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rss_1.0 Recursos de colección

Archivo Digital UPM (45.541 recursos)
This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Energías Renovables

Mostrando recursos 1 - 20 de 407

1. Biodiésel de ésteres etílicos de ácidos grasos : correlación composición-propiedades - Alonso Castro, Elena
Debido a la situación energética actual, el aumento de la demanda de petróleo y precio, así como su carácter no renovable, hace necesaria la búsqueda de alternativas viables para su uso como combustible. Una de ellas es el biodiésel, ya que tiene características similares y puede ser usado como sustituto de los combustibles convencionales, sin necesidad de grandes modificaciones en el motor. Hasta ahora los estudios se habían centrado en los esteres metílicos de ácidos grasos (FAMEs) por razones meramente económicas. El proyecto tiene como objetivo el estudio de los esteres etílicos de ácidos grasos (FAEEs) para establecer una correlación...

2. Domestic hot water consumption vs. solar thermal energy storage: the optimum size of the storage tank - Rodríguez Hidalgo, María del Carmen; Rodríguez Aumente, Pedro A.; Lecuona Newman, Antonio; Legrand, Mathieu; Ventas Garzón, Rubén
Many efforts have been made in order to adequate the production of a solar thermal collector field to the consumption of domestic hot water of the inhabitants of a building. In that sense, much has been achieved in different domains: research agencies, government policies and manufacturers. However, most of the design rules of the solar plants are based on steady state models, whereas solar irradiance, consumption and thermal accumulation are inherently transient processes. As a result of this lack of physical accuracy, thermal storage tanks are sometimes left to be as large as the designer decides without any aforementioned precise...

3. Extension of the characteristic equation to absorption chillers with adiabatic absorbers - Gutiérrez Urueta, Geydy; Rodríguez Aumente, Pedro A.; Ziegler, F.; Lecuona Newman, Antonio; Rodríguez Hidalgo, María del Carmen
Various researchers have developed models of conventional H2O–LiBr absorption machines with the aim of predicting their performance. In this paper, the methodology of characteristic equations developed by Hellmann et al. (1998) is applied. This model is able to represent the capacity of single effect absorption chillers and heat pumps by means of simple algebraic equations. An extended characteristic equation based on a characteristic temperature difference has been obtained, considering the facility features. As a result, it is concluded that for adiabatic absorbers a subcooling temperature must be specified. The effect of evaporator overflow has been characterized. Its influence on cooling...

4. Effectiveness of improved cookstoves to reduce indoor air pollution in developing countries. The case of the cassamance natural subregion, Western Africa - Sota, Candela de la; Lumbreras Martin, Julio; Mazorra Aguiar, Javier; Narros Sierra, Adolfo; Fernández García, Luz; Borge García, Rafael
The Spanish NGO "Alianza por la Solidaridad" has installed improved cookstoves in 3000 households during 2012 and 2013 to improve energy efficiency reducing fuelwood consumption and to improve in-door air quality. The type of cookstoves were Noflaye Jeeg and Noflaye Jaboot and were installed in the Cassamance Natural Subregion covering part of Senegal, The Gambia and Guinea-Bissau. The Technical University of Madrid (UPM) has conducted a field study on a sample of these households to assess the effect of improved cookstoves on kitchen air quality. Measurements of carbon monoxide (CO) and fine particle matter (PM2.5) were taken for 24-hr period...

5. Wind intermittency and CO2 reductions: the case of the spanish power system - Gutierrez Martin, Fernando; Da Silva Alvarez, Ricardo A.; Montoro Pintado, Pablo
Renewable energy sources are believed to reduce drastically greenhouse gas emissions that would otherwise be generated from fossil fuels used to generate electricity. This implies that a unit of renewable energy will replace a unit of fossil-fuel, with its CO2 emissions, on an equivalent basis (with no other effects on the grid). But, the fuel economy and emissions in the existing power systems are not proportional with the electricity production of intermittent sources due to cycling of the fossil fuel plants that make up the balance of the grid (i.e. changing the power output makes thermal units to operate less...

6. Ab-Initio calculations including Van der Waals interactions: the SnS2 layered material - Seminóvski Pérez, Yohanna; Palacios Clemente, Pablo; Wahnon Benarroch, Perla; Grau-Crespo, Ricardo; Wahnón Benarroch, Perla
Tin disulfide SnS2 was recently proposed as a high efficiency solar cell precursor [1]. The aim of this work is a deep study of the structural disposition of the most important polytipes of this layered material, not only describing the electronic correlation but also the interatomic Van der Waals interactions that is present between the layers. The two recent implementations to take Van der Waals interactions into account in the VASP code are the self-consistent Dion et al. [2] functional optimized for solids by Michaelides et al [3] and the Grimme [4] dispersion correction that is applied after each autoconsistent...

