Entropy Balance Equation: Entropy Generation Through Viscous Friction Description: Entropy is spontaneously generated due to several reasons - friction, heat transfer across finite temperature difference, flow of electricity across a resistnace, mixing, chemical reaction, etc. These mechanisms of entorpy generation are lumped into a single term, generalized friction, in the textbook.  In this steady closed system, the heat loss balances the shaft work transfer into the system. Where does the entropy that is tranferred by heat into the surroundings come from? It is generated through viscous friction as high quality work is dissipated into internal energy of the system.