The Road to Zero: DOE's Next-Generation Heating and Cooling R&D Strategy

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The Department of Energy is supporting the U.S. hydrofluorocarbon (HFC) phasedown proposal, which targets an 85% reduction by 2035, through R&D and testing of low-to zero-GWP technologies.

The U.S. Department of Energy’s Building Technologies Office (BTO) is supporting the Administration’s efforts to phase down the use and emissions of highly potent greenhouse gases known as hydrofluorocarbons (HFCs). BTO has created a multi-pronged strategy, outlined below, to develop, demonstrate, and deploy low- to zero- global warming potential (GWP) HVAC, water heating, and refrigeration technologies. This strategy supports the United States’ amendment to the Montreal Protocol to phase down the production and consumption of HFCs globally. BTO’s vision is that non-vapor compression systems—a revolutionary new class of technologies that don’t use refrigerants and can approach zero-GWP—become dominant in some end uses.


HFCs are factory-made chemicals primarily used in air conditioning, refrigeration, and foam insulation, and they can be up to 10,000 times more potent than carbon dioxide in contributing to climate change. Absent ambitious action to limit their use, emissions of HFCs are expected to nearly triple in the U.S. by 2030. But, with strong international action to phase down HFCs, we can avoid up to 0.5°C of warming by 2100, substantially furthering our goal to limit goal temperature rise.

Phasing down HFCs presents not only a huge climate opportunity, but also one of the biggest opportunities to cut energy costs for consumers. HVAC, water heating, and refrigeration systems are the largest energy end-use in buildings, using nearly 50% of all energy in U.S. commercial and residential buildings. With such a large impact on the buildings sector, DOE’s Quadrennial Technology Review identified technological efficiency improvements in HVAC systems—which go hand-in-hand with reducing HFC emissions—as one of the nation’s most promising research opportunities.

  • Apr. 2016: Trane Commercial Systems and Oak Ridge National Laboratory improve a baseline commercial rooftop air-conditioning unit's mechanical design and substitute R-410 for a lower-GWP refrigerant (DR-55), demonstrating a 25% improvement in efficiency and 67% lower GWP.
  • Feb. 2016: As part of the Energy Materials Network, DOE launches a new research consortium at Ames Laboratory to discover and develop caloric materials that could lead to advanced, low-GWP refrigeration technology. BTO is serving as a technical advisor.
  • Nov. – Dec. 2015: DOE convenes two workshops to solicit input from over 100 industry stakeholders—including manufacturers, national laboratories, and universities—on the technical focus and overall structure needed for a successful next-generation HVAC&R research effort.
  • Nov. 2015: All 197 parties to the Montreal Protocol on Substances that Deplete the Ozone Layer agree on a "Dubai Pathway"—to work together, within the Montreal Protocol, to an HFC amendment in 2016 by first resolving challenges and generating solutions in the contact group on the feasibility and ways of managing HFCs at Montreal Protocol meetings.
  • Oct. 2015: Oak Ridge National Laboratory’s (ORNL) performance evaluation of alternative lower global warming potential refrigerants shows that they could be used to successfully replace hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in hot climates. The results are of particular interest to many developing countries that have hot climates, and support the proposed amendment to the Montreal Protocol to phase down the use of HFC refrigerants.
  • Sept. 2015: Xergy develops the first electrochemical compressor for home water heaters, and ships it to their industry partner for development of a complete prototype. Xergy’s technology is one of the first in a new class of super-efficient, low-GWP technologies called "non-vapor compression"—which are transforming how heating and cooling technologies have operated for the past 100 years.
  • April 2015: DOE invests nearly $8 million to develop advanced vapor compression and non-vapor compression HVAC systems.
  • Jan. 2015: Honeywell, working with ORNL, commercializes Solstice N40, a low-global warming potential (GWP) non-HFC refrigerant that provides a 67% reduction in GWP and up to 10% increased energy efficiency for supermarket refrigeration.
  • Nov. 2014: Leading refrigeration systems manufacturer Hillphoenix, working with ORNL, commercializes a CO2-based supermarket refrigeration system that does not use HFCs, reduces greenhouse gas emissions by 75%, and lowers energy consumption by 25% compared to existing systems. The system has been installed in over 130 stores across the U.S.
Strategy & Related Projects

Short-Term Strategy: Develop, evaluate, and deploy low-GWP alternative refrigerants and systems.

Mid-Term Strategy: Develop advanced HVAC&R systems that can handle low-GWP refrigerants.

Long-Term Strategy: Develop non-vapor compression systems that use zero-GWP refrigerants.