Experiment With Different Wind Turbines

Two months ago I was tasked to build a wind generator that can be use to charge batteries and power LED lights here in our main office. The first thing that I was thinking is the vertical axis wind turbine (VAWT) suitable enough for our other projects that will provide back-up power in some of our remote  installation of met sensors. After a month long planning and fabrication, I came up with a Savonius turbine that drives our 350W motor hub from an electric bicycle. During the testing, I was a bit disappointed with the result, the wind generator starts to spin at 2.5m/s wind speed and only reaches at 15 to 25 rpm from a wind velocity of 5m/s, not enough speed to generate few volts of electricity!

This prompted me to think with other turbine designs that are more efficient and have less wind drag as compared to my existing Savonius turbine. Anyway, earlier this morning I was busy setting my small test fixture that will test 2 other types of vertical axis wind turbine. We have an old anemometer that we no longer use and found that I can use the optical sensor to measure the relative wind speed of the turbine under test.

The first is the small scale model of my Savonius turbine, I'm aware that this is the least efficient from the rest of turbines but i would like to see how well it does when seated on the test fixture.

Not bad at all, the Savonius turbine able to spin at 0.2m/s., rotation sometimes varies over time but is still provides me a consistent slow rotational speed.

The next is a Darrieus turbine installed in the fixture. It has a hard time getting to start initially even if the wind is moving at the blades at substantial speeds. It sways back and forth until it catches the right angle and start to spin rapidly. I was able to get an average of 0.5m/s wind speed as displayed in the anemometer unit but it is not self-starting, not a good candidate for my project.

The last model of turbine that I'm going to test is the Lenz turbine. From the appearance of the model, it looks like a combination of Savonius and Darrieus turbine.

The performance is very promising, it automatically start to spin rapidly and I was able to obtain an average of 0.8m/s of wind speed reading from the anemometer unit.

 Comparing all the three models that were evaluated, the Lenz turbine is very well suited in my project and just a matter of time, an actual turbine will be made and soon running in my wind generator project. 73 de du1vss