High-efficiency, air-stable manganese–iron oxide nanoparticle-pigmented solar selective absorber coatings toward concentrating solar power systems operating at 750 °C

Spinel Cu–Mn–Cr Oxide Nanoparticle-Pigmented Solar Selective Coatings Maintaining >94% Efficiency at 750 °C

“…The solar spectral selectivity is intrinsic to the band-to-band and d-d transitions of nonstoichiometric spinel Cu–Mn–Cr oxide NPs. Compared to our previous work, , the Cu–Mn–Cr oxide NP pigmented coatings notably enhance solar absorptance in both visible and near IR regime by tuning the cation distribution in the spinel structure. The site inversion brought by multiple valences of cations as well as the observed oxygen vacancies greatly improve the intrinsic solar selective absorption behavior.…”

“…Based on the absorption spectra of the spinel Cu–Mn–Cr oxide NPs, we further modeled the spectrally integrated solar absorptance α Solar and the thermal efficiency η therm for 1000× solar concentration at 750 °C using Lorentz-Mie scattering theory and four-flux radiative model, as detailed in refs and . Figure c,d show α solar and η therm contour maps, respectively, as a function of NP volume fraction and coating thickness when dispersed in silicone matrix for the solar absorber coating.…”

“…Spinel (AB 2 O 4 ) NPs with intrinsic high-temperature thermal stability is a promising candidate since their manifold compositions and cationic valences enable a high degree of freedom to tailor the optical properties. Previously, we have demonstrated MnFe 2 O 4 NP-pigmented solar selective coatings maintaining η therm ∼89% under 1000x solar concentration after serving at 750 °C in air for 700 h . To further enhance the performance, in this article we demonstrate spinel Cu–Mn–Cr oxide NP-pigmented silicone solar selective coatings on Inconel tube sections with a higher solar absorbance α solar = 98.2% and a notably reduced thermal emittance ε therm = 59.4% compared to benchmark Pyromark 2500 (α solar = 96.0%; ε therm = 89.5%).…”

“…Our previous optical design , based on Lorentz-Mie scattering theory and Four-Flux model has found it feasible to achieve good solar selectivity in nanoparticle (NP)-pigmented silicone coatings for NPs with diameters <40 nm and steep optical transition near the optimal cutoff wavelength (λ cut ) between the solar spectrum and the thermal radiation spectrum. The computational design has taken into account experimentally measured size distribution of the NPs and achieved very good agreement with our experimental results.…”

Near-perfect spectrally-selective metasurface solar absorber based on tungsten octagonal prism array

“…Furthermore, the performance of the near-perfect MA was compared with that of some previously developed absorbers in Table 2. As can be seen in Table 2, Wu et al designed a MA based on nanoporous W/SiO 2 film, which can obtain the η of 90.32% that is 2.52% lower than the 92.84% of the near-perfect MA when C = 1 and T abs = 373 K. 20 Wang et al reported an absorber using manganese-iron oxide nanoparticles, achieving the η of 89.30% that is 5.74% lower than the 95.04% of the present near-perfect MA under C = 1000 and T abs = 1023 K. 40 Niranjan et al studied a W/WAlSiN/SiON/SiO 2 multilayer, which can obtain the η of 89.50% that is 5.01% lower than the 94.51% of the near-perfect MA when C = 100 and T abs = 773 K. 41 He et al studied an absorber based on alloy nitride MoTaTiCrN nanofilms, obtaining the η of 86.90% that is 6.92% lower than the 93.82% of the near-perfect MA under C = 100 and T abs = 823 K. 42 Ye et al reported an absorber based on a tungsten sphere and cuboid array, which can achieve the η of 87.56% that is 0.81% lower than the 88.37% of the near-perfect MA when C = 100 and T abs = 1000 K. 43 Zhang et al designed a chimney-like absorber, which can obtain the η of 91.62% that is 1.83% lower than the 93.45% of the near-perfect MA when C = 1000 and T abs = 1200 K. 44 Li et al reported an absorber based on TiN particles, obtaining the η of 93.00% that is 1.12% lower than the 94.12% of the near-perfect MA when C = 1 and T abs = 373 K. 45 Zhao et al proposed a Al 0.4 Hf 0.6 NbTaTiZrN MA, which can achieve the η of 74.90% that is 20.45% lower than the 95.35% of the near-perfect MA under C = 100 and T abs = 673 K. 46 Raza et al designed an absorber using SiC–W nanoparticles, achieving the η of 82.68% that is 3.13% lower than the 85.81% of the near-perfect MA under C = 100 and T abs = 1050 K. 47 Qiu et al studied an absorber based on TiB 2 –ZrB 2 composite ceramic, which can obtain the η of 83.90% that is 10.61% lower than the 94.51% of the near-perfect MA when C = 100 and T abs = 773 K. 48 He et al reported a double-layer alloy nitride HfNbTaTiZrN absorber, obtaining the η of 90.10% that is 3.75% lower than the 93.85% of the near-perfect MA under C = 100 and T abs = 823 K. 49 The above mentioned results demonstrate that the photothermal conversion performance of the present near-perfect MA is better than some previously absorbers.…”