In this study, fast filling process of NGV cylinders is simulated in a FORTRAN based computer program. In this model, AGA-8 equation of state was utilized to compute compressibility factor and other required thermodynamic properties such as internal energy, enthalpy and specific heats of natural gas. The accuracy of model was evaluated by comparing the acquired results with real data. The real data was gathered for three kinds of NGV tanks at a CNG station. Our comparison demonstrated that, there is a reasonable agreement between modeling and experimental data at the whole charging period. Furthermore, it is demonstrated that temperature elevation of natural gas during the fast filling process is the main factor to prevent the 100% full fill in each refueling.
