Ford Motor Company Submits Application to List Natural Refrigerant R290 in Secondary Loop Architecture as Acceptable for Electric Vehicle Cooling and Heating

Washington DC, 19 November 2024 – U.S. automotive manufacturer Ford Motor Company submitted an application to the United States Environmental Protection Agency (US EPA) to list R290 (propane) as acceptable for use in automotive thermal management systems under the Significant New Alternatives Policy (SNAP) Program.

“Congratulations to Ford on this important step toward the introduction of secondary loop mobile climate conditioning systems with the best possible life-cycle climate performance,” said Dr. Stephen O. Andersen, Director of Research at the Institute for Governance & Sustainable Development (IGSD). “We urge EPA to expedite approval of this important application.”

Ford along with other automakers, parts suppliers, and service industry experts have been working together for years under the SAE International (SAE) Thermal Management Refrigerant Cooperative Research Program to identify better refrigerants suitable for use in next-generation electric vehicles equipped with heat pumps. IGSD was the first and only public interest environmental organization to join the R&D effort.

“IGSD is proud of our decades-long partnership with the automotive community developing best available technology to avoid climate tipping points,” said Kristen N. Taddonio, Senior Technical Advisor to IGSD. “The new R290 in secondary loop architecture will safely cool and heat electric vehicle occupants while increasing electric vehicle driving range, which is key to satisfied customers.”

The SAE cooperative research program has spent years carefully evaluating the safety, technical, performance, and environmental characteristics of half a dozen refrigerants with low global warming potentials (GWPs). R290 emerged as a leading contender due to its superior energy efficiency and cooling and heating capacity performance, low refrigerant cost, freedom from restrictive patents on production or use of R290 in automotive systems, and its status as a non-PFAS (Per- and polyfluoroalkyl substance) refrigerant alternative.

R290 is significantly more flammable than the automotive refrigerant most commonly used in new vehicles, R1234yf. However, previous work on R152a automotive air conditioning systems—which is also more flammable than R1234yf—demonstrated that the increased flammability could be mitigated with a secondary loop system architecture. Furthermore, an IGSD-Tata Motors-Mahle demonstration project sponsored by the Climate & Clean Air Coalition (CCAC) proved that efficiency improvements were possible with innovative secondary loop system design.

A secondary loop, or “indirect” heat pump system improves safety by keeping the flammable refrigerant outside the passenger compartment in the primary refrigerant loop. It has the additional advantage of minimizing the amount of refrigerant required per vehicle. Heat or cold is transferred to a secondary fluid, such as glycol, that is circulated in the passenger cabin and throughout the vehicle in a “secondary loop.”

The CCAC-sponsored project went on to win the 2020 SAE Environmental Excellence in Transportation Award. Crucially, the project also led to the update of the automotive risk assessment for a more flammable refrigerant and resulted in the update of over a dozen automotive industry standards for system safety, engineering, design, and servicing equipment for flammable refrigerants.   

“The work we did with IGSD on secondary loop systems and higher flammability refrigerants really laid the foundation,” said SAE Cooperative Research Program steering committee member Tim Craig. “Comparing the flammability of HFO-1234yf vs. R152a vs. R290 has been helpful, and the updated R152a risk assessment funded by IGSD was the starting point.”

• For more information on the SAE International Thermal Management Refrigerant Cooperative Research Program, contact: Mark Klavon Mark.Klavon@sae.org
• For more information on the Significant New Alternatives Policy (SNAP) Program, visit: www.epa.gov/snap