Exergy analysis of ejector-enhanced dual-evaporator cycle using effective temperature method

Abstract

This study compares the exergy of an ejector-based two evaporator cycle (EB-TEC) with a conventional two evaporator cycle (C-TEC). The analysis utilizes a modified Gouy–Stodola equation, which provides a more accurate insight of the system irreversibility compared to the standard Gouy–Stodola formulation. Furthermore, the comparison includes three working fluids, that is, R134a, R1234ze, and R600 in both the cycles. The study examines the effects of varying evaporators and condenser temperatures and the dryness fraction at the exit of Evaporator 1. The data is analyzed using an Engineering Equation Solver. The findings indicate that increasing the temperature of the low-temperature evaporator leads to a drop in exergy losses and enhancement in exergy efficiency in both the cycles. When the temperature of Evaporator 1 is increased, the total exergy of the EB-TEC is decreased but for the C-TEC, it is increased. Furthermore, increasing the condenser temperature results in higher exergy destruction in both EB-TEC and C-TEC. Notably, the maximum exergy destruction is 49.44 kW for R600, whereas the minimum exergy destruction is 14.42 kW for R1234ze in the EB-TEC.