Under the direction of Prof. Wagner (1975-2006), the Chair of Thermodynamics at the Ruhr-University Bochum had dealt with research in the field of thermodynamic properties of fluid substances. Besides a number of highly accurate equations of state, which in many cases, have been considered as international references for the properties of the corresponding substances, an extensive set of algorithms for the calculation of thermodynamic properties from equations of state formulated in terms of the Helmholtz free energy have resulted from this work.
Extensive software packages have been developed during the past years, to make this modern way of easily calculating thermodynamic properties available for users in industry and research. These packages are customized for every individual field of application and are continuously further developed. The functions for the calculation of the thermodynamic properties exported in each case in a Dynamic Link Library (DLL) can be called very conveniently ‒ e.g. by a Microsoft Excel Add-In available in 32-bit or 64-bit ‒ under all Windows operating systems (including Windows 10) and in all Excel versions (2003 – 2019/Microsoft 365). Alternatively, the 32-bit or 64-bit Fortran DLL can be integrated into user specific Fortran applications. The same exported functions can also be called by the .NET programming languages of Microsoft Visual Studio (Visual C#, Visual C++ or Visual Basic) via the likewise available 32-bit .NET DLL.
Software has been developed for more than 70 substances to calculate values of their thermodynamic and transport properties easily and accurately.
Software for the IAPWS-95 Formulation
A comprehensive software package has been developed for the calculation of thermodynamic properties of water based on the scientific standard equation of state IAPWS-95
An extensive software package has been developed for the calculation of thermodynamic properties of water and steam based on the Industrial Formulation IAPWS-IF97. This package allows the user to apply the industrial standards for the calculation of power plants and a number of other technical applications in an easy way.
For the reference equation of state GERG-2008, a comprehensive and user-friendly software package is available. The software enables to calculate several thermodynamic properties in the homogeneous gas, liquid, and supercritical regions and allows to carry out VLE calculations at arbitrary mixture conditions where the prior knowledge of the number of phases (one or two) is not required. The VLE calculation options include different flash options as well as phase envelope, dew point, and bubble point calculations.