1. Getting Started with the: Wind Energy Challenge
Pilot National Engineering Design Challenge
Presented by MESA USA Committee Member:
Carlos Gonzalez - Director UCR MESA Schools Program -
SMART 2008

2. Agenda Objectives General Rules Energy Source & Setup Tasks (MS & HS)
Windmill Types
Experiments & Play Time
Physics Ideas
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3. Event Overview
Students will build a Windmill that meets the criteria outlined in the rules and is designed to perform the following tasks:
Mechanical Power (MS): greatest mass raised 75 cm in the least amount of time. (2 trials) Mechanical Power (HS): greatest volume (mass) of water moved between lower and upper container in fixed time. (2 trials)
Wind-to-Vehicle Transfer: greatest speed achieved by the defined vehicle when accelerated by the energy from the device. (2 trials)
Rotational Speed & Directional Response (HS): nearest combined rotational speed, of a fixed load, in revolutions per minute (rpm). Wind direction will change by 60 degrees between measurements. The target speed is 30 rpm.
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4. General Rules
Teams must design, build and operate their own windmill device(s). This device(s) will include all parts necessary to capture the wind energy and transfer it to the defined tasks.
The device(s) must be solely powered by the wind energy available from the defined commercial fan.
All designs that conform to the energy rules will be allowed to participate. All teams should carefully review design configuration to ensure that no additional energy is applied to the tasks.
Once performance competition begins, student teams may not have contact with non-competitors. Student teams are solely responsible for interaction with judges and addressing problems with devices.
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5. Energy Source & Setup
Box Fan: Lakewood Model 101 – 20” 3-speed or equivalent.
No part of the windmill device(s) may be placed closer than 75 centimeters from the front of the fan.
The device must fit on one end of the table within the Device Area equal to the width of the table (~30”) and 50 centimeters long.
The device may extend over the edge into the Working Area to complete the tasks.
Devices may be taped to the table surface.
An outlet strip will be used as the on/off switch for the fan, allowing desired fan speed to be set.
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6. Tasks – Mechanical Power
Middle School (Raising a mass) 1 - Fan speed will be set to high. 2 - Judge will simultaneously start the box fan wind source, and the stopwatch timer Judge will stop timer when entire mass is above 75 cm, and record time. 4 - Judges will use outlet strip to stop box fan wind source. 5 - Judges will measure and record raised mass value. 6 - Repeat for 2nd trial.
High School (Raising water) 1 - A second six foot table, Table 2 will be arranged perpendicular to Table 1 in the position shown. 2 - Fan speed will be set to high. 3 - Judge will simultaneously start the box fan wind source, and the Stopwatch timer. 4 - Judge will stop box fan-wind source after minutes of running time. 5 - Students will pour successfully collected water into judge provided container. 6 - Judges will measure and record raised water mass. 7 - Repeat for 2nd trial
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7. Tasks – Wind to Vehicle
Middle & High School 1 - The fan speed will be set to High. 2 - Teams will place the vehicle behind the 200 cm “Start Line”. 3 - Teams will design their device to pull the vehicle through the Speed Zone. 4 - Judges will use outlet strip to start box fan-wind source. 5 - Judges will record the speed through the speed gate. 6 - Two trials will be performed; the best speed (cm/second) will determine score. .
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8. Tasks – Rotational Speed & Wind Direction
High School 1 - Student teams are required to rotate the specified “load wheel” Fan speed will be set to High. 3 - Students will arrange their device to face Position of the Box Fan. 4 - Judge will simultaneously start the box fan-wind source, and the Stopwatch timer. 5 - Judge will begin rotational speed measurement after 30 seconds. 6 - Judge will record time to complete 30 revolutions OR record revolutions per minute by another means. 7 - After completing measurement, the box fan–wind source will be slid from left-to-right at approx imately 10 degrees per 10 seconds. 8 - At Position 2, Judges will repeat rotation speed measurement.
