Pumped heat energy storage with liquid media: Thermodynamic assessment by a Brayton-like model

[EN]A thermodynamic model for a steady state pumped heat energy storage in liquid media is presented: it comprises a coupled Brayton-like heat pump and heat engine cycles connected to a cryogenic liquid and a hot molten salt by counter-flow heat exchangers. The model considers non-isothermal heat transfers between the working fluid and the liquid media and explicitly includes a set of parameters accounting for the main internal and external losses, heat leak, and pinch point effects for both the heat pump (charge) and heat engine (discharge) modes. Specific expressions for the main magnitudes in the charge (as the input power and coefficient of performance) and discharge (as power output and efficiency) modes and the global round trip efficiency have been analytically derived in terms of isentropic efficiencies of the compressor and turbine, pressure losses in the heat exchange processes, effectivenesses of the external counter-flow heat exchangers, and coupling between the working fluid and the storage and cryogenic liquid media. Round trip efficiencies around of 35 − 40% have been obtained, internal losses being those with main negative influence on the calculated values. The strong constraints imposed by the pinch point effects and liquid media have been analyzed. The model provides a thermodynamic assessment of the main involved processes and their interplay for a selected arrangement (molten salts, cryogenic fluid, and the charge and discharge power blocks) in order to check parametric strategies for thermodynamic optimization and design. These strategies are based on a reduced set of parameters of the overall installation and without the high computational costs of dynamical models.(ANII); Fondo Sectorial de Energía, Uruguay; contract FSE-1-2018-1-153077

Multicriteria optimization of Brayton-like pumped thermal electricity storage with liquid media

[EN]A multi-objective and multi-parametric optimization of a Pumped Thermal Electricity Storage system based on Brayton cycles is presented by the calculation of different Pareto fronts and the associated Pareto optimal sets for energetic and design analysis, respectively. A large range of internal and external irreversibilities and the thermodynamic properties of the storage media are taken into account. The analysis shows that the heat capacity of the working fluid and the heat capacity of the storage media should be the same in the contact with the hot reservoirs and in the contact with the cold reservoir in the heat pump, but in the contact with the cold reservoir for the heat engine the ratio should be 0.33, this offers information regarding the mass flow increasing significantly the achievable values for the round-trip efficiency, power output and the heat engine efficiency in the discharge process. Optimal values are given in terms of the degree of irreversibilities in the system and a comparison is made with extreme cases of infinite and minimum sizes for the storage system. Round-trip efficiencies in the so-called optimum scale/mass-flow-ratio design point exhibits noticeably larger values compared to previously reported results including the so-called endoreversible limit, where no internal irreversibilities are considered and where the improvement can achieve 49% over the endoreversible case in the most ideal scenario. Explicit numerical values of the maximum round trip efficiency, power output, and efficiency are given for a broad range of both internal and external irreversibilities.Agencia Nacional de Investigación e Innovación (ANII): Fondo Sectorial de Energía (Uruguay), under contract FSE-1-2018-1-153077 Universidad de Salamanca, Spain, under contracts 18.KB.YF/463A.C.01 and 0218463AB01

Pumped heat energy storage with liquid media: Thermodynamic assessment by a transcritical Rankine-like model

[EN]A pumped heat energy storage (PHES) system based on a Rankine cycle for supercritical working fluids, such as carbon dioxide and ammonia, accounting for the irreversible latent and sensible heat transfers between the working fluid and the storage liquid medium, as water or thermal oil, is analyzed. The model also includes several parameters such as pressure losses, heat exchanger efficiencies, and isentropic efficiencies of the compressor, pump, and expansion devices (such as turbines and valves), that take into account the main internal and external losses and heat leak to the environment. The model allows for the calculation of specific energy, the heat pump performance coefficient, heat engine efficiency, and overall round-trip efficiency, as well as the temperatures of the working fluid and reservoirs. A zero-dimensional model is also used to determine the time dependence of heat leak in the tanks. The main results show that this technology could achieve round trip efficiency values in the order of 50–70%. Irreversibilities in compression and expansion appears as the most influential energy losses factor. The time effect of the ambient conditions on the tanks has been analyzed for a wet subtropical climate but it seems that the ambient conditions have no major influence on the performance of the system. In addition, explicit numerical results and temperature–entropy plots are presented for two representative systems as carbon dioxide-water and ammonia-thermal oil to take into account the main values in an operating condition

ECLAPTE: Effective Closure of LAParoTomy in Emergency-2023 World Society of Emergency Surgery guidelines for the closure of laparotomy in emergency settings

Laparotomy incisions provide easy and rapid access to the peritoneal cavity in case of emergency surgery. Incisional hernia (IH) is a late manifestation of the failure of abdominal wall closure and represents frequent complication of any abdominal incision: IHs can cause pain and discomfort to the patients but also clinical serious sequelae like bowel obstruction, incarceration, strangulation, and necessity of reoperation. Previous guidelines and indications in the literature consider elective settings and evidence about laparotomy closure in emergency settings is lacking. This paper aims to present the World Society of Emergency Surgery (WSES) project called ECLAPTE (Effective Closure of LAParoTomy in Emergency): the final manuscript includes guidelines on the closure of emergency laparotomy

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Dimensionamiento de servomotores eléctricos en aplicaciones aeroespaciales de control de posicionamiento

Fil: Cova, Walter J. D. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Jazni, Jorge Elías. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: González, Gustavo J. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: González, Gustavo J. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Investigador Asistente; Argentina.Fil: Salomone, Javier Eduardo. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Pedroni, Juan P. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Dutto, Esteban A. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Dutto, Esteban A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Máquinas; Argentina.Fil: Lagier, Santiago. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Se presenta un conjunto de procedimientos para la selección (o dimensionamiento) de servomotores eléctricos rotativos (brushed o brushless) destinados a aplicaciones de control de posición en vehículos aeroespaciales. Se trata del control de posición de dispositivos y órganos mecánicos (superficies aerodinámicas, válvulas de control de flujo, toberas orientables, etc.) con exigentes requerimientos de performance y restricciones de peso y volumen. Los procedimientos presentados se basan en el análisis del funcionamiento del motor en condiciones de oscilación armónica, para diversos estados de carga mecánica, tanto lineales como no lineales. Las cuplas de carga consideradas se extienden desde las puramente conservativas (cuplas inerciales y/o elásticas) a las disipativas y sus combinaciones. La utilización de la metodología propuesta tiene por resultado la determinación de un motor mínimo, cuyas prestaciones mecánicas y performance térmica (característica cupla-velocidad, potencia mecánica y capacidad de disipación de calor) satisfagan los requerimientos impuestos por la condición operativa de carga a que se encuentra sometido. La exposición se complementa con ejemplos prácticos.www.aate.orgFil: Cova, Walter J. D. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Jazni, Jorge Elías. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: González, Gustavo J. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: González, Gustavo J. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Investigador Asistente; Argentina.Fil: Salomone, Javier Eduardo. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Pedroni, Juan P. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Dutto, Esteban A. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Fil: Dutto, Esteban A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Máquinas; Argentina.Fil: Lagier, Santiago. Instituto Universitario Aeronáutico. Centro de Investigaciones Aplicadas; Argentina.Ingeniería Aeroespacia