This article was written by Frédéric Genest from Natural Resources Canada, the Canadian participant in HPT TCP by IEA Annex 60 on heat pump deployment in large non-domestic buildings.
The Canadian and North American heat pump market is currently undergoing a great change. In accordance with the Kigali amendment to the Montreal Protocol, starting January 1, 2025, refrigerants GWP limits defined in federal regulations of both the Canada and the US for various applications will severely limit the availability of many equipment and systems using higher GWP refrigerants. For the space conditioning industry, this means it will not be possible to import products manufactured after that date using refrigerants such as R-134a and R-410a (those F-gases will be available until 2036 for existing equipment). Provincial regulations also provide additional restrictions in their various jurisdictions. As these two refrigerants are used in most chillers, air conditioners, and heat pumps used for space heating and cooling, this results in a very large number of products currently being discontinued.
After some delays in their approval, the recent updates to ASHRAE 15-2022, Safety Standard for Refrigeration Systems, and CSA B52-2023, Mechanical refrigeration code, introducing specific requirements for lightly flammable refrigerants (Safety Classes A2L and B2L), now fully open the door for low-GWP HFOs and their blends.
Since the beginning of 2024, new products have been announced every month to replace the disappearing product lines. The newly introduced products use a variety of refrigerants, as North American manufacturers have not yet standardized on a specific subset of F-gases as they had before. Among the new offerings today, we see R-454B and R-32 as fairly common options for A/C units and heat pumps, while R-513A appears popular for chillers and larger products. Still, a large selection of new low-GWP refrigerants has been retained for a variety of air-conditioning products, sometimes even as options for a single product line (for example, R-513A, R-1234ze, R-515B, and R-1233zd for the chiller line of a specific manufacturer). Furthermore, specialized refrigeration applications see other sets of HFO-based refrigerants or blends, depending on the use and operating conditions.
Though manufacturers have striven to market products with similar capabilities, the changes in refrigerant often result in different equipment capacities and efficiency. Also, the variety of refrigerants may complicate the maintenance tasks of refrigeration specialists as they will constantly need to adjust to the refrigerant characteristics of the equipment they are dealing with. Hence, it is difficult at this time to judge the impacts that these new products will have on the operation and maintenance activities of building owners.
One interesting side effect of the refrigerant change is that many low-GWP HFOs and their blends tend to have different thermodynamic characteristics. These open new avenues for heat pumps applications, such as operation with a larger temperature lift between source and load, as well as with a higher load supply temperature. Consequently, we expect to see more products in the air-source cold climate heat pump categories (able to operate at outdoor temperatures below -20 C), while high-temperature heat pumps (able to supply hot water at 80 C and more) are already available from a variety of small and large product manufacturers. These new products will greatly support the decarbonization objectives of the building sector in the coming years.
Lastly, natural refrigerants are present in the North American market, though their use is still limited. The regulations in place greatly hinder the market presence of hydrocarbons, though these are present in smaller equipment, such as domestic refrigerators, where the refrigerant charge is below the current limitations. Regarding ammonia and CO2, systems using these are generally limited to specific applications (large chillers/heat pumps, domestic water heating, supermarket refrigeration systems, etc.). But, with the increasing pressure to reduce GHG emissions, as well as the growing concerns with PFAS, interest in natural refrigerants and products using them will certainly increase during the coming decade, as the European market can bear witness to.
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