Reliability and durability are key considerations to successfully deploy Proton Exchange Membrane Fuel Cells (PEMFCs). Since the link between materials defects and performances at the scales of the Membrane Electrode Assembly (MEA) and the stack is now well documented, LOCALI shall provide information about the propagation of these defects to other materials or to other locations in the stack. LOCALI aims to improve the existing systems and will ultimately provide effective tools to control their mass-production, the quality of the stacks and their diagnosis for on-site maintenance (stationary) or for on-board (transportation) applications. To these goals, the study focuses on three main axes, developed for PEMFCs (but which can easily be implemented for E-PEM). Firstly, LOCALI will develop instrumentation dedicated to local current density measurement and local electrochemical impedance spectroscopy: well-instrumented segmented cells and magnetic fields measurement are the core competences to these goals. The second challenge of LOCALI is, by using tailored defective MEAs or thanks to specific operating conditions (flooding, reagent exhaustion, ...) to characterize how local and overall performances of the MEA are affected, and to identify the signatures of the various anomalies. Our target is to identify the source of the heterogeneities as well as to locate degraded areas inside a stack. Finally, LOCALI will enable to track, during ageing, how the initial and controlled defects do propagate upon operation. A particular attention will be paid on two points: (i) does a defect in the one material of the MEA (e.g. a hole in the PEM) influence the local degradation of its neighboring materials (e.g. the catalyst layer); (ii) does the defect propagate spatially, and if so, does it happen only at the MEA scale (e.g. from the inlet to the outlet regions) or at the stack scale (i.e. from the defective cell to its neighboring ones).

Key words: Phase Change Materials (PCM), Suspensions of micro-encapsulated Phase Change Materials (mPCM), Heat transfer, Convection, Physical characterization of mPCM and of the systems, Fluid mechanics, Energetics, urban environment, process optimization. Methodologies: Multi-scale and Multiphysics approaches via experiments and computations. Providing urban thermal comfort and maintaining human mobility in case of icing, snow or heat waves in densely populated areas is of crucial importance in our increasingly urbanized world. The goal of the project Convinces is to investigate reversible systems, cooling during heat waves / heating during icing at strategic urban places via the flow of a microencapsulated Phase Change Materials (mPCM) suspension in the draining layer. In the present project, fundamental and applied research will be carried out to understand physical mechanisms at play in the flow of mPCM suspensions subject to a vertical temperature gradient. Thus, studying buoyancy driven flows in detail is crucial in order to optimize heat transfer. While natural convection involves heat transfer rate enhancement up to 40% during phase transitions, the convective flows of mPCM slurries can involve still better heat transfer. However, in most experimental studies, global temperature measurements have only been obtained by means of thermocouples or IR thermography, since most of the systems are opaque. For similar reasons, local velocity fields are difficult to obtain within the fluid which leads to macroscopic measurements of heat transfer. However, local measurements are required to gain insight regarding the coupling between dynamics and heat transfer as well as to understand physical mechanisms involved. The Convinces project aims at dealing with the mixed convection of mPCM suspensions in porous media considering any relevant scales (from the micron caps to the meter mock-up), facing also with the multi-physics aspects. To achieve this, a wide range of advanced experimental techniques (SThM, laser-based photothermal methods, Digital Holographic Microscopy, IR Thermometry, MRI Velocimetry and Thermometry...) will be implemented to characterize the systems and describe the flows locally. Numerical modeling of these systems is of crucial importance to the success of this project. Sophisticated numerical methods will be implemented. Determining heat transfer in the system (porous layer and surface layer) is also an essential key and a final objective to tend to applicative engineering systems. More particularly, we intend to focus on urban applications (downtown squares, schoolyard, pedestrian area, sidewalks, café terraces, touristic places). Optimizing energy systems places Convinces at the heart of a general thinking on reducing energy consumption supported by “Stratégie Nationale de Recherche sur l'Énergie” (SNRE).

