator Bracket•Hub Connector•Tail Brackets

Wind-AidPrototype – Blades

•Purchased Blades•Sandwiching Hub•Bolts to Connector

Wind-AidPrototype – Tail

•Efficient Tail Design•Mounts 16” Out•1 ft2

Wind-AidPrototype – Electronics Box

•LCD Display•Light Mount•Compact, Simple Design

Wiring Schematic

Wind-Aid

Prototype Results

Wind-Aid

Key Results:•Prototype operated as desired!

• Achieved 20 W at 12 V for ≈ 12-12.5 mph wind.

•Embedded intelligence•Tachometer•Voltage & Current Displays•Load switching abilities

•Passive control to point into wind

•Electric brake for safety

Wind-AidPerformance Rubric and Results (Grade = 94/100 A-)

Wind-Aid

Weight 51 lbs.

Cut-in wind speed 7-8 mph

Wind speed to generate 20 W

≈ 12-12.5 mph

Display of important data

Yes, without errors

Size (components fit in base)

100%

Specific Results

Wind-Aid

Number of tools needed for assembly

2

Maximum tipping moment of base

Stable at all times tested

Time for setup (1 person)

15 min./ 25 min.

Manually stops without damage

incurred

Yes ≈ 10 s

Specific Results

Crescent wrench Socket wrench7/16” socket, 15 mm socket

Overall Efficiency of Prototype

Power Equation:• Theoretical: P = ½ ρ A V3 (where A is the total windswept area)•Actual : P = ½ ρ A V3 Cp Ng

(Cp = performance coefficient ≈ 0.35 for good design, .596 is max)(Ng = generator efficiency ≈ 0.5 – 0.8)

Wind-Aid

Wind Speed Theoretical Power

Actual Power Efficiency (Cp * Ng)

12.5 mph 170 W 20 W 11.8%

13 mph 190 W 24 W 12.6%

From Prototype to Product•The prototype demonstrates key features of product

•Portability•Short setup time•Functionality•Safety

Wind-Aid

•Recommendations for the final product•Base improvements•Tower height•Nacelle and Tail construction•Blades and Hub•Electronics

From Prototype to Product

Wind-Aid

•Base•Lighter durable material•Foam and clips for storage spots•Carrying straps

•Tower•Three sections instead of two•Weatherproof

•Nacelle and Tail•Lighter durable materials•Waterproof•Handholds in molded nacelle

•Blades and Hub•Longer blades•Streamlined hub; clamps on

Wind-AidFrom Prototype to Product

•Electronics improvements•Collect all wires as one cable•Rotating plug in nacelle•Weatherproof box•Integrate all electronics into box•Pulse width modulation for brake

•Generator•Build a generator dedicated to blade design

•Broader performance range•Reduced weight•Increased blade effectiveness•Increased effiency

Summary of Success

•Recommendations indicate prototype success

•Prototype met or surpassed expectations• Portable (50lbs)• Easy to setup (<45min untrained)• Produced sufficient power (more than

the essential 20W in 12 mph winds)• Efficient braking system

Wind-Aid

Wind-Aid

THANK YOUWe wish to thank Dr. Nelson for his advice on wind turbine overall design and especially blade design. We also wish to thank Drs. Batill and Stanisic for their input and critiques of our design process.

We also thank Dr. Schaefer for his help with the electronics.Special thanks go to Mr. Brownell for his patience and extensive advice and help on the electronics side of the design.

Special thanks also to Mr. Hluchota in the machine shop for his manufacture of the hub connection for the generator. We also thank the Theater Department for material donations and use of facilities.