Construction and calibration of a large-area heat flow meter apparatus

Abstract

A large-area heat flow meter apparatus that can measure the thermal conductivity of a 900 mm × 900 mm insulating specimen was constructed in this work with a relative expanded uncertainty of 1.4%. By the use of a reference material certified with an assigned value of thermal conductivity, the heat flux transducers in the apparatus were calibrated in the mean temperature range of −10 °C to +50 °C. The following three tests on the robustness of measurement results were conducted: (1) assessment of the reproducibility upon reloading the specimen a few times into the apparatus, (2) use of various temperature differences on the two surfaces of the specimen, and (3) configuration of the vertical temperature profile around the specimen differently while maintaining the temperatures on the specimen surface and their difference the same. The results of the three robustness tests supported that the measurements were consistent and the uncertainty assessment for the thermal conductivity measurement using the constructed heat flow meter apparatus was valid.