"About ThermoSolver" window.

ThermoSolver is a software program which accompanies the textbook Engineering and Chemical Thermodynamics by Milo Koretsky [1]. The software was developed as part of the Honors Baccalaureate of Science thesis [2] of Connelly Barnes, a student of computational physics and mathematics. This software allows students to perform complex thermodynamics calculations, and explore thermodynamics for systems which would be impossible to solve without a significant investment in programming.

Table of Contents
5.Integration with textbook


The program can be downloaded from the website of the publisher: John Wiley & Sons. ThermoSolver runs on Windows 95 or later.


Printout of various Gibbs energy models fit to an isothermal vapor-liquid system.
  • Thermodynamic properties for 350+ compounds are provided.
  • Saturation pressure calculator can be used with 338 species in the database.
  • Solver for the Peng-Robinson and Lee-Kesler equations of state is provided.
  • Fugacity coefficients can be solved for pure species or mixtures.
  • Models for Gibbs energy can be fit to isobaric or isothermal vapor-liquid equilibrium data. Sample data sets are provided. The results can be plotted.
  • Bubble-point and dew-point calculations can be made.
  • Equilibrium constant (KT) solver is provided.
  • General chemical reaction equilibria solver is provided.
  • Equations used in the calculation process can be viewed.


Main menu.
Choosing an isothermal sample data set for a binary vapor liquid system.
An activity coefficient model and objective function are chosen. The best-fit parameters are found.
Various plots can be made.
A plot of the best Wilson model fit for the chloroform (a) - heptane (b) system.
HTML documentation gives the thermodynamic equations and algorithms used for every component of the software.
Back at the main menu.
Choose to make a binary phase diagram.
Select species (a) and (b). Wilson parameters for 470+ systems are pre-entered.
Again, various plots can be created.
Pressure vs xa (red) and ya (green) at 40 °C.
Equation of state solver solves Lee-Kesler and Peng-Robinson equations of state.
The KT solver, here used to solve a methanol combustion reaction.
A plot of KT vs 1/T. The in-program plots can be printed: here the plot was printed to a PDF writer print device.
Reaction equilibria calculator: uses minimization of gE technique developed in Section 9.6.3 of the textbook.
The solved equilibrium system.
A fugacity coefficient solver, uses Peng-Robinson and Lee-Kesler equations of state.
Saturation pressure calculator, uses Antoine coefficients, which are available for almost every species in the database.
A dew point calculation.
This system happens to obey Raoult's law. That fact can be verified by comparison with more complex thermodynamic models.


ThermoSolver provides context-sensitive HTML documentation. Press F1 at any time to get help on the current window. For the documentation table of contents, choose "Documentation" from the ThermoSolver programs menu in the Start bar, or press F1 at the ThermoSolver main menu. The Thermodynamic Principles section of the documentation explains the relevant thermodynamic equations and the algorithm used to solve the system. The References section cites the sources from which the software's databases were developed.

Integration with textbook

Sixteen problems in the textbook ask the student to use ThermoSolver. Often these problems extend simple problems to more complex thermodynamic models, or ask the student to solve a complex thermodynamic system such as a dew point system which does not obey Raoult's law. Several examples in the textbook use ThermoSolver to derive saturation pressure values or solve nonlinear systems.

In the textbook, on pp. 345-347, sixteen binary vapor-liquid gE systems are randomly chosen from the DECHEMA data collection, and the best-fit models for the textbook software are compared with those reported by DECHEMA. Maximum and average pressure deviations for the software and DECHEMA are approximately equal, except for the water-acetic acid system, where DECHEMA corrects for gas-phase association, whereas the text software does not.


Questions and comments about the software should be directed to Milo Koretsky.


  1. Koretsky, Milo. Engineering and Chemical Thermodynamics, 1st Ed., Wiley (2003). (Website).
  2. Barnes, Connelly. ThermoSolver: An Integrated Educational Thermodynamics Software Program. H.B.S. thesis, defended June 2, 2006. Oregon State University Library: Special Collections. (PDF).

All content Copyright 2006 Milo Koretsky.