Auto-cascade refrigeration systems: A key review with energetic and exergetic perspectives

Abstract

Auto-cascade refrigeration (ACR) systems are known for their innovative solutions, especially suitable for low and ultra-low-temperature applications. However, ACR cycles are not solely confined to refrigeration applications; they are also utilized in heating and electricity generation cycles. While the fact that this subject has been addressed in only two studies in the literature reveals the gap in this regard, this study offers an important contribution by comprehensively reviewing ACR systems in terms of energy, exergy, exergoeconomics, and exergoenvironmental aspects for the first time to the best of the authors’ knowledge. This review also differs from others in that it categorizes ACR cycles in their most general form and outlines basic operating principles not covered in previous reviews, such as not only refrigeration but also heating and electricity generation. Modifications aimed at improving ACR cycle performance are then summarized, covering both experimental and theoretical studies available in the literature. This review paper also addresses the selection of refrigerants. Another unique aspect of this study is its examination of the refrigerant mixtures used in ACR cycles based on the type of application and the improvements they involve. Finally, to illustrate the obtained results from review, the study concludes with an illustrative example, where an ACR cycle is modelled for performance evaluation in terms of energetic and exergetic aspects. This work is expected to be highly beneficial for individuals interested in the design, simulation, analysis, and performance assessment of ACR cycles.