Transferencia de resultados de investigación sobre enseñanza y aprendizaje de la geometría al aula

En este trabajo presentamos algunos ítems del test que hemos diseñado con objeto de obtener información sobre la Geometría que se enseña en escuelas de primaria de algunos estados de México y así poder, por un lado, valorar si la Geometría que se contempla en el currículum de primaria mexicano se corresponde con la que imparten estos maestros y, por otor, determinar las posibles causas que han llevado a la enseñanza de la geometría a la situación actual. En este informe hacemos también referencia a un estudio que estamos realizando en el que analizamos algunos libros de texto de primaria mexicanos y algunos de los test utilizados en este país para la evaluación de los estudiantes de este nivel

Cp*Ir(NHC) complexes as highly versatile and efficient catalysts for the cross-coupling of alcohols and amines

A comparative study on the catalytic activity of a series of Cp*Ir(NHC)Cl2 complexes in several C-O and C-N coupling processes implying hydrogen-borrowing mechanisms has been performed. The compound Cp*Ir(InBu)Cl2 (InBu = 1,3-di-n-butylimidazolylidene) showed to be highly effective in the cross coupling reactions of amines and alcohols, providing high yields in the production of unsymmetrical ethers and N-alkylated amines. A remarkable feature is that the processes were carried out in the absence of base, phosphine or any other external additive. A comparative study with other well known catalysts, such as Shvo’s catalyst, is also reporte

Potential fuel saving in a powertrain derived from the recovery of the main energy losses for a long haul European mission

[EN] The reduction of automotive fuel consumption and emissions remains one of the main challenges. This paper presents the potential fuel saving in a CNG-powertrain derived from the recovery of the main energy losses. The analysis includes the kinetic energy recovery by a belt starter generator (BSG), the exhaust gas waste heat recuperation by using in a cascade approach, a thermoelectric generator (TEG) and a turbo-generator (TBG)- and the electrification of the main auxiliaries. An additional 48 V board net as well as the addition of a storage system are also included in the study. To support on the design phase of the project and in the operation strategy, a dynamic model in Matlab/Simulink (R) has been used. The model includes all the new components/major changes required in the vehicle- experimentally validated-. It has been used on backward simulations for the ACEA long haul mission in order to maximize the vehicle's efficiency. Estimations at rating point (600 Nm and 1200 rpm) result in an electric production up to 4 kW h and a fuel saving of 7.5%. The most convenient technologies in the ACEA cycle turns out to be the KERs followed by the TBG.This work has been developed in the frame of the project of the European Seventh Union Framework Program by the project High efficiency energy conversion for future heavy duty transport High efficiency energy conversion for future heavy duty transport GASTone grant agreement 605456. The authors are grateful for the given support.Hervas-Blasco, E.; Navarro-Peris, E.; De Rosa, M.; Corberán, JM. (2017). Potential fuel saving in a powertrain derived from the recovery of the main energy losses for a long haul European mission. Energy Conversion and Management. 150:485-499. https://doi.org/10.1016/j.enconman.2017.08.01848549915

A novel TRNSYS type for short-term borehole heat exchanger simulation: B2G model

[EN] Models of ground source heat pump (GSHP) systems are used as an aid for the correct design and optimization of the system. For this purpose, it is necessary to develop models which correctly reproduce the dynamic thermal behavior of each component in a short-term basis. Since the borehole heat exchanger (BHE) is one of the main components, special attention should be paid to ensuring a good accuracy on the prediction of the short-term response of the boreholes. The BHE models found in literature which are suitable for short-term simulations usually present high computational costs. In this work, a novel TRNSYS type implementing a borehole-to-ground (B2G) model, developed for modeling the short-term dynamic performance of a BHE with low computational cost, is presented. The model has been validated against experimental data from a GSHP system located at Universitat Politecnica de Valencia, Spain. Validation results show the ability of the model to reproduce the short-term behavior of the borehole, both for a step-test and under normal operating conditions. (C) 2015 Elsevier Ltd. All rights reserved.The present work has been supported by the FP7 European project Advanced ground source heat pump systems for heating and cooling in Mediterranean climate (GROUND-MED).De Rosa, M.; Ruiz Calvo, F.; Corberán Salvador, JM.; Montagud Montalvá, CI.; Tagliafico, L. (2015). A novel TRNSYS type for short-term borehole heat exchanger simulation: B2G model. Energy Conversion and Management. 100:347-357. https://doi.org/10.1016/j.enconman.2015.05.021S34735710

