DOE Ultra-low GWP
Ram Narayanamurthy presenting at ATMO America Summit 2024.

ATMO America: DOE Invites HVAC&R Stakeholders to Join Work Groups for Early Introduction of Ultra-Low GWP Refrigerants

Refrigerant leaks and efficiencies account for one-sixth of a building’s emissions, says DOE’s Deputy Director of Building Technologies.

The U.S. Department of Energy (DOE) is inviting HVAC&R industry stakeholders to participate in two working groups ‒ one focused on codes and standards and one on research and development ‒ to support the early, voluntary market introduction of ultra-low GWP refrigerants in various building sectors.

The working groups, announced in April, will set market priorities and draft documents in preparation for future U.S. building code regulations and energy efficiency standards, according to Ram Narayanamurthy, the Deputy Director of the DOE’s Building Technologies Office.

“Between leaks and energy efficiencies, we realized that refrigerants account for about one-sixth of a building’s total emissions,” said Narayanamurthy. “As part of our national blueprint to decarbonize the building sector and cut emissions by 90% by 2050 compared to the 2005 baseline, we want to advance refrigerant technology and adoption, especially for space conditioning.”

Narayanamurthy extended the DOE invitation and outlined the goals and objectives of the working groups during a presentation at the ATMOsphere America Summit 2024, held in Washington D.C. June 10‒11. ATMOsphere is the publisher of

“Between leaks and energy efficiencies, we realized that refrigerants account for about one-sixth of a building’s total emissions.”

Ram Narayanamurthy, DOE’s Deputy Director, Building Technologies Office

DOE objectives

According to Narayanamurthy, the DOE wants input and collaboration from manufacturers, trade associations, utilities, advocacy groups and other industry participants to help define the crossroads between affordable, efficient and safe HVAC, water heating and refrigeration technologies to reduce carbon emissions of buildings in conjunction with electrical grid capacities.

“We want to advance ultra-low GWP refrigeration technology across multiple sectors to reduce emissions,” Narayanamurthy explained. With regulatory efforts outside of the scope of the working groups, the focus instead will be on transforming the refrigeration market, including the technologies and the acceptance of those technologies.

By taking a “holistic approach” ‒ looking at emissions, risk management, maintenance, efficiencies, safety and life cycles of equipment, and the various refrigerant options for residential, commercial and industrial applications, the two groups will provide valuable input for future regulations, Narayanamurthy said. “It’s a voluntary effort, but we are not going to advance without these conversations,” he added.

“As we move to electrify buildings, cars and industries for decarbonization, we need to make our systems more energy efficient, but we need to do so safely and cost-effectively,” he said, noting that the DOE is paying attention to the international market, too, having just awarded $5 million (€4.7 million) to two different projects developing CO2 (R744) heat pump water heaters.

Working group examples

Narayanamurthy provided several working group examples, ranging from the advantages of CO2 (R744) residential water heaters to the development of propane (R290) heat pumps.

Using CO2 refrigerant for water heaters, according to Narayanamurthy, may reduce total installation costs, especially with thermal storage capacity. “Its heat storage potential shrinks the size needed to meet the capacity load, driving power requirements from 240V to 120V,” he said, which has a “huge impact” on installation costs.

From a prioritization standpoint, Narayanamurthy indicated that the DOE was starting with evaluating indirect A3 systems commonly used in Europe. “Basic architecture in the U.S. revolves around direct systems where the refrigerant goes into the built environment,” he said. “However, indirect hydrocarbon air-to-water systems for commercial and residential buildings bring higher efficiencies, but the EPA SNAP [U.S. Environmental Protection Agency’s Significant New Alternatives Policy] limits allowable charges.”

He acknowledged strides made by the Oak Ridge National Laboratory to produce a functioning water heater using less than 114g (4oz) of propane, which meets the SNAP limits. “We are looking for similar small charge A3 systems that fit under the current regulations to get these products in the market.”

Other focuses for the working group that Narayanamurthy mentioned included:

  • Refrigerant costs and training issues, both of which affect the serviceability of the equipment
  • Characterization of refrigerants
  • Developing new heat exchanger designs to reduce hydrocarbon charges
  • Low GWP leak detector sensors
  • Multifunction propane heat pumps
  • High-temperature CO2 heat pumps
  • Heat recovery chillers for hybrid systems for large building electrification
  • Pumped liquid systems using natural refrigerants to replace VRF (variable flow refrigerant)
  • Codes and standard issues related to ammonia (R717), CO2 and hydrocarbon refrigerants

“We are collaborating with state agencies, so we can take all these advancements in ultra-low GWP refrigerants and move the technology into the market,” Narayanamurthy said.

He said professionals in the sector should contact him if they are interested in participating in a working group or for more information. “We want to take this journey with everyone in this room,” Narayanamurthy added, inviting key stakeholders to join the working groups to help hasten this transition.

“Working together, we can increase a building’s efficiency and reduce its emissions with ultra-low GWP refrigerants to meet our decarbonization goals,” he concluded.

In past year, the DOE has announced several programs and grants to facilitate ultra-low GWP equipment production and installation in the U.S., including $63 million (€58.5 million) to accelerate domestic production of residential heat pumps and heat pump water heaters, a grant to support a $2.5 million (€2.3 million) research project by Copeland to develop propane-based HVAC systems, and a rooftop heat pump accelerator program with implementation and evaluation by commercial end users, including Amazon, IKEA and Target.

“Working together, we can increase a building’s efficiency and reduce its emissions with ultra-low GWP refrigerants.”

Ram Narayanamurthy, DOE’s Deputy Director, Building Technologies Office

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