Testing a solar-blind pyrometer
Surface temperatures are key parameters in many concentrated solar radiation applications. Pyrometric temperature measurement of solar irradiated material surfaces is the alternative to contact measurement techniques, which are inadequate for measuring the temperatures of such surfaces. However, reflected solar radiation is an important uncertainty variable in this non-contact methodology. A promising method for eliminating this solar perturbation is by using centred passband filters on the atmospheric solar absorption bands, creating solar-blind pyrometric systems. A commercial pyrometer has been tested in the wavelength band at around 1.4 µm in the solar furnace at Plataforma Solar de Almería, showing its advantages and limitations. An estimation of temperature measurement uncertainty for a real case is presented with theory and experiment in agreement: the higher the temperature, the lower the uncertainty. Another experiment has shown that the pyrometer measures temperature properly even through quartz windows in this spectral range.