Optical Analysis of a Hexagonal 42kWe High-flux Solar Simulator

AbstractA 42-kWe high-flux solar simulator with hexagonal reflector symmetry has been designed, built and optically characterized at IMDEA Energy Institute, Spain. This facility makes possible the lab-scale generation of a quasi-uniform high radiation flux density and high stagnation temperatures and it will be used as a platform for analyzing processes under concentrating solar energy conditions; for instance, central receivers in concentrating solar power plants and solar fuel production process in thermochemical reactors. The high-flux solar simulator consists of seven reflector-lamp pairs arranged in the center and vertices of a regular hexagon. The 6-kWe Xe short arc lamps are allocated in the primary focus of the corresponding truncated ellipsoidal reflector. This hexagonal symmetry provides compactness and quasi-uniform spatial distribution of the radiation at the system common focal plane.This work presents the experimental characterization of the solar simulator optical performance. Preliminary measurements indicate an average flux density at the focal plane of 3.5 MW/m2 that means 3,500 suns (1 sun = 1kW/m2) and stagnation temperature of approximately 2,800K

Assessment of Carbon Metabolism of Cherry Tomato Fruits: How Does Affects Potassium Biofortification During Crop Cycle at Postharvest Storage?

In the present work, we evaluate the implementation of a K biofortification programme that increases the dose of this macronutrient in the nutrient solution for growing tomatoes. The aim is assess whether this treatment improves the response of fruits to postharvest for 21 days at 4°C. Three K treatments were applied during the crop cycle of the plants: 5, 10, and 15 mM of KCl. The enzymes involved in carbon metabolism and sugar concentration were studied, both on the day of harvest and after 21 days of storage in cold room at 4°C. Similarly, enzymes related to the metabolism of organic acids as well as their concentration were studied. The application of this supplement, aside from increasing K concentration in the fruits, stimulated the sucrose (Suc) degradation by sucrose synthase (SuSy) activity while increasing fructose (Fruc) and glucose (Gluc) as well as raising malate accumulation induced by the activity of PEPC and MDH enzymes during storage of 21 days at 4°C. The KCl treatments could be related to changes in carbon metabolism and suggest a protective role against cold storage, improving the quality of tomato fruits

Numerical analysis of latent heat storage system with encapsulated phase change material in spherical capsules

Solar energy has been considered as one of the promising solutions to replace the fossil fuels. To generate electricity beyond normal daylight hours, thermal energy storage systems (TES) play a vital role in concentrated solar power (CSP) plants. Thus, a significant focus has been given on the improvement of TES systems from the past few decades. In this study, a numerical model is developed to obtain the detailed heat transfer characteristics of lab-scale latent thermal energy storage system, which consists of molten salt encapsulated spherical capsules and air. The melting process and the corresponding temperature and velocity distributions in every capsule of the system are predicted. The enthalpy-porosity approach is used to model the phase change region. The model is validated with the reported experimental results. Influence of initial condition on the thermal performance of the TES system is predicted

Deriva intrínseca en heliostatos

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En este trabajo se analiza numéricamente, mediante simulaciones de trazado de rayos basadas en él método de Montecarlo, la deriva intrínseca en heliostatos debida al hecho de que el rayo central no necesariamente coincide con el centro de gravedad del mapa de flujo. La instalación de torre ubicada en el Instituto IMDEA Energía, Móstoles, Madrid (España), se ha usado como caso de prueba. La deriva se evalúa simulando los mapas de flujo de cada heliostato a distintas horas del día y calculando posteriormente sus centros de gravedad. La influencia en la deriva de la distancia focal de los heliostatos y del ángulo de proyección de la distribución de flujo sobre el blanco es investigada en detalle. Los resultados muestran la relevancia de la deriva intrínseca en heliostatos con distancias focales cortas y cómo ésta puede ser minimizada al acomodar la distancia focal del heliostato a su distancia al receptor.ABSTRACT: In this work, we numerically evaluate with Monte Carlo ray-tracing simulations the intrinsic drift in heliostats. This drift is associated to the fact that the central ray does not necessarily coincide with the center of gravity of the flux map. For this investigation, the solar tower facility located at IMDEA Energy in Móstoles, Madrid (Spain) is used as a test case. By simulating flux maps at different times of the day and representing their centers of gravity the intrinsic drift is evaluated. The influence on the drift of the focal length of the heliostats and the projection angle of the flux distribution on the target is investigated in detail. Results show the relevance of the intrinsic drift in heliostats with short focal lengths and how this drift can be reduced by making the focal length of the heliostat closer to its slant range.info:eu-repo/semantics/publishedVersio

