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© P. Georgeault

Structures, Processes, Flow, Energy

In summary

In a word


  • 54 permanent staff including 50 researchers, engineers and technicians 
  • 25 top-ranking publications per year on average
  • 11 patents
  • 1 research and technology platform dedicated to multimodal imaging and spectroscopy (PRISM, Rennes)

Lines of scientific research

  • Refrigeration equipment, energy efficiency and energy storage
  • Control of flows and transfers in the cold chain and associated processes
  • Using NMR-MRI to characterise agri-food products and production-line processes
  • Air processing and the control of turbulent atmospheres

Editorial : A partnership with the refrigeration and agri-food industries

Tiphaine Lucas, Deputy science director SPEE

The growth of developing countries in the coming decades is likely to bring changes to many consumers’ eating habits. In the agri-food and refrigeration industries this will require increased and improved production and reduced energy use. The OECD tells us that processes need to become three times as efficient if we are to maintain their environmental footprint at its 2004 level. And we should remember that, in the agri-food industry, temperature control represents approximately 60% of energy consumption (including the distribution network).

In its study of the processes and equipment involved in the agri-food and refrigeration industry, the SPEE research topic (Structures, processes, flow, energy) is able to draw on a range of expertise in the physical sciences including thermics, thermodynamics, fluid mechanics, energetics and automation. Our research makes it possible to maximise the performance of existing technologies, introduce new technologies and support the latter’s development by industrial partners. We are also tackling the major scientific challenge of energy efficiency.

Our multi-scale approach with its focus on method and processes has expanded in recent years to incorporate larger-scale models. For example, findings on the formation and characterisation (temperature and flow patterns) of hydrous slurry are being used to address energy storage in a factory’s refrigeration units as part of energy load reduction. Likewise, an initial model of the growth of a single bubble in a cheese mould has been scaled up to a full wheel of cheese and then expanded to include the whole cheese ripening room so that variations in composition within each mould and differences in temperature between moulds can be factored in. By characterising the velocity fields in mixed airflows and studying zones of turbulence we have achieved improved control of the thermic and particle exchanges between two different atmospheres divided by an air curtain, for example, where a production line is not closed off from the surrounding workshop. And our understanding of airflows and thermal transfers, from cold rooms to refrigerators, has enabled us to develop simplified models for each stage of the cold chain. We then simulate the statistical behaviour of food products and compare the various distribution chains.

Last, our approach combines measurement with modelling, calling for substantial investment in metrology (including new methods of measurement), prototyping and data processing. Our experimental methods also require large-scale technical facilities (such as wind tunnels and imaging platforms).

Selected research projects

Diffusion localisée d'air froid ultrapropre : Froiloc


From factory to kitchen: innovations in the cold chain

Industrial partnerships

The virtuous circle of CIFRE scheme theses

The Cifre package funds business recruitment of doctoral students whose research is conducted in partnership with a state-funded laboratory. A notable feature of the SPEE research topic is that all its teams, and by extension all lines of research, have benefited from this scheme.

With 7 Cifre theses begun since 2010 (three in 2016), the Cifre package is encouraging increasing numbers of manufacturers to engage in projects with the SPEE research teams.

From Air Liquide, Brioche Pasquier and CNIEL (National Centre for Interprofessional Dairy Industries) to Valéo, the verdict is unanimous : their relationship with Irstea has provided our partners with scientific expertise, technical skills and, in some instances, innovative equipment designed to suit their particular interests. It has also allowed them to move beyond the traditional scope of their research and development projects. Christine Charrier heads research and development at Brioche Pasquier which shares a Cifre doctoral student with Irstea. She explains: "it enables us to stay in touch with developments in fields that interest us, especially where we have less in-house expertise. We were initially concerned that the research might not be directly relevant to our manufacturing priorities so the thesis topic was defined jointly to make sure that everybody would gain from the project". Other benefits include scientific support from the research laboratory, an advantageous three-year funding package for such posts through ANRT grants for the duration of the thesis and also the opportunity to publish some of the findings, particularly in peer-reviewed journals which provide a mechanism for results to be endorsed.

Such collaborations often continue beyond the completion of a thesis – they effectively allow the doctoral student to establish a professional network and sometimes even to be directly recruited by the manufacturing partner.

Industrial agreements for training through research

National Association  Research and Technology (www.anrt.asso.fr)


Technological platform

MRI and NMR get an inside view of bioproducts
The Rennes Platform for Multimodal Imaging and Spectroscopy, PRISM, is unique in Europe in its use of imaging equipment to investigate bioproducts. Here, Irstea brings its strengths in MRI and NMR imaging to the field of agronomy and to the agri-food industry.
A first MRI scanner was acquired in 1996, a second in 2008, followed by a NMR micro-imaging system in 2013. By using these non-destructive study methods, Irstea’s researchers have developed new skills in the characterisation of the structure and composition of many bioproducts. Samples can be analysed in their entirety with equipment able to reproduce representative temperature conditions for production-line processes. Irstea also owns a number of NMR machines which provide the analytical tools necessary to study molecular diffusion mechanisms.
All this equipment forms part of the PRISM platform created by Irstea, INRA and the University of Rennes in 2005 as part of the Biogenouest Scientific Interest Group (GIS). PRISM is certified to ISO 9001 and is also IBiSA certified. One of the criteria for the latter is the use of our imaging equipment by external public or private research teams. Here, manufacturers in the agri-food industry can use Irstea’s facilities to understand and improve their food processing. In the case of Les Fromageries BEL this has involved a reduction of the ripening period while the French Cider Producers’ Institute has improved its juice yield and reduced pulp waste in apple pressing to a minimum.
Further applications relating to the impact of climate on agricultural production are being developed. For example, NMR is being used to detect foliar senescence, making it possible to study the impact of water stress on plant physiology. Potential practical applications are currently being evaluated.