Wind turbines generate energy, just like old windmills. Instead of using it to grind grain, however, modern turbines harness the wind to generate and store electricity, helping to meet the demand for renewable energy. Industrial turbines are too big for households, but you can learn how to build a smaller version to meet your energy needs. Read this guide to learn.
Steps
Method 1 of 4: Design Your Turbine
Step 1. Determine the average wind speed in the area where you plan to build
To be economically viable, the turbine must be exposed to winds of at least 11-16km / h to generate electricity, and will perform best in winds between 19 and 32km / h. To calculate the average annual wind speed in your area, see the following address:
Step 2. Study the laws governing the construction of wind turbines in your country
They may have prescriptions about the minimum distance between them or the boundary of your land.
You should discuss your project with your neighbors before starting to build to allay their concerns about turbine noise or the possibility of interference with radio or TV reception
Step 3. Evaluate how much free space you have available horizontally and vertically
The turbine itself does not take up much space, but it is advisable to provide a space of 2000 square meters for turbines up to 3 kW and 4000 square meters for those up to 10 kW of power. You should also have enough headroom to place the turbine above buildings and trees.
Step 4. Decide whether to build or buy the blades
Old windmills were basically sails attached to a rotating mast, while modern turbines consist of huge propellers. Their blades must be sized and oriented for proper operation. Their length varies from 20 to 60% of the entire height of the turbine.
- If you choose to build the blades, you can use wood or PVC pipe. Instructions for making blades from pipe sections can be found at the following address:
- Either way, you'll probably want to copy the 3-blade design of most industrial turbines. Using an even number of blades, for example 2 or 4, it is easier for vibrations to occur, while adding more blades will increase the torque but reduce the speed of rotation.
Step 5. Choose a generator
The propeller must be connected to a generator to produce electricity. Most generators run on direct current, which means that to use the electricity produced at home you will first need to convert it to alternating current with an inverter. Or you can use an AC generator, but the rotation may not be enough to generate the necessary magnetic field.
- If you decide to buy a direct current generator, look for one capable of withstanding high voltages, large powers and a low rotation speed (hundreds of revolutions per minute instead of thousands). You must generate at least 12 volts for a sufficiently long period of time. The generator must be connected to a battery pack with charge regulator between the generator and the inverter to protect the components from peak currents and continue to supply power even in the absence of wind.
- Car alternators are not suitable as generators due to the necessary rotation speed that is too high compared to that which a wind turbine can guarantee.
Method 2 of 4: Assemble the Turbine
Step 1. Secure the blades to their housing
The latter will be connected to the motor shaft. The blades must be evenly spaced and have the same angle. In a 3-blade turbine they must have an angle of 120 ° between them, while in a 4-blade turbine they must be placed at 90 ° from each other.
- If you don't have a pre-built housing, you will need to build it by joining together one piece to mount the blades on and another one to slide onto the shaft.
- Once assembled, you could add a conical or spherical spinner to enhance the aesthetics.
Step 2. Drill the hub
You can build a hub with a 5x10cm joist, long enough to keep the blades spaced from the tower and also leave enough space to install a wind vane of sufficient size to bring the turbine back to the correct position, following wind changes. The hole should be about one quarter to one third of the length of the hub long enough to mount the generator at one end and run the cables through.
Step 3. Secure the generator to the hub
You can secure the engine with metal clamps and protect it from the elements by covering it with a section of PVC or metal pipe. You can also fix a block of wood under the generator.
After fixing the pieces of wood you can paint them, to protect them from the elements
Step 4. Attach the weather vane to the opposite side of the hub
You can build one from a sheet of metal one-third along the hub. The easiest way to fix it is to drill the hub halfway up and insert it.
Step 5. Screw a 2.5cm flange under the hub
This will house the bearing.
Step 6. Insert a 2.5 cm wide threaded rod into the flange
This will act as a bearing, allowing the hub to turn freely following the direction of the wind.
Step 7. Secure the blades and their housing to the generator shaft
After performing this step, lift everything up and check that it is balanced. The weather vane at the opposite end should compensate for the weight on the other side, otherwise add some weights to one side or the other until a balance is achieved.
Method 3 of 4: Building the Tower
Step 1. Build a strong base
The construction of the base depends on the use you intend to make of the turbine. You can choose to mount it permanently or move it from place to place. In any case, the base must be strong enough to support the turbine even in strong winds.
- For a permanent turbine, the base will need to be wide, strong and heavy. You can cast concrete or use sandbags to anchor a wooden base. The base must be at least one third of the height of the turbine. If the tower is 1.5m high, the base will be around 50cm on the side, weighing about 45kg. Attach a 2.5 cm diameter pipe to the base (or drown it in concrete before it hardens), then attach a 2.5 cm T-joint to the pipe and another piece of pipe at the other end.
- If you don't want a permanent base, cut a thick plywood disc. If the tower is one and a half meters high, the disc must have a diameter of 60 cm. Slip a 3cm T-joint onto a 2.5cm diameter piece of pipe, then secure two elbow joints to the ends of the pipe and to the wooden base with metal flanges. You will get a U on which the T joint can rotate freely. Put a 2.5cm reducer on the joint and attach another T-joint to the reducer. At the other end of the latter put another piece of threaded tube. You can also drill the wooden base to anchor it to the ground.
Step 2. Cut a PVC pipe for the tower
This will need to be larger than the tube attached to the base. An inner diameter of 3cm will be fine. The length of the pipe will determine the height of the tower.
Method 4 of 4: Raise the Turbine
Step 1. Connect the charge controller to the battery before connecting it to the generator, in order to avoid current spikes that could damage the components
Step 2. Wire the controller with insulated electrical wire
The cable will transfer the current produced by the generator to the regulator and from this to the battery. You can use the same cable as the power cords of appliances, with two separate cables inside. If you want you can also reuse an old power cable, removing the connectors.
Once the regulator is wired, you can connect it to a dummy load or short the wires by touching them, instead of connecting it to the battery. This will slow down or freeze the turbine, avoiding moving the blades while you mount the turbine
Step 3. Run the electrical wire through the base and tower
Insert the cable from the T-joint to the base and run it all the way to the top. You can use a lanyard or electrician's probe to get it through.
Step 4. Mount the tower on the base
You can increase stability by anchoring the tower to the ground with wire ropes.
Step 5. Mount the generator on the tower
Run the cable through the flange under the turbine and connect it to the generator.
If the base of the tower is permanently fixed to the ground, you can remove the blades before raising the tower and reassemble them after anchoring the structure
Step 6. Connect the cable to the generator and the regulator to the battery
Advice
- Protect the regulator from moisture and insert a voltmeter to monitor the output voltage.
- Periodically check that the turbine, while rotating, does not twist the power cables.
- Learn about the presence of migratory birds in your area. Avoid building wind turbines in areas populated by migratory birds.
Warnings
- If you want to connect the turbine to your home electrical system, contact a qualified electrician to install the necessary inverters and switches. In some countries this work must necessarily be carried out by a professional.
- If you plan to sell the excess energy produced to the electricity grid, know that the supplier sells you energy at retail but buys it at wholesale price. You will need to install an inverter to convert the current to the voltage used by the supplier and a suitable switch. You may not only not make a profit, but you may not even cover the cost of the installation.