Vegetation establishment in soils polluted by heavy metal(loid)s after assisted natural remediation

Background and aims This field-base study evaluates the long-term effectiveness of in-situ remediation measures applied to soils residually polluted by potentially toxic elements (PTEs) in an area affected by a mining spill in SW Spain. Methods To evaluate the remediation treatments success, their influence on key soil properties and on the development of spontaneous vegetation in the treated soils was investigated. The treatments were based on human derived by-products valorization, and consisted of: biopiles, marble sludge and gypsum mining spoil addition, and their combination with an organic amendment (vermicompost). Results Amendments application improved the soil properties and reduced PTEs availability. As a result, an enhancement in spontaneous development of vegetation cover and diversity of plant species in the treated soils was followed. Spergularia rubra and Lamarckia aurea, two primary plant species growing in the studied area and that exhibit strong association to soils with the highest levels of pollution, showed high Pb and As accumulation in shoots ande in roots. Exceptionally, accumulation of these pollutants occurred in L. aurea roots, which can explain its high presence in soils with more limited vegetation development and in which no additional plant species can thrive. Conclusions The occurrence of S. rubra and L. aurea in the amended soils may be indicative of improved soil conditions and reduced toxicity induced by the remediation measures implemented. They may also be considered key species in the area since their presence can promote the recolonization of the degraded soils by species less tolerant to their residual pollution

Multi-Tubular Reactor for Hydrogen Production: CFD Thermal Design and Experimental Testing

This study presents the Computational Fluid Dynamics (CFD) thermal design and experimental tests results for a multi-tubular solar reactor for hydrogen production based on the ferrite thermochemical cycle in a pilot plant in the Plataforma Solar de Almería (PSA). The methodology followed for the solar reactor design is described, as well as the experimental tests carried out during the testing campaign and characterization of the reactor. The CFD model developed for the thermal design of the solar reactor has been validated against the experimental measurements, with a temperature error ranging from 1% to around 10% depending on the location within the reactor. The thermal balance in the reactor (cavity and tubes) has been also solved by the CFD model, showing a 7.9% thermal efficiency of the reactor. CFD results also show the percentage of reacting media inside the tubes which achieve the required temperature for the endothermic reaction process, with 90% of the ferrite pellets inside the tubes above the required temperature of 900 C. The multi-tubular solar reactor designed with aid of CFD modelling and simulations has been built and operated successfullyFondo Europeo de Desarrollo Regional (FEDER) IPT- 2011-1323-920000Programa Operativo FEDER para Andalucía 2007–2013 RNM-612

Ecotoxicological Assessment of Polluted Soils One Year after the Application of Different Soil Remediation Techniques

This research was funded by the project RTI 2018-094327-B-I00 (Spanish Ministry of Science and Innovation) and by the project E-RNM-444-UGR20 (Operating Research Program FEDER 2014- 2020). The APC was funded by E-RNM-444-UGR20.The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/toxics11040298/s1, Table S1: Guideline values (mg/kg) to declare a soil as potentially polluted by legislations of different countries [51–54,90]The present work evaluated the influence of eight different soil remediation techniques, based on the use of residual materials (gypsum, marble, vermicompost) on the reduction in metal(loid)s toxicity (Cu, Zn, As, Pb and Cd) in a polluted natural area. Selected remediation treatments were applied in a field exposed to real conditions and they were evaluated one year after the application. More specifically, five ecotoxicological tests were carried out using different organisms on either the solid or the aqueous (leachate) fraction of the amended soils. Likewise, the main soil properties and the total, water-soluble and bioavailable metal fractions were determined to evaluate their influence on soil toxicity. According to the toxicity bioassays performed, the response of organisms to the treatments differed depending on whether the solid or the aqueous fraction was used. Our results highlighted that the use of a single bioassay may not be sufficient as an indicator of toxicity pathways to select soil remediation methods, so that the joint determination of metal availability and ecotoxicological response will be determinant for the correct establishment of any remediation technique carried out under natural conditions. Our results indicated that, of the different treatments used, the best technique for the remediation of metal(loid)s toxicity was the addition of marble sludge with vermicompost.Ministry of Science and Innovation, Spain (MICINN) Spanish Government RTI 2018-094327-B-I00Operating Research Program FEDER 2014-2020 E-RNM-444-UGR2

Diseño y análisis de un campo solar para un sistema de generación basado en turbina de gas

