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CO2 as working fluid

CO2 has gone through a renaissance as refrigerant due to the need to replace the chemical refrigerants with highly negative environmental impact.

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The main applications where CO2 systems has been commercialized so far are heat pump water heaters (heat pumps for heating of sanitary water), refrigeration systems for supermarkets and within small size commercial refrigeration. SINTEF-NTNU initiated this development in the end of the 1980s. More than 4 million systems are installed to date, corresponding to a turnover of more than 200 billion NOK.

Several other applications are emerging as promising for use of CO2 as working fluid. Availability of components is rapidly increasing, enabling such a development. Industry and research institutions world-wide are pursuing development within several applications, among these are refrigeration for fishing vessels, transport refrigeration, heat pumps for space conditioning and power process plants for utilization of surplus heat.

Our current client base ranges from the major national and international companies to smaller SMEs. In technical terms, our activities range from basic activities, such as experimental and theoretical understanding of different flow phenomena to the development and testing of components and systems.

We are currently working in the following fields

  • Concept- and system development for new applications important for national and international industry, society, that require more R&D prior to commercialisation
  • Thermodynamic data, heat transfer and pressure drop, flow phenomena
  • Development of more efficient components and systems with the objective to gain energy efficiency for new application areas


When developing new components or systems, we generally combine theory with modelling and simulation studies, and experiments. New concepts commonly require experimental verification. Our work is grounded in good thermodynamic libraries and component and system models developed over many years. Many of the models are based on programmes developed at SINTEF-NTNU. This provides us with unique opportunities to adapt the models to carry out the evaluation and development of new concepts, both for components and complete systems.

We typically carry out the following types of project

  • Multi-client projects co-funded by industry and the Research Council of Norway
  • Projects funded directly by industry in the fields of development, testing and consultation
  • Everything from basic skills development projects to applied research

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