Experimental validation of MED forward feed steady-state model

In this work the validation of a physical model to simulate the performance of an MED forward feed system is done by comparing results of the model with real data obtained. The data was obtained using the experimental MED plant at Plataforma Solar de Almeria (PSA) under steady-state operation near design conditions. The results indicate that the model can be used to make a first analysis on these type of systems.

Techno-economic analysis of stand-alone solar desalination at variable load conditions

The operation of large-scale reverse osmosis units in combination with different solar power plants, both, Concentrating Solar Power (CSP) and Photovoltaics (PV) has been evaluated under variable load conditions. In the case of the Reverse Osmosis (RO) unit, configurations with and without an energy recovery device have been considered. In the case of the CSP plant, a thermal storage system with several capacities (8-14 h) covers the periods with low solar radiation and no storage has been taken into account for the PV plant due to the prohibitively high cost of batteries at large scale. The analysis has been done for a specific location in Algeria, considering different scenarios to adapt the operation of the RO unit at partial load in order to assure a stable operation. The dynamic performance of the RO unit is presented for each scenario, together with an economic analysis

Solar desalination by combination with concentrated solar power: Exergy cost analysis

Some regions of the world with high solar irradiation conditions have a growing demand for electricity and freshwater that could cause supply problems in the industries and population. To reduce this risk, the use of solar energy to generate electricity and freshwater is an interesting option to consider. Electricity could be generated from concentrated solar power (CSP) plants fuelled by solar energy and natural gas, while freshwater could be produced from multi-effect distillation (MED) and reverse osmosis (RO) technologies driven by thermal energy and electricity, respectively. An exergy cost analysis of the integration of two desalination technologies (MED and RO) with a CSP plant is carried out to compare in terms of exergy cost. The symbolic exergoeconomics method is applied in the configurations analyzed. The different configurations are evaluated in a representative region with high irradiation conditions. Results show that the best configuration for producing electricity and freshwater is achieved when the stand-alone RO plant is connected to the grid where the unit exergy cost of electricity and water is 31% and 54% lower than in the stand-alone CSP plant and stand-alone MED, respectively. However, CSP-MED is the recommended configuration for the solar cogeneration scheme evaluated. Additionally, the most influential components in the cost formation of electricity are solar collectors (46.6% in CSP-MED and 44.3% in CSP-RO) while for freshwater they are solar collectors (27.6% in CSP-MED and 42.0% CSP-RO), multi-effect distillation module (15.7% in CSP-MED), and reverse osmosis module (20.5% in CSP-RO). In these components the design should be improved to reduce the unit exergy cost of electricity and freshwater

Isolated HBsAg positivity in a Mexican patient with newly diagnosed lupus nephritis

Abstract Introduction: Hepatitis B surface antigen (HBsAg) is usually regarded as a marker of hepatitis B virus (HBV) infection. The concurrence of lupus nephritis (LN) and HBsAg-positivity is a challenge for the clinician, since immunosuppressant use may be associated with an increase in viral replication and an exacerbation of liver disease. Case presentation: Here, we describe the case of a 30-year-old Mexican woman with newly diagnosed focal proliferative LN who also tested repeatedly positive for HBsAg by chemiluminescent microparticle immunoassay (CMIA). She had no clinical features of hepatitis and her liver function tests were within normal limits. Her abdominal ultrasound was also normal. While waiting for further results, she was started on lamivudine (100 mg daily). However, total HBV core antibody test was negative. Owing to the infrequency of this serological pattern, an in vitro polymerase chain reaction (PCR) assay was performed and HBV was not detected. Overall, we interpreted these results as a false-positive screening. Methylprednisolone pulse therapy was subsequently given (1 g daily for three doses) without hepatic repercussion, neither clinically nor biochemically. Conclusions: Isolated HBsAg positivity may result from multiple causes, one of which is crossreactivity. To the best of our knowledge, this is the first report of a false-positive reading using CMIA technique in an active lupus patient. It is reasonable to stress that lupus patients with a positive screening for HBV should undergo a confirmatory assay (such as genomic detection), since this diagnosis may have important therapeutic implications. � 2016 Egyptian Society of Rheumatic Diseases. Publishing services provided by Elsevier. B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/

Exergy cost assessment of solar trigeneration plant based on a concentrated solar power plant as the prime mover

An exergy cost assessment of solar trigeneration plant to generate electricity, fresh-water, and heat is carried out in order to study the process of exergy cost formation, to determine the key components that contribute to the cost of each product, and to establish the best configuration in term of unit exergy cost. The solar trigeneration plants evaluated consist of a concentrated solar power (CSP), a multi-effect distillation plant, and a process heat module, in which the CSP plant is the prime mover. The methodology includes modeling and evaluating the performance of standalone and trigeneration plants using the symbolic exergoeconomic methodology. Results show that the best configuration, in terms of exergy cost, is when the multi-effect distillation plant replaces the power cycle condenser. Regarding the costs formation, the key components which could be improved in their design are: solar collectors, evaporator, re-heater, dissipative systems, and productive subsystems

