Exergy, exergoeconomic and exergoenvironmental studies and optimization of a novel triple-evaporator refrigeration cycle with dual-nozzle ejector using low GWP refrigerants

Abstract

In this work, a novel dual-nozzle ejector enhanced triple-evaporator refrigeration cycle (DETRC) without separator is proposed to improve the performance of the conventional ejector one (CETRC). The performance of DETRC is analyzed and compared with CETRC in term of energy coefficient of performance (COP_en). Under given operating conditions, the COP_en improvement of the novel cycle could reach about 24.35% which shows the excellent energy-saving potential of DETRC in comparison with CETRC. Then, a comprehensive comparison between R717, R600a, R1234yf and R290 as low global warming potential (GWP) refrigerants of DETRC is conducted from the energy, exergy, economic and environmental impact (EI) aspects. It is observed that R717 gives better energetic and exergetic performances by 3.21 and 0.583 and R1234yf causes the lowest total product cost and EI rates of 8.186 $/h and 0.665 Pts/h, respectively for DETRC. Moreover, increasing the high evaporating temperature improves all desired performances of DETRC, simultaneously due to the reduction of compressor consumed power. Finally, a multi-objective optimization based on an evolutionary algorithm and LINMAP decision making are carried out to ascertain the optimum exergetic, economic and EI performances of DETRC for each refrigerant.