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Classroom Turbines/Turbine Projects

Below are plans, ideas, and other relevant information for building basic to advanced wind turbines for large classroom experiments or for individual science fair projects. For information on how wind energy works, click here.

1) Getting Started

Before building a wind turbine for a project, we recommend that you have a working knowledge of wind energy concepts, so that when you test your turbine, you have a basic idea of which variables to test. Please take a look at our "learn about wind" section. This section has tons of information on wind turbine design, blade design, electricity and power output, wind meteorology, and much more.

Building your own wind turbine from scratch is not a simple task! You first need to make a list of the parts and materials that go into making a wind turbine. We have compiled this list to help you get started. Many of these materials are available at the Kidwind shop, but creative, unique designs are always encouraged!

Electrical Materials: You might need to do some basic soldering to connect wires to motors. The multimeters and alligator clips are used to hook up the measuring devices. Understanding the electrical output can be confusing, but you can learn more about it here.

Building Materials: This list depends on what types of windmills you are going to build. If you are all going to build similar models then you can keep it simple. If you are looking for lots of variability then you can open things up.

  • A Hub to attach your blades to your generator
  • Balsa wood, PVC pipe and fittings, dowels, plastic cardboard, fabric, building "junk"
  • Gears, pulleys, tinker toys, k'nex, legos
  • Construction tools hammers, small saws, scissors, exacto knifes, glue guns, PVC cutters
  • Safety goggles

Other testing materials: (not required but sure are neat!)

Don't forget that you can find most of these materials in the KidWind Shop. Check out the Science Fair Kit and the Gears and Motors Kit if you want the basic materials to build your own turbine.

2) Time to Build

There are many different plans and designs, but they all share a few things in common. No matter what kind of model turbine you build, it will require some of the same parts as a real wind turbine. You need a tower, a generator on top of the tower (unless it is a weightlifting turbine!), a hub, some blades, and of course wind! You will also need some materials to build your wind turbine. The Kidwind Shop has a lot of great materials for building model turbines, but you might not find everything you need there.

3) Experiment!

This page demonstrates an example setup of a wind turbine experiment. This activity focuses on variables to keep in mind when recording and interpreting power output. Remember that a good scientific experiment should follow the scientific method:

  • 1. Ask a question (i.e. What effect does wind speed have on voltage?)
  • 2. Do background research
  • 3. Construct a hypothesis
  • 4. Test your hypothesis by doing an experiment
  • 5. Analyze your data and draw a conclusion
  • 6. Change variables and repeat tests
  • 7. Communicate your results

To learn more about the scientific method, click here.

What is a wind turbine experiment?

We'll begin with the equation that determines how much power you can produce with your wind turbine (from awea.org):

P = 0.5 x rho x A x Cp x V^3(cubed) x Ng x Nb

  • P = power in watts (746 watts = 1 hp) (1,000 watts = 1 kilowatt)
  • rho = air density (about 1.225 kg/m3 at sea level, less higher up)
  • A = rotor swept area, exposed to the wind (m2)
  • Cp = Coefficient of performance (.59 (Betz limit) is the maximum theoretically possible, .35 for a good design)
  • V = wind speed in meters/sec (20 mph = 9 m/s)
  • Ng = generator efficiency (50% for car alternator, 80% or possibly more for a permanent magnet generator or grid-connected induction generator)
  • Nb = gearbox/bearings efficiency (depends, could be as high as 95% if good)

The main variables that you should keep in mind for your experiment are:

  • 1) Swept area of your rotor
  • 2) Coefficient of performance (this will actually include all aspects of turbine and blade design, discussed below and on other sections of our site)
  • 3) Wind speed
  • 4) Generator (unless you really know about generators, it is advisable to keep the motor constant in your experiments
  • 5) Gear ratio attached to your generator

In order to see the effects these variables have on the power output of a wind turbine, you have to set up an experiment to test each variable. In a wind turbine experiment, when you change one variable, remember to keep all other variables constant.

Setup:

You will need to setup a model wind turbine and a fan. You will also need some kind of meter to measure the power output of your data, unless you are using your turbine to do non-electrical work such as weight lifting.

Here are some materials besides a turbine and fan that you may want for the experiment:

  • Tape: (for marking a constant spot for your turbine to remain)
  • Multimeter or some kind of meter or load device that will measure the amount of electricity your turbine produces.
  • Wind Speed Meter : If you want to see how wind speed affects power output, you should use an anemometer to measure the wind speed of your fan.

Fans:

You should use a floor fan that has at least 3 settings so you can experiment with how wind speed affects power output. We recommend a fan that has a diameter of at least 20" and that can be propped to the height of your turbine. Lasko fans are usually good.

Variables:

For a more thorough discussion of variables, please read our "learn about wind" section.

  • Blade Design: Without blades, your turbine wouldn’t produce any electricity. Some blade factors to consider are:
    • Size
    • Shape
    • Number
    • Pitch
    • Weight
    • Material
  • Wind speed: Most fans have 3 different speed settings. You can also change the wind speed by moving your turbine closer or further from the fan.
    • Wind tunnel: If you’re really serious and want non-turbulent wind, you can try to smooth the air by making a wind tunnel.
    • Generators: You will need a generator that produces recordable voltage at relatively low RPM. For a discussion of generators, click here.
    • Gear ratios: You may want to attach a gear system to your generator. For more information about gear ratios, check out the Gear Ratios Document (pdf).

Different kinds of experiments :

When conducting an experiment, decide which variables you want to test. Do you want to know how wind speed affects power output? Or do you wan to know how the number of blades affects power output? You can set up different experiments to test different variables. Here are a few examples. Remember to only change one variable per experiment.

Voltage based on wind speed (mph)

? v
4 v
3 v
2 v
1 v
7 mph
8 mph
9 mph
10 mph
11 mph
12 mph


Voltage based on Blade pitch (degrees)

? v
4 v
3 v
2 v
1 v
5 deg
15 deg
25 deg
35 deg
45 deg
55 deg


Voltage based on Blade shape

? v
4 v
3 v
2 v
1 v
Rectangle
Trapezoid
Triangle
Bowl
Twist
Bart Simpson
 
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