As the global automotive industry accelerates its transition to electrification,New energy vehiclesThe need for efficient thermal management systems is becoming increasingly urgent. With its advantages in low-temperature heating efficiency and cruising range, heat pump technology has become the key to improving the driving experience and energy efficiency of electric vehicles. However, finding new refrigerants that meet environmental regulations (GWP<150), are safe, reliable, and perform well is one of the core challenges in the development of current heat pump systems.
Yang Yun, technical service manager of Chemours Chemical (Shanghai) Co., Ltd. in the Asia Pacific region, introduced that for automotive applications, Chemours has launched R-457C refrigerant to meet the requirementsNew energyHigher demands on energy efficiency and cooling and heat in vehicles.
She noted that R-457C refrigerant is compatible with metal, plastic, and rubber parts in existing systems, as well as lubricants. In China’s joint development program for hydrofluorocarbon substitution technology for automotive air conditioners, R-457C refrigerant demonstrated its superior comprehensive performance.
Yang Yun|Technical Service Manager of Chemours Chemical (Shanghai) Co., Ltd. Asia Pacific
The following is a summary of the speech:
Innovative genes and sustainable layout
As a company spun off from DuPont with a deep chemical research and development background, Chemours is committed to creating a better world through the power of chemistry. The company employs approximately 6,200 people worldwide and has a business footprint in more than 110 countries around the world, with more than 60 factories, laboratories, joint ventures and offices.
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Chemours’ main business spans titanium dioxide technology, thermal management and specialty solutions, and high-performance materials, focusing on providing sustainable solutions to meet the world’s demand for high-performance materials, zero-emission green hydrogen, high-speed connectivity, and sustainable refrigeration.
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In the areas of thermal management and specialty solutions, Chemours has a proven line of refrigerants, including traditional HCFCs and HFCs products (Freon™ brand) and future-proof next-generation environmentally friendly refrigerants (Opteon™ brand). Its technology roadmap clearly shows that Chemours is focusing on promoting R-457C and R-454C solutions for new energy vehicle heat pump applications to meet the challenge of the national HFCs reduction program (requiring a new announcement of GWP>150 refrigerants to be banned for air conditioners in M1 vehicles from July 1, 2029).
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Analysis of R-457C core characteristics
R-457C is a hybrid refrigerant composed of R-1234yf (78%), R-152a (14.5%) and R-32 (7.5%). The key physical properties parameters showed that the boiling point under atmospheric pressure was lower than that of R-134a and R-1234yf, which was conducive to operating at lower ambient temperature to meet the heating demand in winter. The GWP value is 72, which is far below the regulatory limit of 150, meeting the requirements of Chinese and global environmental protection regulations. The safety grade is A2L (low toxicity, weak flammability), which is the same as the safety level of R-1234yf, which is widely used today. The thermodynamic properties show that the pressure curve of R-457C is close to that of R-134a and R-1234yf, indicating that it has good pressure adaptability to the existing system.
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Rigorous material compatibility testing is carried out according to industry standards: metal compatibility test (carbon steel, copper, aluminum) after 14 days of accelerated aging at 175°C, no significant corrosion or high concentration of refrigerant decomposition was observed;
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The results of the plastic-elastomer compatibility test (sealing test with POE ND-11 refrigeration oil at 100°C for two weeks) are comparable to the R-134a benchmark, indicating that it is compatible with commonly used sealing materials (e.g., EPDM, HNBR). The oil solubility test (POE ND-11) showed that R-457C had good compatibility with lubricating oil in a wide temperature range of -65°C to 90°C, and only a few high temperature and high concentration points had delamination but did not affect use.
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Joint testing verifies the feasibility of the scheme
In the “China Automotive Air Conditioning Hydrofluorocarbon Replacement Technology Joint Development Plan” led by China Automotive Research Institute, R-457C, as one of the key evaluations of mixed working fluids, has undergone rigorous bench and vehicle tests. Bench testing covers a full range of cooling (27°C to 50°C), dehumidification (15°C) and heating (5°C to -20°C) conditions.
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The results of refrigeration performance showed that the system energy efficiency (COP) of R-457C was significantly higher than that of R-1234yf in the whole cooling area (especially the high temperature area), and the COP increased by up to 27% in the high temperature area (such as 45°C working conditions). At the same time, the power consumption of the compressor is significantly reduced, with a maximum reduction of more than 600W. Thanks to its increased cooling capacity, the compressor pressure ratio and speed are lower than those of the R-1234yf system (approximately 30% reduction in speed) when achieving the same cooling effect. Importantly, the maximum exhaust pressure is only 2.08MPa under the existing system pressure limit (2.4MPa), which provides sufficient operational safety margin.
