JAPAN: Refrigerant manufacturer AGC claims to have developed a new HFO1123 blend which resolves safety issues associated with this gas as a low GWP replacement for R410A in air conditioning.
Developed by AGC in 2014 as part of Japan’s New Energy and Industrial Technology Development Organisation (NEDO) funded project, HFO1123, which AGC brands as Amolea 1123, has a GWP of less than 1, while maintaining the same performance as R410A.
The new blend has been developed in cooperation with the University of Tokyo.
Significantly, AGC says it is on track to resolve the safety issue that had been one of the challenges for the practical application of the refrigerant, claiming “the development of the world’s first refrigerant with GWP below 10 for air conditioners has entered the final stage”.
The safety issues regarding HFO1123 relate to the fact that it can undergo what is called a disproportionation reaction under high-temperature and high-pressure conditions. While this does not occur during the ordinary operating range of air conditioning equipment, if, for example, a short circuit was to occur inside the motor of the compressor, and discharge energy above a certain value is supplied, disproportionation may occur. This reaction has been described as rapid, violent, exothermic and accompanied by a rapid pressure rise.
The most recent Bitzer Refrigerant Report, produced in 2020, observes that R1123 has a significantly higher volumetric refrigeration capacity than R1234yf or R1234ze(E) but states that the pressure level is even higher than that of R32 and the critical temperature is only about 59°C. “Apart from that, there are unanswered questions about the chemical long-term stability under the special requirements of the refrigeration cycle,” the report compilers state.
Previous studies blending HFO1123 with R32, R1234yf or mixtures thereof, have all been found to suppress disproportionation. The University of Tokyo and AGC now claim to have succeeded in developing a safe composition that suppresses the rapid pressure increase due to the decomposition of HFO1123 to a certain level by adding propane.
It is not revealed what percentage of propane is used in the new blend, and it is not stated whether it is likely to qualify as an A2L or an A3 refrigerant. In any case, it is yet to undergo ASHRAE flammability and toxicity assessment.
Based on the results of this development, AGC says it will sequentially launch new refrigerants with ultra-low GWP and high safety, for use in a variety of equipment, including residential and commercial air conditioners.
“In addition, as a next-generation refrigerant for electric vehicles, Amolea 1123 mixed refrigerant (Amolea 10X) with a GWP of 10 or less, which will be applied for ASHRAE in June 2022, is under consideration for certification in 2025 by SAE,” AGC says.
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