Participating Countries - Germany

Germany aims to reduce its total CO₂ emissions by at least 65% by 2030 compared to 1990 levels. Industrial production accounts for 23% of these emissions, with a major portion resulting from the generation of process heat, which represents 18% of final energy consumption (as of 2023). As a result, Germany has a strong interest in high-temperature heat pump systems and is represented by 7 partners in the Project 68.

The German working group is coordinated by the Fraunhofer Institute for Solar Energy Systems ISE. Fraunhofer ISE is active in heating and cooling technologies and has extended its well-established building-sector expertise in natural-refrigerant heat pumps to industrial and high-temperature applications. It operates a HTHP test bench dedicated for steam and water temperatures up to around 165 °C. Fraunhofer ISE participates in several national and EU-funded projects (e.g. Push2Heat, IndHP2Chem), focusing on HTHPs with natural refrigerants for industrial processes and district heating.

The Fraunhofer Institute for Energy Infrastructures and Geothermal Systems IEG conducts advanced research on industrial-scale heat pumps within its “Thermal Energy Systems” group, combining simulation and experimental approaches. The institute advises the manufacturing and district heating sectors on their transition toward CO₂ neutrality and works closely with industry partners to develop
the required technologies. With comprehensive testing facilities at its Bochum and Cottbus sites, Fraunhofer IEG facilitates joint technology development and testing of large-scale heat pumps, as well as direct electric processes, hydrogen combustion, and both above- and underground thermal storage systems. In addition, the institute explores flexible operation strategies for large, electrified heat
generators to reduce electricity costs and enhance grid stability, supports investment decisions through market analyses and due diligence studies, and develops transformation concepts and implementation projects to integrate innovative heating technologies into industrial and district heating systems.

The Institute of Low-Carbon Industrial Processes at the German Aerospace Center (DLR-DI) is conducting research aimed at reducing CO2 emissions in energy-intensive industries. The institute is developing two types of HTHP systems capable of supplying heat above 200 °C using natural refrigerants, a reverse Brayton cycle heat pump employing dried air, and a multi-stage water vapor Rankine cycle heat pump. In addition, DLR-DI is actively involved in several EU-funded projects (e.g.,SPIRIT, EEETHOS, E-Fryer, EMPHATICAL, CHASE, and others) to demonstrate the benefits of HTHP technology in real industrial applications, focusing not only on CO2 emission reduction but also on economic viability.

The Center of Energy technology (ZET) at the University of Bayreuth conducts research in various fields, like engineering thermodynamics, hydrogen technologies or sector coupling. The chair of engineering thermodynamics and transport processes (LTTT) as member of the ZET has extensive experience in both experimental and theoretical investigations related to high-temperature heat pumps (HTHPs). Experimental research activities include the measurement of thermophysical properties of lubricants, refrigerants, and their mixtures, as well as the characterization of HTHP performance and part-load behavior. Theoretical work focuses on the integration of HTHPs in geothermal and industrial energy systems and the use of innovative working fluids in HTHPs. The chair participates in numerous, primarily national research projects, often in close collaboration with industrial and academic partners.

The Department of Energy System Technologies (EST) at Paderborn University conducts research on HTHPs within its two complementary research groups. In Energy Transition in Industry, the focus lies on standardizing and supporting the process integration of HTHPs in industrial applications, enabling efficient decarbonization of high-temperature processes. The Urban Heating Transition group investigates HTHP deployment in district heating systems, optimizing integration with renewable and industrial waste heat sources. Together, these groups involve various stakeholders and develop technical, methodological, and systemic solutions to promote the large-scale implementation of HTHPs.

The Cross-Energy Systems Chair at Ruhr University in Bochum, headed by Prof. Christian Doetsch, focuses its application-oriented research activities on sector coupling to expand the use of renewable energies in industrial energy supply. Alongside systemic and applied research on hydrogen utilisation, the chair’s primary focus is the electrification of industrial heat via heat pump technology. A key area of research is investigating new refrigerants and working fluid mixtures for use in absorption-based heat pump processes.