7. SolarPaces 2013: Innovations on direct steam generation in linear fresnel collectors - Coco Enriquez, Luis; Muñoz Antón, Javier; Martínez-Val Peñalosa, Jose Maria
Direct Steam Generation (DSG) in Linear Fresnel (LF) solar collectors is being consolidated as a feasible technology for Concentrating Solar Power (CSP) plants. The competitiveness of this technology relies on the following main features: water as heat transfer fluid (HTF) in Solar Field (SF), obtaining high superheated steam temperatures and pressures at turbine inlet (500ºC and 90 bar), no heat tracing required to avoid HTF freezing, no HTF degradation, no environmental impacts, any heat exchanger between SF and Balance Of Plant (BOP), and low cost installation and maintenance. Regarding to LF solar collectors, were recently developed as an alternative to...

8. Comparison between SAM and Thermoflow for Linear Fresnel Solar Power Plants design - Coco Enriquez, Luis
System Advisor Model is a software tool develped by National Renewable Laboratory (NREL), Department Of Energy, USA to design Solar Power Plants.

9. Utzon and the sun path as an organizing element of life in a house - Rupérez Escribano, Miguel Ángel
The present text intends to analyze the hypothesis stating that the path of the sun can be an organizing element for how you live in the houses designed by Jørn Utzon. To do so, I have selected twenty houses and building complexes designed by him between the years 1950-94, in Denmark, Sweden, The United Kingdom and Spain. In these projects I will look for elements which are repeated and their possible meaning. The aim is to reach practical conclusions that could help us decide how to orientate a house.

10. The impact of sustainable construction and knowledge management on sustainability goals. A review of the venezuelan renewable energy sector - Pietrosemoli de Dikdan, Licia; Rodríguez Monroy, Carlos
The recognition of the relevance of energy, especially of the renewable energies generated by the sun, water, wind, tides, modern biomass or thermal is growing significantly in the global society based on the possibility it has to improve societies′ quality of life, to support poverty reduction and sustainable development. Renewable energy, and mainly the energy generated by large hydropower generation projects that supply most of the renewable energy consumed by developing countries, requires many technical, legal, financial and social complex processes sustained by innovations and valuable knowledge. Besides these efforts, renewable energy requires a solid infrastructure to generate and distribute...

11. Sewage sludge gasification. Dolomite performance under different operating conditions - Andrés Almeida, Juan Manuel de; Roche, Elena; Narros Sierra, Adolfo; Rodriguez Hurtado, Encarnación
Gasification is a technology that can replace traditional management alternatives used up to date to deal with this waste (landfilling, composting and incineration) and which fulfils the social, environmental and legislative requirements. The main products of sewage sludge gasification are permanent gases (useful to generate energy or to be used as raw material in chemical synthesis processes), liquids (tars) and char. One of the main problems to be solved in gasification is tar production. Tars are organic impurities which can condense at relatively high temperatures making impossible to use the produced gases for most applications. This work deals with the...

12. Energía renovable a partir de los lodos de depuradoras urbanas - Roche, Elena; Andrés Almeida, Juan Manuel de; Narros Sierra, Adolfo; Rodriguez Hurtado, Encarnación
El lodo de depuradora es el residuo líquido o semilíquido procedente de las Estaciones Depuradoras de Aguas Residuales (EDARs) del que puede obtenerse una energía renovable empleando la tecnología de la gasificación. Esta tecnología consiste en la oxidación parcial del sustrato carbonoso del lodo a altas temperaturas bajo condiciones subestequiométricas de aire, oxígeno u otros agentes gasificantes. Los productos obtenidos mediante gasificación son: un gas de síntesis (SYNGAS, con composición variable de H2, CO) un residuo carbonizado (char) y una fracción líquida de compuestos orgánicos de distinto peso molecular denominados alquitranes. El gas de síntesis tiene aplicaciones como son la...

13. Cultivo de microalgas (Chlorella sorokiniana) con iluminación mediante LEDs - Plasencia Álvarez, Juan
Con el fin de establecer si es posible llevar a cabo el cultivo de microalgas empleando LEDs (Light Emitting Diodes) y si el empleo de los mismos supone alguna ventaja, se llevaron a cabo cinco experiencias con el microalga Chlorella sorokiniana en las que se varió la cantidad y la calidad de la luz aplicada. En las dos primeras experiencias se empleó luz de un solo color, roja en la primera y azul en la segunda, ambas al 50 % de su intensidad. En las tres siguiente se ensayaron mezclas de ambas, aplicando en la tercera 50 % de luz...

