ExpertThermo is a thermodynamic developer tool for analysis of basic non-electrolytes fluid properties. This is a software package, which consists of routines mainly programmed by Michael L. Michelsen during his career at DTU CERE.

The calculation methods used for the implementation of different routines are described in the book of Michael Michelsen and Jørgen Mollerup [1]. The book and ideas are also used in the PhD course “Thermodynamic Models, Fundamentals and Computational Aspects”.

The ExpertThermo package is a DLL implementation, which can be called from any programming language. Currently, the model has a well explained API and plugin to MATLAB with numerous examples. The framework contains 100 typical components from processing industry ranging from hydrocarbons, gases, amines etc. You can easily implement new components with add-in files and perform the following calculations:

  1. Two-phase flash calculation
  2. Multiphase flash calculations
  3. Bubble and dew points calculation
  4. PT phase envelopes
  5. P-xy and T-xy diagrams
  6. Ternary LLE diagrams at constant T and P

ExpertThermo has a library of the following thermodynamic models and mixing rules.

Equation of State

Activity Coefficient Model

Mixing Rules for SRK/PR



CPA (SRK basis)

CPA (PR basis)


Ideal solution




Modified UNIQUAC

Original UNIFAC


Linear UNIFAC (Linear temperature dependence of interaction coefficients)

Modified UNIFAC (Larsen et al.)

Classical Mixing Rule

Modified Huron Vidal 1

Modified Huron Vidal 2

Modified Huron Vidal Xtrapolate

Huron Vidal

Wong Sandler

It is possible to use the MATLAB routines for different applications. The asphaltene and gas hydrate models have been developed in MATLAB with the same philosophy. The software is currently being developed so that you can use your own thermodynamic models in the above phase calculation routines.

[1] Thermodynamic Models: Fundamentals and Computational Aspects, Michael L. Michelsen & Jørgen Mollerup, Tie-Line Publications, 2008, ISBN : 87-989961-3-4.


Philip Loldrup Fosbøl
Associate Professor
DTU Chemical Engineering
+45 45 25 28 68