Multi-Ejector Concept: A Comprehensive Review on its Latest Technological Developments

Paride Gullo, Armin Hafner, Krzysztof Banasiak, Silvia Minetto and Ekaterini E. Kriezi
Additional contact information
Paride Gullo: Department of Energy and Process Engineering, NTNU Norwegian University of Science and Technology, Kolbjørn Hejes vei 1D, 7491 Trondheim, Norway
Armin Hafner: Department of Energy and Process Engineering, NTNU Norwegian University of Science and Technology, Kolbjørn Hejes vei 1D, 7491 Trondheim, Norway
Krzysztof Banasiak: Department of Thermal Energy, SINTEF Energy Research, Kolbjørn Hejes vei 1A, 7491 Trondheim, Norway
Silvia Minetto: Construction Technology Institute, CNR National Research Council of Italy, Corso Stati Uniti 4, 35127 Padua, Italy
Ekaterini E. Kriezi: Danfoss A/S, Nordborgvej 81, 6430 Nordborg, Denmark

Energies, 2019, vol. 12, issue 3, 1-29

Abstract: The adoption of the EU F-Gas Regulation 517/2014 and the resulting development of the multi-ejector concept have led carbon dioxide to take center stage as the sole refrigerant (R744) in several applications. Therefore, a knock-on effect on the number of supermarkets relying on “CO 2 only” refrigeration systems has been experienced. Additionally, a global consensus of commercial multi-ejector based R744 units is also intensifying as a consequence of both the promising results obtained and the other measures in force for environment preservation. Furthermore, the multi-ejector concept is expected to offer significant energy savings in other high energy-demanding buildings (e.g., hotels, gyms, spas) as well, even in warm climates. In this investigation, the evolution of R744 ejector supported parallel vapor compression system layouts for food retail applications was summed up. Furthermore, their technological aspects, the results related to the main theoretical assessments and some relevant field/laboratory measurements were summarized. Also, the experience gained in the adoption of the multi-ejector concept in transcritical R744 vapor-compression units aimed at other energy intensive applications was presented. Finally, the persistent barriers needing to be overcome as well as the required future work were brought to light.

Keywords: air conditioning; chiller; CO 2; commercial refrigeration; heat pump; heat recovery; industrial refrigeration; R744; transcritical vapor-compression system; two-phase ejector (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (11)

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