John Wloch Wind-Aid Critical Design Review 4/22/2008 Andy CrutchfieldJames Gates Keri Macaulay David Rupp

Wind-Aid Problem 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-Aid Customers People in emergency situation (primary) Relief organizations ProsCons 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-Aid Key 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-Aid Decision 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 Prototype Final Product

Wind-Aid Trade Studies Wind Turbine Base Estimate drag force generated on blades (C D = 1): F= 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 strengthDensity Al MPa2800 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 FX inch twisted airfoil carbon fiber epoxy blades designed

Wind-Aid Prototype - Base Folding Design All Components Fit Inside Material - Wood

Wind-Aid Prototype - Tower Coupling Design Material – Aluminum Wires Through Center

Wind-Aid Prototype – Nacelle Sleeve Bearing Generator Bracket Hub Connector Tail Brackets

Wind-Aid Prototype – Blades Purchased Blades Sandwiching Hub Bolts to Connector

Wind-Aid Prototype – Tail Efficient Tail Design Mounts 16” Out 1 ft 2

Wind-Aid Prototype – 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 ≈ mph wind. Embedded intelligence Tachometer Voltage & Current Displays Load switching abilities Passive control to point into wind Electric brake for safety

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

Wind-Aid Weight51 lbs. Cut-in wind speed7-8 mph Wind speed to generate 20 W ≈ 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 wrench 7/16” socket, 15 mm socket

Overall Efficiency of Prototype Power Equation: Theoretical: P = ½ ρ A V 3 (where A is the total windswept area) Actual : P = ½ ρ A V 3 Cp Ng (Cp = performance coefficient ≈ 0.35 for good design,.596 is max) (Ng = generator efficiency ≈ 0.5 – 0.8) Wind-Aid Wind SpeedTheoretical Power Actual PowerEfficiency (Cp * Ng) 12.5 mph170 W20 W11.8% 13 mph190 W24 W12.6%

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-Aid From 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

THANK YOU We 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.