Almacenamiento de energ��a t��rmica por calor latente en los edificios: bases para la optimizaci��n de aplicaciones pasivas, opacas y trasl��cidas

La principal motivaci��n para la elecci��n del tema de la tesis es nuestra realidad energ��tica y ambiental. Y m��s espec��ficamente, la necesidad urgente de dar una respuesta a esta realidad desde el sector de la edificaci��n. Por lo que, el trabajo parte de la b��squeda de soluciones pasivas que ayuden a la reducci��n del consumo energ��tico y de las emisiones de C02 de los edificios, tanto nuevos como existentes. El objeto de estudio son aplicaciones innovadoras, basadas en el uso de materiales reactivos, con un efecto t��rmico de memoria bidireccional. La energ��a es un elemento imprescindible para el desarrollo. Sin embargo, el modelo energ��tico predominante, basado principalmente en la utilizaci��n de combustibles de origen f��sil, es uno de los importantes responsables del deterioro ambiental que sufre el planeta. Adem��s, sus reservas son limitadas y est��n concentradas en unas pocas regiones del mundo, lo que genera problemas de dependencia, competitividad y de seguridad de suministro. Dado el gran potencial de ahorro energ��tico del sector de la edificaci��n, la Uni��n Europea en sus directivas enfatiza la necesidad de mejorar la eficiencia energ��tica de los edificios. A��adiendo, adem��s, la obligatoriedad de desarrollar edificios ���energ��a casi nula���, cuyo prerrequisito es tener un muy alto rendimiento energ��tico. En Espa��a, los edificios son responsables del 31% del consumo de energ��a primaria. La mayor parte de este consumo se relaciona a la utilizaci��n de sistemas activos de acondicionamiento. Una medida efectiva para reducir la demanda es mejorar la envolvente. Sin embargo, hay que buscar estrategias adicionales para aumentar a��n m��s la eficiencia de los edificios nuevos y existentes. Para los climas de Espa��a, el uso de la inercia t��rmica ha probado ser una estrategia v��lida. Sin embargo, su funcionamiento est�� vinculado al peso y al volumen de los materiales utilizados. Esto limita sus posibilidades en la rehabilitaci��n energ��tica y en los nuevos edificios basados en la construcci��n ligera. Una alternativa es el uso de aplicaciones de almacenamiento t��rmico por calor latente, utilizando materiales de cambio de fase (PCM). Los PCM son sustancias con un muy alto calor de fusi��n, capaces de almacenar una gran cantidad de energ��a t��rmica sin requerir aumentos significativos de peso o volumen. Estas caracter��sticas los hacen id��neos para reducir el consumo relacionado con el acondicionamiento t��rmico, en edificios nuevos y existentes. En la parte preliminar de la investigaci��n, se encontr�� que para lograr un aprovechamiento ��ptimo de las aplicaciones con PCM es necesario tener un conocimiento profundo de su funcionamiento y de las variables del sistema. De ah�� que el objetivo principal de la presente tesis sea: establecer las bases para la optimizati��n integral de las aplicaciones con almacenamiento de energ��a t��rmica por calor latente, identificando y validando sus variables m��s relevantes. La investigaci��n consta de tres partes. La primera, documental, sistematizando y jerarquizando la informaci��n cient��fica publicada; la segunda, num��rica, basada en un an��lisis param��trico de una aplicaci��n con PCM, utilizando simulaciones t��rmicas; y la tercera, experimental, monitorizando el funcionamiento t��rmico y energ��tico de diferentes aplicaciones con PCM en m��dulos a escala real. Los resultados brindan un m��s profundo entendimiento del funcionamiento de las aplicaciones evaluadas. Han permitido identificar sus variables relevantes, cuantificar su influencia, y determinar condiciones ��ptimas para su utilizaci��n as�� como situaciones en las que ser��a muy dif��cil justificar su uso. En el proceso, se realiz�� la caracterizaci��n t��rmica y energ��tica de aplicaciones con PCM, tanto opacas como trasl��cidas. Adem��s, se ha encontrado que las aplicaciones con PCM son capaces de aumentar la eficiencia energ��tica inclusive en recintos con dise��os optimizados, demostrando ser una de las estrategias adecuadas para lograr el muy alto desempe��o energ��tico requerido en los edificios energ��a nula. ABSTRACT The main motivation for choosing the theme of the thesis is our energy and environmental reality. And more specifically, the urgent need to respond to this reality from the building sector. This is why, the work start with the search of passive solutions that help reduce energy consumption and C02 emissions of buildings, in both new and existing ones. The object of study is innovative applications based on the use of responsive materials, with bidirectional thermal memory. Energy is an essential element for development. However, the predominant energy model, based primarily on the use of fossil fuels, is one of the major responsible for the environmental deterioration of the planet, the cause of most of the CO2 emissions. Furthermore, reserves of fossil fuels are limited and are concentrated in a few regions of the world, which creates issues related to dependency, competitiveness, and security of supply. Given the large potential for energy savings in the building sector, the European Union in its directives emphasizes the need to improve energy efficiency in buildings. Also, adding the obligation to develop "nearly zero energy" buildings, whose first prerequisite is to achieve a very high energy efficiency. In Spain, buildings are responsible for 31% of primary energy consumption and most of this consumption is related to the used of HVAC systems. One of the most effective measures to reduce demand is to improve the envelope. However, it is necessary to look for additional strategies to further increase the efficiency of new and existing buildings. For the predominant climates in Spain, use of the thermal inertia may be a valid strategy. Nevertheless, its operation is linked to weight and volume of the materials used. This limits their possibilities in the existing buildings energy retrofitting and in the new buildings based on lightweight construction. An alternative is the use of latent heat thermal energy storage applications (LHTES), using phase change materials (PCM). PCM are substances with a high heat of fusion, capable of storing a large amount of thermal energy without requiring significant increases in weight or volume. These features make them ideal for reducing energy consumption associated with thermal conditioning in both new and existing buildings. In the preliminary part of the investigation, it was found that to get optimum utilization of the PCM applications is needed to have a deep understanding of its operation and, in particular, how the system variables affect its performance. Hence, the main objective of this thesis is: to establish the basis for the integral optimization of applications with latent heat thermal energy storage, identifying and validating the most relevant variables. The research comprises of three parts. The first, documentary, systematizing and prioritizing published scientific information. The second, numeric, based on a parametric analysis of an application PCM using thermal simulations. The third, experimental, monitoring the thermal and energy performance of different applications with PCM on real scale test cells. The results provide a complete understanding of the functioning of the evaluated LHTES application. They have allowed to identify their relevant variables, quantify their influence and determine optimum conditions for use as well as situations where it would be very difficult to justify its use. In the process, it was carried out the power and thermal characterization of various opaque and translucent PCM applications. Furthermore, it has been found that applications with PCM can increase the energy efficiency, even in buildings with optimized designs; proving to be one of the appropriate measures to achieve the high energy performance required in zero energy buildings.

