Malik Maaza
UNESCO UNISA Africa Chair in Nanosciences & Nanotechnology, South Africa
Title: Novel Black Selective Solar Absorbers For High Temperature Concentrated Sola Power Applications
Biography
Biography: Malik Maaza
Abstract
The most significant concern of our world today is the energy derived mainly from fossil fuel which exceeds 87 % both inrnadvanced & developing economies including African nations. A shift towards greener energy technologies has producedrnenergy changes worldwide; Africa included. In view of the large direct normal solar irradiation in the continent (average ofrn220 W/m2 in Africa against 150 and 100 W/m2 in the USA and Europe respectively), several African nations have embarkedrnin large solar energy parks and programs. One could quote Morocco and South Africa specifically with a target of 3.7 GW andrn5 GW at Ourzazat and Upington solar parks respectively. There are 2 major solar energy technologies: the Photovoltaics (PVs)rn& the Concentrated Solar Power (CSP). While the PVs are dominated by household & small to average businesses’ usage, thernCSP is geared towards high throughput and grid based consumption. In the CSP plants, known also as solar photo-thermalrnpower plants, the electricity is produced in much the same way as conventional power stations. The difference is that theyrnobtain their energy input by concentrating solar radiations and converting them to high temperature steam or gas to drive arnturbine/engine. More precisely, the incoming radiations are reflected by parabolic mirrors which concentrate the solar energyrntowards a selective solar absorber coatings deposited on metallic tubes. Hence, the most important and critical part of the solarrncollector is the black selective absorber surface itself, which should absorb a maximum of solar radiations & convert them intornheat, which in its turn transferred to the heat transfer fluid. In this sense, 6 configurations of the black selective solar absorberrnnano-coatings can be adopted technologically: (1) intrinsic, (2) semiconductor-metal tandems, (3) multilayered absorbers,rn(4) multi-dielectric composite coatings, (5) textured surfaces, and (6) selectively solar-transmitting coating on a blackbodylikernabsorber. This contribution reports on recent advances in novel class of selective solar absorber nanostructures for highrntemperature CSP applications.