A thermodynamic model is used to analyze a transcritical carbon dioxide heat pump cycle integrating a vortex tube. The objective is to prove that a vortex tube is beneficial in raising heat pump efficiency. The novelty of the current work lies in implementing a sophisticated thermodynamic model of the vortex tube operating with carbon dioxide at high pressures or in a two-phase state. However, for all other components of the heat pump, a commercial library (TIL) associated with the Dymola software is used to simulate the system. A transcritical carbon dioxide conventional heat pump model is validated to determine the feasibility of implementing the TIL library. Then, the vortex tube heat pump is analyzed to test the heat pump performance and the effect of different parameters under various operating conditions. Of the parameters discussed, the hot exit pressure of the vortex tube and the desuperheater glycol mass flow rate are the most effective parameters on the desuperheater heating capacity and the overall coefficient of performance. Meanwhile, the hot exit pressure significantly controls the desuperheater glycol exit temperature, yet, with limitation. On the other hand, the variation of the cold mass fraction shows insignificant changes in the desuperheater glycol exit temperature. The final conclusion is that the heating coefficient of performance of the vortex tube heat pump is improved by a maximum of 43.7% when compared to that of the conventional heat pump.