Energy efficiency evaluation of zero energy houses

Given the global energy and environmental situation, the European Union has been issuing directives with increasingly demanding requirements in term of the energy efficiency in buildings. The international competition of sustainable houses, Solar Decathlon Europe (SDE), is aligned with these European objectives. SDE houses are low energy solar buildings that must reach the near to zero energy houses��� goal. In the 2012 edition, in order to emphasize its significance, the Energy Efficiency Contest was added. SDE houses��� interior comfort, functioning and energy performance is monitored. The monitoring data can give an idea about the efficiency of the houses. However, a jury comprised by international experts is responsible for carrying out the houses energy efficiency evaluation. Passive strategies and houses services are analyzed. Additionally, the jury's assessment has been compared with the behavior of the houses during the monitoring period. Comparative studies make emphasis on the energy aspects, houses functioning and their interior comfort. Conclusions include thoughts related with the evaluation process, the results of the comparative studies and suggestions for the next competitions.

Passive design strategies and performance of Net Energy Plus Houses

The first step in order to comply with the European Union goals of Near to Zero Energy Buildings is to reduce the energy consumption in buildings. Most of the building consumption is related to the use of active systems to maintain the interior comfort. Passive design strategies contribute to improve the interior comfort conditions, increasing the energy efficiency in buildings and reducing their energy consumption. In this work, an analysis of the passive strategies used in Net Energy Plus Houses has been made. The participating houses of the Solar Decathlon Europe 2012 competition were used as case studies. The passive design strategies of these houses were compared with the annual simulations, and the competition monitored data, especially during the Passive Monitored Period. The analysis included the thermal properties of the building envelope, geometric parameters, ratios and others passive solutions such as Thermal Energy Storage systems, evaporative cooling, night ventilation, solar gains and night sky radiation cooling. The results reflect the impact of passive design strategies on the houses' comfort and efficiency, as well as their influence in helping to achieve the Zero Energy Buildings category.

La implementaci��n arquitect��nica de los acristalamientos activos con agua circulante, y su contribuci��n en edificios de consumo de energ��a casi nulo