Plate-form(E)3 project: "Digital Platform for calculation and optimization of Energy Efficiency and Environmental at different scales for industry (Component / Process / Plant / Planning)" should contribute to the optimization of energy efficiency and environmental industry and territories, considering the thermal aspects but also materials and integrating the system dynamics. This project submitted to the ANR represents a first step of a global platform, following the group's reflections programmatic 8 "Industry and Agriculture" of the ANCRE. The vision of this group is summarized in this sentence from the report ANCRE "The proposed program responds to a triple need: to evaluate the flow of energy and matter, evaluate the contribution of an added improved component or improved technology energy efficiency of a process or plant, and finally have a repository shared between all stakeholders (academia, industry, communities, etc.). Plate-form(E)3 will be concretized in a numerical tool to help design and decision based on cost/benefit, the costs and benefits can be economic and/or environmental. This tool for researchers, engineers from industry, energy consultants, engineers, local authorities will assess the impact of new technologies on a large scale, and to propose an energy integration across the territory seeking potential interconnections between industries (Territory scale ), to optimize process efficiency (plant/process scale) and help the optimal design of new technologies (component level). The platform will be based on existing tools, with defined methodologies, software and platforms. For this objective, an analysis study will be made (Tasks 1 and 2). Development tools and the missing tools will be realized in the project to complete the gaps identified (Task 3). Taking into account the needs of users, close links will be through for example with industry and local authority (Task 2), as a part of the overall project. Today this partnership represents the "designers" of this tool but will be extended to users in the following steps. They will be consulted to ensure the adequacy of the platform and its functionality to their needs. We can already mention the following entities as being interested in participating in the overall construction of the platform: • industrials such as Lafarge, INEOS, Arcelor Mittal who want to reduce their energy and environmental impact, • communities like Grand Lyon who wishes to develop their territory at best in terms of energy and environmental, • engineering companies such as Technip using this tool that could take into account environmental plant energy before its amendment or its implementation. This ANR project partnership includes key stakeholders in the field in France and abroad. Methodological aspects and software for the process are investigated within the framework of the ANR project CERES-2 by EDF, Armines, and the LEMTA IFPEN. The partners cover the areas of energy efficiency technologies (EDF), optimization methodology and modeling efficiency (Armines and LEMTA), processes, technical-economic and environmental impact (IFPEN, INDEED). Building efficiency (Plant) reflects the activities of CETIAT. The developed tool aiming to be valued and must willing optimized high performance digital Federation Hermite Charles will bring his expertise on these topics.

By 2028, the share of geothermal energy in the energy mix will double. To achieve this ambitious objective, the major problem of geothermal fluids circulation in aquifers has to be overcome in order to gain in plant efficiency. The microorganisms, evolving in these porous media, form biofilms that grow and clog the pores leading to a reduction in the production rate. To solve this issue, biocides are injected but are not very efficient. The BIOCIDES project proposes an experimental approach covering a broad spectrum of space and time scales to enrich the fundamental knowledge of bio-clogging mechanisms and their remediation in porous media. These tools, coming from fundamental sciences and mastered by the partners of our consortium will be used to determine innovative indicators assessing the effectiveness of biocide-based treatments in porous media and thus achieving their reasoned use.

The challenge of the DURACELL project is to improve the durability of PEM fuel cells by optimizing the mechanical properties of the interfaces within the membrane-electrode assemblies (MEAs), where the electrochemical reactions take place. The latter are subjected to complex and variable mechanical stresses depending on the hygrothermal conditions related to the operation of the fuel cell, which can lead to the damage of its components and the shutdown of the system. The initial objective of the project will be to measure, identify and control the manufacturing parameters of the MEA that impact the adhesion between its layers. To that goal, specific mechanical characterizations will be implemented in order to quantify the level of adhesion at the interfaces of MEAs manufactured within the DURACELL project consortium. The measured properties will then be implemented in a numerical model in order to contribute to the prediction of the optimal physical properties of the MEA and its assembly conditions to limit the mechanical damage of its components. These results will be verified by comparing the lifetime of MEAs assembled under these different adhesion conditions, via in situ and ex situ accelerated stress tests (hygrothermal cycling and coupled mechanical/chemical degradation). These different tests will provide a better understanding of the mechanical/chemical degradation synergies that occur in the membrane and at the membrane|electrode|gas diffusion layers interfaces. They will also allow to unbundle the different mechanisms responsible for the degradation of MEAs in a system environment. The analysis of the results of the DURACELL project will lead to recommendations to be shared with the scientific and industrial community to limit the level of mechanical stresses undergone by the different components of a PEMFC, thus contributing to the increase of its life span in operation.