Honeywell has announced that it is now offering the lower GWP R410A replacement R454B, a refrigerant previously associated with its rival Chemours as Opteon XL41.

Without the fanfare that we normally expect from a Honeywell refrigerant introduction, the announcement of the addition of R454B to the Honeywell portfolio was included as a secondary item in a newsletter sent to customers this week. It will market the refrigerant as Solstice 454B.

Meanwhile, the industry still awaits Honeywell’s much-lauded non-flammable R410A alternative R466A.

Wide acceptability

An A2L refrigerant, R454B has previously always been associated with Chemours, from its time as DR-5, a DuPont development refrigerant and its subsequent passage through the ASHRAE classification process in 2015.

Despite this, Honeywell lays claim to a patent on this refrigerant. When asked, Honeywell told the Cooling Post: “Honeywell identified the usefulness of R-454B as a R-410A replacement for air conditioning in 2009 and has patented this discovery.”

What is clear is that R454B has been accepted by an increasing number of chiller, heat pump and rooftop equipment manufacturers. These include Carrier, Lennox, Trane, York, Mitsubishi Electric, Rhoss, MTA, Swegon, Flakt, Engie and GI.

A blend of R32 and R1234yf with a GWP of 466, R454B appears to be the best current option for new equipment in applications where a lower-flammability refrigerant is an option.

Honeywell notes that the discharge temperature of R454B is much lower than R32 and, thanks to its higher critical temperature (77°C) and broader operating envelope in low evaporating temperatures, it outperforms other alternatives such as R32 in heating applications.

Where’s R466A?

The news of Honeywell’s new addition comes while the market still awaits news of its much-lauded non-flammable R410A alternative R466A.

First announced by Honeywell in 2018 as Solstice N41, R466A was described as “a breakthrough” with its A1, non-flammable classification addressing “one of the most vexing regulatory and safety challenges facing the HVAC industry”.

An eagerly-awaited potential option for use in VRF systems, it was originally going to be available in commercial quantities in the fall of 2019, then early 2020. Since then, there has been little news of this refrigerant, although it is accepted that OEM testing can be a protracted process, a process which may have been further delayed by the coronavirus pandemic.

A number of OEMs were initially reported to be working with R466A, including Chinese manufacturer Midea and Toshiba Carrier – a company which described the new refrigerant as “promising” after initial performance testing in a VRF air conditioning system. Component manufacturers Sanhua and Parker Hannifin were also known to be carrying out compatibility testing.

There have however been rumours of stability and compatibility concerns related to the refrigerants blend’s key CF3I (R13I1) component. Honeywell has previously denied any problems, telling the Cooling Post last year that R466A was stable: “As seen with past introduction of new refrigerants, the stability and shelf life can be addressed with standard measures practiced in the industry,” it said.

As we approach the third anniversary of the initial announcement of the refrigerant, Honeywell maintains that R466A is now in the “advanced stages” of commercialisation, with samples having been provided to OEMs for evaluation to ensure compatibility with their equipment.

“To date, Solstice N41 has undergone extensive testing by over 15 OEMs and leading compressor manufacturers and accumulated more than 100,000+ hours in different applications like commercial AC (VRF, rooftops) and residential AC (unitary),” the company said, but would not be drawn on a new release timetable.