Hello,

For understanding non-equilibrium thermodynamics the thermodynamic equilibrium has to be understood.

Thermodynamic Equilibrium - A system is in thermodynamic equilibrium if its fundamental properties do not undergo any change with time , i.e., Change in volume, pressure, temperature , no of molecules all equal to zero.

Thermodynamic Non-Equilibrium - This kind of system is actually trying to achieve thermodynamic equilibrium and therefore all the fundamental properties like Volume, Pressure, Temperature and number of moles are undergoing change with respect to time.

So for Thermodynamic Non-Equilibrium >>  Δ V ≠  Δ P ≠ Δ T ≠  Δ n ≠  0 . This is the criteria followed