A new district energy network has been developed by using CO2 as a heat transfer fluid. Only two pipes are required by the network, thus allowing the recovery of waste heat from the cooling users to be valorized by the heating users. Understanding and predicting the dynamics as well as identifying control methods and strategies is one of the key issues for the development of such a CO2 network that would operate in a safe, reliable and energy efficient manner. To assess the technical feasibility and address the safety problems, a physical-based model was developed to describe the fluid dynamics of CO2 pipelines used for transportation of a fluid near the saturation. Dynamic simulations were carried out to investigate pressure and flow fluctuation during transient flow and under changes of external perturbations. It shows that the system was able to response all these perturbations although the corresponding pressure wave propagates along the pipe.