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Bearings for Solar Tracking Systems
Photovoltaic tracking systems offer a series of benefits. By automatically following the position of the sun, they perfectly absorb the sun's energy and therefore have a particularly high level of efficiency. This supplier guarantees that the modules in its system remain completely out of the shade. So that these can work in wind and weather over decades without problems, the company relies on maintenance-free, durable plastic plain bearings. “Tracking systems pay for themselves very quickly despite higher purchasing costs,” explains graduate engineer Gerhard Dirscherl, Head of Development at RWenergy GmbH from the Bavarian town of Schwandorf.
Optimally aligned
In 2006 the company came into the market with the single axis “s:wheel” tracking system. The ground-level system, which is hence not affected by wind, achieves up to a 30 percent higher energy yield than stationary systems. The azimuthal tracking allows the sun's energy to be perfectly utilized. The consistent alignment takes place at ten minute intervals. The system guarantees maximum yield due to this exact alignment with the actual course of the sun. At the same time, both the longitude and latitude of the place of installation is taken into account, as well as the shift between the actual solar time and the local time. “In recent years we have gained other footholds in the market besides this,” reports Gerhard Dirscherl. “Besides our tracker systems, we provide solutions both for rooftop systems and for ground installations.” In the tracking systems sector, the sturdy “s:track” model rounds off the product range at the bottom end. Compared to stationary systems, the yield here is up to 15 percent higher. The first text plant was put into operation recently in Mexico. More plants are in the pipeline.
Whereas the “s:wheel” single axis system rotates on a vertical axis, the “s:track” involves a horizontal tilting system. One axis runs in a north-south direction and makes the pivoting movements from when the sun rises in the east, through to the midday position, and continues westwards in the horizontal plane to the evening position in short motion intervals.
“Other manufacturers also make the classic horizontal tilting unit,” explains Gerhard Dirscherl. “We guarantee total freedom from shade, however, as a unique selling point in our systems. Highly complex control software ensures that the modules stay out of the shade both in the early morning and late evening hours. The unit continually moves into the ideal position in increments of 2°, whereby the system is optimally aligned with the sun to give the best yield curve for the operator.” The young company RWenergy GmbH, which belongs to the Josef Rädlinger group of companies in Cham, has settled on the premises of a former power plant. Here it operates its test plants on the roof of a decommissioned flue gas desulfurization plant at a height of almost 230 ft. Although the photovoltaic market is undergoing change, the company is looking to the future with optimism. “From homeowners to investor groups – with the right systems we can satisfy all the market requirements,” declares the head of development.
Endurance tests conducted in advance
