High-temperature Solar Selective Absorbers Using Transparent Conductive Oxide Coated Metal

In these days, the application of using thermal energy of sunlight has become widely used in concentrated solar power generation systems (CSP). In CSP, property of the receiver directly contributes to the system efficiency of CSP. The solar selective absorber is used for the receiver to reduce energy loss of thermal radiation. To investigate the mass production technology of fabricating solar selective absorber that can be utilized in high temperature condition, we focused on transparent conductive oxides (TCO) thin film on metal substrate. TCO material has plasma wavelength in infrared region. Therefore the electromagnetic wave with shorter wavelength than plasma wavelength goes through the material, while the electromagnetic wave with longer wavelength is reflected on the surface. It is realized that TCO on metal substrate showed high performance as solar selective absorbers, i.e. high absorptance in visible light range and low emittance in infrared range by numerical simulations. The optical property of fabricated TCO coated metal is well consistent with the simulated property. Consequently, we attain high performance solar selective absorber of which solar absorptance is 0.71 and hemispherical total emittance is 0.11. The thermal stability is also confirmed at 600oC in vacuum for 3 hr.