Full-scale multi-ejector module for a carbon dioxide supermarket refrigeration system: Numerical study of performance evaluation

Bodys, Jakub; Palacz, Michał; Haida, Michał; Smołka, Jacek; Nowak, Andrzej J.; Banasiak, Krzysztof; Hafner, Armin

doi:10.1016/j.enconman.2017.02.007

Cited by 55 publications

(16 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The various constraints of a single ejector system can be overcome by the multi-ejector concept discussed by Hafner et al [48] and later developed by Banasiak et al [49], experimentally analysed by Haida et al, [50] and numerically studied by Body et al [51]. The multi-ejector system discussed in these studies consists of a pack of ejectors placed in parallel as shown in Figure 15.…”

Section: Mechanical Expandermentioning

confidence: 99%

See 1 more Smart Citation

CO2 Refrigeration and Heat Pump Systems—A Comprehensive Review

2019

View full text Add to dashboard Cite

An increased awareness of the impacts of synthetic refrigerants on the environment has prompted the refrigeration industry and researchers worldwide to seek better alternatives in terms of technical, economic and environmental performance. CO2 refrigerant, also known as R744, has re-emerged as a potential alternative to existing refrigerants with its zero ozone depletion potential (ODP) and impressively low global warming potential (GWP). A refrigeration system utilising this refrigerant, however, suffers performance degradation when it operates in warm or hot climatic regions due to its inevitable operation in the supercritical region. In addition, the CO2 refrigerant properties necessitate the need for components designed to withstand very high operating pressures. These challenges have not been let unnoticed; related industries and researchers are actively involved in research and development of various components and systems which in turn encourages increased applications of these systems. In this paper, a comprehensive review of CO2 refrigeration systems and the state of the art of the technology and its applications in various industries is presented. In particular, the paper reviews recent research and developments on various aspects of CO2 systems including cycle modifications, exergy analysis of the systems, system modelling, transcritical operation consideration and various existing and potential applications.

show abstract

Section: Mechanical Expandermentioning

confidence: 99%

“…It was also observed that the compression efficiency is affected by the cooling load and heat rejection. Danfoss [52], which is supported by SINTEF Energy research [51], has developed various multi-[vapor and liquid] ejector products which it claims to improve the performance of CO 2 systems.…”

Section: Compression Stagingmentioning

confidence: 99%

CO2 Refrigeration and Heat Pump Systems—A Comprehensive Review

2019

View full text Add to dashboard Cite

show abstract

“…However, until relevant data based on the experimental tests focused on the local flow field visualisation will be available such a verification process is not possible. Nevertheless, the employed approach of the turbulence modelling was successfully validated in the study of R744 ejector optimisation (Palacz et al 2017) and multi-ejector block simulations (Bodys et al 2017). For this reason, the realisable k-ε model was utilised in this study as well.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…The multi-ejector module mentioned in the previous paragraph was evaluated numerically in the work of (Bodys et al 2017). The parallel work of the ejectors examined including motive, suction and outlet collectors was based on the 3-D simulations.…”

Section: Introductionmentioning

confidence: 99%

Performance improvement of the R744 two-phase ejector with an implemented suction nozzle bypass

Bodys

Smołka

Banasiak

et al. 2018

International Journal of Refrigeration

Self Cite

View full text Add to dashboard Cite

In this study, the concept of an R744 ejector with a bypass duct of a suction nozzle was presented. The design of the geometry and bypass positioning in a mixing section, and the idea of regulation, as well as integration, with a suction nozzle duct was described. A preliminary numerical analysis of the proposed bypass geometry was also presented. The computational platform ejectorPL integrated with an extensively validated mathematical model of transcritical R744 two-phase flow was used. Motive nozzle inlet and suction nozzle inlet conditions reflecting gas cooler and evaporator conditions characteristic of large systems, such as supermarket refrigeration units, were examined. Three different separation pressures in liquid receivers were assumed for two bypass geometries and six bypass inlet positions. The bypass positioning as a function of a mixer length was presented. Uniquely positive results were obtained for the lowest pressure conditions. Namely, the increment of the suction mass flow rate was substantial and equal to 36.9% for the bypass angle of 19°. Hence, the bypass implementation resulted in distinct potential of an efficiency improvement-from 22.2% to 30.4%. A higher pressure lift case did not result in any improvement of the ejector work. The influence of the bypass geometry on the overall ejector efficiency was preliminarily characterised. Finally, the pressure distribution in the bypass type ejector was described.

show abstract

“…With the advantages of a concise structure, low energy consumption, and high reliability, the ejector is extensively utilized in a number of industrial applications such as refrigeration systems [1][2][3][4], fuel cell systems [5] and multi-effect distillation desalination systems [6,7]. The ejector is formed from five parts: a primary nozzle; a suction chamber; a constant-pressure mixing chamber; a constant-area mixing chamber; and a diffuser (displayed in Fig.…”

Section: Introductionmentioning

confidence: 99%