New Methodology for Measuring the Thermal Conductivity of Small Samples Using the Boxes Method with Reduced Sensors

The reduction of device components is of a major interest for the conception of low-cost devices with a simple design. Generally, the boxes method measures the effective thermal conductivity of relatively large-sized samples due to its industrial purposes. However, to determine the thermal conductivity of small samples, additional sensors are required. In this work, a new experimental procedure is developed to characterize the thermal conductivity of small samples without any additional sensor. A detailed uncertainty analysis in the thermal conductivity measurements is conducted. The improvement of the instrument uncertainty was also considered. Three different scenarios were examined, from ideal to worst-case, in order to assess the performance of the proposed methodology. The values of the measured thermal conductivity were compared with those obtained by a reference method (hot disk). The comparison shows a good agreement and proves the effectiveness of the used technique. The overall study of the propagation of measurement uncertainties shows that the instrument’s uncertainty was found to be less than 6.1 %.