La presente Tesis Doctoral eval��a la contribuci��n de una fachada activa, constituida por acristalamientos con circulaci��n de agua, en el rendimiento energ��tico del edificio. Con especial ��nfasis en la baja afecci��n sobre su imagen, su integraci��n ha de favorecer la calificaci��n del edificio con el futuro est��ndar de Edificio de consumo de Energ��a Casi Nulo (EECN). El prop��sito consiste en cuantificar su aportaci��n a limitar la demanda de climatizaci��n, como soluci��n de fachada transparente acorde a las normas de la energ��a del 2020. En el primer cap��tulo se introduce el planteamiento del problema. En el segundo cap��tulo se desarrollan la hip��tesis y el objetivo fundamental de la investigaci��n. Para tal fin, en el tercer cap��tulo, se revisa el estado del arte de la tecnolog��a y de la investigaci��n cient��fica, mediante el an��lisis de la literatura de referencia. Se comparan patentes, prototipos, sistemas comerciales asimilables, investigaciones en curso en Universidades, y proyectos de investigaci��n y desarrollo, sobre envolventes que incorporan acristalamientos con circulaci��n de agua. El m��todo experimental, expuesto en el cuarto cap��tulo, acomete el dise��o, la fabricaci��n y la monitorizaci��n de un prototipo expuesto, durante ciclos de ensayos, a las condiciones clim��ticas de Madrid. Esta fase ha permitido adquirir informaci��n precisa sobre el rendimiento del acristalamiento en cada orientaci��n de incidencia solar, en las distintas estaciones del a��o. En paralelo, se aborda el desarrollo de modelos te��ricos que, mediante su asimilaci��n a soluciones multicapa caracterizadas en las herramientas de simulaci��n EnergyPlus y IDA-ICE (IDA Indoor Climate and Energy), reproducen el efecto experimental. En el quinto cap��tulo se discuten los resultados experimentales y te��ricos, y se analiza la respuesta del acristalamiento asociado a un determinado volumen y temperatura del agua. Se calcula la eficiencia en la captaci��n de la radiaci��n y, mediante la comparativa con un acristalamiento convencional, se determina la reducci��n de las ganancias solares y las p��rdidas de energ��a. Se comparan el rendimiento del acristalamiento, obtenido experimentalmente, con el ofrecido por paneles solares fotot��rmicos disponibles en el mercado. Mediante la traslaci��n de los resultados experimentales a casos de c��lulas de tama��o habitable, se cuantifica la afecci��n del acristalamiento sobre el consumo en refrigeraci��n y calefacci��n. Diferenciando cada caso por su composici��n constructiva y orientaci��n, se extraen conclusiones sobre la reducci��n del gasto en climatizaci��n, en condiciones de bienestar. Posteriormente, se eval��a el ahorro de su incorporaci��n en un recinto existente, de construcci��n ligera, localizado en la Escuela de Arquitectura de la Universidad Polit��cnica de Madrid (UPM). Mediante el planteamiento de escenarios de rehabilitaci��n energ��tica, se estima su compatibilidad con un sistema de climatizaci��n mediante bomba de calor y extracci��n geot��rmica. Se describe el funcionamiento del sistema, desde la perspectiva de la operaci��n conjunta de los acristalamientos activos e intercambio geot��rmico, en nuestro clima. Mediante la parametrizaci��n de sus funciones, se estima el beneficio adicional de su integraci��n, a partir de la mejora del rendimiento de la bomba de calor COP (Coefficient of Performance) en calefacci��n, y de la eficiencia EER (Energy Efficiency Ratio) en refrigeraci��n. En el recinto de la ETSAM, se ha analizado la contribuci��n de la fachada activa en su calificaci��n como Edificio de Energ��a Casi Nula, y estudiado la rentabilidad econ��mica del sistema. En el sexto cap��tulo se exponen las conclusiones de la investigaci��n. A la fecha, el sistema supone alta inversi��n inicial, no obstante, genera elevada eficiencia con bajo impacto arquitect��nico, reduci��ndose los costes operativos, y el dimensionado de los sistemas de producci��n, de mayor afecci��n sobre el edificio. Mediante la envolvente activa con suministro geot��rmico no se condena la superficie de cubierta, no se ocupa volumen ��til por la presencia de equipos emisores, y no se reduce la superficie o altura ��til a base de reforzar los aislamientos. Tras su discusi��n, se considera una alternativa de valor en procesos de dise��o y construcci��n de Edificios de Energ��a Casi Nulo. Se proponen l��neas de futuras investigaci��n cuyo prop��sito sea el conocimiento de la tecnolog��a de los acristalamientos activos. En el ��ltimo cap��tulo se presentan las actividades de difusi��n de la investigaci��n. Adicionalmente se ha proporcionado una mejora tecnol��gica a las fachadas activas existentes, que ha derivado en la solicitud de una patente, actualmente en tramitaci��n. ABSTRACT This Thesis evaluates the contribution of an active water flow glazing fa��ade on the energy performance of buildings. Special emphasis is made on the low visual impact on its image, and the active glazing implementation has to encourage the qualification of the building with the future standard of Nearly Zero Energy Building (nZEB). The purpose is to quantify the fa��ade system contribution to limit air conditioning demand, resulting in a transparent fa��ade solution according to the 2020 energy legislation. An initial approach to the problem is presented in first chapter. The second chapter develops the hypothesis and the main objective of the research. To achieve this purpose, the third chapter reviews the state of the art of the technology and scientific research, through the analysis of reference literature. Patents, prototypes, assimilable commercial systems, ongoing research in other universities, and finally research and development projects incorporating active fluid flow glazing are compared. The experimental method, presented in fourth chapter, undertakes the design, manufacture and monitoring of a water flow glazing prototype exposed during test cycles to weather conditions in Madrid. This phase allowed the acquisition of accurate information on the performance of water flow glazing on each orientation of solar incidence, during different seasons. In parallel, the development of theoretical models is addressed which, through the assimilation to multilayer solutions characterized in the simulation tools EnergyPlus and IDA-Indoor Climate and Energy, reproduce the experimental effect. Fifth chapter discusses experimental and theoretical results focused to the analysis of the active glazing behavior, associated with a specific volume and water flow temperature. The efficiency on harvesting incident solar radiation is calculated, and, by comparison with a conventional glazing, the reduction of solar gains and energy losses are determined. The experimental performance of fluid flow glazing against the one offered by photothermal solar panels available on the market are compared. By translating the experimental and theoretical results to cases of full-size cells, the reduction in cooling and heating consumption achieved by active fluid glazing is quantified. The reduction of energy costs to achieve comfort conditions is calculated, differentiating each case by its whole construction composition and orientation. Subsequently, the saving of the implementation of the system on an existing lightweight construction enclosure, located in the School of Architecture at the Polytechnic University of Madrid (UPM), is then calculated. The compatibility between the active fluid flow glazing and a heat pump with geothermal heat supply system is estimated through the approach of different energy renovation scenarios. The overall system operation is described, from the perspective of active glazing and geothermal heat exchange combined operation, in our climate. By parameterization of its functions, the added benefit of its integration it is discussed, particularly from the improvement of the heat pump performance COP (Coefficient of Performance) in heating and efficiency EER (Energy Efficiency Ratio) in cooling. In the case study of the enclosure in the School of Architecture, the contribution of the active glazing fa��ade in qualifying the enclosure as nearly Zero Energy Building has been analyzed, and the feasibility and profitability of the system are studied. The sixth chapter sets the conclusions of the investigation. To date, the system may require high initial investment; however, high efficiency with low architectural impact is generated. Operational costs are highly reduced as well as the size and complexity of the energy production systems, which normally have huge visual impact on buildings. By the active fa��ade with geothermal supply, the deck area it is not condemned. Useful volume is not consumed by the presence of air-conditioning equipment. Useful surface and room height are not reduced by insulation reinforcement. After discussion, water flow glazing is considered a potential value alternative in nZEB design and construction processes. Finally, this chapter proposes future research lines aiming to increase the knowledge of active water flow glazing technology. The last chapter presents research dissemination activities. Additionally, a technological improvement to existing active facades has been developed, which has resulted in a patent application, currently in handling process.

