Celebrating Heat Pumps Day with Björn Palm: Scientific Leadership and IIR Engagement

As a renowned researcher and the Swedish delegate to the IIR, Professor Palm has made significant contributions to the advancement of heat pump technologies. This interview was conducted by Souhir Al-Hammami, Director of Scientific and Technical Information at IIR. 
 

His work spans fundamental research, applied innovation, and international collaboration, making him a key voice in shaping the future of sustainable heating and cooling. The interview explores his insights on scientific breakthroughs, technological development, global trends, and the role of the IIR in promoting sustainable solutions. 

 

Section 1: Scientific Contributions and Research Focus 

1. Could you describe the main focus of your current research on heat pump technologies and how it addresses key challenges in the field? 

My research focuses on several key areas: the use of natural refrigerants such as hydrocarbons and CO₂, safety considerations with flammable refrigerants, and the stability of HFO refrigerants. We also explore geothermal and high-temperature heat pumps, as well as heat transfer in evaporators. 

A major challenge is transitioning from fossil fuels – particularly gas – to electric heating. This shift demands new types of heat pumps, especially for apartment buildings. The F-gas regulation is also pushing the industry toward flammable refrigerants (HC) and systems with low refrigerant charge. These are critical issues we’re working to address. 

 

2. What have been the most significant scientific breakthroughs in heat pump development over the past decade, in your view? 

The introduction of hydrocarbons as refrigerants stands out as a major breakthrough. 

 

3. How do you approach the balance between theoretical research and applied innovation in your work? 

We span the full spectrum – from fundamental research, such as modeling bubble formation in heat exchangers, to applied research on components and systems, and systems analysis for heat pumps implementation in the energy system. Our work includes both computer modeling and experimental studies, conducted in the lab and in real-world settings. 

 

Section 2: Technological Development and Deployment 

4. What are the most promising technological advancements in heat pump systems for residential, commercial, and industrial applications? 

• Residential: Miniaturisation, adoption of HC refrigerants, and development of compressors with low or no oil charge and minimal internal volume. 
• Commercial: Innovations in CO₂ technology. 
• Industrial: High-temperature heat pumps are particularly promising. 

 

5. How do you assess the role of refrigerants in the future of heat pump performance and environmental impact? 

The F-gas regulation and potential bans on PFAS will drive a shift toward natural refrigerants – first in the EU, and eventually worldwide. 

 

6. What are the current limitations in heat pump design and efficiency, and what research directions could help overcome them? 

Cost remains a significant barrier, both for purchasing and installation. Current products also don’t fully meet future needs. Research into safety with flammable fluids, component miniaturisation, and the use of alternative materials, like aluminum instead of copper, will be key to overcoming these limitations. 

 

 

Section 3: Global Trends and Policy Implications 

7. How do you see the role of heat pumps in achieving climate targets and energy transition goals globally? 

To meet the Paris Agreement goals, we must phase out fossil fuels. This means replacing hundreds of millions of gas and oil heaters with electric heating, primarily heat pumps. I don’t see how electrification of the heating sector can happen without them. 

 

8. What are the key barriers to widespread adoption of heat pumps in different regions, particularly in developing economies? 

The safe use of flammable refrigerants requires proper training and certification of technicians, which can be a major hurdle. 

 

9. How can scientific research better inform policy and regulatory frameworks to support heat pump deployment? 

Researchers need to be actively involved in regulatory bodies and produce high-quality studies and publications on these topics. Strengthening connections with policy frameworks is challenging but essential. 

 

 

Section 4: Collaboration and the Role of IIR 

10. As the Swedish delegate to the IIR, how do you see the Institute’s role in advancing international collaboration on heat pump research and standards? 

The IIR plays a vital role by organising conferences that bring researchers together. Its strong network could be leveraged more effectively to support the development of new standards. 

 

11. What opportunities exist for the IIR to strengthen its impact in promoting sustainable heating and cooling technologies? 

Primarily through hosting more conferences focused on these technologies. 

 

12. How can the scientific community engage more effectively with organisations like the IIR to accelerate innovation and knowledge exchange? 

A well-designed website is crucial, IEA HPT recently revamped theirs, which could serve as inspiration. Increasing the number of technical briefs is another effective way to engage researchers and foster collaboration. 

 

Section 5: Future Outlook 

13. What emerging research areas in heat pump technology do you believe will shape the next generation of systems? 

I don’t foresee a radical shift in technology, but rather gradual improvements. There’s significant potential in developing more compact, possibly oil-free compressors. 

 

14. What advice would you offer to early-career researchers entering the field of thermal systems and energy efficiency? 

The heat pump sector is poised for massive growth. There’s a strong demand for both developers and installers, making it an excellent field for young professionals.