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Food forests

Food forests…

Over the past few years, we have been slowly planting areas of "food forests". This concept uses per…

Research centre for appropriate technology

Research centre for appropriate technology…

As the transition to a resource-based economy requires a high level of integrated technology, our lo…

Top priorities for 2019

Top priorities for 2019…

We finished 2018 on a positive note, feeling that good progress was made. After around two years and…

Vortex hydroelectric plant

Vortex hydroelectric plant…

The vortex hydroelectric project was started in 2015 and construction of the tank and channels was c…


The vortex hydroelectric project was started in 2015 and construction of the tank and channels was completed in June 2016. We spent the next few months constructing the first prototype turbine and we connected the first power to the house in August 2016. After six months of testing the system and the electrical control systems, we were achieving a power of around 3.5 kW. This was enough energy to run household appliances, such as the washing machine, freezer, computers, and internet, and most of the workshop tools. However, this was not enough power to pump water up the steep hill from the river or provide for future projects. Hence, we decided to install a much larger turbine designed to produce around 7.5 kW. During installation of this turbine, we began to encounter problems with the transmission of so much power and after a short time the gearbox failed due to the high torque applied by the turbine. We spent some time investigating gearbox options and found an exciting alternative: a magnetic planetary gearbox design that allows contact-free transmission, automatic overload protection, and requires little maintenance as it does not require lubrication. As this seemed to be a perfect solution for our needs, we invested some months doing complex mathematics and writing a code to design a small prototype magnetic gear to test the concept. Meanwhile, we intermittently ran the vortex with small turbine blades to limit the power and a temporary transmission system using rubber belts. We encountered challenges in constructing the large metal pieces for the gearbox as they required very precise machining. During installation and testing of the full-scale two-stage gearbox in early 2018 we discovered errors in the initial design. The gearbox has since been redesigned with the help of an expert in field and preliminary testing of the large stage in early 2019 showed promising results. In addition, we have installed a new radial gate at the entrance of the cortex tank that can be dropped quickly in an emergency to stop the turbine and protect the system. The second smaller stage of the gearbox is currently being modified slightly and we expect to resume operation of the plant in the first half of 2019.

You can see videos of the turbine running on our YouTube page.

 

Overview of vortex running with the large turbine

 

Large stage (1:10) of the magnetic gearbox showing the outer ring of magnets

 

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