Study Types
Stationary, time-dependent, and frequency domain studies are available with the Heat Transfer interfaces.
You can consider a heat transfer problem as stationary if the temperature field is independent of time at each point. The system is said to be at thermal equilibrium. It happens when the conditions are independent of time or vary on a time scale large enough so that they can be approximated as constant. This type of study can be used as an initial step for a time-dependent analysis.
For other cases, use a time-dependent or a frequency domain study.
Study and Study Step Types
in the
COMSOL Multiphysics Reference Manual