Concept Design ReviewConcept Design Review

Pinwheel Technologies (C3)Pinwheel Technologies (C3)Heather BlahaHeather Blaha

Matt FuxaMatt FuxaJoey KingJoey King

Michael McConnellMichael McConnellDomenic TassoniDomenic Tassoni

ObjectivesObjectives

Portable Wind Energy SystemPortable Wind Energy System Extract wind energy and convert it to storable, electric Extract wind energy and convert it to storable, electric

energy source. energy source. The system should be able to extract enough energy The system should be able to extract enough energy

from a wind that is nominally 15 mph from a wind that is nominally 15 mph Provide DC power of 20 watts at 12 volts DC Provide DC power of 20 watts at 12 volts DC

continuouslycontinuously Packaged to be either carried or air-droppedPackaged to be either carried or air-dropped

Weight < 50lbsWeight < 50lbs Fit in a Space < 30in x 36in x 48inFit in a Space < 30in x 36in x 48in Setup Time < 30min for 2 peopleSetup Time < 30min for 2 people

ConceptConcept

Vertical Axis, Drag Vertical Axis, Drag BasedBased

Interchangeable ShaftInterchangeable Shaft Battery StorageBattery Storage LCD DisplayLCD Display

Design ConsiderationsDesign Considerations

Transmit Power from Hub to GeneratorTransmit Power from Hub to GeneratorChain DriveChain Drive

SizeSizeLarge enough for 20 W Large enough for 20 W Small enough forSmall enough for

PortabilityPortabilityEasy assemblyEasy assembly

Design – Blade AttachmentDesign – Blade Attachment

Sandwiching between Sandwiching between two boardstwo boards HeavierHeavier Less portableLess portable

Bolt directly to the shaftBolt directly to the shaft Lose added efficiency from Lose added efficiency from

blade offsetblade offset

Flange with bracketsFlange with brackets Feasible supportFeasible support Portable – could improvePortable – could improve Preserves offsetPreserves offset

Design – IntelligenceDesign – Intelligence

Design IntelligenceDesign IntelligenceConstant 20WConstant 20WCharge BatteryCharge BatteryProtect GeneratorProtect GeneratorBrake TurbineBrake Turbine

Prototype IntelligencePrototype IntelligenceConstant 20WConstant 20WProtect GeneratorProtect GeneratorConserve BatteryConserve Battery

Design – Clevis PinDesign – Clevis Pin

3/16” Diameter3/16” Diameter

Design – Clevis Pin ctd.Design – Clevis Pin ctd.

FeasibleFeasible

Expected force on pin is 250 NewtonsExpected force on pin is 250 Newtons

Technical Issues - SizeTechnical Issues - Size

Linearly increasing Linearly increasing power with diameterpower with diameter

Theoretically: Theoretically: Maximize height and Maximize height and diameter for diameter for maximum powermaximum power

P = 0.5*P = 0.5*ρρ*A*V*A*V33

Technical Issues - SizeTechnical Issues - Size

Moment of inertia Moment of inertia increases increases exponentially with exponentially with diameterdiameter

More difficult to start More difficult to start spinning with higher spinning with higher moment of inertiamoment of inertia

Final decision: Plastic Final decision: Plastic drum with 0.89 meter drum with 0.89 meter height and 0.59 meter height and 0.59 meter diameterdiameter

I = m*r2

Technical Issue – Blade GeometryTechnical Issue – Blade Geometry

What overlap, e, is What overlap, e, is most power efficient?most power efficient? ~20% Based on the ~20% Based on the

torque calculationstorque calculations

Most effective Most effective curvature of the curvature of the individual blades?individual blades? A full semi-circleA full semi-circle

Technical Issue – Stability Technical Issue – Stability

Determine the dimensions Determine the dimensions of the turbine blades and of the turbine blades and base to avoid tippingbase to avoid tipping

Force of the wind is Force of the wind is balanced by the weight of balanced by the weight of the entire system.the entire system.

Stable base width Stable base width determined to be 2.5 feet.determined to be 2.5 feet.

Additional weight in the Additional weight in the base will increase stability base will increase stability in uneven terrain. in uneven terrain.

Technical Issue – Turbine ShaftTechnical Issue – Turbine Shaft

Turbine Shaft Geometry and SizeTurbine Shaft Geometry and SizeMaximum Shear Stress Theory:Maximum Shear Stress Theory:

Theoretical Results:Theoretical Results:

Actual Result: ¾” 1080 SteelActual Result: ¾” 1080 Steel

Model

Point Supports at Bearings

Distributed Load from Turbine

Point Gear Force

30mph Wind

Round Shaft

Technical Issue – Hub DesignTechnical Issue – Hub Design OptimizingOptimizing

Height, hHeight, hThickness, tThickness, t

Feasibility of clevis pinFeasibility of clevis pin

Technical Issue – Hub DesignTechnical Issue – Hub Design

h = 0.26 mh = 0.26 m t = 1.25 cmt = 1.25 cm

StrengthsStrengths

Self-starting under nominal wind speedsSelf-starting under nominal wind speedsApproximately 5 miles per hourApproximately 5 miles per hour

Ease of assemblyEase of assembly5 minutes for two people5 minutes for two people

Interchangeable hand crankInterchangeable hand crankProduced power to supplement battery in Produced power to supplement battery in

wind speeds less than 15 miles per hourwind speeds less than 15 miles per hour

WeaknessesWeaknesses

Portability Sacrificed for Assembly TimePortability Sacrificed for Assembly TimeOver sizedOver sizedOver weight (80 lbs)Over weight (80 lbs)

Current gear ratio does not produce the Current gear ratio does not produce the proper amount of powerproper amount of powerUnderestimated Turbine TorqueUnderestimated Turbine Torque

Prototype is electronically simplifiedPrototype is electronically simplifiedSmall niche market to compete with Small niche market to compete with

batteriesbatteries

Prototype DemonstrationPrototype Demonstration

Prototype Testing ResultsPrototype Testing Results

12 mph wind:12 mph wind:81 W turning turbine81 W turning turbineGenerator produced 7 W at 320 rpmGenerator produced 7 W at 320 rpm9% Total System Efficiency9% Total System Efficiency

Expected in 15 mph wind:Expected in 15 mph wind:Should produce 13.7 WShould produce 13.7 W68% of the required 20 W68% of the required 20 W

SummarySummary

Prototype succeeded in converting wind Prototype succeeded in converting wind power into electrical energy.power into electrical energy.

Achieved rapid set-up and tear-down time Achieved rapid set-up and tear-down time (< 5 mins.)(< 5 mins.)

Remained StableRemained StablePrototype showed flaws to be fixed in next Prototype showed flaws to be fixed in next

version.version.Very pleased with overall experience. Very pleased with overall experience.

Next Step – Turbine 2.0Next Step – Turbine 2.0

Higher gear ratio (9:1 or higher?)Higher gear ratio (9:1 or higher?)Generator better suited to our designGenerator better suited to our designLighter MaterialsLighter Materials

Thinner bladesThinner bladesDifferent shaft materialDifferent shaft material

Faster/Simpler blade attachmentFaster/Simpler blade attachmentSecuring/StabilizingSecuring/Stabilizing

Turbine 2.0Turbine 2.0

Better BearingsBetter BearingsMore complex electronicsMore complex electronics

BrakeBrake24 hour continuous operation24 hour continuous operation

WeatherproofingWeatherproofingExtract power from other sourcesExtract power from other sourcesStyling/AestheticsStyling/Aesthetics

Thank YouThank You

Questions?Questions?