THE STUDY OF A TWO-STAGE COMPRESSION CO_2 CYCLE WITH TWO DIFFERENT TEMPERATURE EVAPORATORS

摘要

The basic simulation research on the performance of two-stage compression cycle with two different temperature evaporators using CO_2 has carried out with variable operating condition. The performance characteristics and comparison of the two-stage CO_2 cycle with outdoor temperature, middle pressure, 1st-and 2nd-stage EEV opening have analyzed in order to improve the understanding for thermodynamic CO_2 cycle characteristics and provide the basic performance data for developing high performance system. As a result, the cooling COP increases as the middle pressure rises until 4.1 MPa and it improves with the increase of 1st-stage EEV opening. However, the cooling COP decreases when the outdoor temperature and 2nd-stage EEV opening increases for given operating conditions.