Title: Energy and exergy analysis of transcritical CO₂ two-stage compression cycle

Authors: Hongli Wang; Jingrui Tian; Yitai Ma

Addresses: College of Metallurgy and Energy, North China University of Science and Technology, Tangshan, 063009, China ' College of Elementary Medicine, North China University of Science and Technology, Tangshan, 063009, China ' Institute of Thermal Energy Research, Tianjin University, Tianjin, 300072, China

Abstract: Based on theoretical analysis and experimental testing, the performances of transcritical CO₂ two-stage compression cycle with two gas coolers were analysed. The maximum experimental refrigeration COP_c and heat COP_h are 2.24 and 3.25, the maximum theoretical COP_c and COP_h are 2.85 and 3.85. The COP both of COP_c and COP_h decrease gradually with increasing of the outlet temperature of gas cooler, and the average value of experimental COP_c and COP_h are 2.02 and 3.13, the average value of theoretical COP_c and COP_h are 2.54 and 3.54. Range of the evaporating temperature from −5°C to 17°C, the average value of experimental COP_c and COP_h are 1.99 and 3.17. The exergy loss both of theoretical value and experimental value are all increase gradually with increasing of differential pressure of throttling valve. The error of exergy loss percentage on theoretical calculation and experimental testing are almost all within +20% and −20%.

Keywords: transcritical CO₂ two-stage cycle; theoretical analysis; experimental testing; energy analysis; exergy loss.

DOI: 10.1504/IJEX.2020.108171

International Journal of Exergy, 2020 Vol.32 No.2, pp.150 - 173

Received: 19 Sep 2019
Accepted: 12 Dec 2019
Published online: 03 Jul 2020 *

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