Wind Turbine Design and Implementation.

Team Members Members: Luke Donney Lindsay Short Nick Ries Dario Vazquez Chris Loots Advisor: Dr. Venkataramana Ajjarapu Client: Dr. Dionysios Aliprantis

Our Project Purpose: Create a wind turbine that will be installed on the roof of Coover Hall on the Iowa State University campus. The turbine will supply approximately W of power to the Coover power grid. The turbine will only generate power when the wind speed is high enough for the gears to turn at the rated speed of the generator.

Proposed Solution Fixed speed, upwind, AC turbine facing west for maximum wind power Tower height - 6 m (20 ft) ‏ Optional: connection to PC located inside Coover Hall to display power output and other data Image from

Operating Environment The turbine will function outdoors on top of the Coover hall roof. It will be subjected to every sort of weather including rain, extreme wind, snow, ice, and lightning

Concept Sketch

System Description Process starts with energy collection from the wind via the turbine. The mechanical energy is transferred through the gearbox to the generator, where it is converted to electrical power. The power is fed directly into the Coover grid at 3- phase, 60 Hz.

System Block Diagram

Blades and Gearbox Blades shall be in the area of 4.5 feet in radius, and will be designed by a manufacturer. Gearbox shall be rated at 9:1 and shall have the appropriate strength to deal with torque generated.

Blade Calculations Available power in wind: P = 1 kW Average wind speed (Ames, IA): v = 14 mph (6.25 m/s) ‏ Air density: ρ = kg/m 3 Area = πr 2 Using this information, we find:

Tower Kurtis Stockton designed the tower. Note that the actual turbine blades do not look like the ones in this model.

Gearbox Calculations Optimum Tip Speed Ratio (TSR) for 3 blade turbines: 6 Start up wind speed (Ames, IA) at 10 mph (4.47 m/s) ‏ Blade length at 4.5 ft (1.37 m) ‏ Generator Rated at 1725 rpm Using this information, we find:

Gearbox Michael Renoe and a team of his fellow mechanical engineers designed the gearbox. Note that the actual turbine blades do not look like the ones in this model.

AC Generator 2 Hp 3 Phase 60 Hz 1725 rpm V line-line 6.5 A full load

Controls – Overview Atmel microcontroller controls components. Anemometer serves as wind speed detector. Speed sensor on gearbox measures rotation speed of the turbine. DC relay releases brake on turbine. AC relay connects the generator output to the grid.

Controls – Considerations Atmel ATtiny85 microcontroller was selected because it is automotive-grade. It operates in temperatures from -40° C to 125° C. All electrical components were chosen to operate at least in the range of -10° C to 60° C. For safety reasons, brake is applied by default and grid connection is disconnected by default. By waiting until generator is spinning at optimal speed before connecting to grid, a startup current surge is eliminated.

Controls – Functionality When the cut-in wind speed is reached, brake is released and turbine allowed to spin up. When turbine has reached optimal speed, it is connected to the grid to generate power. When the cut-off wind speed is reached, brake is activated and generator disconnected from the grid. If electrical power is lost, brake is automatically applied and generator is automatically disconnected from grid.

Controls – Input/Output

Controls – Schematic

Controls – Circuit Layout

Deliverables Wind Turbine and Mounting Tower Power and Control Systems User’s Manual

Users and Uses Iowa State Electrical and Computer Engineering faculty and students Research purposes and classes The connection to PC for display may show extra information such as the wind speed, graphs of power output over time

Work Breakdown

Assumptions and Limitations Assumptions: Funded by group budget and outside resources Similar wind turbine designs are currently being used Limitations: Turbine height and weight must be fit for Iowa State and City of Ames building regulations Turbine must not interfere with other objects on Coover hall roof Turbine can only output as much power as there is wind to supply it Coover Hall is currently under construction and might interfere with its placement Funding is limited

Estimated Project Cost

Estimated Personnel Effort

Risks Risks: 1.Team member leaves project due to illness, co-op,… etc. 2.High winds could damage blades, throw turbine off roof 3.Lightning could strike turbine 4.Ice could freeze up the turbine 5.Birds could fly into turbine Risk Management: 1.More than one person assigned to each task 2.Brake system will stop rotor in high winds and will be bolted into roof to prevent it from blowing off 3.Install lightning rod near turbine and possibly ground blades to prevent damage to system 4.Heat tracing on moving parts to prevent ice buildup or keep turbine close to rooftop for easy maintenance. 5.Speakers to play sounds to keep crows away.

Issues Not enough funding Brake not finalized Mounting for turbine onto tower not finalized Gearbox too expensive

Questions?