A methodology for sizing backup fuel-cell/battery hybrid power systems

Hybridization of fuel cells and batteries combines the advantages of both power sources. This paper proposes the use of fuel-cell/battery hybrid power systems as backup power systems and develops a methodology for sizing both fuel cell and battery bank, according to a minimum lifecycle cost criterion, from any defined hourly load profile and any defined backup time. For this purpose, an existing power-system-sizing computer tool has been used, but its initial capabilities have been extended. The developed methodology allows decisions to be taken before any investment is made. As a practical application, the methodology is used for the sizing of a backup power system for a telecommunication system

Calculating the profits of an economic MPC applied to CSP plants with thermal storage system

Electricity producers participating in a day-ahead energy market aim to maximize profits derived from electricity sales. The daily generation schedule has to be offered in advance, usually the previous day before a certain moment in time. The development of an economically-optimal generation schedule is the core of the generation scheduling problem. To solve this problem, renewable energy plant owners need, besides energy prices forecast, weather prediction. Among renewable energy sources, concentrated solar power (CSP) plants with thermal energy storage (TES) may find it easier to participate in electricity markets due to their semi-dispatchable generation. In any case, the limited accuracy of forecasting solar resource brings about the risk of penalties that may be imposed to CSP plants for deviation from the submitted schedule. This paper proposes a model-based predictive control (MPC) approach with an economic objective function to tackle the scheduling problem in CSP plants with TES. By this approach, the most recent forecast and the current status of plant can be used by the proposed economic MPC approach to reschedule the generation conveniently at regular time intervals. On the other hand, a more feasible generation schedule for the next day is performed at the appropriate time thanks to the use of short-term forecast. The proposed approach is applied, in a simulation context, to a 50 MW parabolic trough collector-based CSP plant with TES under the assumptions of perfect price forecasts and participation in the Spanish day-ahead energy market. A case study based on a half-year period to test several meteorological conditions is performed. In this study, an economic analysis is carried out using actual values of energy price, penalty cost, solar resource data and its day-ahead forecast. Results show an economic improvement in comparison with a traditional day-ahead scheduling strategy, especially in periods with a bad weather forecast. To overcome the lack of short-term weather forecast data for this study, a synthetic short-term predictor, whose accuracy level can be tuned by means of a parameter, is used. Sweeping this accuracy level between the situation with no forecast improvement and perfect shortterm forecast, the MPC strategy reaches an improvement in total profits during the six months period between 13.9% and 33.3% of the maximum room for improvement. This maximum ideal improvement is defined as the difference in profits between the MPC strategy with perfect forecasts and the dayahead scheduling strategy.This research has been supported by DPI2016-76493-C3-2-R Project of Ministerio de Economía y Competitividad (Spain). The authors would like to thank Acciona Energa S.A. for expressing interest in the projec

Predictor intervalar basado en hiperplano soporte

En este trabajo se aborda el problema de construir un modelo predictor. Dicho modelo debe ser capaz de predecir la salida futura de un sistema dinámico, haciendo uso de información pasada guardada en históricos. Este trabajo se centra en el estudio de modelos predictores que proporcionan una predicción de tipo intervalar. Una predicción intervalar está compuesta por un límite inferior y otro superior. La salida del sistema debe estar comprendida entre ambos límites del intervalo. Dado un conjunto de datos obtenidos del sistema dinámico, la predicción intervalar se calcula utilizando hiperplanos soporte a dichos datos. Cualquier punto dentro del intervalo se puede utilizar como predicción puntual. En concreto, en este trabajo se propone la utilización del punto central entre hiperplanos soporte. La principal bondad del predictor propuesto es su capacidad de proporcionar predicciones donde el tamaño del intervalo y el error de la predicción puntual están balanceados. Un parámetro de diseño incluido en el predictor permite compensar dichos objetivos. Además el trabajo propone una metodología basada en validación cruzada para realizar el ajuste de dicho parámetro. El trabajo incluye un ejemplo con datos reales con el fin de ilustrar el comportamiento del predictor.Ministerio de Educación y Ciencia (España) DPI2013-48243-C2-2-RMinisterio de Educación y Ciencia (España) DPI2016-76493-C3-1-RMinisterio de Educación y Ciencia (España) DPI2016-76493-C3-2-

Contribuciones al diseño y optimización de sistemas renovables de potencia basados en energía fotovoltaica y conversión energética de hidrógeno