Validación del modelo B2G para un intercambiador enterrado en funcionamiento ON/OFF

El diseño y optimización de sistemas de climatización requiere de la capacidad de predecir y reproducir el comportamiento dinámico de cada componente del sistema. Para sistemas de climatización por bomba de calor acoplada al terreno, uno de los elementos principales a estudiar es el intercambiador enterrado. A lo largo de los últimos años se han desarrollado varios tipos de modelos de intercambiador enterrado, con distintas características en función del planteamiento utilizado. Sin embargo, muchos de los modelos existentes se basan en aproximaciones de régimen permanente, por lo que no permiten simular el comportamiento dinámico del intercambiador, mientras que los que sí lo permiten resultan ser modelos altamente complejos, con un elevado coste computacional, lo que dificulta y restringe su uso. En la Universitat Politècnica de València (UPVLC) se ha estado desarrollando un modelo completo de una instalación de climatización por bomba de calor acoplada al terreno. En el marco del desarrollo de este modelo, ha sido necesario desarrollar un nuevo modelo de intercambiador enterrado, capaz de predecir el comportamiento dinámico del intercambiador y suficientemente rápido como para poder ser integrado en el modelo completo de la instalación sin elevar excesivamente el coste computacional. Este modelo, llamado modelo B2G (Borehole-to-Ground) ha sido presentado y validado con datos experimentales de una instalación situada en Estocolmo, Suecia [1]. Su funcionamiento ha sido comparado con el de un modelo estándar, basado en el comportamiento en régimen permanente [2], con resultados satisfactorios. En el presente trabajo se presenta una extensión de la validación de este modelo, utilizando datos experimentales correspondientes a la instalación de la UPVLC. Para ello se realizan dos tipos de validación, usando como datos de entrada al modelo la temperatura del agua a la entrada del intercambiador y, posteriormente, la carga térmica intercambiada con el terreno. Comparando los resultados con los datos experimentales se comprueba la capacidad del modelo para predecir el comportamiento dinámico del intercambiador enterrado.Este trabajo se encuentra enmarcado en el proyecto europeo dentro del séptimo programa Marco “Advanced ground source heat pump systems for heating and cooling in Mediterranean climate” (GROUND-MED)

Dual source heat pump, a high efficiency and cost-effective alternative for heating, cooling and DHW production

[EN] This article presents the characteristics and performance of an innovative dual source heat pump (DSHP) for heating, cooling and domestic hot water (DHW) production. The research work was carried out in the framework of the H2020 European project: Geot€ch `GEOthermal Technology for economic Cooling and Heating¿. The DSHP is able to choose the most favourable source/sink in such a way that it can work as an air-to-water heat pump using the air as a source/sink, or as a brine-to-water heat pump coupled to the ground. The DSHP is manufactured as an outdoor `plug & play¿ unit, working with R32 refrigerant and including a variable speed compressor, which gives full capabilities for an efficient modulating operation. The DSHP was fully characterized in steady state conditions at the IUIIE laboratory. In order to assess its dynamic performance and to identify key control strategies to optimize its annual operation, a complete integrated model of the DSHP system in TRNSYS including the DSHP and all the other system components was developed. A first energy assessment, carried out for an office building located in the Netherlands, proves that the DSHP system would be able to reach a similar efficiency than a pure ground source heat pump (GSHP) system with half the ground source heat exchanger area needed. Therefore, the DSHP system could become a cost-effective alternative solution for heating, cooling and DHW production in buildings, as the initial investment would be significantly reduced compared to GSHPs, with similar or even higher energy efficiency.The present work has been supported by the European Union under the Horizon 2020 Framework Programme for European Research and Technological Development (2014-20) inside the framework of the project 656889-GEOTeCH (Geothermal Technology for Economic Cooling and Heating). Additionally, funding was received by the Generalitat Valenciana inside the programme 'Ayudas para la contratacion de personal investigador en formacion de caracter predoctoral (ACIF/2016/131)' and by the Ministerio de Educacion, Cultura y Deporte inside the programme 'Formacion de Profesorado Universitario (FPU15/03476)'.Corberán, JM.; Cazorla-Marín, A.; Marchante-Avellaneda, J.; Montagud, C. (2018). Dual source heat pump, a high efficiency and cost-effective alternative for heating, cooling and DHW production. International Journal of Low-Carbon Technologies (Online). 13(2):161-176. https://doi.org/10.1093/ijlct/cty008S16117613

