Experimental assessment of different extraction points for the integrated mechanical subcooling system of a CO2 transcritical plant

Subcooling systems are positioned in recent years as one of the best solutions to improve efficiency transcritical CO2 cycles. Specifically, integrated mechanical subcooling cycle allows improvement these only using a refrigerant. This can be designed with three different architectures: extracting from gas-cooler outlet, subcooler outlet or liquid tank. In this work, configurations experimentally analysed and main differences between them studied. An experimental plant has been tested at heat rejection levels (25.0, 30.4 35.1 °C) fixed temperature secondary fluid evaporator inlet 3.8 °C. The results show that an energy point view, all have practically same COP, certain variations cooling capacity greatest cycles found subcooler.