Ventanas con c��mara de agua circulante en edificios de consumo de energ��a casi nulo

Seg��n la normativa Europea relacionada con la eficiencia energ��tica en edificios, a partir del a��o 2020 todos los edificios de nueva planta deber��n considerarse como Edificios de consumo energ��tico casi nulo o Near zero energy buildings (nZEB). Aunque a��n no existe una definici��n exacta de los requisitos que tendr��n que cumplir este tipo de edificios, resulta evidente que deber��n tener una demanda energ��tica reducida. Dado que las ventanas pueden llegar a ser responsables de aproximadamente el 30% del consumo energ��tico destinado a acondicionar t��rmicamente un edificio, constituyen uno de los elementos cuya eficiencia debe mejorarse para lograr este tipo de edificios. Frente a este panorama, las ventanas con c��mara de agua circulante constituyen un tipo de ventana din��mica poco conocido, pero cuya contribuci��n a los edificios de consumo de energ��a casi nulo tanto nuevos como rehabilitados, puede ser muy interesante en climas c��lidos como Jos del sur de Europa.

Ventanas con c��mara de agua circulante en Edificios de consumo de Energ��a Casi Nulo

Seg��n la normativa Europea relacionada con la eficiencia energ��tica en edificios, a partir del a��o 2020 todos los edificios de nueva planta deber��n considerarse como Edificios de consumo energ��tico casi nulo o Near zero energy buildings (nZEB). Aunque a��n no existe una definici��n exacta de los requisitos que tendr��n que cumplir este tipo de edificios, resulta evidente que deber��n tener una demanda energ��tica reducida. Dado que las ventanas pueden llegar a ser responsables de aproximadamente el 30% del consumo energ��tico destinado a acondicionar t��rmicamente un edificio, constituyen uno de los elementos cuya eficiencia debe mejorarse para lograr este tipo de edificios. Frente a este panorama, las ventanas con c��mara de agua circulante constituyen un tipo de ventana din��mica poco conocido, pero cuya contribuci��n a los edificios de consumo de energ��a casi nulo tanto nuevos como rehabilitados, puede ser muy interesante en climas c��lidos como los del sur de Europa

M��todo experimental para la caracterizaci��n de las diferentes tecnolog��as de integraci��n arquitect��nica de la energ��a fotovoltaica en condiciones de funcionamiento real = Experimental method for characterization of several building integrated photovoltaic technologies under real working conditions

