Performance comparison of very low GWP R404A alternatives in a commercial freezer application

International efforts to reduce the global warming impact of refrigerants are advancing, as evidenced by the Kigali Agreement and European F-Gas regulations. R-404A is widely used for medium and low temperature refrigeration applications. Given the GWP of this HFC blend (GWP100 Year = 3,922 per AR4), lower GWP alternatives are required. For smaller self-contained equipment, several new very low GWP HFC-HFO blends are now under consideration, such as XL40 (R-454A), XL20 (R-454C), and R-455A. While mildy flammable, these products allow for significantly larger charge sizes than the highly flammable hydrocarbons.
Soft-optimized system testing was conducted to quantify the relative performance, to R-404A, of these alternatives using a commercially available two-door reach-in freezer. Energy consumption and other operating characteristics were monitored, as well as potential impacts on compressor functionality (e.g. lubrication).