Performance Analysis of Two-Phase Constant Pressure Ejector Used in Ejector Expansion Refrigeration System (EERS)

Abstract

As the urgency to reduce high-grade energy consumption grows, it is crucial to investigate innovative alternatives to energy-intensive technologies like vapor compression refrigeration. One promising approach is the integration of a two-phase ejector in place of the traditional throttle valve, which can significantly lower power usage in standard vapor compression refrigeration systems. This study focuses on designing a constant-pressure two-phase flow ejector and assessing the performance of an ejector expansion refrigeration system using R134a as the refrigerant. To optimize performance, a simulation program was created to analyze how various operating and geometric parameters of the ejector affect system efficiency. A comparison with existing experimental data revealed that the developed model can accurately predict the system's coefficient of performance (COP). Notably, the COP improved by 8.86% when the evaporator temperature was raised from -25°C to 20°C and by 14% when the condenser temperature increased from 30°C to 70°C. Furthermore, the study provides correlations for sizing the key parameters of the ejector based on operating conditions, system cooling capacity, and ejector efficiencies.