Hoy en d��a, el proceso de un proyecto sostenible persigue realizar edificios de elevadas prestaciones que son, energ��ticamente eficientes, saludables y econ��micamente viables utilizando sabiamente recursos renovables para minimizar el impacto sobre el medio ambiente reduciendo, en lo posible, la demanda de energ��a, lo que se ha convertido, en la ��ltima d��cada, en una prioridad. La Directiva 2002/91/CE "Eficiencia Energ��tica de los Edificios" (y actualizaciones posteriores) ha establecido el marco regulatorio general para el c��lculo de los requerimientos energ��ticos m��nimos. Desde esa fecha, el objetivo de cumplir con las nuevas directivas y protocolos ha conducido las pol��ticas energ��ticas de los distintos pa��ses en la misma direcci��n, centr��ndose en la necesidad de aumentar la eficiencia energ��tica en los edificios, la adopci��n de medidas para reducir el consumo, y el fomento de la generaci��n de energ��a a trav��s de fuentes renovables. Los edificios de energ��a nula o casi nula (ZEB, Zero Energy Buildings �� NZEB, Net Zero Energy Buildings) deber��n convertirse en un est��ndar de la construcci��n en Europa y con el fin de equilibrar el consumo de energ��a, adem��s de reducirlo al m��nimo, los edificios necesariamente deber��n ser autoproductores de energ��a. Por esta raz��n, la envolvente del edifico y en particular las fachadas son importantes para el logro de estos objetivos y la tecnolog��a fotovoltaica puede tener un papel preponderante en este reto. Para promover el uso de la tecnolog��a fotovoltaica, diferentes programas de investigaci��n internacionales fomentan y apoyan soluciones para favorecer la integraci��n completa de ��stos sistemas como elementos arquitect��nicos y constructivos, los sistemas BIPV (Building Integrated Photovoltaic), sobre todo considerando el pr��ximo futuro hacia edificios NZEB. Se ha constatado en este estudio que todav��a hay una falta de informaci��n ��til disponible sobre los sistemas BIPV, a pesar de que el mercado ofrece una interesante gama de soluciones, en algunos aspectos comparables a los sistemas tradicionales de construcci��n. Pero por el momento, la falta estandarizaci��n y de una regulaci��n armonizada, adem��s de la falta de informaci��n en las hojas de datos t��cnicos (todav��a no comparables con las mismas que est��n disponibles para los materiales de construcci��n), hacen dif��cil evaluar adecuadamente la conveniencia y factibilidad de utilizar los componentes BIPV como parte integrante de la envolvente del edificio. Organizaciones internacionales est��n trabajando para establecer las normas adecuadas y procedimientos de prueba y ensayo para comprobar la seguridad, viabilidad y fiabilidad estos sistemas. Sin embargo, hoy en d��a, no hay reglas espec��ficas para la evaluaci��n y caracterizaci��n completa de un componente fotovoltaico de integraci��n arquitect��nica de acuerdo con el Reglamento Europeo de Productos de la Construcci��n, CPR 305/2011. Los productos BIPV, como elementos de construcci��n, deben cumplir con diferentes aspectos pr��cticos como resistencia mec��nica y la estabilidad; integridad estructural; seguridad de utilizaci��n; protecci��n contra el clima (lluvia, nieve, viento, granizo), el fuego y el ruido, aspectos que se han convertido en requisitos esenciales, en la perspectiva de obtener productos ambientalmente sostenibles, saludables, eficientes energ��ticamente y econ��micamente asequibles. Por lo tanto, el m��dulo / sistema BIPV se convierte en una parte multifuncional del edificio no s��lo para ser f��sica y t��cnicamente "integrado", adem��s de ser una oportunidad innovadora del dise��o. Las normas IEC, de uso com��n en Europa para certificar m��dulos fotovoltaicos -IEC 61215 e IEC 61646 cualificaci��n de dise��o y homologaci��n del tipo para m��dulos fotovoltaicos de uso terrestre, respectivamente para m��dulos fotovoltaicos de silicio cristalino y de l��mina delgada- atestan ��nicamente la potencia del m��dulo fotovoltaico y dan fe de su fiabilidad por un per��odo de tiempo definido, certificando una disminuci��n de potencia dentro de unos l��mites. Existe tambi��n un est��ndar, en parte en desarrollo, el IEC 61853 (���Ensayos de rendimiento de m��dulos fotovoltaicos y evaluaci��n energ��tica") cuyo objetivo es la b��squeda de procedimientos y metodolog��as de prueba apropiados para calcular el rendimiento energ��tico de los m��dulos fotovoltaicos en diferentes condiciones clim��ticas. Sin embargo, no existen ensayos normalizados en las condiciones espec��ficas de la instalaci��n (p. ej. sistemas BIPV de fachada). Eso significa que es imposible conocer las efectivas prestaciones de estos sistemas y las condiciones ambientales que se generan en el interior del edificio. La potencia nominal de pico Wp, de un m��dulo fotovoltaico identifica la m��xima potencia el��ctrica que ��ste puede generar bajo condiciones est��ndares de medida (STC: irradici��n 1000 W/m2, 25 ��C de temperatura del m��dulo y distribuci��n espectral, AM 1,5) caracterizando el��ctricamente el m��dulo PV en condiciones espec��ficas con el fin de poder comparar los diferentes m��dulos y tecnolog��as. El vatio pico (Wp por su abreviatura en ingl��s) es la medida de la potencia nominal del m��dulo PV y no es suficiente para evaluar el comportamiento y producci��n del panel en t��rminos de vatios hora en las diferentes condiciones de operaci��n, y tampoco permite predecir con convicci��n la eficiencia y el comportamiento energ��tico de un determinado m��dulo en condiciones ambientales y de instalaci��n reales. Un adecuado elemento de integraci��n arquitect��nica de fachada, por ejemplo, deber��a tener en cuenta propiedades t��rmicas y de aislamiento, factores como la transparencia para permitir ganancias solares o un buen control solar si es necesario, aspectos vinculados y dependientes en gran medida de las condiciones clim��ticas y del nivel de confort requerido en el edificio, lo que implica una necesidad de adaptaci��n a cada contexto espec��fico para obtener el mejor resultado. Sin embargo, la influencia en condiciones reales de operaci��n de las diferentes soluciones fotovoltaicas de integraci��n, en el consumo de energ��a del edificio no es f��cil de evaluar. Los aspectos t��rmicos del interior del ambiente o de iluminaci��n, al utilizar m��dulos BIPV semitransparentes por ejemplo, son a��n desconocidos. Como se dijo antes, la utilizaci��n de componentes de integraci��n arquitect��nica fotovoltaicos y el uso de energ��a renovable ya es un hecho para producir energ��a limpia, pero tambi��n ser��a importante conocer su posible contribuci��n para mejorar el confort y la salud de los ocupantes del edificio. Aspectos como el confort, la protecci��n o transmisi��n de luz natural, el aislamiento t��rmico, el consumo energ��tico o la generaci��n de energ��a son aspectos que suelen considerarse independientemente, mientras que todos juntos contribuyen, sin embargo, al balance energ��tico global del edificio. Adem��s, la necesidad de dar prioridad a una orientaci��n determinada del edificio, para alcanzar el mayor beneficio de la producci��n de energ��a el��ctrica o t��rmica, en el caso de sistemas activos y pasivos, respectivamente, podr��a hacer estos ��ltimos incompatibles, pero no necesariamente. Se necesita un enfoque hol��stico que permita arquitectos e ingenieros implementar sistemas tecnol��gicos que trabajen en sinergia. Se ha planteado por ello un