01.10.2019
The project aimed to develop humidity calibration methods and measurement techniques for air temperatures above 100 °C in industrial applications. For this purpose, TU Darmstadt has developed a laser based, absolute (dTDLAS) hygrometer, the measurement principle of which was established in accordance with those developed by WG 3.42. The dTDLAS hygrometer was validated for temperatures up to 100 °C by means of a humidity standard in a measurement facility for humidity sensors, which was designed for this purpose at PTB (WG 3.41/3.42). Furthermore, PTB assisted in planning, completion and evaluation of measurements below 100 °C air temperature. Based on the validation by PTB, the dTDLAS hygrometer of TU Darmstadt has been successfully installed and applied at a roast house in Italy by INRIM and TU-Darmstadt.