Esta Tesis forma parte del conjunto de Tesis que se han desarrollado con relación a los proyectos de investigación siguientes: proyecto I+D Sistema generador de energía eléctrica autónomo, contínuo y no contaminante DPI 2007-62336, y proyecto de transferencia tecnológica Diseño, desarrollo, construcción y pruebas de un sistema generador de energía eléctrica basado en pilas de combustible, integrado por un depósito de hidrógeno y un electrolizador para la producción del mismo. En el contexto de ambos proyectos, esta Tesis abarca las realizaciones siguientes: 1. Desarrollo de una metodología para optimizar el dimensionado de sistemas fotovoltaicos aislados usando convertidores CC/CC en paralelo. 2. Desarrollo de una metodología para dimensionar sistemas de potencia pilas de combustible + baterías aplicados a sistemas SAI. 3. Diseño de un laboratorio para la investigación del hidrógeno como vector energético.______________________________This Thesis belongs to the set of Theses that have developed in relation to the following research: 1) Research and development project Stand-alone, continuous and no-pollution electrical power system DPI 2007-62336, and 2) Technological transfer project Design, development, assembly and tests of a electrical power system based on fuel cells, integrating a hydrogen storage and an electrolyzer for the production of hydrogen. In the context of both projects, this Thesis includes the following accomplishments: 1.Development of a methodology for optimizing stand-alone photovoltaic system size using parallel-connected DC/DC converters. 2. Development of a methodology for sizing back-up fuel cell/battery hybrid power systems. 3. Design of a flexible laboratory for the research on hydrogen as energetic vector

Optimal planner for a cooling plant using binary regularization

[Resumen] En este artículo se presenta un planificador óptimo para decidir tanto el nivel de carga instantáneo como el estado encendido/apagado de una serie de máquinas enfriadoras que funcionan en paralelo para abastecer la demanda de frío de una gran instalación. El optimizador tiene un objetivo doble: minimizar el consumo eléctrico de las enfriadoras manteniendo el número de conmutaciones lo más bajo posible. La principal novedad es el uso del concepto de regulación binaria en la función de coste del optimizador. Para seleccionar los valores más adecuados de los pesos de ponderación asociados a los distintos términos de la función de coste se ha realizado un estudio de las posibles soluciones mediante una batería de simulaciones.[Abstract] This article presents an optimal scheduler to decide both the instantaneous part load and the on/off status of a series of chillers which work in parallel to supply the cold load demand of a large installation. The optimizer has a double objective: to minimize the electrical consumption of the chillers while keeping the number of commutations as low as possible. The main novelty is the use of the concept of binary regulation in the cost function of the optimizer. In order to select the most appropriate values of the weighting factors associated with the different terms of the cost function, a study of the possible solutions has been carried out using a battery of simulations.Esta investigación ha sido financiada como Proyecto RTI2018-101897-B-I00 por FEDER / Ministerio de Ciencia e Innovación – Agencia Estatal de Investigación.Ministerio de Ciencia e Innovación; RTI2018-101897-B-I0

Moving beyond unsolicited consultation: additional impact of a structured intervention on mortality in Staphylococcus aureus bacteraemia

[Background] Some evidence-based bundles have tried to standardize the management of Staphylococcus aureus bacteraemia (SAB) to improve the outcome. The aim of our study was to analyse the additional impact on mortality of a structured intervention in patients with SAB.[Methods] Compliance with the bundle was evaluated in an ambispective cohort of patients with SAB, which included a retrospective cohort [including patients treated before and after the implementation of a bacteraemia programme (no-BP and BP, respectively)] and a prospective cohort (i-BP), in which an additional specific intervention for bundle application was implemented. Multivariate logistic regression was used to measure the influence of the independent variables including compliance with the bundle on 14 and 30 day crude mortality.[Results] A total of 271 adult patients with SAB were included. Mortality was significantly different among the three groups (no-BP, BP and i-BP): mortality at 14 days was 18% versus 7% versus 2%, respectively, P = 0.002; and mortality at 30 days was 20% versus 12% versus 5%, respectively, P = 0.011. The factors associated with 14 and 30 day mortality in multivariable analysis were heart failure (OR = 7.63 and OR = 2.27, respectively), MRSA infection (OR = 4.02 and OR = 4.37, respectively) and persistent bacteraemia (OR = 11.01 and OR = 7.83, respectively); protective factors were catheter-related bacteraemia (OR = 0.16 and OR = 0.19, respectively) and >75% bundle compliance (OR = 0.15 and OR = 0.199, respectively). Time required to perform the intervention and the follow-up was 50 min (IQR 40–55 min) per patient.[Conclusions] High-level compliance with a standardized bundle of intervention for management of SAB that requires little time was associated with lower mortality at 14 and 30 days.This study was performed with support from the Mentorship programme of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID). L. E. L.-C. and J. R.-B. are supported by Plan Nacional de I + D+i 2013–2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía, Industria y Competitividad, Spanish Network for Research in Infectious Diseases (REIPI RD12/0015/0010 and REIPI RD16/0016/0001), co-financed by European Development Regional Fund ‘A way to achieve Europe’, Operative Programme Intelligent Growth 2014–2020.Peer reviewe

