Abstract- This study focuses on the exergy and energy analysis of the general power plant system containing vapor- compressor cycles. As the result of the exergy analysis, the amount of irreversibility of the interior of each subsystem is computed and the efficiency of the total system is improved by optimizing manipulated variables of subsystems which include the most dominant exergy loss. The energy analysis based on the first law of thermodynamics shows that the condenser is the most dominant part of the energy loss. On the other hand, the exergy analysis based on the second law of thermodynamics shows that the boiler is optimized for reducing the energy loss in practice and improving the efficiency of the total power plant system. yEXERGY, a user friendly program, is also developed for the analysis of the general power plant system.