Applicability of Mid-Infrared Thermography to Study Full-Size SOFC
Solid oxide fuel cells (SOFC) are promising devices for the production of cogenerated electricity and heat (CHP), both, in portable and stationary applications [1-3].
One of the major problems in case of fuel cells is the use of materials for their construction retaining chemical, structural, electrical and thermo-mechanical properties for a long time (40000 hours) under extreme conditions of temperature and pressure. In order to meet these requirements, fuel combustion processes in different operating conditions as well as the chemical and structural changes leading to a reduction in the efficiency of the SOFC cell type should be examined and analyzed.
Midwave-infrared (MWIR) thermography is a method allowing observation of the cell electrode surface and examination of its temperature providing much more detailed information on the processes occurring on the surface of cells than spot temperature by thermocouple measurement.
Recent studies of SOFC cells support the potential of the method for testing thermal imaging of the small (a few millimeters in diameter) fuel cells [4, 5]. Brett et al. independently  indicated a necessity for use of large full-scale fuel cells, due to the lack of the fuel cell polarization in case of small size cells.
An innovative presented in this work relies on showing the applicability of the midwave infrared thermography to study full-size, solid oxide fuel cells (diameter approximately 100 mm). Infrared observations were made via quartz plate. Measurements has been performed using thermal imaging camera equipped with cooled to 85 K InSb detector. The test stand for thermal and electrical measurements of fuel cell has been constructed using a resistance tube furnace. Diagram of the furnace together with the measuring holder is shown in Figure 1.
Significance of the work
Infra-red thermography has been applied to the study of the operational IT-SOFC’s to determine the temperature changes and spatial distribution associated with different current densities for anodes of full-size SOFC cells. Recorded images of full-scale commercial fuel cells showed a very good resolution. There is much more detailed information about the reactions at the surface, than from small button-type fuel cells. The small surface temperature variations detected by mid-infrared camera provide real-time analysis of the early stages of SOFC failure, demonstrating the promise of this convenient imaging technique for system diagnostics.
Reasearch support from the National Science Center. Grant no. UMO-2013/11/N/ST8/00834 is gratefully acknowledged.
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