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9. Windmill Types Horizontal Axis:
Vertical Axis:_________________________________________________
1st Generation
2nd Generation
3rd Generation
Savonius
Giromill
Darrieus
Tjasker
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10. Experimental Ideas: Get to know the system…
Each task has unique expectations…
What are the variables:
Controlled - who or what controls them?
Manipulated - change one at a time!
Responding - what are you monitoring?
Engineering Design
Get familiar with key scientific concepts.
Use good experimentation to learn how design choices change performance.
What does your teams design process look like?
Variable
Trial 1
Trial 2
Trial 3
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11. Physics Ideas Wind Power: How much power is available in the wind?
Torque: Why is torque important?
Blades: What blade characteristics should be considered?
Simple Machines: How might simple machines be used?
Pumps: How could you get started with a pump?
Other ideas:
Wind Patterns and Speed
Generating Electricity
Storing Energy for later
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12. How much power is in the wind?
Energy:
As molecules in motion wind has kinetic energy based on its mass
Calculated in Joules (kg m2/s2)
Kinetic Energy = ½ mass x (velocity)2
Power:
Calculated by dividing the total energy used by the amount of time in which the energy is used.
How do we do this for wind?
The mass of the wind is based on the area of the windmill and velocity of the wind.
The formula for how much air mass goes through the windmill based on the wind velocity takes a little algebra.
Using that to find Kinetic Energy is next.
Finally dividingng Kinetic Energy by time leads us to the KEY FACTORS
Area of Windmill & Wind Velocity
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13. For a more mathematical and visual Representation…
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14. Why is torque important?
Rotation:
The force of the wind rotates all types of windmills.
That rotation creates torque which is transferred to the shaft.
Torque:
We can calculate the torque by measuring the force in Newtons (N) that our windmill can pull with, OR
By finding the mass (kg) that the windmill can hold in place (need to multiply by gravity – 9.8m/s2)
Then multiply that force by the radius of the lifting wheel (in meters).
What do you think would happen if:
the lifting wheel were bigger/smaller?
the windmill were bigger/smaller?
the wind was faster or slower?
the friction was increased/decreased?
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15. What blade or rotor characteristics should be considered?
Key Principles:
Drag forces act in the direction of the wind like a sail and provide the most obvious way to turning the rotor. - These are usually flat, curved or cup shaped blades. - Decreasing drag improves efficiency
Lift forces act perpendicular to the wind like aircraft wing and usually provide a more efficient way to turn the rotor. - These use the difference in wind speed on each side of the airfoil to create lift. - Increasing lift captures more energy
Number of blades
Shape of blades
Orientation or Angle of blades
Mass of blades
Strength of blades
wind
wind
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16. How might simple machines be used?
Since applying the kinetic energy of the wind to the tasks is the goal…
A few simple machines come to mind…
Wheel and Axle – a rotating 3rd Class Lever The force of the wind works on the blades (effort force) The axle of the rotor turns (fulcrum) The wheel turns and raises a mass (resistance force)
Pulleys & Gears These devices change the direction of forces, transmit rotational motion or change the amount of the forces.
Inclined Planes & Screws These devices make it easier to move objects or materials.
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17. How could you get started with a pump?
A couple of ideas for getting started:
Hand Pump Uses two “flap-type” check valves to allow water in and out
Pump Jack Uses two “ball-type” check valves to allow water in and out
Rope Pump Uses multiple washers, bead, rags to create a sealed column of water
Chain or Bucket Pump Uses multiple containers or buckets attached to a chain or belt to raise water
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18. Other ideas?
Wind Patterns and Wind Speed How do wind patterns and speed affect placement and design choices?
Storing Energy What forms can wind energy be converted to? How and when can that energy be used?
Design Challenges and Limitations In what ways are the WEC tasks and rule realistic? In what ways are they unrealistic?
Lost Energy How much energy can be captured from wind? How much is lost in the process? Where are these losses?
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