Ibrahim KaracayliLutfiye AltayA. Hepbasli2025-10-06202509575820, 174435980957-582010.1016/j.psep.2024.11.105https://www.scopus.com/inward/record.uri?eid=2-s2.0-85210642322&doi=10.1016%2Fj.psep.2024.11.105&partnerID=40&md5=9c4d630649c2d52ed37a5fe88eb666bdhttps://gcris.yasar.edu.tr/handle/123456789/8051The 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 ℃. 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. © 2024 Elsevier B.V. All rights reserved.EnglishAuto-cascade, Cascade Refrigeration, Compressor Discharge Temperature, Environmentally Friendly, Zeotropic Mixture, Energy Efficiency, Environmental Impact, Auto-cascade, Auto-cascade Refrigeration, Cascade Refrigeration, Comparative Analyzes, Compressor Discharge Temperature, Discharge Temperature, Environmentally Friendly, Refrigeration Cycles, Zeotropic Mixture, Zeotropic Refrigerant Mixtures, ExergyEnergy efficiency, Environmental impact, Auto-cascade, Auto-cascade refrigeration, Cascade refrigeration, Comparative analyzes, Compressor discharge temperature, Discharge temperature, Environmentally friendly, Refrigeration cycles, Zeotropic mixture, Zeotropic refrigerant mixtures, ExergyArticle