Methodology to optimize fluid-dynamic design in a redox cell

[EN] The present work is aimed at the optimization of a redox cell design. The studied redox cell consists on a device designed to convert the energy of reactants into electrical energy when a liquid electrolyte reacts at the electrode in a conventional manner. In this particular sort of cells, the two electrolytes are present and separated by a proton exchange membrane. Therefore, the flow of the electrolyte and the interaction with the membrane takes a paramount importance for the general performance of the cell. A methodology for designing the inlet part of the cell based on optimizing the uniformity of the flow and the initial position of the membrane is presented in this study. This methodology, based on the definition and optimization of several parameters related to the electrolyte flow in different regions of the geometry, is depicted. The CFD (Computational Fluid Dynamics) model coupled with the statistical study pointed to several practical conclusions on how to improve the final geometry construction of the redox cell. A particular case study of redox cell is implemented in order to validate the proposed methodology[ES] El presente trabajo tiene como objetivo la optimización de un diseño de la batería redox. La pila redox estudiada consiste en un dispositivo diseñado para convertir la energía de los reactivos en energía eléctrica cuando un electrolito líquido reacciona en el electrodo de una manera convencional . En este tipo particular de células , los dos electrolitos están presentes y separados por una membrana de intercambio de protones . Por lo tanto , el flujo del electrolito y la interacción con la membrana tiene una importancia primordial para el rendimiento general de la célula . La metodología propuesta para el diseño de la parte de entrada de la celda en base a la optimización de la uniformidad del flujo y la inicial posición de la membrana se presenta en este estudio . Esta metodología, basada en la definición y optimización de varios parámetros relacionados con el flujo de electrolito en las diferentes regiones de la geometría , es representado . El modelo de CFD (Computational Fluid Dynamics ), junto con el estudio estadístico se refirió a varias conclusiones prácticas sobre la manera de mejorar la construcción geometría final de la pila redox . El estudio de caso particular de célula redox que se describe, se implementa con el fin de validar la metodología propuestaEscudero González, J.; López Jiménez, PA. (2014). Methodology to optimize fluid-dynamic design in a redox cell. Journal of Power Sources. 251(1):243-253. doi:10.1016/j.jpowsour.2013.11.058S243253251

Performance characterization and cost assessment of an iron hybrid flow battery

Verkefnið er unnið í tengslum við Háskóla Íslands og Háskólann á AkureyriElectrolyte solutions are a large percentage of the total cost of commercial flow battery systems. Decreasing the cost of the electrolyte has the potential to lower flow battery system costs. In this study, a design and corresponding cost model is developed for a 10 kW/20 kWh flow battery that uses an all-iron based electrolyte with a nominal open-circuit voltage of 1.2 V. Electrolyte costs for large-scale production of this battery are estimated to be 23 cents per liter (88 cents per gallon). Expected system costs are $1492/kW and$715/kWh for a production of 1000 units per year. A hypothetical scaled-up system is analyzed in a simulated area regulation application for one year of operations. Parallel studies were conducted on a small 50 cm2 cell with current densities from 20 mA/cm2 to 80 mA/cm2, and charge densities of 50 mA-hr/cm2 to 100 mA-hr/cm2. Symmetric electrolyte tests show reversible and repeatable reaction behavior on the positive electrode, with reactant utilization up to 67%. The iron flow battery can function with a microporous membrane, although electrolyte crossover problems were identified and the best results were achieved with a non-porous Nafion membrane. 56% energy efficiency was achieved at a current density of 50 mA/cm2. Coulombic efficiencies as high as 91% and voltaic efficiencies as high as 76% were observed

Comparison of conventional, amplification and bio-assay detection methods for a chronic wasting disease inoculum pool.

Longitudinal studies of chronic wasting disease (CWD) in the native host have provided considerable understanding of how this prion disease continues to efficiently spread among cervid species. These studies entail great cost in animal, time and financial support. A variety of methods have emerged including transgenic mouse bioassay, western blot, enzyme-linked immunoassay (ELISA), immunohistochemistry (IHC), serial protein misfolding cyclic amplification (sPMCA) and real time quaking-induced conversion (RT-QuIC), that deepen our understanding of this and other protein misfolding disorders. To further characterize an inoculum source used for ongoing CWD studies and to determine how the readouts from each of these assays compare, we assayed a CWD-positive brain pool homogenate (CBP6) and a mouse dilutional bioassay of this homogenate using the above detection methods. We demonstrate that: (i) amplification assays enhanced detection of amyloid seeding activity in the CWD+ cervid brain pool to levels beyond mouse LD50, (ii) conventional detection methods (IHC and western blot) performed well in identifying the presence of PrPSc in terminal brain tissue yet lack sufficient detection sensitivity to identify all CWD-infected mice, and (iii) the incorporation of amplification assays enhanced detection of CWD-infected mice near the LD50. This cross-platform analysis provides a basis to calibrate the relative sensitivities of CWD detection assays

Engineering aspects of the design, construction and performance of modular redox flow batteries for energy storage

Despite many studies and several extensive reviews of redox flow batteries (RFBs) over the last three decades, information on engineering aspects is scarce, which hinders progress with scale-up and implementation of this energy storage technology. This review summarises cell design requirements then critically considers design, construction and cell features together with their benefits and problems, leading to good practice through improved cell performance, knowledge and experience. Techniques for the characterisation of the reaction environment are illustrated by measurements of mass transport to (and from) electrode surfaces as a function of flow conditions, as well as pressure drop and electrolyte flow dispersion. The effect of design features on performance is illustrated by the effect of process conditions on the components of cell potential. Adequate attention to engineering aspects is seen to be critical to the effective performance of RFBs, particularly during scale-up and long-term operation. Techniques for the characterisation of reaction environment are summarised and a list of essential design and construction factors is provided. Finally, critical areas needing research and development are highlighted

Reproducibility of fluorescent expression from engineered biological constructs in E. coli

We present results of the first large-scale interlaboratory study carried out in synthetic biology, as part of the 2014 and 2015 International Genetically Engineered Machine (iGEM) competitions. Participants at 88 institutions around the world measured fluorescence from three engineered constitutive constructs in E. coli. Few participants were able to measure absolute fluorescence, so data was analyzed in terms of ratios. Precision was strongly related to fluorescent strength, ranging from 1.54-fold standard deviation for the ratio between strong promoters to 5.75-fold for the ratio between the strongest and weakest promoter, and while host strain did not affect expression ratios, choice of instrument did. This result shows that high quantitative precision and reproducibility of results is possible, while at the same time indicating areas needing improved laboratory practices.Peer reviewe