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The heating performance is even more outstanding: in the typical temperature range of -10°C to 5°C, R-457C can stably output heat, COP is up to 21% higher than R-1234yf, and compressor power consumption is reduced by up to 3000W. At extremely low temperatures of -15°C and -20°C, the R-457C system can still operate and provide some heat output (COP about 1.14-1.45), while the R-1234yf and R-134a systems rely entirely on PTC electric auxiliary heat at this temperature.
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The exhaust pressure (up to 2.36MPa) and pressure ratio (Ratio<12) under heating conditions are still controlled within the existing compressor performance curve, but the control logic (such as pressure ratio limit, low pressure protection setting) needs to be optimized to fully unleash its potential.
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After simulating the 6-year service cycle (annual leakage rate of 6-7g) (annual leakage rate of 6-7g) due to the high permeability of R-32 components, the heating capacity decreased, but the cooling COP was not affected.
The life cycle carbon emission assessment (according to relevant standards, according to the use conditions in Beijing, the service life is 10 years) shows that the R-457C can reduce total carbon emissions by 51% compared to the R-134a system (mainly due to the significant reduction in direct emissions). Compared to the R-1234yf system, its indirect emissions are also reduced by about 11%, demonstrating the value of energy efficiency improvement. The vehicle temperature rise test (-7°C to 20°C and 40°C to 25°C) confirmed that the R-457C temperature rise and fall rate was significantly faster than that of the R-1234yf system.
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System optimization direction and risk assessment
Based on the results of the first phase of the joint development program, Chemours proposed the following key optimization directions to realize the full potential of R-457C and promote its mass production applications: First, optimize the heat exchanger design. The existing R-134a system heat exchanger may limit the full performance of R-457C, so it is necessary to optimize the flow path design for its thermodynamic properties to reduce pressure loss and uneven heat transfer, and improve the overall heat transfer efficiency. Secondly, the system control logic is upgraded. It is necessary to develop an automated control system to optimize the setting of key parameters, such as compressor pressure ratio limits, high and low pressure protection thresholds, and superheat control (from manual to automatic), especially under extremely low temperature conditions, to ensure the safe and efficient operation of the system and release maximum performance. Third, strengthen the system seal. In view of the relatively high leakage rate of R-32 components, which will lead to component shifts and performance degradation (especially heating capacity) after long-term use, it is necessary to optimize the hose and fitting technology to further reduce the leakage of R-32 components and maintain a stable component ratio. Finally, a comprehensive risk assessment is crucial. Although R-457C and R-1234yf belong to the same A2L safety class, there are differences in the specific combustion characteristics (such as minimum ignition energy, combustion speed, and minimum ignition concentration LFL).
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Chemours has accumulated key data related to the combustion characteristics of R-457C and tested the impact of multiple ignition sources, recommending methods such as fault tree analysis (FTA) to conduct in-depth risk assessment in combination with specific application scenarios (such as leak location, concentration distribution, and potential ignition sources) to ensure its safe use under various working conditions.
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Future prospects and challenges
With its regulatory compliance (GWP 72, A2L), excellent material compatibility, significant energy efficiency improvements, strong low-temperature heating capabilities, and good compatibility with existing 134A systems, Chemours R-457C hybrid refrigerant provides a competitive solution for new energy vehicle heat pump systems as an approximate drop-in replacement option for existing systems.
Successful large-scale application of R-457C still requires industry collaboration to overcome two major challenges: first, continuously optimize the system design (heat exchanger, control logic) to fully unlock its performance potential; Second, through material innovation and process improvement (such as sealing solutions for R-32), the risk of component shift in long-term use is effectively reduced to ensure stable performance throughout the life cycle. Chemours will continue to invest in research and development and work closely with industry partners to advance efficient and environmentally friendly automotive heat pump technology.
(The above content is from the keynote speech “R-457C Chemours New Generation Automotive Heat Pump Solution” delivered by Yang Yun, Technical Service Manager of Chemours Chemical (Shanghai) Co., Ltd. Asia Pacific Co., Ltd., at the 3rd New Energy Vehicle Thermal Management Forum 2025 on June 18, 2025. ）
