• Energy Research
• French National Research Agency (AN... close

Energy conversion is a sector whose development is strategic for our future. The objective of this collaborative project is to develop multifunctional nanocomposites coatings solutions with high performance for concentrated solar thermal conversion into electricity (CSP). CSP technologies are currently in full development (up to 25% of the global electricity production forecast for 2050). Nevertheless, the solar fields of the CSP plants require an increase in their conversion efficiency and a lowering of costs because they represent, whatever the technologies, about 30% of the installation costs and 50% of the yield losses (mirrors, protections, absorbers). NANOPLAST project is focused on the development of high performance coatings for solar absorbers. One of the important points is the sustainability of the systems in function (# 25 years required). Aging studies of coated systems in order to predict their lifetime are therefore imperative, whereas they are almost non-existent at present. In the NANOPLAST project, low environmental impact and commercially transferable plasma processes will be developed. Their versatility will make possible to achieve a wide range of composition and structuring 2D (multi-nanolayer) and 3D (inclusions at the nanoscale) of thin layers. The thermo-optical performance of nanocomposite structures (SiC / metal, TaON) will be evaluated by the consortium (4 laboratories and 1 industrial) recognized in the fields of CSP applications envisaged. The aim of this project is to meet the growing demand for nanocomposites on a European scale through an integrated understanding of the complete chain, from synthesis to performance evaluation. Given the needs for the CSP, the objectives of the NanoPLaST project are: - the development of multilayered multi-functional nanocomposite materials - developed by high-density versatile plasma technologies with high transfer potential to industry - with a high efficiency of solar thermal conversion via spectral selectivity - with high durability: resistance to high temperature into air (500

The objectives of STOCK-CAR fit into the current requirements for environment-friendly and energy-saving processes. The project targets the development and experimental evaluation of innovative thermochemical heat storage (TCHS) materials for heating (during off periods) the cabin of a truck. The TCHS system will use the waste heat lost to the engine coolant or the exhaust gases for charging the material and water vapor for discharging. The optimization of the TCHS system needs progress not only on the material level (the available materials do not satisfy all needed requirements) but also on the functioning of the reactor model. STOCK-CAR will tackle both issues by starting from synthesis of original materials, going through a deep characterization of their physico-chemical properties and storage performances and then testing in a small-scale reactor. Functionalized and composite materials with added salts on mesoporous structures will be investigated. Mesoporous oxides (SiO2, Al2O3, ZrO2) and phosphates as well as hierarchical materials (with micro/meso/macropores) will be synthesized as supports of hydrated salts (Na3PO4, CaCl2, MgSO4, SrBr2). Surface modification of the porous oxides will induce modifications of the chemical and textural properties. Great improvements in the understanding of the key parameters for an efficient heat thermal storage are expected by controlling the oxide porosity and the chemical nature of the walls (organic functionalization). In the domain of phosphates, more stable mesoporous ALPO and SAPO will be synthesized with various chemical composition and pore size as well as hierarchical ALPO/SAPO containing both mesopores and macropores. Screening methodology will be developed for controlling the physical and thermodynamic factors governing the performance and durability of the storage systems, and to rationalize the materials design and elaboration. In order to assess the reliability of the composite, the thermal behaviour and physical structure of the synthesized materials in water vapor presence, will be studied. By determining the thermodynamic parameters and kinetics of the water/solid interaction by calorimetry, energy density vs sorption capacity, the best TCHS materials will be selected for reactor modeling and optimization of the process. Reactor at lab scale will be designed and processed for testing maximum of samples before the realization of a real heat storage system adapted at truck cabin dimensions. In parallel with the experimental approaches, the numerical developments will be also performed by involving both energy and exergy analysis of the process in order to highlight the critical components of the system, the critical phases of the cycle and to provide outlooks over optimization potential. The partners of STOCK-CAR believe that by significant advancements in new materials with tuned ability to store heat for a variable, controllable period of time and with controlled rate of charging/discharging reactions, it will be possible to develop a high efficient TCHS system. STOCK-CAR seeks not only the industrial application but also the fundamental understanding of the absorption/desorption process of developed compounds which is an important step for such application. This will make the developed methodology transferrable to many other complex/extended systems in sorption processes where solid-vapor interactions are prevailing. The goals proposed in STOCK-CAR are achievable taking into account the involved teams (LMCPA, LMI, IRCELYON and LOCIE) which comprises engineers/scientists specialized in materials, thermodynamics, heat science and process development.

