. . . . . . . "Selective surface"@en . . . . . . . . . . . . . . . "772834"^^ . . . . . . "5022"^^ . . . . . . . . . . "In solar thermal collectors, a selective surface or selective absorber is a means of increasing its operation temperature and/or efficiency. The selectivity is defined as the ratio of solar radiation absorption (\u03B1sol) to thermal infrared radiation emission (\u03B5therm). Selective surfaces take advantage of the differing wavelengths of incident solar radiation and the emissive radiation from the absorbing surface:"@en . . . . . . . . . . . . . . . "In solar thermal collectors, a selective surface or selective absorber is a means of increasing its operation temperature and/or efficiency. The selectivity is defined as the ratio of solar radiation absorption (\u03B1sol) to thermal infrared radiation emission (\u03B5therm). Selective surfaces take advantage of the differing wavelengths of incident solar radiation and the emissive radiation from the absorbing surface: \n* Solar radiation covers approximately the wavelengths 350 nm to 4000 nm; UV-A, visible and near infrared (NIR, or IR-A plus IR-B). \n* Thermal infrared radiation, from materials with temperatures approximately in the interval -40 to 100 \u00B0C, covers approximately the wavelengths 4000 nm to 40,000 nm = 4 um to 40 um; The thermal infrared radiation interval being named or covered by: MIR, LWIR or IR-C."@en . . . . . . . "1100715773"^^ . . . . . . .