Performance Analysis of Single-Stage and Vapor Injection Transcritical CO2 Refrigeration Cycles: Energy, Exergy, and Component-Wise Evaluation
Articles > Article · 2026
Authors: İbrahim KARAÇAYLI
Afyon Kocatepe Üniversitesi Fen Ve Mühendislik Bilimleri Dergisi, National Refreed University Journal, National, TR DİZİN (ULAKBİM), 2026, vol 26, pp 790-801
DOI: 10.35414/akufemubid.1878224
Summary
<p><span style="color: rgb(15, 23, 42); background-color: rgb(248, 250, 252);">This study investigates the energy and exergy performance of single-stage and vapor injection transcritical CO₂ refrigeration cycles under different operating conditions. The analysis includes low and moderate evaporation temperatures and various gas cooler pressures. The vapor injection cycle consistently shows lower compressor power consumption and reduced total exergy destruction compared to the single-stage cycle. At low evaporation temperatures, the compressor power and total exergy destruction decrease by about 32% and 46%, respectively. At moderate temperatures, the vapor injection cycle also achieves higher COP and exergy efficiency, increasing by 13.1% and 11.0% at the optimum gas cooler pressure. Although the heat rejected from the gas cooler and its thermal exergy slightly decrease, the reduction is small compared to the gains in system performance. Component-wise analysis shows that the throttle valve is the main source of irreversibility in both cycles, and its absolute exergy destruction is reduced significantly with vapor injection. Overall, the results demonstrate that the vapor injection transcritical CO₂ cycle provides improved energy and exergy performance while maintaining considerable potential for waste heat utilization.</span></p>