CFD model-based analysis and experimental assessment of key design parameters for an integrated unglazed metallic thermal collector façade

Active façade systems incorporating solar thermal collectors currently offer very promising energetic solutions. From among the available systems, a simple solution is the unglazed heat collector for potential integration in low-temperature applications. However, when adopting system definitions, the modification of some design parameters and their impact has to be fully understood. In this study, the case of an unglazed collector integrated into a sandwich panel is assessed and a specific analysis is performed for a proper assessment of the influence of key design parameters. Based on that case study of the real built system, a CFD model is developed and validated and a parametric assessment is then performed, by altering the configurations of both the panel and the hydraulic circuit. In this way, the potential of each measure to harness solar energy can be evaluated and each parameter with its different level of impact can be highlighted, to identify those of higher relevance. A characterization of the real solution completes the study, by providing the efficiency curves and the total energy collected during the experimental campaign. The maximum estimate of the efficiency of a 6 m2 façade was within a range between 0.47 and 0.34 and the heat loss factor was between 4.8 and 7.5. The case study exercises reveal the real energy efficiency and solar production patterns. There was also an opportunity to consider significant improvements to increase the output of the active façade. The main conclusions concerned the different criteria that improved the definition of the system and greater comprehension of alternative designs that may be integrated in the underlying concept.The authors are grateful to the Basque Government for fundingthis research through projects IT781-13 and IT1314-19 and to allthose involved in the different stages for their guidance andinvaluable help.The authors would also like to thank all those companies andresearchers participating in the BASSE project for their stronginvolvement during that research. Results from BASSE project haveinspired present research. The BASSE project received funding fromthe European Union, RFCS Program, Research Fund for Coal and Steel project Building Active Steel Skin (BASSE, Grant Agreement noRFSR-CT-2013-00026

New Simplified Algorithm for the Multiple Rotating Frame Approach in Computational Fluid Dynamics

This paper deals with rotating effects simulation of steady flows in turbomachinery. To take into account the rotating nature of the flow, the frozen rotor approach is one of the widely used approaches. This technique, known in a more general context as a multiple rotating frame (MRF), consists on building axisymmetric interfaces around the rotating parts and solves for the flow in different frames (static and rotating). This paper aimed to revisit this technique and propose a new algorithm referred to it by a virtual multiple rotating frame (VMRF). The goal is to replace the geometrical interfaces (part of the computer-aided design (CAD)) that separate the rotating parts replaced by the virtual ones created at the solver level by a simple user input of few point locations and/or parameters of basic shapes. The new algorithm renders the MRF method easy to implement, especially for edge-based numerical schemes, and very simple to use. Moreover, it allows avoiding any remeshing (required by the MRF approach) when one needs to change the interface position, shape, or simply remove or add a new one, which frequently happened in practice. Consequently, the new algorithm sensibly reduces the overall computations cost of a simulation. This work is an extension of a first version published in an ASME conference, and the main new contributions are the detailed description of the new algorithm in the context of cell-vertex finite volume method and the validation of the method for viscous flows and the three-dimensional (3D) case which is of significant importance to the method to be attractive for real and industrial applications.BCAM-BALTOGAR CFD Platform for Turbomachinery Simulation and Design (BFA/DFB - 6/12/TK/2012/00020

Use of an object-based system with reasoning capabilities to integrate relational databases

The integration of heterogeneous and autonomous information sources is a requirement for the new type of cooperative information systems. In this paper we show the advantages of using a terminological system for integrating pre-existing relational databases. From the resulting integrated schema point of view, using · a terminological system allows for the definition of semantically richer integrated schema. From the integrated schema generation process point of view, the use of a terminological system permits the definition of a more consistent, broad and automatic process. Last, from the query processing point of view, terminological systems provide interesting features for incorporating semantic and caching query optimization techniques. The advantages are presented in detail for each main step of the integration process: translation, integration and query processing

Efficient Rotating Frame Simulation in Turbomachinery

This paper deals with the simulation of steady flows in tur- bomachinery. Two approaches are proposed, the first one is the classical multiple-rotating frame method (MRF) by multi- zone approach where the different zones are separated by non- overlapping interfaces and solved independently. Since each zone is loaded separately, a transferring system should be prop- erly implemented at the interface boundaries. Two techniques are considered, in the first one the conservative variables are in- terpolated between zones while in the second one the fluxes are transferred through the interfaces. The other proposed approach is a new version of the MRF using a virtual interface (VMRF). This is a simplified of the pre- vious one where the interfaces are created virtually at the solver level, rendering the method easy to implement especially for edge-based numerical schemes, and avoiding any re-meshing in case one needs to change interface position, shape or simply re- move or add new one. Finally, numerical tests are performed to demonstrate the efficiency of the proposed methods by compari- son with commercial codes (ANSYS FLUENT)

SHORT-TERM EFFECTS OF CROP HUSBANDRY ON THE WEED COMMUNITY OF A CEREAL-LEGUME ROTATION, “TILMAN-ORG session”

