CO_2 Trans-Critical Two-Stage Compression System with Inter-Stage Cooler

The performance of two-stage compression system with inter-stage cooler was studied theoretically.At the given evaporating temperature and outlet temperature of gas cooler,there exists an optimum discharge pressure of compressor,leading to the optimum performance.Meanwhile,under each discharge pressure of compressor,there also exists an optimum intermediate pressure.The inter-stage cooler was designed and simulated with the selected heat transfer and pressure drop correlation of super-critical and sub-critical CO2 in or out of tube.A two-stage compression system with inter-stage cooler was established to study the rules of this system.The experimental results indicate that the two-stage compression system with inter-stage cooler has the optimum compressor discharge pressure and the op-timum intermediate pressure,and that it can also improve the performance of CO2 trans-critical system.By using the self-designed inter-stage cooler,the COP can reach 2.5 and COPh 3.5 under the experimental condition.