Performance analyses of novel two-phase ejector enhanced multi-evaporator refrigeration systems

摘要

In the present study, four novel layouts (namely EECRS1, EECRS2, EECRS3 and EECRS4) of three evaporator two-stage compression refrigeration system have been proposed using double two-phase ejectors. Thermodynamic analysis and ejector area ratio optimization have been done to study the effects of cycle operating temperature and evaporator load distribution on the cycle and ejector performance parameters. Performance comparisons with basic valve expansion two-stage compression, ejector enhanced single-stage compression and basic valve expansion single-stage compression three evaporator refrigeration systems are presented as well. Study shows that for typical combination of air-conditioning (5 degrees C), refrigeration (-20 degrees C) and freezing (-40 degrees C) applications, proposed refrigeration cycles yield the COP enhancement of about 20% compared to basic valve expansion two-stage compression, 67% compared to ejector enhanced single-stage compression and 117% compared to basic valve expansion single-stage compression system. Volumetric cooling capacity also improves significantly. Within proposed layouts, EECRS4 is most efficient; however, the operation is more challenging than others. Simulation results also reveal that the performance improvement is more sensitive with cooling load distribution compared to operating temperature. Present study may serve as a good guideline for promising use of ejector in three-evaporator system. (C) 2016 Elsevier Ltd. All rights reserved.