An experimental investigation of performance and instabilities of the R744 vapour compression rack equipped with a two-phase ejector based on short-term, long-term and unsteady operations

Haida, Michał; Palacz, Michał; Bodys, Jakub; Smołka, Jacek; Gullo, Paride; Nowak, Andrzej J.

doi:10.1016/j.applthermaleng.2020.116353

Cited by 16 publications

(2 citation statements)

References 42 publications

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“…To address this, extensive effort towards novel design, optimisation and operation strategies is needed [35]. Barta et al [36] proposed a design tool for two-phase flow ejectors for vapour compression cycles, while Haida et al [37] experimentally studied performance and instabilities of the R744 vapour compression system equipped with a two-phase ejector. It should be noted that such design tools should consider local-scale fluid dynamics and should be validated against test data [38].…”

Section: Refrigeration and Air Conditioningmentioning

confidence: 99%

Overview and outlook of research and innovation in energy systems with carbon dioxide as the working fluid

Bianchi

Besagni

Tassou

et al. 2021

Applied Thermal Engineering

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Carbon dioxide (CO 2 , R744) is a natural working fluid with interesting thermophysical properties that have stimulated strong attention by the academic and industrial communities for a broad range of energy applications. The technology readiness level of CO 2 -based energy systems is very diverse due to the increasing consideration that the fluid has been receiving since the 1990s. Hence, the state of the art in CO 2 energy research spans from fundamental thermofluid and chemistry science to commercial system innovations. After a brief compendium on ongoing activities, this paper proposes a roadmap for CO 2 energy research with reference to the cooling, heating and power sectors. The key knowledge gaps and the main challenges at system and component levels are critically discussed. Pathways to advance the understanding and the technological maturity of CO 2 energy systems are also outlined.

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Section: Refrigeration and Air Conditioningmentioning

confidence: 99%

Overview and outlook of research and innovation in energy systems with carbon dioxide as the working fluid

Bianchi

Besagni

Tassou

et al. 2021

Applied Thermal Engineering

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show abstract

“…Much of the recent work on two-phase ejectors has been focused on the transcritical CO 2 cycles as this substance has a larger throttling loss than most other refrigerants [7][8][9][10][11][12]. In addition, recently, the refrigerants R134a and R1234yf in refrigeration applications with ejectors have been investigated more [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Experimental Assessment of the Efficiency of Two-Phase Ejector Components for Isobutane

et al. 2022

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Two-phase ejectors as well as single phase ejectors can be applied in many branches of industry: refrigeration and heat pump systems, chemical engineering, food processing, and others. Due to the complicated nature of the process of momentum transfer in two-phase ejectors, their design procedure based on the accurate theoretical prediction of the ejector performance is still an open issue. The paper provides its own experimental results of the velocity coefficients of the components of the two-phase ejector, i.e., the motive nozzle, suction chamber, mixing chamber, and diffuser. The results were obtained in the case of isobutane as the working fluid. It was demonstrated that the velocity coefficients may not be treated as constant quantities. Therefore, our own proposed dimensionless relationships describe the velocity coefficients of the components of the ejector that may be applied in the design procedure of the ejector. The two physical parameters, the wet vapour quality and the volumetric entrainment ratio, were selected as the key parameters. In addition, the aspects of the prediction of the critical mass flow rate of the motive nozzles was considered on the basis of the Henry–Fauske model. It was demonstrated that the model accurately predicts the two-phase critical flow under the conditions of a higher range of wet vapour quality.

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Experimental and numerical study on the R744 ejector with a suction nozzle bypass

Bodys

Smołka

Palacz

et al. 2021

Applied Thermal Engineering

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An experimental investigation of performance and instabilities of the R744 vapour compression rack equipped with a two-phase ejector based on short-term, long-term and unsteady operations

Cited by 16 publications

References 42 publications

Overview and outlook of research and innovation in energy systems with carbon dioxide as the working fluid

Overview and outlook of research and innovation in energy systems with carbon dioxide as the working fluid

Experimental Assessment of the Efficiency of Two-Phase Ejector Components for Isobutane

Experimental and numerical study on the R744 ejector with a suction nozzle bypass

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