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A Novel Generator Design Utilised for Conventional Ejector Refrigeration Systems

Department of Applied Mechanics, Faculty of Mechanical Engineering, Technical University of Liberec, Stdentská 1402/2, 46117 Liberec, Czech Republic
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Academic Editors: Xiaolin Wang and Firoz Alam
Energies 2021, 14(22), 7705; https://doi.org/10.3390/en14227705
Received: 29 September 2021 / Revised: 11 November 2021 / Accepted: 13 November 2021 / Published: 17 November 2021
(This article belongs to the Topic Exergy Analysis and Its Applications)
Ejector refrigeration systems are rapidly evolving and are poised to become one of the most preferred cooling systems in the near future. CO2 transcritical refrigeration systems have inherently high working pressures and discharge temperatures, providing a large volumetric heating capacity. In the current research, the heat ejected from the CO2 gas cooler was proposed as a driving heating source for the compression ejector system, representing the energy supply for the generator in a combined cycle. The local design approach was investigated for the combined plate-type heat exchanger (PHE) via Matlab code integrated with the NIST real gas database. HFO refrigerants (1234ze(E) and 1234yf) were selected to serve as the cold fluid on the generator flowing through three different phases: subcooled liquid, a two-phase mixture, and superheated vapour. The study examines the following: the effectiveness, the heat transfer coefficients, and the pressure drop of the PHE working fluids under variable hot stream pressures, cold stream flow fluxes, and superheated temperatures. The integration revealed that the cold fluid mixture phase dominates the heat transfer coefficients and the pressure drop of the heat exchanger. By increasing the hot stream inlet pressure from 9 MPa to 12 MPa, the cold stream two-phase convection coefficient can be enhanced by 50% and 200% for R1234yf and R1234ze(E), respectively. Conversely, the cold stream two-phase convection coefficient dropped by 17% and 37% for R1234yf and R1234ze(E), respectively. The overall result supports utilising the ejected heat from the CO2 transcritical system, especially at high CO2 inlet pressures and low cold channel flow fluxes. Moreover, R1234ze(E) could be a more suitable working fluid because it possesses a lower pressure drop and bond number. View Full-Text
Keywords: ejector; CO2; plate heat exchanger; refrigeration system; pressure drop ejector; CO2; plate heat exchanger; refrigeration system; pressure drop
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MDPI and ACS Style

Elbarghthi, A.F.A.; Hdaib, M.Y.; Dvořák, V. A Novel Generator Design Utilised for Conventional Ejector Refrigeration Systems. Energies 2021, 14, 7705. https://doi.org/10.3390/en14227705

AMA Style

Elbarghthi AFA, Hdaib MY, Dvořák V. A Novel Generator Design Utilised for Conventional Ejector Refrigeration Systems. Energies. 2021; 14(22):7705. https://doi.org/10.3390/en14227705

Chicago/Turabian Style

Elbarghthi, Anas F.A., Mohammad Y. Hdaib, and Václav Dvořák. 2021. "A Novel Generator Design Utilised for Conventional Ejector Refrigeration Systems" Energies 14, no. 22: 7705. https://doi.org/10.3390/en14227705

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