The ^18th International Conference on the Properties of Water and Steam (^18th ICPWS) took place in Boulder, CO, U.S.A., from June 23 to 28, 2024. It is organized every four to six years by the International Association for the Properties of Water and Steam (IAPWS). The IAPWS is an international association of several national committees with the aim of researching the properties of water and steam and formulating the results as internationally binding standards, which then correspond to ISO standards. Precise knowledge of the properties of water is of great importance in many areas, especially in energy technology.

This year's conference was attended by Prof. Dr.-Ing. Matthias Kunick, Prof. Dr.-Ing. habil. Hans-Joachim Kretzschmar and Dr.-Ing. Sebastian Herrmann from the Zittau/Görlitz University of Applied Sciences (HSZG) took part in this year's conference. Prof. Kunick is a representative of the HSZG and a voting member of the German-Swiss National Committee (GSAPWS) of the IAPWS; Prof. Kretzschmar is the current GSAPWS chairman. At the conference, Prof. Kunick presented the SBTL method for calculating the material properties of working fluids in energy technology using spline interpolation. This method is characterized by high accuracy and extremely short calculation times, which is why it is very well suited for simulating energy technology processes and for taking real material properties into account in numerical flow simulations and is already being used. Following his presentation, a working group was set up under his leadership to develop a new industry standard for water and water vapor using the SBTL method he developed.

The "^22nd Symposium on Thermophysical Properties", which is the most important international conference in the field of research into the thermophysical properties of gases, liquids and solids, took place at the same time as the ICPWS conference. All three of the above-mentioned persons also contributed to the content. Two posters and a computer presentation illustrated material value calculation programs that have been developed in recent years at the Department of Technical Thermodynamics under the direction of Prof. Kretzschmar and are now also being further developed by Prof. Kunick.

Connections for these material value programs were presented for many software products used in everyday engineering, such as Excel, MATLAB or Mathcad. In a further lecture, Prof. Kunick presented the practical application of the SBTL method to pure substances and substance mixtures. Dr. Herrmann presented the results of the re-evaluation of viscosity measurements on natural gas mixtures, which are being taken into account in current research into the most accurate substance data possible for substance mixtures. In addition, the three representatives of the HSZG also chaired some of the lecture sessions at the 22nd symposium, which underlines the acceptance of research at the HSZG among international colleagues.