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Improved solar trackers for better solar energy harvesting

Researchers from the Indian Institute of Science have developed an improved version of a device that can track and orient mirrors, also called heliostats, towards the Sun. These tracking devices are important components of large scale solar thermal power plants, and are not new. But, the new version, developed at the Indian Institute of Science, is lighter, cheaper, remains stable even in strong winds, and of course, is better at tracking the sun.

India currently generates about 3,000 MW of power from solar energy and the Indian government plans to expand this to 100,000 MW with a $100 billion investment. According to the International Energy Agency, by 2050, solar would be the largest source of electricity at the global scale.

To produce solar energy at large scale, we need to look beyond the conventional rooftop solar panels. One of the ideas is to concentrate sunlight onto a central receiver using a large number of mirrors that follow the sun. The solar thermal energy from the mirrors is then used to heat a fluid to a high temperature which in turn runs a turbine and generates electricity. This technique, called the 'concentrated solar power', is predicted to generate about 11% of the total electricity consumed all across the globe by 2050.

The 'solar tracker', the device that helps mirrors orient towards the sun as it moves across the sky, in its present form has a few limitations. They are expensive and are easily affected by wind, causing deflections in the mirrors and consequent loss of concentration. The new design proposed by mechanical engineers from the IISc, can function even in winds blowing as fast as 22 m per second.

The researchers, Ashith Shyam R Babu and Ashitava Ghosal, used a new arrangement called the '3-RPS parallel manipulator', which improved the performance of the tracker. “The use of parallel manipulators for solar energy harvesting is the first of its kind and this will address the shortcomings of the existing designs", says Ashitava Ghosal, Professor of Mechanical Engineering, Indian Institute of Science, Bangalore. According to him, the 3-RPS manipulator is supported at three points, and this helps keep mirror deflection to a minimum and also reduces the cost of the heliostat.

Renewable energy sources, like solar, don't depend on fossil fuels, and pollute the environment. Innovations like this, will take us one step closer to realising the dream of having a world run by cleaner energy sources.

About the authors: Ashitava Ghosal is a Professor at the Department of Mechanical Engineering, Indian Institute of Science Bangalore, India. Ashith Shyam R Babu is a PhD student in the same department.

Prof. Ashitava Ghosal can be contacted at +91(80) 22932956.

Link to abstract of the publication:

http://link.springer.com/article/10.3901/CJME.2015.0210.055