Modeling multi effect distillation powered by CSP in TRNSYS

This work presents the results of using a new tool to simulate the cogeneration of water and electricity with Concentrating Solar Power (CSP) and Forward Feed Multi-Effect-Desalination (FF-MED) plants, by adding a new functionality to the System Advisor Model (SAM) developed by the US National Renewable Energy Laboratory (NREL). The controlling strategy of the MED model is presented in detail, and a case study application is shown. This study compares the results obtained with a CSP plant operating in San Diego, CA, with four different cooling systems: an MED/Seawater Cooling Circuit (SWCC), dry cooling, wet cooling, and a SWCC standalone. The results show that the usage of an MED/SWCC system in cogeneration with a CSP plant can be feasible and has the potential to be economically interesting

Las relaciones humanas y la gestión pedagógica en docentes de las instituciones educativas estatales de la provincia de Ocros – Ancash - 2014

El presente trabajo de investigación, tiene por objetivo determinar la relación que existe entre las Relaciones Humanas y la Gestión Pedagógica en Docentes de las Instituciones Educativas Estatales de la provincia de Ocros – Ancash - 2014. La investigación es tipo básica, descriptivo correlacional dado que se ha descrito y caracterizado la dinámica de cada una de las variables en estudio, por otro lado el diseño fue de tipo no experimental, de corte transversal y correlacional ya que no se manipuló ni sometió a pruebas las variables de estudio. La muestra fue probabilística aleatoria simple, conformada por una población de 180 Docentes de las Instituciones Educativas Estatales de la provincia de Ocros – Ancash - 2014. Para ver la relación entre las variables se hizo uso del estadístico de coeficiente de correlación de Spearman obteniéndose un resultado de Rho=0,567 llegándose a la conclusión que existe una relación significativa moderada y positiva entre las relaciones humanas y la gestión pedagógica en docentes de las Instituciones Educativas Estatales de la provincia de Ocros – Ancash - 201

Optimización del desarrollo de la energia termosolar en españa en el contexto de la transición energética

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: Este artículo presenta un resumen de los resultados obtenidos al estudiar cuál debe ser la evolución del mix eléctrico en España durante los próximos 30 años si se desea cumplir con determinados escenarios de reducción de las emisiones de CO2 del sector eléctrico en relación a las del año 1990. El estudio se ha realizado usando un algoritmo genético con optimización multiobjetivo. Se han considerado dos escenarios de reducción de emisiones de CO2: 1) escenario moderado del 40% (2030), 60% (2040) y 80% (2050); 2) escenario agresivo del 50% (2030), 75% (2040) y 100% (2050). Los resultados mostrados en este artículo indican que el escenario moderado es factible, sin que ello conlleve altos costes de la electricidad o excesivos vertidos. Una reducción del 80% en las emisiones de CO2 en el año 2050 requerirá un mix eléctrico renovable en un 86.34% y conllevaría un coste aproximado de la electricidad de 47,4 €/MWh. Pero si se desea cumplir el escenario agresivo (mercado eléctrico sin emisiones de CO2 en 2050) el mix eléctrico necesario supondría un coste de 62,9 €/MWh para la electricidad suministrada a la red y unos vertidos de 222,38 TWh frente a una demanda total de 316,55 TWh, lo que supone un excesivo porcentaje de vertidos. Los resultados obtenidos también han mostrado que la única forma de poder obtener un mix eléctrico 100% renovable en 2050 sin unos excesivos vertidos sería disponer de tecnologías competitivas de almacenamiento y gestión a gran escala de la electricidad excedente, porque esto permitiría reducir de forma muy importante la potencia instalada de fotovoltaica, eólica y termosolar, consiguiéndose menores costes de la electricidad y menores vertidos.ABSTRACT: This paper shows a summary of the results obtained when analysing how the Spanish electricity mix must evolve during next 30 years to fulfil two different scenarios of CO2 emissions reduction in comparison with those in 1990. A multi-objective genetic algorithm has been used to perform the study. Two different scenarios have been analysed: 1) moderate trend of 40% (2030), 60% (2040) y 80% (2050) reduction; 2) aggressive trend of 50% (2030), 75% (2040) and 100% (2050). Results given in this paper show that the moderate trend is feasible regarding both the electricity cost and the curtailments. A reduction of 80% in 2050 would require an 86.34% renewable electricity market with an electricity cost of 47,4 €/MWh. On the other hand, for the fulfilment of the aggressive trend (no CO2 emissions in 2050) the electricity cost and the curtailments would be 62,9 €/MWh and 222,38 TWh, respectively, with a total electricity demand of only 316,55 TWh. This level of curtailments is clearly excessive. The obtained results have also shown that the only way to achieve a 100% renewable electricity market in Spain in 2050 without excessive curtailments would be the use of cost-effective electricity storage technologies because they would allow a significant reduction of the required installed power of photovoltaic, wind and solar thermal electricity plants, while reducing the electricity cost and the curtailments simultaneously.info:eu-repo/semantics/publishedVersio