Recently, a 1D lumped-CFD (Computational fluid dynamics) coupled model has been used for thermal analysis of refrigerant compressors. However, this model assumes that only the piston is in motion, assuming the other part is stationary. Therefore, it is difficult to simulate the transient refrigerant flow caused by the internal body vibration due to the spring inside the compressor. In this paper, we apply the momentum source to the 1D lumped-CFD coupled model to simulate the unsteady flow caused by the spring. The results showed that the coupled mode with momentum source successfully predicts heat transfer enhancement due to spring vibration.