This article introduces the energetic macroscopic representation (EMR) as approach for the dynamic nonlinear modeling of a reciprocating air compressor. EMR has been introduced recently for research development in complex electromechanical systems. It is based on action reaction principle, which organizes the system as interconnected subsystems according to the integral causality. The graphical modeling based on EMR has advantages such as readability, modularity, structural and functional characteristics. The EMR is the first step toward model-based control structure development. The air compressor system containing: slider-crank mechanism, cylinder head and valves, is divided into multitude simple subsystems. Each subsystem describes an elementary step of the energy conversion, several of these blocks may occur in a single module. Calculations are carried out using two basic principles: mass and energy balances. Models are developed for different subsystems, which are assembled into a final overall system EMR. The EMR modeling presented here allows the modeling of multi-physics components and highlights the interactions of the electromechanical, thermodynamical, heat transfer and fluidic phenomena that occur simultaneously in an air compressor.