Secret of Honeywell’s new refrigerant

Honeywell’s development of a non-flammable low GWP alternative to R410A has created huge interest, but what’s in it? The Cooling Post may have the answer.

Yesterday’s announcement of a potential new substitute for the air conditioning refrigerant R410A has created considerable global interest. Since publishing the story, yesterday evening, the Cooling Post has, overnight, received more than 6,000 visitors, keen to learn more.

Particular interest is expected from Europe where, due to the HFC phase down, R410A has experienced extreme price and supply issues. And, until now, there has been no lower GWP alternative for R410A in larger systems, including VRF.

The new refrigerant, Solstice N41, now designated R466A, is not expected to be available until next year. Honeywell has so far been keeping further details under wraps, but the Cooling Post may have uncovered some of the answers to its chemical constituents.

We believe that the new refrigerant contains two components that users of R410A will be very familiar with – R32 and R125. However, the blend proportions are very different: R32 still makes up nearly 50% of the blend but the proportion of R125 is greatly reduced.

The trifluoroiodomethane molecule

The key third component, and the main reason for the blends non-flammability, is trifluoroiodomethane (CF3I), a relatively new gas which has not previously been used in refrigerant blends. A fire suppressant, CF3I is thought to be being considered as a replacement for halon 1301.

Significantly, CF3I is also a major contributor to Solstice N41’s low GWP. The new gas makes up 39.5% of the new blend (R32 is 49% and R125 11.5%) but its 100-year GWP is less than 1 (in fact, 0.4).

Those blend proportions would give the new refrigerant a GWP of around 733, just slightly more than R32’s GWP of 675, but with zero flammability.

Both Solstice N41 and CF3I are still going through the ASHRAE approval process.

The Cooling Post has sought verification of the above information, but Honeywell has so far chosen not to confirm or deny that the above information is correct. They have, however, confirmed that the GWP of Solstice N41 is below 750.