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En este trabajo, se ha realizado el análisis de un ciclo Brayton cerrado, sin combustión, con un sistema de regulación del flujo másico de aire. El bloque de potencia tiene una potencia máxima de 20 MW, una eficiencia nominal de 42% y es alimentado por un campo solar de helióstatos y un sistema de almacenamiento de energía térmica basado en partículas. La información de la Irradiación Directa Normal para Hermosillo, México y de la temperatura ambiente, así como de la curva de la demanda de la red eléctrica se ha empleado para las simulaciones realizadas. Se ha llevado a cabo un análisis de sensibilidad de cuatro Múltiplos Solares (SM) y doce horas de almacenamiento y, con el uso del Levelized Cost of Electricity (LCoE), se ha elegido la configuración más rentable. Se ha usado un análisis estadístico para el dimensionamiento del almacén de energía, basado en el análisis de frecuencia de las categorías de demanda de potencia. Los resultados muestran que la mejor configuración tiene un LCoE de 14.84 c$/kWh, que corresponde a un SM de 1.5 y 8 horas de almacenamiento, el cual permite satisfacer el 52.91$/kWh for the configuration of SM 1.5 and 8 hours of storage, allowing to satisfy the 52.91% of the electric energy demand and producing 56.60 GWh.info:eu-repo/semantics/publishedVersio

Technosols Derived from Mining, Urban, and Agro-Industrial Waste for the Remediation of Metal(loid)-Polluted Soils: A Microcosm Assay

This research was funded by the project RTI2018-094327-B-I00 (Spanish Ministry of Science and Innovation). A.A.-G. thanks the Spanish Ministry of Science and Innovation for their predoc- toral fellowship granted under application references FPU-18/02901; M.P.-L. thanks the Research Project RTI2018-094327-B-I00 (Spanish Ministry of Science and Innovation) for his contract; and A.R-F. thanks the Junta de Andalusia Post-doctoral Operating Research Program FEDER 2014-2020 (ref. E-RNM-444-UGR20) for her contract.Supplementary Materials: The following supporting information can be downloaded at https://www.mdpi.com/article/10.3390/toxics11100854/s1This study evaluated the effectiveness of six Technosols designed for the remediation of polluted soils (PS) by metal(loid)s at physicochemical, biological, and ecotoxicological levels and at a microcosm scale. Technosols T1–T6 were prepared by combining PS with a mix of organic and inorganic wastes from mining, urban, and agro-industrial activities. After two months of surface application of Technosols on polluted soils, we analysed the soil properties, metal(loid) concentration in total, soluble and bioavailable fractions, soil enzymatic activities, and the growth responses of Trifolium campestre and Lactuca sativa in both the Technosols and the underlying polluted soils. All Technosols improved the unfavourable conditions of polluted soils by neutralising acidity, increasing the OC, reducing the mobility of most metal(loid)s, and stimulating both the soil enzymatic activities and growths of T. campestre and L. sativa. The origin of organic waste used in the Technosols strongly conditioned the changes induced in the polluted soils; in this sense, the Technosols composed of pruning and gardening vermicompost (T3 and T6) showed greater reductions in toxicity and plant growth than the other Technosols composed with different organic wastes. Thus, these Technosols constitute a potential solution for the remediation of persistent polluted soils that should be applied in large-scale and long-term interventions to reinforce their feasibility as a cost-effective ecotechnology.Spanish Ministry of Science and Innovation RTI2018-094327-B-I00, FPU-18/02901Junta de Andalusia FEDER 2014-2020 E-RNM-444-UGR2

Uso de evaluación continua para incrementar la motivación del alumnado en asignaturas de Ingeniería

The guided and evaluated learning at the end of the course is a vestige inherited from the old curricula. With the reduction of the number of students, as well as with the implementation of the new curricula, the teaching system has to be changed, turning towards a way in which the student is the main actor and the teacher carries out a continuous feedback (guided process). In the present research it has been shown that the continued work of students, with real problems associated with Engineering, allows the learning process to be carried out with a greater motivation and, therefore, involvement by the students, improving their academic performanceEl aprendizaje guiado y evaluado al final del curso es un vestigio heredado de los antiguos planes de estudios. Con la reducción del número de alumnos, así como con la implementación de los nuevos planes de estudio se hace necesario cambiar el sistema de enseñanza, virando hacia un modeo en el que el alumno sea el protagonista y que el profesor lleve a cabo un proceso de retroalimentación (guiado) continuado. En el presente estudio queda demostrado que el trabajo continuo de los alumnos con problemas reales asociados a la Ingeniería permite que el proceso de aprendizaje lleve acarreado una mayor motivación y, por ende, implicación por parte de los estudiantes, mejorando el rendimiento de los mismos.Universidad de Sevilla. Ayuda 1.2.3 del III Plan Propio de Docenci