CO2 as secondary fluid as alternative to DX-systems energy evaluation in a MT cabinet.

Abstract

The current F-Gas Regulation restricts the use of fluorinated refrigerants with high GWP100 in commercial refrigeration where centralized refrigeration is commonly use. Alternatives to make these systems more ecofriendly are mainly focused in the use of low-GWP refrigerants as natural refrigerants or flammable fluorinated substances. Since flammability makes centralized DX-systems not suitable for commercial refrigeration, the use of secondary fluids based on brines (water base) or volatile fluids (CO2 mainly) is presented as a long-term solution or transitioning towards more sustainable refrigeration systems. Accordingly, the aim of this work is to compare the energy consumption of three commercial refrigeration systems. The first one is a classic R134a DX-system, the second one is a basic R744 DX-system with an IHX, and finally, the last one, is a HFC indirect expansion system using CO2 as secondary fluid. This comparison has been experimentally assessed in a medium temperature cabinet at three heat rejection temperatures.