Ibrahim KaracayliLutfiye AltayArif HepbasliKaracayli, IbrahimHepbasli, ArifAltay, Lutfiye2025-10-0620250957-58201744-359810.1016/j.psep.2024.11.1052-s2.0-85210642322http://dx.doi.org/10.1016/j.psep.2024.11.105https://gcris.yasar.edu.tr/handle/123456789/7399https://doi.org/10.1016/j.psep.2024.11.105The two primary challenges in auto-cascade refrigeration (ACR) cycles are high compressor discharge temperatures and low efficiency at ultra-low temperatures. This study proposes a modified cascade refrigeration cycle (MCR) combined with an ACR cycle for cooling to -60 degrees C. The innovative aspect of this work is to improve the ACR performance with simpler designs without increasing the system complexity contrary to the common trend. For the high-temperature cycle (HTC) a dual evaporator refrigeration cycle with R1234yf is used while an ACR cycle is used for the low-temperature cycle (LTC). Environmentally friendly refrigerant mixtures such as R170/ R290 R170/R600a and R170/R600 were analyzed using energy exergy and exergoeconomic methods. The results show that compared to R23/R134a the R170/R600 significantly improves the performance of the MCR by increasing the COP and exergy efficiency by 24.0 % and reducing the exergy destruction by 26 % unit cooling cost by 11.2 % and total investment cost by 9.7 %. Moreover when compared with theoretical studies COP improvements range from 38.7 % to 94.1 % demonstrating the importance and superiority of the system proposed in this study.Englishinfo:eu-repo/semantics/closedAccessCascade refrigeration, Auto-cascade, Compressor discharge temperature, Environmentally friendly, Zeotropic mixtureTHERMODYNAMIC PERFORMANCE, EJECTOR, SYSTEM, OPTIMIZATIONCascade RefrigerationAuto-cascadeEnvironmentally FriendlyCompressor Discharge TemperatureZeotropic MixtureArticle