Control de un sistema fotovoltaico con asistencia de red para la producción de hidrógeno

La capacidad de almacenamiento y transporte de energía de alta calidad hace del hidrógeno un excelente vector energético. Debido a que no se encuentra naturalmente aislado, este elemento requiere una determinada cantidad de energía para su extracción de diversas fuentes, las cuales se pueden clasificar en combustibles fósiles, biomasa o agua. Entre los diversos métodos de producción de hidrógeno existentes se destaca la electrólisis del agua, cuya principal ventaja es que admite la energía eléctrica generada a partir de fuentes renovables. El hidrógeno producido de esta manera queda exento de emisiones de carbono, condición necesaria para que este vector energético constituya una alternativa sustentable a los combustibles fósiles

Producción de H2 Basada en GDR y Asistida por Red Débil. Topología, Operación y Control del Sistema

Renewable Distributed Generation (RDG), as a production of electrical power near to the load, is particularly beneficial when the grid is “weak” compared to specific demands, as in the case of hydrogen production systems connected to rural electrification networks. In this situation, the wind resource may be suitable for this type of generation.This paper proposes the topology, operation strategy and control for a hydrogen production station, “assisted” by a weak AC network and “fed” by a variable speed wind turbine based on a three-phase induction machine with double stator. The wind energy conversion is optimized by proper control of the generator, the electrolyser current is regulated to take maximum advantage of the generated power, the rapid fluctuations in power, due to turbulences, are compensated by a controlled energy storage system with flywheel.System configuration, mode of operation and control, and validation by simulation are presentedLa Generación Distribuida Renovable (GDR), como producción de energía eléctrica en proximidades de la carga, resulta particularmente beneficiosa cuando la red de distribución es “débil” frente a demandas puntuales, como sucede en los sistemas de producción de hidrógeno conectados a redes de electrificación rural. En este ámbito, el recurso eólico puede ser adecuado para este tipo de generación. En el trabajo se propone la topología y la estrategia de operación y control para una estación de producción de hidrógeno, “asistida” por una red débil de CA y “alimentada” por un aerogenerador de velocidad variable, basado en una máquina de inducción trifásica de doble estator. La conversión eólica es optimizada mediante un adecuado control del generador; la corriente del electrolizador es regulada para el máximo aprovechamiento de la potencia generada; las fluctuaciones rápidas de potencia, por turbulencias, son compensadas mediante un sistema controlado de almacenamiento de energía con volante de inercia. Se presenta la configuración del sistema, su modo de operación y control, y la validación por simulació

Reduction of cardiac imaging tests during the COVID-19 pandemic: The case of Italy. Findings from the IAEA Non-invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Background: In early 2020, COVID-19 massively hit Italy, earlier and harder than any other European country. This caused a series of strict containment measures, aimed at blocking the spread of the pandemic. Healthcare delivery was also affected when resources were diverted towards care of COVID-19 patients, including intensive care wards. Aim of the study: The aim is assessing the impact of COVID-19 on cardiac imaging in Italy, compare to the Rest of Europe (RoE) and the World (RoW). Methods: A global survey was conducted in May–June 2020 worldwide, through a questionnaire distributed online. The survey covered three periods: March and April 2020, and March 2019. Data from 52 Italian centres, a subset of the 909 participating centres from 108 countries, were analyzed. Results: In Italy, volumes decreased by 67% in March 2020, compared to March 2019, as opposed to a significantly lower decrease (p < 0.001) in RoE and RoW (41% and 40%, respectively). A further decrease from March 2020 to April 2020 summed up to 76% for the North, 77% for the Centre and 86% for the South. When compared to the RoE and RoW, this further decrease from March 2020 to April 2020 in Italy was significantly less (p = 0.005), most likely reflecting the earlier effects of the containment measures in Italy, taken earlier than anywhere else in the West. Conclusions: The COVID-19 pandemic massively hit Italy and caused a disruption of healthcare services, including cardiac imaging studies. This raises concern about the medium- and long-term consequences for the high number of patients who were denied timely diagnoses and the subsequent lifesaving therapies and procedures