CSIR researchers have increased solar absorbency by incorporating the use of photonic materials – a perfect solution for Africans looking for cost efficiency and reliability.
The ideal solar absorber would not re-emit any radiation that occurs when a material gets too hot from the solar absorption, maximizing energy transfer by methods like heating by conduction. CSIR said the requirements needed to create low reflectance of less than 10% in the wavelength range from 300 nm to 2500 nm and a high reflectance of greater than 90% for wavelengths greater than 2500 nm.
CSIR researchers specializing in advanced photonic materials have succeeded in tailoring the optical and structural properties of materials to achieve the desired wavelength selectivity. Their selective solar absorber comprises carbon nano-particles embedded in a NiO (nickel oxide) matrix on an aluminum substrate. It shows enhanced solar radiation absorption and low thermal release properties – laboratory tests reportedly show that it is approximately 30% more efficient than the best alternative on the market.
Furthermore, the sol-gel recipe that is used to manufacture the composite materials has additional advantages of being environmentally friendly and having low production cost. Control of the spectral selectivity in the coating is achieved by adjusting various parameters of the coatings, such as composition, thickness, porosity, surface morphology and nanostructure, among others.
This technology is set to impact the lives of the poorest people in South Africa by providing them with a reliable energy source for domestic heating applications. For example, boiling water without the need for electricity or lighting a fire would have a huge impact on a rural household’s safety and health and would generally result in a better quality of life for such communities.
A consortium of local universities, the private sector and NGOs, led by the CSIR’s laser experts, has started a three year implementation program to see that this laboratory research is realized in local communities for cleaner, safer energy.