The topic of heat pumps has experienced a meteoric rise in HVACR discussions. No matter where you turn, there’s eat pump talk—ranging from the basic merits of the technology to the nuances of heat pump operation, installation, and maintenance. Members of the industry have enthusiastically embraced heat pump solutions and expanded their applications. However, before going all in, some have cautiously questioned whether this focus is short-term “hype” or indicates that heat pumps will have longevity as a “hero,” supporting energy-efficient and sustainable new-generation and next-generation heating and cooling.
I’m often asked why technology that has been commercially available and in use since the 1950s is now suddenly taking center stage. The answer can be found by looking at what heat pumps do, how they are being used presently, and what potential they offer for meeting changing demands.
What Heat Pumps Do
The term can be misleading, because “heat pumps” do not generate heat. They extract heat energy from where it’s not needed or wanted and move it to where it is needed or wanted. In cold weather, for example, the refrigerant in heat pumps evaporates as it absorbs heat from the outside. The heat released as the refrigerant condenses is then transferred to interior spaces. In warm weather, the process is reversed, as heat is extracted inside and released outside.
One reason for the heightened focus on heat pumps is that they do not generate heat, unlike combustion-based technology. This provides several potential benefits to society:
- Heat pumps support the megatrend toward decarbonization.
- They replace fossil-fuel heating with high-efficiency technology.
- They can be paired with lower global warming potential (GWP) A2L refrigerants—such as R-454B and R-32—to further increase environmental benefits, while offering similar performance to the legacy R-410A.
- They offer the ability to tap into alternative energy sources, such as waste heat as well as heat sourced from the air, (ambient) ground (geothermal), or lakes/ponds (water).
How Heat Pumps are Being Used
Early versions of heat pumps were essentially reversible air conditioning units, and most used traditional refrigerants—like R-22 and, more recently, R-410A. These units performed well and operated safely using lower-toxicity, nonflammable (A1) refrigerants. However, they were known to sometimes struggle at lower ambient temperatures.
Today’s heat pump systems reflect the HVACR industry’s desire to expand the environmental benefits of heat pump technology to more places and spaces—and the industry’s need to heed regulations advancing the transition to systems reducing climate impact. Emerging systems use mildly flammable (A2L) refrigerants. They are similar in design to legacy systems and include modifications to mitigate risks associated with the change to A2Ls.
Innovations are also coming into play that optimize various heat pump components, such as compressors, heat exchangers, expansion valves, and their controls. These innovations enable broader adoption by allowing systems to be used more effectively in colder climates.
Heat Pump Potential
The industry is just starting to unleash what heat pump technology can achieve, and we can expect to see continued innovation as end-user needs and environmental priorities continue to evolve. Some foreseeable growth areas for heat pumps include:
- Traditional applications—that is, moderate climates
- Expansion into nontraditional climates—heating in very cold climates and cooling in hotter regions
- Domestic water heating, replacing fossil-fuel systems
- Leveraging a variety of heat sources—geothermal, air-sourced, and water-sourced
- Harnessing waste heat generated by energy-intensive industrial processes
Supporting these growth areas will be innovations that optimize high-performance, high-efficiency delivery of extracted heat, using a combination of traditional and new split-ducted, ductless/mini-splits, and mono-block technologies. System optimization will also drive increased use of lower-GWP A2Ls, such as R-454B, and limited use of highly flammable refrigerants such as R-290.
Conclusion: Hero not Hype
The industry will continue to focus on evolving heat pump technology and expanding applications. The current uses alone position heat pumps as one of several environmental “heroes” in HVACR, and additional benefits will be realized as engineers and scientists tap their potential. As the technology evolves and options expand, it will become increasingly important for HVAC contractors to understand customers’ heating and cooling needs, climate challenges, and sustainability goals, then select the best heat-pump refrigerant solution.