nuevo concepto: "C-BIPV, elemento fotovoltaico consciente integrado", esto significa necesariamente conocer los efectos positivos o negativos (en t��rminos de confort y de energ��a) en condiciones reales de funcionamiento e instalaci��n. Prop��sito de la tesis, m��todo y resultados Los sistemas fotovoltaicos integrados en fachada son a menudo soluciones de vidrio f��cilmente integrables, ya que por lo general est��n hechos a medida. Estos componentes BIPV semitransparentes, integrados en el cerramiento proporcionan iluminaci��n natural y tambi��n sombra, lo que evita el sobrecalentamiento en los momentos de excesivo calor, aunque como componente est��tico, asimismo evitan las posibles contribuciones pasivas de ganancias solares en los meses fr��os. Adem��s, la temperatura del m��dulo var��a considerablemente en ciertas circunstancias influenciada por la tecnolog��a fotovoltaica instalada, la radiaci��n solar, el sistema de montaje, la tipolog��a de instalaci��n, falta de ventilaci��n, etc. Este factor, puede suponer un aumento adicional de la carga t��rmica en el edificio, altamente variable y dif��cil de cuantificar. Se necesitan, en relaci��n con esto, m��s conocimientos sobre el confort ambiental interior en los edificios que utilizan tecnolog��as fotovoltaicas integradas, para abrir de ese modo, una nueva perspectiva de la investigaci��n. Con este fin, se ha dise��ado, proyectado y construido una instalaci��n de pruebas al aire libre, el BIPV Env-lab "BIPV Test Laboratory", para la caracterizaci��n integral de los diferentes m��dulos semitransparentes BIPV. Se han definido tambi��n el m��todo y el protocolo de ensayos de caracterizaci��n en el contexto de un edificio y en condiciones clim��ticas y de funcionamiento reales. Esto ha sido posible una vez evaluado el estado de la t��cnica y la investigaci��n, los aspectos que influyen en la integraci��n arquitect��nica y los diferentes tipos de integraci��n, despu��s de haber examinado los m��todos de ensayo para los componentes de construcci��n y fotovoltaicos, en condiciones de operaci��n utilizadas hasta ahora. El laboratorio de pruebas experimentales, que consiste en dos habitaciones id��nticas a escala real, 1:1, ha sido equipado con sensores y todos los sistemas de monitorizaci��n gracias a los cuales es posible obtener datos fiables para evaluar las prestaciones t��rmicas, de iluminaci��n y el rendimiento el��ctrico de los m��dulos fotovoltaicos. Este laboratorio permite el estudio de tres diferentes aspectos que influencian el confort y consumo de energ��a del edificio: el confort t��rmico, lum��nico, y el rendimiento energ��tico global (demanda/producci��n de energ��a) de los m��dulos BIPV. Conociendo el balance de energ��a para cada tecnolog��a solar fotovoltaica experimentada, es posible determinar cu��l funciona mejor en cada caso espec��fico. Se ha propuesto una metodolog��a te��rica para la evaluaci��n de estos par��metros, definidos en esta tesis como ��ndices o indicadores que consideran cuestiones relacionados con el bienestar, la energ��a y el rendimiento energ��tico global de los componentes BIPV. Esta metodolog��a considera y tiene en cuenta las normas reglamentarias y est��ndares existentes para cada aspecto, relacion��ndolos entre s��. Diferentes m��dulos BIPV de doble vidrio aislante, semitransparentes, representativos de diferentes tecnolog��as fotovoltaicas (tecnolog��a de silicio monocristalino, m-Si; de capa fina en silicio amorfo uni��n simple, a-Si y de capa fina en diseleniuro de cobre e indio, CIS) fueron seleccionados para llevar a cabo una serie de pruebas experimentales al objeto de demostrar la validez del m��todo de caracterizaci��n propuesto. Como resultado final, se ha desarrollado y generado el Diagrama Caracterizaci��n Integral DCI, un sistema gr��fico y visual para representar los resultados y gestionar la informaci��n, una herramienta operativa ��til para la toma de decisiones con respecto a las instalaciones fotovoltaicas. Este diagrama muestra todos los conceptos y par��metros estudiados en relaci��n con los dem��s y ofrece visualmente toda la informaci��n cualitativa y cuantitativa sobre la eficiencia energ��tica de los componentes BIPV, por caracterizarlos de manera integral. ABSTRACT A sustainable design process today is intended to produce high-performance buildings that are energy-efficient, healthy and economically feasible, by wisely using renewable resources to minimize the impact on the environment and to reduce, as much as possible, the energy demand. In the last decade, the reduction of energy needs in buildings has become a top priority. The Directive 2002/91/EC ���Energy Performance of Buildings��� (and its subsequent updates) established a general regulatory framework���s methodology for calculation of minimum energy requirements. Since then, the aim of fulfilling new directives and protocols has led the energy policies in several countries in a similar direction that is, focusing on the need of increasing energy efficiency in buildings, taking measures to reduce energy consumption, and fostering the use of renewable sources. Zero Energy Buildings or Net Zero Energy Buildings will become a standard in the European building industry and in order to balance energy consumption, buildings, in addition to reduce the end-use consumption should necessarily become selfenergy producers. For this reason, the fa��ade system plays an important role for achieving these energy and environmental goals and Photovoltaic can play a leading role in this challenge. To promote the use of photovoltaic technology in buildings, international research programs encourage and support solutions, which favors the complete integration of photovoltaic devices as an architectural element, the so-called BIPV (Building Integrated Photovoltaic), furthermore facing to next future towards net-zero energy buildings. Therefore, the BIPV module/system becomes a multifunctional building layer, not only physically and functionally ���integrated��� in the building, but also used as an innovative chance for the building envelope design. It has been found in this study that there is still a lack of useful information about BIPV for architects and designers even though the market is providing more and more interesting solutions, sometimes comparable to the existing traditional building systems. However at the moment, the lack of an harmonized regulation and standardization besides to the non-accuracy in the technical BIPV datasheets (not yet comparable with the same ones available for building materials), makes difficult for a designer to properly evaluate the fesibility of this BIPV components when used as a technological system of the building skin. International organizations are working to establish the most suitable standards and test procedures to check the safety, feasibility and reliability of BIPV systems. Anyway, nowadays, there are no specific rules for a complete characterization and evaluation of a BIPV component according to the European Construction Product Regulation, CPR 305/2011. BIPV products, as building components, must comply with different practical aspects such as mechanical resistance and stability; structural integrity; safety in use; protection against weather (rain, snow, wind, hail); fire and noise: aspects that have become essential requirements in the perspective of more and more environmentally sustainable, healthy, energy