To access the functionality for thermodynamic calculations, right-click the Global Definitions node in the
Model Builder tree and select
Thermodynamics (
![](images/chem_ug_thermo.11.04.1.png)
). Using the Reaction Engineering or Chemistry interfaces,
Thermodynamics is also available on the
Reaction Engineering toolbar.
![](images/chem_ug_thermo.11.04.2.png)
Select Thermodynamic System in the context menu to add a thermodynamic system that uses the database included in the Chemical Reaction Engineering Module.
As an alternative, selecting External Thermodynamic System can make use of an installed thermodynamics software to make the corresponding calculations.
Use User-Defined Species to add new species that are not available in COMSOL database. You can also edit available species in the database.