The technology to enable the promise of solar energy has quite some way to go, with one requirement being an efficient way of tracking the sun during its daily movement across the horizon. Two city-based entrepreneurs here say they’ve developed a more efficient system in this regard, of a motor guided by a microchip, fed with information on the sun’s movement in different seasons.
A wind sensor helps the motor run at a measured level of revolutions per minute, moving the panel on the axis to a position where it faces the sun. The tracker also moves the panel to a tow position in the event of high velocity winds, to save the panels from damage. The tracker system is expected to provide 25-30 per cent additional generation capacity to solar panels.
“Several firms and institutions are adopting this technology, which has a slightly higher capital cost,” says Raghuram Kondubhatla, 30, managing director and co-founder of SmartTrack Systems Pvt Ltd, launched this January. “The added efficiency in electricity generation outweighs this (extra) spending.”
There are companies here and abroad which offer tracking systems to solar power developers. Raghuram says his relatively lower price and additional features would drive their product ahead of others. A 1-Mw solar power plant requires eight tracker systems. The company offers this for Rs 25 lakh per unit, thus adding Rs 1 crore to the capital cost, which otherwise is Rs 15 crore.
Apart from successfully demonstrating their product, fitted to the rooftop solar panels installed at the Chaitanya Bharati Institute of Technology here, SmartTrack has so far bagged orders worth Rs 33 lakh and is in the process of firming up deals worth Rs 1.7 crore, according to Raghuram, who launched the company with his friend, G Bhagwan Reddy.
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Hurdles, plans
Besides approaching solar farm developers, the start-up is also trying to tie up with solar PV module manufacturers. SmartTrack would also provide EPC (engineering, procurement and construction) services and other structures that support solar panels. However, getting bank finance is a problem. It doesn’t come easily, even after making several rounds of presentations, he says. The duo plan to offer tailormade solar PV units to households, depending on their average usage of power. “With household power rates going up, people may need an alternative source of power to supplement their energy needs,” he says.
Developing solar panels that orient themselves to face the sun continuously has been on for some time. These panels are much more efficient than stationary models. They are more expensive, but the extra energy they generate more than makes up for the small amount of energy required to track the sun, through movement by electric motors and tiny computers which compute the angle at various points throughout the day.
In flat-panel photovoltaic (PV) applications, trackers are used to minimise the angle of incidence between the incoming light and a photovoltaic panel. Concentrated photovoltaic systems use optics to concentrate a large amount of sunlight on to a small area of solar photovoltaic materials to generate electricity. The optics in concentrated solar applications accept the direct component of sunlight light and, therefore, must be oriented appropriately to collect energy.
Experiments
There have been experiments without use of a motor. In 2008, students at the Massachusetts Institute of Technology, participating in the annual MADMEC (Making And Designing Materials Engineering Contest) devised a zero-input energy solution. This allowed solar panel arrays to track the sun’s movement, thereby increasing efficiency by 38 per cent over stationary panels. The three-person team of Forrest Liau, Vyom Sharma and George Whitfield won a $10,000 prize for their invention.
The device was basically a temperature sensor that responded mechanically to changes in heat. Constructed from bimetal aluminum and steel, two materials which expand at different rates when exposed to identical changes in temperature, the device was built into a type of arch, affixed permanently at one side and attached to a pivot arm on the other. As the sun moved, it heated different portions along the arch, causing it to flex and bend to varying extents, allowing the solar panel to track with the sun’s movement, in line with expansion of the arch.
Last month, a 19-year-old Princeton University student won the Scotiabank EcoLiving Student Leadership Award for her invention, a $20 tracking rotation system that maximises the output of solar panels. It means 40 per cent fewer panels are required, compared to stationary systems. Engineering student Eden Full, founder of Roseicollis Technologies, began working on a device while in high school, called the SunSaluter. Developed primarily for the developing world, the system is driven by bi-metallic strips that expand during the day and contract as they cool at night. In the process, they move the solar panel to the optimal angle for capturing sunlight.
