Influence of atmospheric water vapor on infrared measurement systems in central receiver systems

Abstract

This thesis investigates a new system that can measure the temperature and emittance of the receiver in a solar tower power plant. These measurements are important for the efficiency and maintenance of the receiver. The system uses a multispectral camera that works in the short wavelength infrared spectrum. It uses two filters that are sensitive to water vapor in the air, which helps to reduce the effect of solar reflections on the signal. The system is based on ratio thermography, which is a method that compares the signals from different wavelengths. The aim of this report is to assess the influence of atmospheric water vapor absorption on the precision and accuracy of infrared temperature measurements in the context of solar towers. It shows that the atmosphere plays a significant role in the measurement accuracy, the most important being absolute humidity, and uses methods to correct errors due to the atmosphere. It concludes that SWIR ratio thermography is only suitable with specific conditions, for example at dusk at the tower of Cerro Dominador, Chile.