thermodynamic process that returns a system to its initial state is a cyclic process. In this process, the initial and the final state is the same. For a cyclic process, the total change in the internal energy of a system is zero. or In a cyclic process, the system starts and returns to the same thermodynamic state. ... A cyclic process is the underlying principle for an engine. If the cycle goes counterclockwise, work is done on the system every cycle. An example of such a system is a refrigerator or air conditioner.