Influence of Using Different SiO2 Antireflective Coatings and Sintering Conditions on the Durability and Optical Performance of the Selective Solar Absorber
Abstract
A multilayered absorber for low temperature thermal applications on aluminum substrate (Al-CuMnOx/FeMnCuOx/SiO2) has been reported in the previous work. It is based on a single layer of CuMnOx as absorber material and two antireflective (AR) coatings deposited by the dip-coating method. Given the appealing values of solar absorptance (0.957) and thermal emittance at 100ºC (0.038) reached for this three layers configuration, an additional research was carried out for completing the feasibility study of the proposed absorber. As this selective absorber is intended to use in low-temperature solar collectors which operate in outdoor conditions, it has to accomplish the crucial requirement to withstand some ambient conditions such as high humidity and high temperatures, among others. Therefore, with a view to achieve the best durability performance of the selective absorber, a comparative study focused on using two different SiO2 antireflective solutions as third layer and different sintering conditions of this specific layer was carried out. The influence of this layer on the optical parameters as well as the long term durability of the final selective absorber has been studied.