02 March 2009
Conergy is using igus components to boost efficiency of production of energy by approximately 30 per cent. The German based renewable energy specialist turned to igus for plain bearing applications, rod end bearings and linear units in its SolarOptimus tracking systems.
SolarOptimus systems, designed by Conergy, can increase energy production
Conergy was founded in 1996 as a solar system integrator and provides complete system solutions for the production of renewable energy, recently presenting its new tracking solution for photovoltaic systems, the SolarOptimus.
This system has the task of always optimising the alignment of the photovoltaic generators, an investment that can increase energy production by more than 30 per cent using twin-axis tracking systems. In Northern Europe, this optimum position detection always moves to the brightest spot in cloudy conditions. In southern Europe, where the sky is often cloudless and there is a high brightness level, a system that keeps the photovoltaic modules at a right angle to sunray incidence on the basis of astronomical data is more effective.
The SolarOptimus was developed especially for the radiation-intensive southern Europe regions. Philipp Vanicek, product manager, explained how the modules moved ‘in two horizontal axes according to an astronomical algorithm.’
During development of the frame system, the main focus was on durability and maintenance freedom, since the systems are often set up in remote areas without any on-site personnel. For this reason, the developers consciously eliminated complex drive systems, choosing simple components for motors and bearings.
SolarOptimus turned to igus for components that would withstand the harsh conditions in Spain
Bernd Krabbe, also a project manager for SolarOptimus development, asked bearing system suppliers for suggestions on how to deal with challenging environments. Locations for the solar systems are often very dry, with high levels of sand and fine dust. Additionally there is a very wide temperature spectrum.
Following the consultation, the main axes of the frame systems, which are around 20m long, were fitted with iglidur plastic bearings, from igus, which has its UK base in Northampton. The ‘built-in’ solid lubricant of the polymer ensures that no lubricants have to be added.
To reduce the strain on the drive systems, the Conergy development engineers have used linear bearings in the adjustment systems. Igus DryLin linear plain bearings aim to guarantee the exact linear motion of the axes. The DryLin W bearing slides on a hard anodised aluminium rail profile, providing low-friction running without ‘stick/slip effects’. Igus adapted the mounting plate for the moving components to the requirements of the Conergy developers. The system is designed so any debris is pushed away by a ‘snowplough effect’ without affecting the gliding properties.
Philipp Vanicek, product manager of SolarOptimus, says the main focus was maintenance free operation
Finally, Conergy used igubal rod end bearings for the couplings, which link the solar module carriers together.
The drives of the module frames, which are responsible for the north-south alignment, apply a force of 6,800 N, the drive of the main frames for east-west tracking 10,000 N.
The speed is low, at maximum 4 mm/s, and the drive is moved through a maximum of one full revolution per day. Nevertheless, high demands are made on wear resistance, because the environmental conditions affect all components. Igus carried out a series of tests for Conergy, and had extremely abrasive sand flown in from southern Spain, where the first SolarOptimus systems have been installed. Igus claims the result showed its bearings did not have to be replaced over the whole calculated service life of the SolarOptimus. This also applies to the UV resistance of the plastic as well as the wide temperature range and the humidity.
When the project is complete, 800 movable systems will be producing solar energy at the Spanish location and feeding it into the power network.
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