Experimental evaluation of a CO2 transcritical refrigeration plant with dedicated mechanical subcooling

• DOI: 10.1016/j.ijrefrig.2016.06.009
• Publication Date: 2016-06-14T04:34:29Z
• Authors: Rodrigo Llopis; Laura Nebot-Andrés; Ramón Cabello; Daniel Sánchez; Jesús Catalán-Gil
• Keywords: Subcooling; Transcritical cycle; Coefficient of performance; Cooling capacity; Economizer

CO2 transcritical refrigeration cycles require optimization to reach the performance of conventional solutions at high ambient temperatures. Theoretical studies demonstrated that the combination of a transcritical cycle with a mechanical subcooling cycle improves its performance; however, any experimentation with CO2 has been found. This work presents the energy improvements of the use of a mechanical subcooling cycle in combination with a CO2 transcritical refrigeration plant, experimentally. It tested the combination of a R1234yf single-stage refrigeration cycle with a semihermetic compressor for the mechanical subcooling cycle, with a single-stage CO2 transcritical refrigeration plant with a semihermetic compressor. The combination is evaluated at two evaporating levels of the CO2 cycle (0 and −10 °C) and three heat rejection temperatures (24, 30 and 40 °C). The optimum operating conditions and capacity and COP improvements are analysed with maximum increments on capacity of 55.7% and 30.3% on COP. The authors gratefully acknowledge the Ministerio de Economía y Competitividad (project ENE2014-53760-R.7) and Jaume I University (project P11B2015-66) for financing this research work.