Thermo-economic analysis of low Global Warming Potential refrigerants for food refrigeration application

Regulations imposing a reduction of the impact of refrigeration systems (e.g. Kigali Amendment to the Montreal Protocol) are pushing towards adoption of low-GWP refrigerants and increase of efficiency (e.g. Ecodesign in Europe) of the entire cold chain. For food refrigeration, large consumer of energy of the cold chain, a redesign of refrigeration systems is needed. In this regard, several refrigerant options are available. In order to compare some of the most promising options, introduced on the market as temporary or definitive solutions based on the current regulations, this paper presents an analysis from both a thermodynamic and an economical perspective. More in detail, a preliminary part of the paper discussed the thermodynamic properties of the following refrigerants: HFC/HFO blends (R452A, R449A), a HFC/HFO/CO2 blend (R455A) and R290. Then, for the cost and technical aspects, a case study for a walk-in cold room is implemented. For a fair comparison, given the same cooling load and the same thermodynamic penalization for the pure fluids and the zeotropic mixtures in terms of average temperature difference between the refrigerant and the heat source at each heat exchanger, the results in terms of COP, size of components and costs are presented.