R454C
Also known as: Opteon XL20, R-454C
Short definitionA mildly flammable (A2L) blend of R32 and R1234yf with a GWP of 148. In newly built cold room and frozen store units it is regarded as the lasting successor to R404A.
If a unit installed today is expected to find gas fifteen years from now, this is one of the first options that comes to mind. The reason is its GWP of 148; it stays under the 150 threshold in the F-gas rules, so those restrictions do not cover it. Roughly one fifth of it is R32, the rest R1234yf. Its trade name is Opteon XL20. In monoblocs, split units and supermarket plants it serves both chilled and frozen rooms. Its glide is 6–8 K.
It cannot be charged into an existing R404A or R449A plant; the panel, fans, valves and compressor must be A2L-approved. The same compressor gives 15–20% less capacity, so one size larger is selected. The permitted charge is calculated under EN 378 from the volume of the smallest room the unit feeds; with large charges an emergency shut-off valve, a detector and ventilation are added. The evaporator is selected on the mean evaporating temperature. In service, spark-free equipment and liquid charging from the cylinder are the rule.