Refrigerants of the future in a holistic perspective
This article is a takeaway from the HTHP Symposium 2024, and it sums up the different points of view on the choice of refrigerants expressed by the presenters as well as the participants.
Published: May 2024
The Global Warming Potential is driving the political agenda for future refrigerants, but safety, operational economy, and energy efficiency also play an important role in the industry's choice of refrigerants for high-temperature heat pumps.
Approximately 85 percent of the upcoming high-temperature heat pump technologies have been developed to be able to use natural refrigerants. This is stated in the project Annex 58 High-Temperature Heat Pumps, which – so far – is the most comprehensive overview of technologies and planned or commissioned high-temperature heat pumps in Europe, the USA, Canada, Japan, China, and South Korea.
- According to Annex 58, at least two-thirds of the developed technologies will be using a natural refrigerant. In 26 percent of the technology developments, HFO is indicated as refrigerant, but several HFO projects are considering using natural refrigerants. So possibly up to 85 percent of the upcoming high-temperature heat pumps will be using natural refrigerants. It seems that there are solutions based on natural refrigerants for all applications, and almost every supplier is working on a product with natural refrigerants, said Benjamin Zühlsdorf, Innovation Director at Danish Technological Institute, at the High-Temperature Heat Pump Symposium 2024 in Copenhagen.
One of the sessions at the High-Temperature Heat Pump Symposium 2024 in Copenhagen was dedicated to refrigerants, and here it was mentioned that the new EU F-gas regulation will further reduce the use of fluorinated refrigerants. A Global Warming Potential of 150 will be the limit that the refrigerant industry must stay below to be sure to be able to sell its refrigerants in the EU. By 2050, the goal is to completely phase out fluorinated refrigerants in the EU. Both for environmental reasons, but now also due to the risks associated with TFA and PFAS in synthetic refrigerants.
Strategic choice of natural refrigerants
The title of the session on refrigerants was "Refrigerants – which is the safer choice?". Safety understood as both physical safety and environmental safety, but also the safety of being able to use the refrigerant in the future.
Regarding personal and material safety, natural refrigerants are often flammable, while the synthetic ones are not flammable to the same extent. However, parameters such as temperature, energy efficiency, and operating economy over the entire lifetime of the heat pump are also considered when the industry chooses a new heat pump solution.
- All refrigerants have advantages and disadvantages. At GEA, we have chosen to only deliver heat pumps using natural refrigerants. This is the path politically chosen in Europe, and this is the way we see the market moving in the future, said Kenneth Hoffmann, Application Manager at GEA.
But for many customers, the choice of heat pump is primarily based on economy – in other words, they choose the cheapest solution.
- Phasing out F-gases is important because there are customers who will always base their choice on price. Therefore, a political regulation of refrigerants is necessary if we want to achieve more climate-friendly heat pumps, said Kenneth Hoffmann.
A holistic approach to refrigerants
Another panel participant was Harald Nes Rislå, Chief Technology Officer at the heat pump supplier Heaten. He called himself an agnostic when it comes to choosing refrigerants.
- We deliver the solutions that the customers want, whether it's HFO or natural refrigerants. I would like to advocate for a holistic approach to refrigerants and heat pumps. Regardless of the choice of refrigerant, fossil fuels are displaced when we use a heat pump. A heat pump can compensate for its own greenhouse gas impact from refrigerants in a few months, because it can be operated with green electricity and is more energy efficient than a boiler, said Harald Nes Rislå.
He also mentioned that a heat pump in some cases may be operated more energy-efficiently with an HFO refrigerant than with a natural refrigerant. So, what is the most climate-friendly solution?
- We will offer HFO refrigerants as long as they are legal to use, and as long as our customers demand these refrigerants, he continued.
In another session at the symposium, Sander Geelen from Geelen Counterflow said about the choice of refrigerants:
- Today, our solutions run on HFO refrigerants, but our customers demand natural refrigerants. We must be ready to deliver both types of systems – depending on what the customers want. In this connection, risks and safety can also play a role for the customer. Refrigerants have different risk profiles and thus different safety requirements. Some natural refrigerants – for example hydrocarbons – are categorized at the highest risk level A3, and this can also influence the customer's choice of refrigerant, said Sander Geelen.
Safety and new risks
Mikkel Aaman Sørensen from the Miljøministeriet (Danish Ministry of Environment) stated that the definition of refrigerant safety has been broadened over time. Today, safety and risks have become much more complex issues that not only include the classic risks like toxicity, flammability, explosion risk, and pressure sensitivity, but also environmental and climate impacts – seen over the entire lifecycle of the machine.
First, the greenhouse gas impact was added as a risk factor, and most recently, PFAS and TFA have been mentioned as new possible environmental and health threats coming from the fluorinated refrigerants.
- PFAS is a relatively new problem, and who knows what might happen in the future. There may be new risks that we are not yet aware of. It can also be considered a leakage problem. As long as the refrigerants stay inside the heat pump, they don't pose a problem. Therefore, an important task is to prevent leaks, even though it is hard to avoid them completely, said Mikkel Aaman Sørensen, Head of Section at the Danish Ministry of Environment.
Leaks are unacceptable regardless of the refrigerant, said another panel participant.
- The climate impact from refrigerants typically occurs through leaks and human errors, but with the right design and the right handling of the refrigerants, leaks can be reduced to 1 percent. Provided that you train your refrigeration technicians correctly, and if you do regular checks for leaks, said Mohammed Youbi Idrissi, Technical Leader, Europe MEA, from Honeywell.
According to him, the reality is that the industry thinks in business cases and therefore looks a lot at energy efficiency and operating costs over time – and not just at environmental and climate impacts.
- Especially when we talk about new high-temperature heat pumps, energy efficiency can become very important, and here you will also look at whether HFO refrigerants or natural refrigerants deliver the best energy efficiency, said Mohammed Youbi Idrissi.
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