Humidity Impact on Thermal Conductivity Sensors

The thermal conductivity of humid air at different saturation levels has been investigated at 70 °C. A MEMS-based thermal conductivity sensor was calibrated and used to measure the thermal conductivity of humid air. The obtained results were compared to different equations for calculating the thermal conductivity of gas mixtures, in this case, dry air and water vapor. The selected equations predict contradicting behaviors of humid air at different temperatures and saturation levels. A semi-empirical equation by Melling et al. for the temperature range of 100 °C to 200 °C has shown the best agreement with the experimental data. We intend to study the temperature range from 0 to 100 °C in more detail and plan to adapt the interpolation to fit this temperature range.