Estudio del profesorado de Preescolar y EGB de Valladolid y Palencia. Su ordenación y reconversión de cara a la implantación de la LOGSE

Proyecto realizado por un grupo de diez profesores de diferentes centros de las provincias de Valladolid y Palencia y tiene como objetivos: -Analizar la influencia que la implantación del nuevo sistema educativo va a tener en la ordenación y reconversión del profesorado de Preescolar y EGB en las provincias de Valladolid y Palencia; -Estudiar el cupo, situación, especialidades del profesorado actual; -Estudiar la red de Centros en cada provincia, el nuevo catálogo de plantillas en los Centros. En contenido viene dado por la elaboración de una ficha por cada Centro y paralelamente unas tablas globales en las que se recopilan los datos actualizados y las necesidades de profesorado que la implantación del nuevo sistema educativo requiere. El análisis concluye con propuestas que el equipo de trabajo estima necesarias para llevar a cabo la adecuación del profesorado actual a la LOGSE. El desarrollo se propone en cuatro fases: -Elaboración de muestreos y discusiones de equipo; -Recopilación de datos; -Análisis de resultados; -Elaboración y redacción de conclusiones. El trabajo no está publicado..Comunidad Autónoma de Castilla y León, Consejería de Educación y Cultura, Dirección General de EducaciónCastilla y LeónES

Pseudomonas aeruginosa antibiotic susceptibility profiles, genomic epidemiology and resistance mechanisms: a nation-wide five-year time lapse analysisResearch in context

Summary: Background: Pseudomonas aeruginosa healthcare-associated infections are one of the top antimicrobial resistance threats world-wide. In order to analyze the current trends, we performed a Spanish nation-wide high-resolution analysis of the susceptibility profiles, the genomic epidemiology and the resistome of P. aeruginosa over a five-year time lapse. Methods: A total of 3.180 nonduplicated P. aeruginosa clinical isolates from two Spanish nation-wide surveys performed in October 2017 and 2022 were analyzed. MICs of 13 antipseudomonals were determined by ISO-EUCAST. Multidrug resistance (MDR)/extensively drug resistance (XDR)/difficult to treat resistance (DTR)/pandrug resistance (PDR) profiles were defined following established criteria. All XDR/DTR isolates were subjected to whole genome sequencing (WGS). Findings: A decrease in resistance to all tested antibiotics, including older and newer antimicrobials, was observed in 2022 vs 2017. Likewise, a major reduction of XDR (15.2% vs 5.9%) and DTR (4.2 vs 2.1%) profiles was evidenced, and even more patent among ICU isolates [XDR (26.0% vs 6.0%) and DTR (8.9% vs 2.6%)] (p < 0.001). The prevalence of Extended-spectrum β-lactamase/carbapenemase production was slightly lower in 2022 (2.1%. vs 3.1%, p = 0.064). However, there was a significant increase in the proportion of carbapenemase production among carbapenem-resistant strains (29.4% vs 18.1%, p = 0.0246). While ST175 was still the most frequent clone among XDR, a slight reduction in its prevalence was noted (35.9% vs 45.5%, p = 0.106) as opposed to ST235 which increased significantly (24.3% vs 12.3%, p = 0.0062). Interpretation: While the generalized decrease in P. aeruginosa resistance, linked to a major reduction in the prevalence of XDR strains, is encouraging, the negative counterpart is the increase in the proportion of XDR strains producing carbapenemases, associated to the significant advance of the concerning world-wide disseminated hypervirulent high-risk clone ST235. Continued high-resolution surveillance, integrating phenotypic and genomic data, is necessary for understanding resistance trends and analyzing the impact of national plans on antimicrobial resistance. Funding: MSD and the Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea—NextGenerationEU