14. Estudio de la viabilidad económica de la tecnología de captura y almacenamiento de Co2 - Seijas Morató, José
El informe más reciente del Grupo Intergubernamental de Expertos sobre el Cambio Climático (IPCC) define que las emisiones globales de CO2 deben ser recortados en un 50-80 % para el año 2050 con el fin de evitar los efectos más dañinos del cambio climático. El mundo depende actualmente de los combustibles fósiles para satisfacer el 80% de sus necesidades energéticas. La demanda de energía va en aumento y no se puede satisfacer a medio plazo únicamente por las energías renovables. Para hacer frente a los retos de esta creciente demanda de energía y la necesidad de reducir rápidamente emisiones de...

15. Aplicación de nuevas tecnologías en los sistemas de alumbrado - Mahtani Bhagwandas, Navin
A medida que transcurre el tiempo la sociedad evoluciona, las ciudades crecen, se modernizan, mejoran su infraestructura y se ofrecen más y mejores servicios a sus ciudadanos. Esto ha hecho que durante muchos años las ciudades se hayan desarrollado sin pensar en lo que vendrá más adelante, contaminando el medio ambiente y consumiendo mucha energía y de forma ineficiente. Ante esta situación, y gracias a las innovaciones tecnológicas en materia de comunicaciones, se están adoptando medidas para dirigir la evolución de las ciudades hacia un modelo de ciudad inteligente y sostenible. Las redes de comunicaciones constituyen uno de los pilares sobre los...

16. Assessing the solar irradiation potential for solar photovoltaic applications in buildings at low latitudes ¿ Making the case for Brazil - Vega Sanchez, Sergio; Cronemberger Ribeiro Silva, Joara
In Brazil, a low-latitude country characterized by its high availability and uniformity of solar radiation, the use of PV solar energy integrated in buildings is still incipient. However, at the moment there are several initiatives which give some hints that lead to think that there will be a change shortly. In countries where this technology is already a daily reality, such as Germany, Japan or Spain, the recommendations and basic criteria to avoid losses due to orientation and tilt are widespread. Extrapolating those measures used in high latitudes to all regions, without a previous deeper analysis, is standard practice. They...

17. Effect of soiling in CPV systems - Vivar García, Marta; Herrero Martin, Rebeca; Anton Hernandez, Ignacio; Martinez Moreno, Francisco; Moreton Villagra, Rodrigo; Sala Pano, Gabriel; Blakers, Andrew W.; Smeltink, John
The effect of soiling in flat PV modules has been already studied, causing a reduction of the electrical output of 4% on average. For CPV's, as far as soiling produces light scattering at the optical collector surface, the scattered rays should be definitively lost because they cannot be focused onto the receivers again. While the theoretical study becomes difficult because soiling is variable at different sites, it becomes easier to begin the monitoring of the real field performance of concentrators and then raise the following question: how much does the soiling affect to PV concentrators in comparison with flat panels??...

18. Parque eólico off-shore en Guardamar del Segura (Alicante) - Orozco Rendueles, Leticia
El presente proyecto se redacta con el objetivo de estudiar las posibles alternativas de construcción de un parque eólico offshore frente a las costas del término municipal de Guardamar del Segura, en la provincia de Alicante, y concluir, después de una valoración detallada y desde el punto de vista de distintos criterios, con la solución óptima. En él se realiza además una descripción de las obras e instalaciones necesarias para llevar a cabo la construcción del parque eólico offshore de Guardamar del Segura. Tienen un carácter de estudio previo y comparativo de alternativas; pues en él se evaluarán las distintas soluciones...

19. Dry cooling with night cool storage to enhance solar power plants performance in extreme conditions areas - Muñoz Antón, Javier; Martínez-Val Peñalosa, Jose Maria; Abbas Camara, Rubén; Abánades Velasco, Alberto
Solar thermal power plants are usually installed in locations with high yearly average solar radiation, often deserts. In such conditions, cooling water required for thermodynamic cycles is rarely available. Moreover, when solar radiation is high, ambient temperature is very high as well; this leads to excessive condensation temperature, especially when air-condensers are used, and decreases the plant efficiency. However, temperature variation in deserts is often very high, which drives to relatively low temperatures during the night. This fact can be exploited with the use of a closed cooling system, so that the coolant (water) is chilled during the night and...

20. Steady-state thermal analysis of an innovative receiver for linear Fresnel reflectors - Abbas Camara, Rubén; Muñoz Antón, Javier; Martínez-Val Peñalosa, Jose Maria
The study of the performance of an innovative receiver for linear Fresnel reflectors is carried out in this paper, and the results are analyzed with a physics perspective of the process. The receiver consists of a bundle of tubes parallel to the mirror arrays, resulting on a smaller cross section for the same receiver width as the number of tubes increases, due to the diminution of their diameter. This implies higher heat carrier fluid speeds, and thus, a more effective heat transfer process, although it conveys higher pumping power as well. Mass flow is optimized for different tubes diameters, different...

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