Wind energy is one of the promising energy sources to reach the objective set by the French regulation of increasing renewable energies to about one third of the final energy consumption by 2030. In spite of a strong growth of the wind energy sector these last 10 years, and in spite of a solid potential for development, France has fallen behind on this goal. This may be partly explained by the constraint framework in which wind energy is developing, as well as the opposition of wind farm neighbors who very often mention noise as a potential annoyance. First French collaborative research project on wind turbine noise, the goal of the PIBE project is to improve prediction methods for wind turbines noise and to explore new solutions for noise reduction. The project brings together experts in aeroacoustics, sound propagation, experimental characterization of noise, and wind turbine engineering. The research program is structured in 3 work packages (WP). The first WP aims to study the amplitude modulation phenomena, known to be a major source of annoyance when they occur. This axis focuses particularly on characterizing and modeling the dynamic stall of the flow around the blades, as well as the conditions of amplitude modulation generation at the receiver. These phenomena will be studied both in wind tunnels, and near a wind farm managed by one of the project partner. The publication of a detailed database of the wind tunnel characterization of dynamic stall noise will help advance knowledge about a poorly understood phenomenon. The second WP focuses on quantifying the variability of noise predictions. To achieve this goal, the uncertainties and variabilities of the parameters influencing both the noise emission and the noise propagation will firstly be calculated; secondly, a model of uncertainty propagation (associated with advanced and appropriate statistical methods) will estimate the overall uncertainty. The results will be disseminated through the implementation of an open access online database. The last WP of the project will study and propose new noise reducing devices, using blades with modified leading and/or trailing edges. The efficiency of the solutions will be characterized in wind tunnels, from both acoustic and aerodynamic points of view. An estimate of their performance potential at scale 1: 1 will also be conducted. Results of the projects will eventually allow a better control of the risk of wind turbine noise pollution by the wind energy industry from the wind farm design phase, and thus improve the integration of wind power in the territory. It will help to reduce litigation risks by proposing a better response to noise reduction concerns raised by local residents of existing wind farms (efficient noise reduction devices). It will also enable wind farm developers to optimize production of wind turbine energy, thanks to a better prediction of producible energy during the wind farm phase of development. The results for the uncertainties related to the variability of atmospheric phenomena on the emission and propagation of noise will also feed future works of standardization. It will help to improve the practices of noise prediction, even for other environmental noise sources than wind turbines. In a context in which the reduction of noise pollution remains a major challenge for the authorities, the project will contribute to the limitation of noise emissions and of the possible associated extra auditory effects on health, such as effects on sleep or activities cognitive. Wind farms generating less noise pollution, because designed more optimally, will contribute to a better acceptance of wind power by the citizens. It will thereby support the growth of renewable energy development that guarantee the reduction of greenhouse gases, while respecting the well-being of local populations.

Few studies showed that the effects of rainfall (rain rate and drop size distribution –DSD-) on wind turbine efficiency are significant, but have surprisingly received little attention. The main goal of WR-Turb is to overcome the current lack of knowledge on this topic through a genuine collaboration between an academic institution (the Hydrology, Meteorology and Complexity laboratory of Ecole des Ponts ParisTech) and a wind power production firm (Boralex). Literature review shows that: (i) wind turbulence is a complex feature requiring appropriate framework such as Universal Multifractals (UM, a parsimonious framework that enables to quantify the variability across scales of fields extremely variable across wide range of scales) for analysis and simulations; and intermittency of the input power is further propagating to the wind turbine and power output; (ii) Rainfall also exhibits scale invariant multifractal features. WR-Turb will combine the existing knowledge on wind turbulence and rainfall fields to create a coupled framework enabling to tackle its objectives. Two distinct aspects will be studied: first the rainfall effect on the wind energy resources notably taking into account its non Gaussian extreme small spatio-temporal scale fluctuations and second the rainfall effect on the conversion process of wind power to electric power by the wind turbine. A scientific programme to be primarily implemented through two PhD projects was designed: - WP 1: Experimental set-up and data collection. An observatory for combined high resolution measurements of wind (speed, direction, shear and turbulence), rainfall (DSD, and fall velocities) and power production will be installed for 2 years on a wind farm operated by Boralex and having a 86 m meteo mast. A user friendly data base will be created and data carefully validated. - WP 2: Analysis and simulation of rainfall effects on the wind power available. It aims at analysing mainly with UM tools the collected data to quantify the influence of rainfall conditions on wind turbulence and air density. A classification of rainfall events will be designed for this purpose. Interpretation will require the development of innovative models. A new 3+1D model of drop fields in a 3D turbulent wind at wind turbine scale will be also developed. Scalar and vector spatio-temporal wind fields for scales ranging from few cm and to wind turbine size over few tens of seconds will be simulated by improving existing tools based on continuous UM cascades - WP 3: Analysis and simulation of rainfall effects on energy conversion by wind turbine. The transfer of wind intermittency to power production will be analysed from the collected data (WP1). Then, two numerical modelling chains with increasing complexity will be developed to simulate and quantify the effect of wind turbulence on power production. The wind fields simulated in WP2 will be used (i) to compute available torque fluctuations, and (2) as input in a multi-disciplinary model for numerical simulation of wind turbine behaviour (existing to be customized). Ensembles of possible inputs will be used to quantify the sensitivity of the modelling chains to various input parameters corresponding to the different rainfall conditions. The share of renewable energy is rapidly growing in France and Europe. Hence it is highly relevant to understand the uncertainty affecting the electricity production by such resources, notably because its intermittent nature raises complex challenges in terms of grid management. WR-Turb will have a strong impact on this field by providing a quantification of rainfall effects of wind power production and opening perspectives for improving nowcasts. Results will be up-scalable to other site because they will mainly be event-based. The novel findings of WR-Turb, which will be disseminated to both the scientific and professional community, will also open the path for future investigations.