Researchers from the Laboratory for Cooling and District Energy (LAHDE), together with an international team, have published a study in Nature Energy (Springer Nature), one of the world’s leading scientific journals in the field of energy. The paper offers the first comprehensive assessment of an often-overlooked opportunity: alternative high-temperature heat-pump technologies that could replace inefficient fossil-fuel combustion and direct electric heating in industry and the energy sector. Doing so could significantly reduce energy use, greenhouse-gas emissions, and thermal pollution.
Heat lies at the core of the energy challenge. Around 50% of final energy consumption is used for heating and cooling, and roughly 50% of final energy is ultimately released as waste heat—heat that is frequently discharged into the environment via cooling towers, the warming of rivers or seawater, and other outlets. The study shows that high-temperature heat pumps can capture this waste heat and upgrade it efficiently to much higher temperature levels, suitable for demanding industrial processes.
Today’s commercial high-temperature heat pumps are typically limited to about 250 °C, whereas many industrial processes require higher temperatures—up to, or even beyond, 1000 °C. The newly published research therefore systematically presents and compares alternative approaches that could enable a step change: caloric, thermoelectric and thermoacoustic technologies, as well as mechanical processes based on Stirling and Brayton cycles.
“These solutions point to new products and services, while simultaneously delivering major reductions in energy consumption, emissions and thermal stress on the environment, and improving resilience. Now is the time to bring these products to life, stimulate development in the economy, and carry out a thorough revision of our energy systems and industry,” emphasizes Prof. Andrej Kitanovski, the paper’s lead author.
Co-author Assoc. Prof. Katja Klinar (University of Ljubljana, Faculty of Mechanical Engineering) adds: “Our research opens up entirely new application areas for heat pumps. While their use for heating and cooling buildings is now commonplace, the question is why we should not also deploy them in industrial processes—for example, for temperature ranges from 250 °C all the way to 1200 °C.”
A key advantage of high-temperature heat pumps is energy efficiency. Instead of generating heat through direct combustion or resistive electric heating, industry can reuse existing waste heat and lift it to a higher temperature level. The authors highlight that energy use and associated emissions in high-temperature processes could be at least halved compared with today’s dominant approaches. The greatest potential is identified in manufacturing sectors such as metallurgy, non-metallic mineral products, the chemical industry and refineries, and—partly—the food and textile industries. Significant opportunities are also seen in the energy sector, particularly in waste-heat recovery, sector coupling, and more efficient pathways for converting surplus electricity into heat, rather than relying on today’s often inefficient solutions.
The study involved experts from China, Spain, Croatia and the United Kingdom, underscoring the global relevance of the topic and strengthening Slovenia’s position in the international scientific community. The research also points to a broader challenge: waste heat is still widely treated as a burden rather than an opportunity—yet this is precisely where space opens for new technologies, industrial solutions and higher value-added jobs. The authors note that the work lays the foundation for new projects and prototype development, and they are also considering the commercialization of several ideas that have already advanced to conceptual solutions in recent years.
Publication in Nature Energy is highly significant both internationally and for Slovenian science and industry. The authors set new benchmarks in high-temperature heating processes and heat-pump technologies, addressing an area that has not previously been examined in such breadth. At the same time, the study reiterates that globally—and in Slovenia in particular—waste heat is often treated as an unused by-product and simply released into the environment. The solutions presented offer Slovenian industry the opportunity to develop new, globally competitive products and services. For policymakers, the message is clear: a comprehensive reassessment of energy systems and industrial strategy is needed, supported by collaboration among experts from multiple disciplines.
The article is available at: https://www.nature.com/articles/s41560-025-01908-4