efficient and economically affordable products. IEC standards, commonly used in Europe to certify PV modules (IEC 61215 and IEC 61646 respectively crystalline and thin-film ���Terrestrial PV Modules-Design Qualification and Type Approval���), attest the feasibility and reliability of PV modules for a defined period of time with a limited power decrease. There is also a standard (IEC 61853, ���Performance Testing and Energy Rating of Terrestrial PV Modules���) still under preparation, whose aim is finding appropriate test procedures and methodologies to calculate the energy yield of PV modules under different climate conditions. Furthermore, the lack of tests in specific conditions of installation (e.g. fa��ade BIPV devices) means that it is difficult knowing the exact effective performance of these systems and the environmental conditions in which the building will operate. The nominal PV power at Standard Test Conditions, STC (1.000 W/m2, 25 ��C temperature and AM 1.5) is usually measured in indoor laboratories, and it characterizes the PV module at specific conditions in order to be able to compare different modules and technologies on a first step. The ���Watt-peak��� is not enough to evaluate the panel performance in terms of Watt-hours of various modules under different operating conditions, and it gives no assurance of being able to predict the energy performance of a certain module at given environmental conditions. A proper BIPV element for fa��ade should take into account thermal and insulation properties, factors as transparency to allow solar gains if possible or a good solar control if necessary, aspects that are linked and high dependent on climate conditions and on the level of comfort to be reached. However, the influence of different fa��ade integrated photovoltaic solutions on the building energy consumption is not easy to assess under real operating conditions. Thermal aspects, indoor temperatures or luminance level that can be expected using building integrated PV (BIPV) modules are not well known. As said before, integrated photovoltaic BIPV components and the use of renewable energy is already a standard for green energy production, but would also be important to know the possible contribution to improve the comfort and health of building occupants. Comfort, light transmission or protection, thermal insulation or thermal/electricity power production are aspects that are usually considered alone, while all together contribute to the building global energy balance. Besides, the need to prioritize a particular building envelope orientation to harvest the most benefit from the electrical or thermal energy production, in the case of active and passive systems respectively might be not compatible, but also not necessary. A holistic approach is needed to enable architects and engineers implementing technological systems working in synergy. A new concept have been suggested: ���C-BIPV, conscious integrated BIPV���. BIPV systems have to be ���consciously integrated��� which means that it is essential to know the positive and negative effects in terms of comfort and energy under real operating conditions. Purpose of the work, method and results The fa��ade-integrated photovoltaic systems are often glass solutions easily integrable, as they usually are custommade. These BIPV semi-transparent components integrated as a window element provides natural lighting and shade that prevents overheating at times of excessive heat, but as static component, likewise avoid the possible solar gains contributions in the cold months. In addition, the temperature of the module varies considerably in certain circumstances influenced by the PV technology installed, solar radiation, mounting system, lack of ventilation, etc. This factor may result in additional heat input in the building highly variable and difficult to quantify. In addition, further insights into the indoor environmental comfort in buildings using integrated photovoltaic technologies are needed to open up thereby, a new research perspective. This research aims to study their behaviour through a series of experiments in order to define the real influence on comfort aspects and on global energy building consumption, as well as, electrical and thermal characteristics of these devices. The final objective was to analyze a whole set of issues that influence the global energy consumption/production in a building using BIPV modules by quantifying the global energy balance and the BIPV system real performances. Other qualitative issues to be studied were comfort aspect (thermal and lighting aspects) and the electrical behaviour of different BIPV technologies for vertical integration, aspects that influence both energy consumption and electricity production. Thus, it will be possible to obtain a comprehensive global characterization of BIPV systems. A specific design of an outdoor test facility, the BIPV Env-lab ���BIPV Test Laboratory���, for the integral characterization of different BIPV semi-transparent modules was developed and built. The method and test protocol for the BIPV characterization was also defined in a real building context and weather conditions. This has been possible once assessed the state of the art and research, the aspects that influence the architectural integration and the different possibilities and types of integration for PV and after having examined the test methods for building and photovoltaic components, under operation conditions heretofore used. The test laboratory that consists in two equivalent test rooms (1:1) has a monitoring system in which reliable data of thermal, daylighting and electrical performances can be obtained for the evaluation of PV modules. The experimental set-up facility (testing room) allows studying three different aspects that affect building energy consumption and comfort issues: the thermal indoor comfort, the lighting comfort and the energy performance of BIPV modules tested under real environmental conditions. Knowing the energy balance for each experimented solar technology, it is possible to determine which one performs best. A theoretical methodology has been proposed for evaluating these parameters, as defined in this thesis as indices or indicators, which regard comfort issues, energy and the overall performance of BIPV components. This methodology considers the existing regulatory standards for each aspect, relating them to one another. A set of insulated glass BIPV modules see-through and light-through, representative of different PV technologies (mono-crystalline silicon technology, mc-Si, amorphous silicon thin film single junction, a-Si and copper indium selenide thin film technology CIS) were selected for a series of experimental tests in order to demonstrate the validity of the proposed characterization method. As result, it has been developed and generated the ICD Integral Characterization Diagram, a graphic and visual system to represent the results and manage information, a useful operational tool for decision-making regarding to photovoltaic installations. This diagram shows all concepts and parameters studied in relation to each other and visually provides access to all the results obtained during the experimental phase to make available all the qualitative and quantitative information on the energy performance of the BIPV components by characterizing them in a comprehensive way.

