Title: Thermodynamic evaluation of CO2 transcritical refrigeration cycle with ejector

Authors: Nabil Khellaf; Rabah Gomri

Addresses: Faculty of Science and Technology, Research Laboratory of Genie Climatique, Department of Genie Climatique, Constantine University, Constantine 25000, Algeria ' Faculty of Science and Technology, Department of Genie Climatique, Constantine University, 25000 Constantine, Algeria

Abstract: In the present work, an attempt has been made to analyse the use of an ejector as an expansion device. A review of refrigeration cycles with ejector was done. The effect of the introduction of the internal heat exchanger in the single-stage and the two-stage CO2 refrigeration cycles with ejector was analysed. It is concluded that whatever the value of the thermal efficiency of the internal heat exchanger, there is an optimum pressure for which the coefficient of performance (COP) reaches its maximum value and the variation of the heat exchanger thermal efficiency does not affect the optimal pressure, but it is noted that the introduction of the internal heat exchanger negatively affects the maximum performance of single-stage cycle and positively affects the maximum performance of the two-stage cycle. New cycles were proposed and their performance was discussed and compared with the existing cycles in the literature.

Keywords: carbon dioxide; performance; thermodynamic evaluation; CO2 transcritical refrigeration cycles; ejector use; expansion devices; internal heat exchangers; thermal efficiency.

DOI: 10.1504/IJEX.2016.075609

International Journal of Exergy, 2016 Vol.19 No.2, pp.210 - 231

Received: 28 Aug 2014
Accepted: 17 Mar 2015

Published online: 30 Mar 2016 *

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