GWP and Other Matters

When discussing refrigerants and climate change, a natural starting point is global warming potential (GWP). That’s why the focus these days is on A2Ls, which offer significantly lower GWP than legacy refrigerants, such as R-404A (3,920 GWP) and R-410A (2,088 GWP). For example, these three A2Ls are now being selected for new-generation equipment solutions in various HVACR applications:

• R-454A (AR4 GWP of 238);
• R-454B (AR4 GWP of 466); and
• R-454C (AR4 GWP of 146).

It’s also important to consider HFO-1234yf, an A2L currently in air conditioners in 95 million vehicles on U.S. roads. HFO-1234yf has an AR4 GWP of 4 and is also used as a blend component in Chemours’ A1 and A2L products. Lastly, although A2Ls are for new equipment only, lower-GWP A1 refrigerant solutions also exist to help in retrofits. For most applications using a higher-GWP HFC in an existing system, there’s likely a lower-GWP HFC/HFO blend for retrofit applications.

If GWP were the only consideration in HVACR technology, we’d have a single refrigerant with a GWP of <1. The true innovation in refrigerant development lies in striking the optimal balance between environmental impact and performance for a diversity of applications. For example, after developing what are now considered three major players in the future of refrigerants — Chemours Opteon XL40 (R-454A), Opteon XL41 (R-454B), and Opteon XL20 (R-454C) — our chemists remain in the labs, working with leading-industry partners to lower GWP even more without compromising other properties.

Because global temperature matters, in addition to the temperature of a building, vehicle, cooler, freezer, and so forth, it’s important to consider how well a refrigerant addresses several key factors:

• Low GWP and zero ozone depletion potential (ODP);
• Reduced energy consumption;
• Circularity — the ability to be recovered, recycled, and reclaimed;
• Lower operating costs over the lifetime of equipment;
• Safety for everyone, from technicians to end users;
• Overall performance measured by capacity, reliability, and efficiency;
• Can be serviced by the existing, large trained technician workforce;
• Responsible manufacturing focused on reducing carbon emissions; and
• Availability and supply chain strength.

A2L refrigerants have been designed with these factors in mind, raising the bar in terms of performance and support for environmental priorities.

Climate Zone Challenges

ASHRAE divides the U.S. into eight major climate zones, defined by regions ranging from the very cold to the extremely hot. In addition, the zones vary from dry deserts to those with tropical humidity. These climate zones provide system engineers with guidance for choosing the best designs — including refrigerant selection — so that each zone can be equipped with the appropriate system, optimized for year-round capacity, efficiency, reliability, and more.

In a tropical climate, high heat and humidity put heavy demand on cooling equipment -- from air conditioners to refrigeration systems. Because comfort-cooling equipment is likely to run most of the year, it’s important to choose the most energy-efficient options.

Climate zones on the other end of the spectrum — with overall colder ambient temperatures -- present different challenges. Systems in this climate typically have a long offseason, limiting their use throughout the year, but they still must perform reliably. In climates where heating buildings is prioritized over cooling, systems need to be sized appropriately, especially if transitioning from a traditional air conditioner-only unit to a new-generation heat pump.

Today, the proper sizing of heat pumps to ensure occupant comfort — especially in climate zones that are predominantly heating based — is a popular topic of conversation in the industry. An oversized heat pump will likely struggle to control humidity when operated in air conditioning mode.

In addition, there are temperate climate zones that have less variation in conditions over the year, such as dry deserts that can have hot and cold extremes in the same day, and other areas with unique climate factors. What the various climate zones demonstrate is that no matter what the application — supermarket, cold storage, residential air conditioner, or heat pump — the industry will need a full toolbox of systems, components, and refrigerants to meet the increasing demand for high-efficiency cooling and heating.

Climate change will continue to intensify current demands on our industry and introduce new ones, such installing cooling systems in zones that traditionally didn’t need them and efficiently cooling data centers. Other priorities driven by climate change, ranging from conserving water in cooling towers to elevated indoor environmental quality (IEQ), further demonstrate the HVACR industry must continue to be innovative and flexible.

Above all, the industry needs to remain focused on cooling solutions that don’t “heat up” the planet. Everyone can do their part by choosing refrigerants that have lower GWP, support other environmental needs, and offer the right performance attributes for a given climate zone.