Heat transfer of low GWP refrigerant mixtures as possible alternatives to R404A.

R404A is largely used in retail and transportation refrigeration systems. Given the relatively high refrigerant leakage rates of the mentioned systems and the relatively high Global Warming Potential (GWP=3943) of R404A, this refrigerant is increasingly under scrutiny. Furthermore, containment measures are requested by the recent European F-Gas regulation. Several refrigerant mixtures based on HydroFluoroCarbons (HFC), HydroFluoroOlefins (HFO) and HydroCarbons (HC) pure components have been proposed recently. Changing refrigerant thermophysical properties may have a relevant impact on the performance of the heat exchangers. In this paper reference is made to finned coil condenser and evaporators. An advanced simulation model is used in order to compare the heat transfer performances of candidate refrigerant mixtures with R404A referring to typical foodstuff preservation temperatures.