DESIGN AND CONTROL OPTIMIZATION OF R32 TWO-PHASE INJECTION SYSTEM USING SCROLL COMPRESSOR ORIENTED TO DISCHARGE REMPERATURE AND SYSTEM PERFORMANCE

摘要

Two-phase refrigerant injection is a promising method to decrease discharge temperature of R32 compressor in severe conditions. In this work, an improved injection system with economizer was proposed to realize two-phase injection. Based on the validated distributed-parameter model of R32 scroll compressor and the steady-state cycle model, the optimization of heat transfer capability of internal heat exchanger and intermediate pressure according to system performance and discharge temperature was discussed. It is revealed that the intermediate pressure can be optimized by controlling the discharge temperature to safe limit (135℃). Through the design and control optimization of the two-phase injection system, the cooling capacity was enhanced by 7.1%～11.4% and COP was improved by 2.6%～6.2%.