Low-Cost Pyrometric Temperature Measurement in Concentrated Sunlight With Emissivity Determination

A method for correcting pyrometric temperature measurements of high temperature objects with unknown emissivity is presented. The method also estimates surface emissivity a the pyrometer wavelengths. It is particularly useful for correcting errors due to reflected light in solar heating applications. The method requires two or more narrow band pyrometers and can be applied to low-cost commercial instruments. The method analyzes the temperature measurements of multiple pyrometers operating at different wavelengths across a range of sample temperatures to solve for the surface emissivities that minimize the differences in temperature measurements. The temperature measurements are corrected using the new emissivities values. Simulated temperature data with both random noise and systematic errors is used to assess the robustness of the analysis method. When applied to temperature data from a solar furnace, it is shown to significantly decrease the difference in the temperature measurements of two single-color pyrometers. This method provides a potential low cost solution for pyrometric temperature measurement of solar-heated objects.