IIT Scientists Introduce New Nano Material For Faster Conversion Of Sunlight To Heat

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A team of scientists at the Indian Institute of Technology, Bombay, (IIT Bombay) have introduced a new nano material that enhances the efficiency of converting sunlight into heat.

NCFs or nanostructured hard-carbon florets, is made when carbon is deposited onto a substrate of amorphous dendritic fibrous nanosilica (DFNS). This is achieved by employing a technique termed as chemical vapour deposition. This gives rise to a material that is capable of absorbing over 97 per cent of the ultraviolet, visible and infrared light. This is then turned into thermal energy.

Efficiency 

When lined with hollow copper tubes, NCFs can heat the air flown through them to more than 346K. Not just that, this method can help the conversion of water into vapour promising an efficiency of 186 per cent. This is the greatest efficiency every to have been achieved.

As per Prof C Subramaniam, “One metre square of NCF coatings converts 5 litres of water in an hour.” This efficiency is five times greater than commercial solar stills.

Structure

The nanoparticle structure of NCFs looks like marigold flowers as it has small carbon cones connected to each other. The result- phonon is activated when photons strike the material and low phonon thermal conductivity.

What makes NCFs further viable is that the material used in then is easily available and the technique to manufacture them is also easy to scale. Thus, large scale manufacturing of NCFs is not impossible. Additionally, the cost of maintenance is also low.

As per the Ministry of New and Renewable Energy, close to 40 million or 2.5 per cent of households in India already use solar water heaters. But solar heat absorbers are mostly costly, heavy and can harm the environment. “Conventional coatings and materials for solar-thermal conversion are based on chromium or nickel films. While anodised chromium is a heavy metal and toxic to the environment, both Cr and Ni-films exhibit solar-thermal conversion efficiencies ranging between 60-70 per cent. In fact, the best commercial ones in the market operate at 70 per cent solar-thermal conversion efficiencies,” says Dr Ananya Sah, the author who led the research. NCFs have an edge over its competitors since it is commercially viable, easily available and scalable with greater efficiency.

NCFs can also have applications in water heating and space heating devices.

The team of researchers is now looking to exploit the potential of NCFs and has already established a firm Society for Innovation and Entrepreneurship (SINE) at IIT Bombay for commercial manufacturing.