Extended description of tunnel junctions for distributed modeling of concentrator multi-junction solar cells

One of the key components of highly efficient multi-junction concentrator solar cells is the tunnel junction interconnection. In this paper, an improved 3D distributed model is presented that considers real operation regimes in a tunnel junction. This advanced model is able to accurately simulate the operation of the solar cell at high concentraions at which the photogenerated current surpasses the peak current of the tunnel junctionl Simulations of dual-junction solar cells were carried out with the improved model to illustrate its capabilities and the results have been correlated with experimental data reported in the literature. These simulations show that under certain circumstances, the solar cells short circuit current may be slightly higher than the tunnel junction peak current without showing the characteristic dip in the J-V curve. This behavior is caused by the lateral current spreading toward dark regions, which occurs through the anode/p-barrier of the tunnel junction

CPVMatch - Concentrating photovoltaic modules using advanced technologies and cells for highest efficiencies

This paper presents the project Concentrating Photovoltaic modules using advanced technologies and cells for highest efficiencies (CPVMatch), which is funded from the European Union’s Horizon 2020 research and innovation programme. V multi-junction solar cells and CPV modules. Concerning cells, novel wafer bonded four-junction solar cells made of GaInP/GaAs//GaInAs/Ge are optimized with the target of reaching 48% efficiency under concentration at the end of the project. Moreover, multi-junction solar cell technologies with advanced materials - like ternary IV element mixtures (i.e. SiGeSn) and nanostructured anti-reflective coatings - are investigated. Concerning CPV modules the project focuses on both Fresnel-based and mirror-based technologies with a target efficiency of 40% under high concentrations beyond 800x. Achromatic Fresnel lenses for improved light management without secondary optics are investigated. In addition, smart, mirror-based HCPV modules are developed, which include a new mirror-based design, the integration of high efficiency, low cost DC/DC converters and an intelligent tracking sensor (PSD sensor) at module level. A profound life-cycle and environmental assessment and the development of adapted characterization methods of new multi-junction cells and HCPV modules complete the work plan of CPVMatch

Biorefinery of biomass of agro-Industrial banana waste to obtain high-value biopolymers

On a worldwide scale, food demand is increasing as a consequence of global population growth. This makes companies push their food supply chains’ limits with a consequent increase in generation of large amounts of untreated waste that are considered of no value to them. Biorefinery technologies offer a suitable alternative for obtaining high-value products by using unconventional raw materials, such as agro-industrial waste. Currently, most biorefineries aim to take advantage of specific residues (by either chemical, biotechnological, or physical treatments) provided by agro-industry in order to develop high-value products for either in-house use or for sale purposes. This article reviews the currently explored possibilities to apply biorefinery-known processes to banana agro-industrial waste in order to generate high-value products out of this residual biomass source. Firstly, the Central and Latin American context regarding biomass and banana residues is presented, followed by advantages of using banana residues as raw materials for the production of distinct biofuels, nanocellulose fibers, different bioplastics, and other high-value products Lastly, additional uses of banana biomass residues are presented, including energy generation and water treatmen

Directorium divini cultus ad Cathedralis Ecclesiae Minoriccensis : eiusque Dioecesis usum

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L’aliment: un système complexe à modéliser et maîtriser

National audienc

A Tool to Characterize the Electrical Influence of the Thermal and Mechanical Behaviors of Materials of Optics for CPV applications

Concentrating Photovoltaics (CPV) field aims to integrate expensive high efficiency multi-junction cells into modules with low cost concentrating optics. The choice of the optics depends on different factors: easiness of fabrication and integration process, added costs, optical efficiency and the profile of the spot uniformity reaching the cell. Indeed, previous work has shown a dependence between electrical performance and spectral and spatial uniformities of the light on the cell. To analyze it, a solar CPV test bench is developed at CEA-INES facilities. Lens and cell temperature can be applied separately, in order to evaluate independently different test conditions, while electrical or optical parameters are recorded. The present work shows how temperature and mechanical variations on first stage concentrating optic affects module performances. Several optics and materials are compared, in order to present the tool capabilities

First investigation of quantum effects in heterojunction solar cells

International audienceThis paper focuses on the impact of quantum effects in a-Si:H / c-Si heterojunction solar cells simulation. A simulation flow is presented, in which a self-consistent Poisson-Schrödinger approach is coupled with classical physics simulations. It is shown that quantum effects have a significant impact on the calculated charge description at front a-Si:H / c-Si interface and appear mandatory for accurate a-Si:H parameters extraction and confident heterojunction solar cell simulation results

Using cloudy kernels for imprecise linear filtering

IATE Axe 5 : Application intégrée de la connaissance, de l’information et des technologies permettant d’accroître la qualité et la sécurité des alimentsInternational audienceSelecting a particular summative (i.e., formally equivalent to a probability distribution) kernel when filtering a digital signal can be a difficult task. To circumvent this difficulty, one can work with maxitive (i.e., formally equivalent to a possibility distribution) kernels. These kernels allow to consider at once sets of summative kernels with upper bounded bandwith. They also allow to perform a robustness analysis without additional computational cost. However, one of the drawbacks of filtering with maxitive kernels is sometimes an overly imprecise output, due to the limited expressiveness of summative kernels. We propose to use a new uncertainty representation, namely cloud, to achieve a compromise between summative and maxitive kernels,avoiding some of thei rrespective shortcomings. The proposal isthen experimented on a simulated signal