Experimental validation of a short-term Borehole-to-Ground (B2G) dynamic model

[EN] The design and optimization of ground source heat pump systems require the ability to accurately reproduce the dynamic thermal behavior of the system on a short-term basis, specially in a system control perspective. In this context, modeling borehole heat exchangers (BHEs) is one of the most relevant and difficult tasks. Developing a model that is able to accurately reproduce the instantaneous response of a BHE while keeping a good agreement on a long-term basis is not straightforward. Thus, decoupling the short-term and long-term behavior will ease the design of a fast short-term focused model. This work presents a short-term BHE dynamic model, called Borehole-to-Ground (B2G), which is based on the thermal network approach, combined with a vertical discretization of the borehole. The proposed model has been validated against experimental data from a real borehole located in Stockholm, Sweden. Validation results prove the ability of the model to reproduce the short-term behavior of the borehole with an accurate prediction of the outlet fluid temperature, as well as the internal temperature profile along the U-tube.The present work has been supported by the FP7 European project "Advanced ground source heat pump systems for heating and cooling in Mediterranean climate" (GROUND-MED), and by the "Resource-Efficient Refrigeration And Heat Pump Systems" (EFF-SYS+) program.Ruiz Calvo, F.; Rosa, MD.; Acuña, J.; Corberán Salvador, JM.; Montagud Montalvá, CI. (2015). Experimental validation of a short-term Borehole-to-Ground (B2G) dynamic model. Applied Energy. 140:210-223. https://doi.org/10.1016/j.apenergy.2014.12.002S21022314

Unprecedented use of silver(I) N-heterocyclic carbene complexes for the catalytic preparation of 1,2-bis(boronate) esters

Catalytic diboration of internal and terminal alkenes with Ag(I) N-heterocyclic carbene complexes leads to 1,2-bis(boronate) esters as single intermediates, that can be oxidised towards the corresponding diols.Sanau Torrecilla, Mercedes, [email protected]

Borehole modelling: a comparison between a steady-state model and a novel dynamic model in a real ON/OFF GSHP operation

The correct design and optimization of complex energy systems requires the ability to reproduce the dynamic thermal behavior of each system component. In ground source heat pump (GSHP) systems, modelling the borehole heat exchangers (BHE) dynamic response is especially relevant in the development of control strategies for energy optimization purposes. Over the last years, several models have been developed but most of them are based on steady state approaches, which makes them unsuitable for short-term simulation purposes. In fact, in order to accurately predict the evolution of the fluid temperatures due to the ON/OFF cycles of the heat pump, it is essential to correctly characterize the dynamic response of BHE for very short time periods. The aim of the present paper is to compare the performance of an analytical steady-state model, available in TRNSYS environment (Type 557), with a novel short-term dynamic model. The new dynamic model is based on the thermal-network approach coupled with a vertical discretization of the borehole which takes into account both the advection due to the fluid circulating along the U-tube, and the heat transfer in the borehole and in the ground. These two approaches were compared against experimental data collected from a real GSHP system installed at the Universitat Polit ècnica de Val ència. The analysis was performed comparing the outlet temperature profiles predicted by both models during daily standard ON/OFF operating conditions, both in heating and cooling mode, and the between both approaches were highlighted. Finally, the obtained results have been discussed focusing on the potential impact that the differences found in the prediction of the temperature evolution could have in design and optimization of GSHP systems.De Rosa, M.; Ruiz Calvo, F.; Corberán Salvador, JM.; Montagud Montalvá, CI.; Tagliafico, L. (2014). Borehole modelling: a comparison between a steady-state model and a novel dynamic model in a real ON/OFF GSHP operation. Journal of Physics: Conference Series. 547:1-10. doi:10.1088/1742-6596/547/1/012008S11054