Improving the performance of Concentrating Solar Power (CSP) system using Ti/AlN/SiO2 thin film as an alternative renewable energy source
Keywords:
Sputtering, Modified stainless steel substrate, Solar absorptance, Thermal emittanceAbstract
Successful utilization of bigger solar power systems especially concentrating solar power (CSP) as an alternative renewable energy requires not only spectrally selective absorber coatings but also, striking a balance between solar absorptance and emittance at the solar (300 nm-2500 nm) and infrared regions (>2500 nm) of solar spectrum, respectively. In the present study, we developed an ultrathin (~100 nm) tandem coating of Ti and AlN with SiO2 as antireflection layer using magnetron sputtering system at room temperature on modified stainless steel (SS) substrate. The coating was characterized using FESEM, AFM, XRD, UV-Vis-NIR, and FTIR. 0.95 and 0.13 were respectively achieved as solar absorptance and thermal emittance. The multilayer coating exhibited good thermally stability after annealing at 500 oC in air for 2 hours. Though, optical properties of the coatings after annealing at 600 oC, was found to degrade followed by decline in absorptance and emittance from 0.95 to 0.92 and 0.13 to 0.24 respectively. These changes are associated with the decline in roughness of the coating as probed from AFM analysis. The present results show potential application of this coating in high temperature CSP system.