TRI-HP – Trigeneration systems based on multiple renewable sources

In this EU-funded, interdisciplinary project, the project team investigates how end users and stakeholders perceive the innovative TRI-HP technology. The aim of this project is to determine which social needs have to be taken into consideration in order for these systems to be used successfully.

Research approach

Trigeneration systems are systems that combine heat, cooling and electricity generation from multiple predominantly renewable energy sources in order to be used, for example, in apartment buildings. While the majority of the project partners are involved in the development of this innovative technology, the ISOE team's task is to explore the perspectives of the stakeholders who will eventually use or deal with this technology. Taking into account current findings in the social sciences, this ensures that specific needs of end-users and stakeholders are taken into account. 


Despite a steadily growing share of renewable energy supply within the European Union, further efforts are urgently needed to achieve the Paris Agreement Goals. Most greenhouse gas emissions are released by the energy sector, which therefore also offers the greatest savings potential. The TRI-HP project can contribute to CO2 savings as it is an alternative to the use of fossil fuels in the residential sector. Home owners, for whom TRI-HP is also an attractive 3-in-1 solution, can thus not only significantly improve their ecological balance, but are at the same time able to save electricity and heating costs.
However, as we know from social science and technology research, the implementation of technical innovations into social contexts is a complex process in which various stakeholders are involved, such as investors, decision-makers, architects, homeowners or installers. One of the tasks of the ISOE team will therefore be to take this complexity into account in order to be able to identify possible barriers, hindrances and incentives - a process which will involve the direct dialogue with stakeholders. 


Based on the current state of research on social acceptance, innovation, and risk perception, the needs, expectations, and concerns of various affected stakeholders are systematically identified, explicitly including gender aspects. To this end, qualitative data are collected in several European countries with different geographical, climatic, political and cultural conditions. Data will be collected in semi-structured expert interviews, stakeholder workshops and focus group discussions. Finally, data analysis will then enable the researchers to draft recommendations for action.

Project partners

  • SPF Institute for Solar Technology, OST – Eastern Switzerland University of Applied Sciences, Switzerland
  • Fundación Tecnalia Research & Innovation (TECNALIA), Spain
  • Heim AG, Switzerland
  • Catalonia Institute for Energy Research (IREC), Spain
  • ALFA LAVAL Industry (ALFAL), Sweden
  • Industrielack AG (ILAG), Switzerland
  • Norwegian University of Sciences and Technology (NTNU), Norway
  • Danish Institute of Technology (DTI), Denmark
  • Institute of Refrigeration, Air-Conditioning and Environmental Engineering, University of Applied Sciences Karlsruhe (IKKU-UASKA), Germany
  • Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA), Belgium


The project “TRI-HP – Trigeneration systems based on heat pumps with natural refrigerants and multiple renewable sources” is funded by the European Union within the framework of the research and innovation programme “Horizon 2020”.


Stieß, Immanuel/Thomas Friedrich (2022): Accelerating market uptake of heat pump systems: Challenges, visions and steps for change - results from a stakeholder process in four European countries. Peer-reviewed conference paper. Proceedings of the eceee 2022 Summer Study on energy efficiency: agents of change.

Friedrich, Thomas/Immanuel Stieß (2021): Enhancing stakeholders' acceptance of trigeneration heating and cooling systems: Recommendations from the TRI-HP stakeholder process. Brüssel: European Commission

Friedrich, Thomas/Immanuel Stieß (2021): Social acceptance of innovative RE H/C systems: barriers, hindrances, drivers and incentives. Brüssel: European Commission

Friedrich, Thomas/Immanuel Stieß (2019): Social issues of novel renewable energy heating/cooling systems. Brüssel: European Commission


2019/03 – 2023/02