Title: Exergetic performance assessment of solar driven combined CO₂ power and refrigeration system

Authors: Onder Kizilkan

Addresses: Department of Energy Systems Engineering, Faculty of Technology, Süleyman Demirel University, 32260, Isparta, Turkey

Abstract: The scope of this study is to assess a solar driven combined power-refrigeration system working with carbon dioxide (CO₂) through energy and exergy. The system consists of a supercritical Brayton cycle, a transcritical organic Rankine cycle, and a subcritical vapour compression refrigeration cycle. All three subsystems operate with carbon dioxide as the working fluid thanks to its zero-ozone depleting potential and negligible global warming potential. In addition, it is a sustainable working fluid. The combined system's heat energy demand is supplied by using parabolic trough solar collector system. Heat energy demand of organic Rankine cycle is supplied by the rejected heat of supercritical Brayton cycle; while the refrigeration cycle is driven by the power generated from the organic Rankine cycle. The results show that the energy efficiencies of the Brayton and organic Rankine cycles are found to be 12.9% and 4.47%, respectively, while the performance coefficient of the refrigeration cycle is determined to be 3.35. The energy efficiency of the overall system is determined to be 20.89%; while the exergy efficiency of the overall system is determined to be 12.95%. The exergy destruction rate of the whole system is calculated as 4,891 kW.

Keywords: solar energy; combined power-refrigeration system; CO₂; parabolic trough solar collector.

DOI: 10.1504/IJEX.2018.094591

International Journal of Exergy, 2018 Vol.27 No.2, pp.147 - 164

Received: 23 Feb 2018
Accepted: 01 May 2018
Published online: 07 Sep 2018 *

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