Until a couple of years ago, most of the talk about heat pumps occurred around this time of year, when more than half the planet prepares for an autumn cooldown.
These discussions were typically limited to regions that only experienced moderate winters. But as anyone who has recently perused an HVACR trade magazine or website—or participated in an industry webinar, event, or social media conversation—can tell you, the topic of heat pumps is virtually unavoidable. Not only do heat pump discussions now occur year-round, but they’ve also ascended to consistent headline status and transcended the traditional boundaries of moderate climates.
The decarbonization megatrend
One might say heat pumps have taken their place on the global stage. If you’re asking why this has happened, the answer requires just three words: the decarbonization megatrend.
However, for industry professionals looking to grow their businesses, it’s helpful to gain a deeper understanding of heat pumps—how they work, ways they are currently meeting HVACR needs, and where the technology is headed for next-generation applications. Through this understanding, members of the industry can better forecast customer needs as well as identify opportunities for expanding in both current markets and, potentially, new ones.
How heat pumps work—don’t let the name fool you
The heat released as the refrigerant condenses is then transferred to interior spaces
What heat pumps do and, more specifically, how they do it provides the key as to why they are now being considered a “hero” of decarbonization. The term can be misleading, because “heat pumps” do not generate heat. Because of this, heat pumps are being more widely embraced as the lower-carbon-emission alternative to combustion-based heating technology that uses, for example, fossil fuels.
Instead of creating heat, heat pumps extract heat energy from where it’s not needed and move it to where it is needed. When a heat pump is in heating mode, its refrigerant evaporates as it absorbs heat from the outside. The heat released as the refrigerant condenses is then transferred to interior spaces. In warmer weather, a heat pump kicks into cooling mode and the process is reversed, as heat is extracted inside and released outside. This non-combustion process of moving heat from one place to another 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 industrial waste heat as well as heat sourced from the air (ambient), ground (geothermal), or lakes/ponds (water).
Meeting today’s needs—these aren’t your grandfather’s heat pumps
Heat pump technology has been commercially available and in use since the 1950s. 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.
As often happens in the world of science and technology, challenges drive the search for solutions. Today, we’re seeing innovations that result in efficient, effective cold-climate heat pumps that optimize various components, such as compressors, heat exchangers, expansion valves, and their controls. Thanks to these innovations and others, the U.S. and other countries are experiencing broader heat pump adoption and, in turn, supporting progress toward decarbonization.
| Heat pump technology has been commercially available. |
Increasing heat pump accessibility and viability in more places and spaces is also critical to the HVACR industry’s commitments to the environment—and its 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.
Where things are headed—heat pump technology is just getting started
Even with the significant advances we’ve seen in colder-climate heat pumps, there is still untapped potential in terms of what the technology can achieve. 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
Use of lower-GWP A2L refrigerants
System optimization will also drive greater use of lower-GWP A2L refrigerants, such as R-454B
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-split, and mono-block technologies.
System optimization will also drive greater use of lower-GWP A2L refrigerants, such as R-454B, while limiting the use of highly flammable refrigerants such as R-290. Refrigerant selection will also play an increasingly important role and may offer additional opportunities for application-specific technology. As heat pump applications expand, we can expect to see greater focus on selecting the optimum refrigerant to use as the working fluid. Criteria will weigh system design, operating conditions, and other priorities against key refrigerant properties:
- Physical—boiling point, vapor pressure, density, and material compatibility
- Thermodynamic—cooling/heat capacity, energy efficiency, pressure-enthalpy (PH) curves
- Environmental—ozone depletion potential (ODP) and global warming potential (GWP)
- Safety and health—flammability and toxicity
Conclusion: There’s strong and ample reason to “stay pumped”
Over the past several years, members of the HVACR industry have enthusiastically embraced new heat pump solutions. Evolving heat pump technology and expanding applications will continue as the industry progresses along the path of more energy-efficient, lower-GWP, and more sustainable new-generation and next-generation heating and cooling.
This, coupled engineering and science that leverages untapped heat pump potential, will mean more opportunities for HVACR contractors to deliver new options to the markets they serve. With a strong understanding of their customers’ individual heating and cooling needs, climate challenges, and sustainability goals, contractors can confidently select the best heat-pump refrigerant solution.