The Artificial Ground Freezing method (AGF) has been widely used for both civil engineering and mining applications for ground stabilization and water control. In AGF models, the thermal boundary conditions at the freeze pipe wall strongly depend on the cooling conditions and on the heat transfer between the pipe and the ground. These boundary conditions are generally determined based on in situ measurements, which are not readily available. This paper presents a new approach where coupling between the thermal problem in the pipe and in the surrounding ground is numerically modeled. Parametric studies highlight the influence of the operating conditions. Finally, the interest of the proposed new approach is twofold: (i) it im- plicitly determines the boundary conditions of the AGF model and (ii) it enables an optimization of the cool- ing conditions for freeze pipes.