The paper presents the development of an experimental research facility based on a transcritical single stage vapour compression refrigeration cycle with CO2 as the working fluid. The experimental setup includes instrumentation and controls which enable tests in a broad range of operating conditions. The measurements presented refer to external temperatures between 21.0°C and 33.5°C; in this latter operating point, energy and exergy analysis allowed the breakdown of irreversibilities. In particular, the gas cooler contributes to the 42.6% of the total exergy losses while the share due to the high-pressure expansion valve is 27.2%. In order to improve the performance of the refrigeration system, a theoretical model was developed including an ejector as the replacement of the expansion valve. The results show that the Coefficient of Performance (COP) is strongly dependent on the entrainment ratio; a value of greater than 0.6 seem to lead to higher COP values, even at low external temperatures.

Experimental investigations on a transcritical CO 2 refrigeration plant and theoretical comparison with an ejector-based one

Santini, Fabrizio;Bianchi, Giuseppe
;
Battista, Davide Di;Villante, Carlo;
2019-01-01

Abstract

The paper presents the development of an experimental research facility based on a transcritical single stage vapour compression refrigeration cycle with CO2 as the working fluid. The experimental setup includes instrumentation and controls which enable tests in a broad range of operating conditions. The measurements presented refer to external temperatures between 21.0°C and 33.5°C; in this latter operating point, energy and exergy analysis allowed the breakdown of irreversibilities. In particular, the gas cooler contributes to the 42.6% of the total exergy losses while the share due to the high-pressure expansion valve is 27.2%. In order to improve the performance of the refrigeration system, a theoretical model was developed including an ejector as the replacement of the expansion valve. The results show that the Coefficient of Performance (COP) is strongly dependent on the entrainment ratio; a value of greater than 0.6 seem to lead to higher COP values, even at low external temperatures.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/134166
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