Trifluoroiodomethane, also known as trifluoromethyl iodide, perfluoromethyl iodide, Iodotrifluoromethane, Trifluoromethyl Iodide, molecular formula CF3I, is a colourless, odourless, non-flammable gas at room temperature and pressure. It has good environmental properties (ODP=0, GWP＜5, atmospheric lifetime only 1.2 days), good safety, non-toxic, flame retardant, good oil solubility and material compatibility. Trifluoroiodomethane is not only an ideal replacement for halon 1301, but also for conventional Freon refrigerants such as CFCs, HCFCs and HFCs. Trifluoroiodomethane is also an important fluorine-containing intermediate for the introduction of trifluoromethyl in organic synthesis and is widely used in organic synthesis, biochemistry, pesticides, pharmaceuticals, surfactants and dyestuffs. In addition, trifluoroiodomethane has a wide range of applications in semiconductor etching, electrical equipment insulation, magnesium alloy smelting protective gas, foaming agents, aerosol propellants and other fields. As an alternative to traditional Freon refrigerants, Ikon Corporation (not extant) in the USA began patenting trifluoroiodomethane (CF3I) as a component of refrigerant blends in the 1990s. However, as of today, nearly one third of the patents for CF3I as a refrigerant have been filed by Honeywell worldwide. Many global regulations, including F-Gas and the Montreal Protocol, require the reduction of the use of high GWP products. As a result, the HVAC industry has been looking for a low GWP, energy efficient, non-flammable and comparable or better performance solution to replace the R-410A refrigerant currently widely used in the industry. Currently, Honeywell has 2 publicly available grades of the most promising R-410A refrigerant replacement: Solstice® N41 (R-466A) and HDR 147. Trifluoroiodomethane is added as an important flame retardant in both grades.
In June 2018, Honeywell announced the development of Solstice® N41, a refrigerant alternative to R-410A. Solstice® N41 (R32/R125/CF3I (49%/11.5%/39.5%), GWP 733) has a 65% lower GWP than R-410A and is the first R-410A refrigerant alternative to combine these requirements. It is a new refrigerant alternative to R-410A (R-32/125 (50/50), GWP 1920) in stationary air conditioning systems and is as safe as R-410A, meeting some of the most stringent regulatory requirements and safety standards currently faced by the HVAC industry. Test results show that switching to Solstice® N41 requires only minor equipment modifications, is comparable to or more economical than flammable refrigerants, and requires no additional training for installation and service technicians, making it easy for original equipment manufacturers (OEMs) to replace R-410A. More than 15 OEMs and leading compressor manufacturers have already conducted a series of tests in various applications including commercial air conditioning (multi-connectors, rooftop units) and domestic air conditioning (unitary), accumulating more than 30,000 hours of testing without additional safety or liability risks to owners and the entire supply chain. Once commercially available, Solstice® N41 (R-466A) will be the first Class A1, non-flammable and low GWP R-410A replacement refrigerant for stationary air conditioning systems.
Once commercially available, Solstice® N41 (R-466A) will be the first Class A1, non-flammable, low GWP R-410A replacement refrigerant for stationary air conditioning systems. Until now, all other low GWP R-410A alternatives have been flammable, increasing the risk to homeowners and contractors. Solstice® N41 (R-466A), meanwhile, has a GWP 65% lower than R-410A.
“The non-combustibility of Solstice® N41 (R-466A) represents a real breakthrough for the HVAC industry.” Dr. Ningjie Huang, Chief Scientist and Vice President of Sanflower Holdings, said, “Significant progress has been made in the certification of key HVAC components using Solstice® N41 (R-466A) air conditioning refrigerant, and the interactive assessment between the two parties is expected to be completed in the second half of the year. We are confident that we are ready to serve the industry with a smooth introduction of N41 when it is commercially available later this year.”
Solstice® N41 (R-466A) significantly reduces the need for additional design and sensor installation required for flammability risks. Early test results show that this non-flammable, low GWP R-410A alternative eliminates the need for specialist training of engineers on flammability reduction. This is a major benefit to the industry as a whole, which struggles to recruit and retain qualified engineers.
In January 2019, Honeywell disclosed in its report entitled Reduced GWP Refrigerants Heat Pump Systems that HDR-147 is a non-flammable, Class A1, low GWP (399) refrigerant with the performance comparison shown in Table 1. HDR-147 (CF3I and other undisclosed components of blends, GWP ~400) has yet to be evaluated by ASHRAE, but it may be a long-term alternative to R410A.
Table 1: Characteristics of R410A and its alternatives