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The development of photovoltaic systems – through which sunlight is converted to electricity – has accelerated rapidly over the past quarter-century, largely as a result of increased environmental awareness and high oil prices. There’s now a broad range of systems on offer, from the very small – providing power for individual pieces of equipment – to large plants generating electricity for entire communities.
Solar panels are usually deployed in rows, and fixed in position. However, it is much more efficient to use a solar tracking system such as those made by German specialist Danzer Elektro Solar. With automated tracking, the panels follow the sun – like sunflowers – ensuring that sunlight falls vertically on to the solar cells. The effect is impressive: solar systems with integrated tracking systems are up to 35% more efficient than fixed systems.
Precision and efficiency
However, fundamental to maximising this efficiency is the automation equipment and software, which can be adversely affected by clouds and by dust and dirt. At the heart of Danzer’s system is the Omron CP1L PLC which supports both mathematical and PID/algorithm instructions, and also has two-axis control as standard. This makes the CP1L suitable for complex solar-tracking systems where the panels move in two planes – so they point precisely at the sun throughout the day.
In the Danzer system, the photovoltaic modules are moved using a closed-loop hydraulic installation. Sensors calculate the position of the sun, and this data is processed by the CP1L to adjust the angle and attitude of the solar modules. The PLC can also be easily integrated into computer networks, and data can be transmitted via telephone, GPRS or wireless routers to enable remote monitoring, control and error-handling.
Automatic panel positioning
Apart from this, there are some other interesting features. One is that at sunset, the modules can be automatically moved back to the next day’s starting position. In addition, the position of the panels can be adjusted to cope with changes in weather; photovoltaic units are not used solely in countries with wall-to-wall sunshine, 52 weeks in the year. So the panels can be lowered to horizontal in storms, or raised to vertical in the event of snow.
Danzer’s engineers worked with Omron specialists on a very focused requirement to maximise the benefits first of photovoltaic energy, and then of solar tracking. The future for solar energy depends on making it more efficient, which will reduce generating costs still further. Developments such as solar-tracking systems will go a long way towards achieving this objective, making photovoltaic energy even more attractive to businesses, local authorities and homeowners.