The Schaufler Chair of Refrigeration, Cryogenics and Compressor Technology of the TU Dresden brings proven expertise in the fields of heat pump and compressor technology as well as fluid property analysis to Project 68. The chair has many years of globally recognized experience in combining research findings at the fluid level (refrigerants and lubricants), the component level (compressors, expansion devices, heat exchangers) and the system level across a wide temperature range. This experience extends to both theoretical investigations (simulation of steady-state and transient processes) and experiments.

Relevant ongoing or finalized R&D projects of the national team partners:

• Participation in the IEA HPT TCP Annex 58 about High-Temperature Heat Pumps, 2021 – 2023, Project partners: DLR-DI, ISE, EST
• Push2Heat, 2022-2026, 18 partners from 6 different countries, German partners: Fraunhofer IEG, Fraunhofer ISE, Felix Schoeller Group, SPH Sustainable Process Heat, BSNova, TU Berlin
• E-Fryer, 2024 – 2026, CET Partnership Germany, Poland, Sweden, German partners: DLR-DI, Lorenz Bahlsen Snack world
• SPIRIT, 2022 – 2026, 17 partners 3 demo sites, German partners: DLR-DI, GEA, Spilling
• CHASE, 2024 – 2027, 6 partners 4 different countries, German partners: DLR-DI.
• EEETHOS, 2024 – 2028, 18 partners 5 demo sites, German partners: DLR-DI, Felix Schoeller, Univ. of Stuttgart, Heaten.
• EMPHATICAL, 2024 – 2028, 11 partners 7 different countries, German partners: DLR-DI.
• IdWPPro 12/2023 – 08/2024, Fraunhofer ISE, Eastern Switzerland University of Applied Sciences (OST)
• GreenSteam, 2023 – 2025; Project Partners: TU Dresden, Combitherm
• Fern-WP, 2021 – 2026; Project partners: Fraunhofer IEG, Fraunhofer ISE, Fraunhofer ISI, AGFW, JCI, Stadtwerke Cottbus, GESMEX
• SteamScrew, 2023-2026, project partner: Fraunhofer IEG, Aerzen Maschinenfabrik, TU Dortmund
• HeatTransPlan, 2024 –2026, Project Partners: Paderborn University EST (coordinator) Sustainable Process Heat, Limón, Optano, König Metall, Axiotherm, Innozent OWL
• WinPro, 2024-2027; project partners: Fraunhofer IEG, Evonik, BASF, Bayer, Merk, Ineos, FluidVT, Nombian, awama, Atlas Copco
• IndHP2Chem, 2024-2028, project partners Evonik, Fraunhofer ISE
• ZiRa (Development phase), 2021 – 2026, DLR-DI, Water-steam compression Rankine cycle heat pump (> 200 °C).
• CoBra (Commissioning phase), 2024 – Present, DLR-DI, Reverse Brayton cycle heat pump using dried air for simultaneous heating (> 200 °C) and cooling (< −40 °C).
• KETEC – Research Platform for Refrigeration and Energy Technology, 2021 – 2025: Technische Universität Chemnitz; Fraunhofer ISE; Institut für Luft- und Kältetechnik gGmbH Dresden
• Geothermal Alliance Bavaria 2.0 (2021-2024) and 3.0 (2025-2028); project partners: TU Munich (Coordinator), University of Bayreuth, FAU Erlangen, LMU Munich; HM Munich
• Wärme-Klima-freundlich, 2024-2027; project partners: University of Bayreuth, Bavarian State Office for the Environment (LfU)
• Carnot batteries load management, 2025 – 2028, project partners: TU Munich (Coordinator) University of Bayreuth, FAU Erlangen, LMU Munich, HM Munich
• Platform for experimental performance data of HTHPs, ongoing, University of Bayreuth (Coordinator), Eastern Switzerland University of Applied Sciences (OST)
• Information portal for Large-scale Heat Pumps, Landesenergieagentur Hessen, Fraunhofer IEG