john wloch wind-aid critical design review 4/22/2008 andy crutchfieldjames gates keri macaulay david...
TRANSCRIPT
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.