Concept Design Review Pinwheel Technologies (C3) Heather Blaha Matt Fuxa Joey King Michael McConnell Domenic Tassoni

Objectives Portable Wind Energy System Portable Wind Energy System Extract wind energy and convert it to storable, electric energy source. Extract wind energy and convert it to storable, electric energy source. The system should be able to extract enough energy from a wind that is nominally 15 mph The system should be able to extract enough energy from a wind that is nominally 15 mph Provide DC power of 20 watts at 12 volts DC continuously Provide DC power of 20 watts at 12 volts DC continuously Packaged to be either carried or air-dropped Packaged to be either carried or air-dropped Weight < 50lbs Weight < 50lbs Fit in a Space < 30in x 36in x 48in Fit in a Space < 30in x 36in x 48in Setup Time < 30min for 2 people Setup Time < 30min for 2 people

Concept Vertical Axis, Drag Based Vertical Axis, Drag Based Interchangeable Shaft Interchangeable Shaft Battery Storage Battery Storage LCD Display LCD Display

Design Considerations Transmit Power from Hub to Generator Transmit Power from Hub to Generator Chain Drive Chain Drive Size Size Large enough for 20 W Large enough for 20 W Small enough for Small enough for Portability Portability Easy assembly Easy assembly

Design – Blade Attachment Sandwiching between two boards Sandwiching between two boards Heavier Heavier Less portable Less portable Bolt directly to the shaft Bolt directly to the shaft Lose added efficiency from blade offset Lose added efficiency from blade offset Flange with brackets Flange with brackets Feasible support Feasible support Portable – could improve Portable – could improve Preserves offset Preserves offset

Design – Intelligence Design Intelligence Design Intelligence Constant 20W Constant 20W Charge Battery Charge Battery Protect Generator Protect Generator Brake Turbine Brake Turbine Prototype Intelligence Prototype Intelligence Constant 20W Constant 20W Protect Generator Protect Generator Conserve Battery Conserve Battery

Design – Clevis Pin 3/16” Diameter 3/16” Diameter

Design – Clevis Pin ctd. Feasible Feasible Expected force on pin is 250 Newtons Expected force on pin is 250 Newtons

Technical Issues - Size Linearly increasing power with diameter Linearly increasing power with diameter Theoretically: Maximize height and diameter for maximum power Theoretically: Maximize height and diameter for maximum power P = 0.5*ρ*A*V 3

Technical Issues - Size Moment of inertia increases exponentially with diameter Moment of inertia increases exponentially with diameter More difficult to start spinning with higher moment of inertia More difficult to start spinning with higher moment of inertia Final decision: Plastic drum with 0.89 meter height and 0.59 meter diameter Final decision: Plastic drum with 0.89 meter height and 0.59 meter diameter I = m*r 2

Technical Issue – Blade Geometry What overlap, e, is most power efficient? What overlap, e, is most power efficient? ~20% Based on the torque calculations ~20% Based on the torque calculations Most effective curvature of the individual blades? Most effective curvature of the individual blades? A full semi-circle A full semi-circle

Technical Issue – Stability Determine the dimensions of the turbine blades and base to avoid tipping Determine the dimensions of the turbine blades and base to avoid tipping Force of the wind is balanced by the weight of the entire system. Force of the wind is balanced by the weight of the entire system. Stable base width determined to be 2.5 feet. Stable base width determined to be 2.5 feet. Additional weight in the base will increase stability in uneven terrain. Additional weight in the base will increase stability in uneven terrain.

Technical Issue – Turbine Shaft Turbine Shaft Geometry and Size Turbine Shaft Geometry and Size Maximum Shear Stress Theory: Maximum Shear Stress Theory: Theoretical Results: Theoretical Results: Actual Result: ¾” 1080 Steel Actual Result: ¾” 1080 Steel Model Point Supports at Bearings Distributed Load from Turbine Point Gear Force 30mph Wind Round Shaft

Technical Issue – Hub Design Optimizing Optimizing Height, h Height, h Thickness, t Thickness, t Feasibility of clevis pin Feasibility of clevis pin

Technical Issue – Hub Design Technical Issue – Hub Design h = 0.26 m h = 0.26 m t = 1.25 cm t = 1.25 cm

Strengths Self-starting under nominal wind speeds Self-starting under nominal wind speeds Approximately 5 miles per hour Approximately 5 miles per hour Ease of assembly Ease of assembly 5 minutes for two people 5 minutes for two people Interchangeable hand crank Interchangeable hand crank Produced power to supplement battery in wind speeds less than 15 miles per hour Produced power to supplement battery in wind speeds less than 15 miles per hour

Weaknesses Portability Sacrificed for Assembly Time Portability Sacrificed for Assembly Time Over sized Over sized Over weight (80 lbs) Over weight (80 lbs) Current gear ratio does not produce the proper amount of power Current gear ratio does not produce the proper amount of power Underestimated Turbine Torque Underestimated Turbine Torque Prototype is electronically simplified Prototype is electronically simplified Small niche market to compete with batteries Small niche market to compete with batteries

Prototype Demonstration

Prototype Testing Results 12 mph wind: 12 mph wind: 81 W turning turbine 81 W turning turbine Generator produced 7 W at 320 rpm Generator produced 7 W at 320 rpm 9% Total System Efficiency 9% Total System Efficiency Expected in 15 mph wind: Expected in 15 mph wind: Should produce 13.7 W Should produce 13.7 W 68% of the required 20 W 68% of the required 20 W

Summary Prototype succeeded in converting wind power into electrical energy. Prototype succeeded in converting wind power into electrical energy. Achieved rapid set-up and tear-down time (< 5 mins.) Achieved rapid set-up and tear-down time (< 5 mins.) Remained Stable Remained Stable Prototype showed flaws to be fixed in next version. Prototype showed flaws to be fixed in next version. Very pleased with overall experience. Very pleased with overall experience.

Next Step – Turbine 2.0 Higher gear ratio (9:1 or higher?) Higher gear ratio (9:1 or higher?) Generator better suited to our design Generator better suited to our design Lighter Materials Lighter Materials Thinner blades Thinner blades Different shaft material Different shaft material Faster/Simpler blade attachment Faster/Simpler blade attachment Securing/Stabilizing Securing/Stabilizing

Turbine 2.0 Better Bearings Better Bearings More complex electronics More complex electronics Brake Brake 24 hour continuous operation 24 hour continuous operation Weatherproofing Weatherproofing Extract power from other sources Extract power from other sources Styling/Aesthetics Styling/Aesthetics

Thank You Questions? Questions?