Thermodynamic modeling of an improved transcritical carbon dioxide cycle with ejector: Aiming low-temperature refrigeration

Purjam, Mojtaba; Thu, Kyaw; Miyazaki, Takahiko

doi:10.1016/j.applthermaleng.2020.116531

Cited by 22 publications

(6 citation statements)

References 57 publications

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“…The mixed fluid after the mixing section is supersonic, so there will be a shock in the constant area mixing chamber. In the one-dimensional calculation model, it is simply assumed that the complex shock wave phenomenon is a normal shock wave [7], and the calculation equation is as follows: Where the 𝜌 12 is the density of the mixed fluid at the outlet the constant pressure mixing chamber, ℎ 𝑠𝑘 , 𝑢 𝑠𝑘 , 𝜌 𝑠𝑘 are the enthalpy, velocity, and density of the mixed fluid after the shock wave occurs. The pressure of the mixed fluid increases and the velocity decreases after passing through the diffusion.…”

Section: ( )mentioning

confidence: 99%

Thermal analysis of 4 K J-T cryocooler equipped with an ejector

Hu,

Wang,

Wang

et al. 2024

IOP Conf. Ser.: Mater. Sci. Eng.

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This paper introduces a 4 K Helium Joule-Thomson (J-T) refrigeration system equipped with ejector technology to enhance thermodynamic efficiency, reduce the lowest cold head temperature, and avoid higher compressor suction pressure. The J-T cryocooler, pre-cooled by a Stirling cryocooler, typically requires a high compression ratio when operating at 4 K or below. The ejector serves as a device that converts pressure energy into kinetic energy, enabling it to draw in secondary fluid and then reconvert kinetic energy into pressure energy, thus increasing the pressure of the low-pressure fluid. To investigate the impact of the ejector on J-T refrigerator performance, this study employs a one-dimensional theoretical calculation. The results are used to establish a performance chart of the J-T refrigeration system with an ejector, which is compared to the system without an ejector. The analysis reveals a promising 10-20% improvement in performance with the ejector technology implemented.

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Section: ( )mentioning

confidence: 99%

Thermal analysis of 4 K J-T cryocooler equipped with an ejector

Hu,

Wang,

Wang

et al. 2024

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Commercial solutions for CO 2 refrigeration systems are currently available in the market and gained increased popularity for applications at low and moderate temperature climates. The most popular application sector is supermarket refrigeration, in which CO 2 systems have prevailed over systems with alternative refrigerants due to lower footprint and environmental impacts, and capability to achieve low temperatures [28]. At warm climates, CO 2 refrigeration and air conditioning applications experience techno-economic challenges due to the complexity of the transcritical cycles and additional components (e.g.…”

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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“…Most basic exergy expression; 293 (4) where h 0 and s 0 refers to values of enthalpy and entropy at the environmental temperature T 0 . Compressor; Compressor workload is [11]; (5) The exergy recovered in the compressor is; (6) The exergy loss of the compressor is; (7) Evaporator;…”

Section: Thermodynamics Analysismentioning

confidence: 99%

“…COP is 1.4 for evaporator temperature 45 •C in their study. They determined that this presented cycle can not reach a reasonable performance for deep-freezing applications [6]. Elbarghthi et al were carried out exergy analysis of the transcritical CO 2 cooling system with ejector.…”

Section: Introductionmentioning

confidence: 99%

Energy and Exergy Analysis of Transcritical Carbon Dioxide Refrigeration Cycle

Kılıç¹

2021

El-Cezeri Fen Ve Mühendislik Dergisi

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The effects of conventional refrigerants on ozone layer and its effect on global warming are known. Refrigerants based on chlorofluorocarbons (CFC) and hydrochlorofluorocarbons (HCFCs) have been used in refrigeration systems for a long time and are still being used. Instead of these refrigerants, the use of natural refrigerants which are much less harmful to the environment, has been given importance. Carbon dioxide is the first that comes to mind among these fluids. In this study, energy and exergy analysis of transcritical carbon dioxide refrigeration cycle examined as theoretically. Energy and exergy analysis were made for different evaporator temperatures and outlet temperatures from gas cooler. Exergy losses of each component of the transcritical carbon dioxide refrigeration cycle were determined. In addition, the first and second law efficiencies of the refrigeration cycle were determined. When the evaporator temperature is -5 o C and the outlet temperature from the gas cooler is 20 o C, the highest exergy efficiency value was determined as 41.19 in this study.

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Thermodynamic modeling of an improved transcritical carbon dioxide cycle with ejector: Aiming low-temperature refrigeration

Cited by 22 publications

References 57 publications

Thermal analysis of 4 K J-T cryocooler equipped with an ejector

Thermal analysis of 4 K J-T cryocooler equipped with an ejector

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

Energy and Exergy Analysis of Transcritical Carbon Dioxide Refrigeration Cycle

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