The compressor model used in the dynamic simulation of refrigeration system should not only be applicable in the case that the state of the sucked refrigerant varies in a wide range of vapor to two-phase

and also be quick enough in predicting the major dynamic characteristics of the compressor. In order to meet these requirements

a quasi-dynamic hermetic compressor model covering the suction state from vapor to two-phase was presented in this paper. According to its thermodynamic process

the compressor model includes

a dynamic model for the mixing process of refrigerant inside compressor and sucked two-phase or vapor refrigerant

a dynamic model for the compressor shell heat transfer model

and a steady state model for the polytropic compression.The compressor model overcomes the flaw of unreasonable mass flow of the existing models caused by neglecting the mixing process of refrigerant inside of compressor. The maximum differences of steady state mass flow rate and input power of a hermetic compressor between the experimental data and the predicted results are less than 5%

while the deviations of the predicted transient mass flow rate and input power from the experimental data are within 10%.