Improvement of Absorption Refrigeration Cycle Efficiency Using a Novel Diffuser Configuration and Ionic Liquid Working Pairs

The growing demand for cooling is contributing to a global energy challenge, making it essential to improve the efficiency of cooling systems to lower greenhouse gas (GHG) emissions and operational costs. This study focuses on optimizing the absorption refrigeration cycle (ARC) to enhance performance and minimize energy consumption. A novel system, the diffuser absorption refrigeration cycle (D‐ARC), has been developed to achieve this objective. In this system, a diffuser is positioned between the evaporator and the absorber, resulting in higher pressure in the absorber compared to the evaporator. This increased absorber pressure reduces the circulation ratio and boosts efficiency. The study determines the coefficient of performance (COP), the exergetic coefficient of performance (ECOP), and the circulation ratio (f) for the D‐ARC system at various generator temperatures. These calculations consider both traditional working pairs (NH3/H2O) and different ionic liquid working pairs, including NH3/[EMIM][BF4], NH3/[DMIM][DMP], and NH3/[EMIM][ETSO4]. A comparative analysis of d ‐ARC, E‐ARC, and ARC reveals that the d ‐ARC system achieves superior COP and ECOP values. The highest COP and ECOP values are observed with the working pair NH3/[EMIM][BF4] (COP: 0.85, ECOP: 0.35), whereas the lowest values are found with the NH3/H2O pair (COP: 0.63, ECOP: 0.26). With the rising global demand for cooling, there is an urgent need to improve the efficiency of refrigeration systems to reduce greenhouse gas emissions and energy consumption. This study presents a novel configuration of the absorption refrigeration cycle, referred to as the diffuser–absorption refrigeration cycle (D‐ARC). In this system, a diffuser is introduced between the evaporator and the absorber, which raises the absorber pressure. This design lowers the circulation ratio and improves the overall performance of the system. To assess the effectiveness of this approach, the study analyzes the coefficient of performance (COP), the exergetic coefficient of performance (ECOP), and the circulation ratio (f) under different generator temperatures. The evaluation is carried out using both a conventional working pair (NH₃/H₂O) and several ionic liquid–based working pairs—NH₃/[EMIM][BF₄], NH₃/[DMIM][DMP], and NH₃/[EMIM][ETSO₄]. Results show that the d ‐ARC consistently outperforms conventional ARC and ejector‐based E‐ARC systems, with the NH₃/[EMIM][BF₄] pair achieving the highest COP (0.85) and ECOP (0.35). This study is unique in combining a diffuser‐driven pressure boost with environmentally friendly ionic liquids to enhance system efficiency. The proposed system holds strong potential for applications in waste heat recovery and solar‐powered cooling, particularly in remote or industrial areas with limited access to electricity. The outcomes of this study offer valuable insights for future research and development in sustainable refrigeration technologies.