Announcement On January 26, 2015, Trane Commercial Air-Conditioning announced it will offer the new Sintesis air-cooled chiller which will use R513a as a refrigerant.

R513a

R513a is a new product for DuPont who is marketing the azeotropic blend of HFC-134a (44%) and HFO-1234yf (56%) as Opteon® XP10. According to DuPont XP10 is classified as an A1 refrigerant meaning it has low toxicity at air concentrations lower than 400 ppm and does not show flame propagation in air at room conditions. This is the same rating as R134a and R-410a.

GWP Reduction

The GWP for R513a is stated by DuPont to be 631 which is down from 1300 for pure R134a, reducing it roughly by the fraction of pure R134a. The dilution of the R134a has reduced the flammability from the mildly flammable A2L rating of HFO-1234yf. It has also increased the GWP rating from HFO-1234yf which is 4.

The other problem with HFO-1234yf is it appears to have an inherent cycle disadvantage of about 5% with say R-410a.

Flammability It looks like the A2L's are having trouble gaining acceptance due to the risks involved with their flammability and cooler heads are proposing a compromise GWP of around 600 or so with no flammability.

Note

This strategy is consistent with the recent announcement by Trane that their centrifugal chillers will be available using low GWP, A1 safety, high efficiency R-1233zd for their line of centrifugal chillers.