This information is part of the Modelica Standard Library maintained by the Modelica Association.

This example consists of a volume with a carbon dioxide concentration that corresponds to 1.519E-3 kg/kg, which is equal to 1000 PPM. There is a fresh air stream with a carbon dioxide concentration of about 300 PPM. The fresh air stream is such that the air exchange rate is about 5 air changes per hour. After 1 hour of ventilation, the volume's carbon dioxide concentration is close to the concentration of the fresh air.

The nominal value for the trace substance is set to C_nominal={1.519E-3}. This scales the residual equations that are used by the solver to the right order of magnitude.