The Building Technologies Office (BTO) of the U.S. Department of Energy (DOE) seeks to accelerate the development of the next generation of heating, ventilation, and air-conditioning (HVAC) technologies, including both electric- and natural-gas-driven solutions. HVAC is the largest energy end-use for U.S. buildings, consuming approximately 37.3% (~15 Quads) of total energy.[1] Vapor compression based systems have effectively and efficiently served the HVAC needs for residential and commercial buildings for close to 100 years. Vapor compression technologies are currently the dominant HVAC technology due to their scalability, relatively compact size, high reliability, and other attributes. However, the refrigerants used in these systems have detrimental global effects on the environment when released into the atmosphere. The scientific community has responded to such environmental threats by several proposals to phase down refrigerants with large global warming potential (GWP).

What is needed is a paradigm shift in HVAC technologies, moving beyond today’s refrigerants and toward a future based (at least in part) on non-vapor-compression HVAC technologies with the ultimate goal to eliminate high GWP refrigerants all together. This new paradigm is the ultimate environmental solution (zero GWP cooling fluids), provides energy savings for consumers, and will enable manufactures to avoid the challenge of future refrigerant change out cycles.  A primary objective is to focus on an end-state with no refrigerants required, while enabling U.S. manufacturers to innovate in ways that will enhance their competitiveness over the longer term.

What comes after vapor compression technology? U.S. Department of Energy has recently completed a report on the Energy Savings Potential and RD&D Opportunities for Non-Vapor-Compression HVAC Technologies to help frame the state of these next generation technologies. Possible candidate technologies include, but are not limited to: sorption technologies, alternative thermodynamic cycles, solid state technologies, membrane technologies, electrochemical cycles, and mechanical technologies. BTO currently has several projects that use electrochemical cycles in its HVAC, Water Heating and Appliance R&D portfolio.