Evaluating H2 Infiltration via Drone-Based Thermal Imaging

Abstract

This work discusses the analysis of thermal survey data from operating parabolic trough plants. A thermal survey consists of IR images of individual HCEs in a parabolic trough collector, these images are the basis of a non-intrusive methodology for evaluating the heat losses. The HCE performance is affected by issues such as H2 infiltration and lost vacuum, which are difficult to identify visually but significantly increase the heat losses. In this work the glass temperatures from survey data are compared to predictions from a reduced order model of the HCE with good agreement. The model is then used for parametric studies looking at the variation of important ambient conditions, glass envelope conditions, and optical properties. Results indicate the model is a useful and computationally efficient tool to determine the status of a given HCE; however, it can be difficult to distinguish between lost vacuum (from outside air infiltration), and certain levels of H2 infiltration (from decomposition of the HTF). The main methodology for identifying H2 infiltration in these cases involves thermal surveying at different times of the day, taking advantage of the temperature dependence of the getter capacity.