Experimental assessment of dedicated and integrated mechanical subcooling systems vs parallel compression in transcritical CO2 refrigeration plants
Laura Nebot‐Andrés, Daniel Calleja-Anta, Daniel Sánchez, Ramón Cabello, Rodrigo Llopis
Abstract
Mechanical subcooling systems, both dedicated and integrated, have attracted lot of attention in the recent years due to their great potential to improve transcritical CO2 refrigeration systems. Numerous studies have theoretically determined the COP increments that these systems can offer compared to classic systems and experimental works have evaluated the optimum working conditions for each individual system. However, they have not been contrasted experimentally. In this work, the dedicated and integrated mechanical subcooling systems are experimentally contrasted to the parallel compression one, which is considered as base system. The optimum energy performance of the three systems is contrasted for three heat rejection levels: 25.0 °C, 30.4 °C and 35.1 °C. The experimental tests show increments in COP of 4.1% at 25.0 °C, 7.2% at 30.4 °C and 9.5% at 35.1 °C thanks to the use of the integrated mechanical subcooling and of 7.8%, 13.7% and 17.5% respectively when using the dedicated. It is concluded that the dedicated mechanical subcooling system is the best system, however the integrated mechanical subcooling also performed better than the reference system.