Vol.5 No.4 2013

Research paper : Evaluating Uncertainty for the Standardization of Single Cell/Stack Power Generation Performance Tests for SOFC (A. Momma et al.)−252−Synthesiology - English edition Vol.5 No.4 (2013) the testing methods for SOFCs in commercial transactions. Japan’s leadership would allow many types of SOFCs designed for different service conditions to be tested fairly; data obtained from the test results would be used as the basis for commercial transactions of SOFCs, making it possible to select SOFCs appropriate for different applications and thereby accelerating the development and widespread application of SOFCs.Our group has been leading the research efforts relating to the standardization initiatives aimed at the broad-based acceptance and development of SOFCs. Our projects include the preparation of a Japanese Industrial Standard Technical Specifications (JIS TS)[2] on efficiency measurement methods based on such studies as: the development of the flow rate standards of hydrogen and city gas[3]—both of which are potential fuels for fuel cells—and the development of high-precision efficiency measuring methods for SOFC systems (figure 1).[4] In addition, we have been consolidating the SOFC measurement technology by conducting measurements on various types of single cells as well as cell stacks and systems.[5] Based on these technologies and experiences and in light of the future prospects of SOFC, our group was commissioned in 2007 by the Ministry of Economy, Trade and Industry (METI) to begin work on the standardization and harmonization of the single cell/stack testing methods for SOFC. Standardized testing methods were considered vital in order to facilitate the commercial transactions of SOFCs and accelerate the widespread use of SOFCs, which were believed to be close to commercialization. In preparing an international standard for SOFC performance tests, it is necessary to address the accuracy of data to ensure the reliability of measurements. Standards published by the International Electrotechnical Commission (IEC) and other international standards propose the inclusion of uncertainty—a concept traceable to international and national standards—as a benchmark for the quantitative evaluation of the reliability of measurement results. Measurement results with uncertainty data would permit cross-border comparisons of test results, an essential part of any relevant international standard.Against this background, we have taken active steps to introduce the concept of uncertainty into the evaluation of SOFC performance. As part of the JIS TS work and a 2007 project on efficiency measurements using an actual 10-kW SOFC system, we conducted uncertainty analyses of measured input and output values and included uncertainty data in our evaluation of the measured efficiency.[6] This paper describes the three-year project commissioned by METI in 2007 to develop an international standard for the cell/stack performance testing of SOFC, and our group’s work on uncertainty evaluation as part of this project. 2 Study objectives and a scenario for realizing the objectivesAs mentioned above, the objectives of this research were to propose an international standard for SOFC testing methods and to incorporate into the standard the equations and methods for evaluating uncertainty that are practical for the current level of technology. The first step was to form a committee for discussing and reviewing the draft standard. To do so we first conducted an inquiry, which included a questionnaire survey, with Fig. 1 The integration of and relationship between the technologies used for this studyThis workSingle cell performance analysisStack performancetestPressure control single cell test benchPrecision composition analysisCell manufacturing technologyPower generation test equipment using simulated gasUncertainty evaluation of test resultsProposal of standard test methodUncertainty evaluation of power generation efficiencyJIS TS Test method for power generation efficiencyInstruments and materials for calibrationPrecision flow rate measurementPrecision standard gasPrecision flow meterPerformance test method technologyfor cells and stacksHigh precision measurement technologyEstablish IEC standard for test method


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