Several agricultural practices can be used to control weed population thus avoiding the use of herbicides. Tillage, fertilization and growth of a green manure are found among them. In the context of a mid-term experiment set up in an organic field in Gallecs (Barcelona), we analysed the effect of chisel vs mouldboard ploughing, application of fertilizer and growth of a green manure on the density of weeds and on composition of the weed community. We evaluated weed density and community composition in April 2012 (spelt crop), February 2013 (green manure cover) and May 2013 (chickpea crop) and also analysed the sources of variation of density for the most abundant species in all periods. Our results show that, under the cereal crop, mouldboard plough had a negative effect on weed densities and also affected weed community composition. While green manure was standing on the field, its presence also had a negative effect on weed density. We found differences in composition between sown and unsown plots. After removal of green manure, though, these effects disappeared. For total weed density in the chickpea crop, we could not find differences due to any of the treatments applied. However, single species analyses showed that Setaria viridis and Polygonum convolvulus responded positively to tillage and fertilization and that P. convolvulus and Convolvulus arvensis were negatively affected by previous presence of green manure. Weed community composition were found to be unaffected by any of our treatments

Efectos de un sistema integrado de recolección para pequeños productores en la calidad de la aceituna recogida

Small producers confront specific challenges when they opt to produce high-quality olive fruit. Limited resources for investing in harvest machinery and manpower are the main reasons for continuing a traditional harvest method that puts the final product and its economic value at risk. This paper discusses the efficiency of an integrated harvest system as a possible solution to these specific challenges. The system is formed by a newly designed manual harvesting device and the use of a cooling room near the olive grove. Both systems were evaluated to assess their feasibility for optimum conditions before processing. The combined effect of the harvesting method and cold storage on the fruit characteristics (incidence of decay, skin color, weight loss, firmness, respiration, and ethylene production) was evaluated on three different varieties (‘Arbequina’, ‘Picual’ and ‘Verdial’) and four different storage times (0, 4, 8, and 14 days). The results indicate that the proposed harvesting method in combination with an appropriate cooling system offers an affordable alternative for obtaining fruit with the best physiological characteristics.Los pequeños productores se enfrentan a retos específicos, cuando optan por producir aceitunas de alta calidad. La imposibilidad económica de invertir, tanto en maquinaria de cosecha, como en mano de obra es la razón principal que obliga a continuar una recolección tradicional que pone en riesgo el producto final y su valor económico. Este estudio analiza la eficiencia de un sistema de recolección integrado como una posible solución a estos desafíos específicos. El sistema está formado por un dispositivo de recogida manual de nuevo diseño y el uso de una cámara de frío en la finca. El efecto combinado del método de recolección presentado y el almacenamiento en frío sobre las características de la fruta (incidencia de podredumbre, color de piel, pérdida de peso, firmeza, respiración y producción de etileno) se evaluó en tres variedades diferentes (‘Arbequina’, ‘Picual’ y ‘Verdial’) y diferentes tiempos de almacenamiento (0, 4, 8, 14 días). Los resultados indican que la combinación de un método de recolección mecánica y un sistema de enfriamiento adecuado ofrece una alternativa económicamente asequible para obtener frutos con las mejores características fisiológicas

Surco en cabeza femoral como signo de inestabilidad de cadera en pacientes con Síndrome de Down.

La inestabilidad de cadera en pacientes afectos de síndrome de Down es una entidad poco frecuente, en la actualidad todavía existe controversia sobre las anomalías anatómicas asociadas. El objetivo de este trabajo es describir los cambios anatómicos en las caderas de pacientes con inestabilidad en el síndrome de Down (SD). Hemos revisado las tomografías computarizadas (TC) de los pacientes afectos de luxación de cadera con SD. A tres de los 7 pacientes intervenidos en nuestro centro, se les había realizado TC de caderas. En todas las TC mostraban la presen - cia de lesión lineal vertical (surco) localizada en región epifisaria, atravesando la fisis, de localización antero-interna. Creemos que la posición adoptada cuando duermen (flexión, aducto y rotación interna) puede producir hiperpresión de la cabeza femoral sobre la ceja acetabular posterior, produciendo un surco vertical. La presencia de esta lesión puede ser sugestiva de inestabilidad subclínica de cadera en ausencia de episodio de luxación.Hip instability in patients with Down syndrome is a rare entity, currently there is still controversy about the associated anatomical anomalies. The aim of the study is to describe the anatomical changes in the hips of patients with instability in Down syndrome (DS). We have reviewed the computed tomography (CT) of patients with hip dislocation with SD. Three of the 7 patients treated in our center are performed CT had hips. All CT showed the presence of vertical linear lesion (groove) located in epiphyseal region, crossing the physis, antero-internal location. We believe that the position taken when sleeping (flexion, adduction and internal rotation) can produce overpressure of the femoral head over the posterior acetabular rim, producing a vertical groove. The presence of this lesion can be suggestive of subclinical instability in the absence of hip dislocation

Identification of defects originated during the filling of cast pieces through particles modelling

In casting processes, strong recirculation zones may trap air, gases and strip particles of sand off the mold affecting seriously the quality of the cast pieces. Especially during the filling of molten pieces with large surfaces, several faults were detected which are responsible of considerable economic losses in such casting processes. The aim of this work is focused on the correct identification of these physical phenomena, through Computational Fluid Dynamics (CFD). A fully experimental work correlating a saline solution with similar properties than the liquid alloy was carried out in order to guess the flow behavior inside the mold. Different parameters such as filling time, temperature and velocity of the liquid alloy together with the geometrical design of the mold were taken into account. The simulated evolution profiles and propagation speeds were compared with the laboratory experiments showing good agreement, validating thus the numerical model. Through an advanced particles modeling feature from a commercial package, the potential to predict and later correct some casting defects was demonstrated. As a conclusion, the mold together with supply channels need to be carefully optimized in order to control the correct direction of solidification avoiding the appearance of oxides but also to prevent stripping the sand off the walls