A prototype from the Solar Decathlon Competition becomes an educational building in sustanaible architecture

In 2008, the City Council of Rivas-Vaciamadrid (Spain) decided to promote the construction of ���Rivasecopolis���, a complex of sustainable buildings in which a new prototype of a zero-energy house would become the office of the Energy Agency. According to the initiative of the City Council, it was decided to recreate the dwelling prototype ���Magic-box��� which entered the 2005 Solar Decathlon Competition. The original project has been adapted to a new necessities programme, by adding the necessary spaces that allows it to work as an office. A team from university has designed and carried out the direction of the construction site. The new Solar House is conceived as a ���testing building���. It is going to become the space for attending citizens in all questions about saving energy, energy efficiency and sustainable construction, having a permanent small exhibition space additional to the working places for the information purpose. At the same time, the building includes the use of experimental passive architecture systems and a monitoring and control system. Collected data will be sent to University to allow developing research work about the experimental strategies included in the building. This paper will describe and analyze the experience of transforming a prototype into a real durable building and the benefits for both university and citizens in learning about sustainability with the building

Construcci��n modular ligera energ��ticamente eficiente

Esta tesis trata sobre la construcci��n modular ligera, dentro del contexto de la eficiencia energ��tica y de cara a los conceptos de nZEB (near Zero Energy Building) y NZEB (Net Zero Energy Building) que se manejan en el ��mbito europeo y espec��ficamente dentro del marco regulador de la Directiva 2010/31 UE. En el contexto de la Uni��n Europea, el sector de la edificaci��n representa el 40% del total del consumo energ��tico del continente. Asumiendo la necesidad de reducir este consumo se han planteado, desde los organismos de direcci��n europeos, unos objetivos (objetivos 20-20-20) para hacer m��s eficiente el parque edificatorio. Estos objetivos, que son vinculantes en t��rminos de legislaci��n, comprometen a todos los estados miembros a conseguir la meta de reducci��n de consumo y emisiones de GEI (Gases de Efecto Invernadero) antes del a��o 2020. Estos conceptos de construcci��n modular ligera (CML) y eficiencia energ��tica no suelen estar asociados por el hecho de que este tipo de construcci��n no suele estar destinada a un uso intensivo y no cuenta con unos cerramientos con niveles de aislamiento de acuerdo a las normativas locales o c��digos de edificaci��n de cada pa��s. El objetivo de nZEB o NZEB, e incluso Energy Plus, seg��n sea el caso, necesariamente (y as�� queda establecido en las normativas), depender�� no s��lo de la mejora de los niveles de aislamiento de los edificios, sino tambi��n de la implementaci��n de sistemas de generaci��n renovables, independientemente del tipo de sistema constructivo con el que se trabaje e incluso de la tipolog��a edificatoria. Si bien es cierto que los niveles de industrializaci��n de la sociedad tecnol��gica actual han alcanzado varias de las fases del proceso constructivo - sobre todo en cuanto a elementos compositivos de los edificios- tambi��n lo es el hecho de que las cotas de desarrollo conseguidas en el ��mbito de la construcci��n no llegan al nivel de evoluci��n que se puede apreciar en otros campos de las ingenier��as como la aeron��utica o la industria del autom��vil. Aunque desde finales del siglo pasado existen modelos y proyectos testimoniales de construcci��n industrializada ligera (CIL) e incluso ya a principios del siglo XX, ejemplos de construcci��n modular ligera (CML), como la Casa Voisin, la industrializaci��n de la construcci��n de edificios no ha sido una constante progresiva con un nivel de comercializaci��n equiparable al de la construcci��n masiva y pesada. Los t��rminos construcci��n industrializada, construcci��n prefabricada, construcci��n modular y construcci��n ligera, no siempre hacen referencia a lo mismo y no siempre son sin��nimos entre s��. Un edificio puede ser prefabricado y no ser modular ni ligero y tal es el caso, por poner un ejemplo, de la construcci��n con paneles de hormig��n prefabricado. Lo que s�� es una constante es que en el caso de la construcci��n modular ligera, la prefabricaci��n y la industrializaci��n, casi siempre vienen impl��citas en muchos ejemplos hist��ricos y actuales. Con relaci��n al concepto de eficiencia energ��tica (nZEB o incluso NZEB), el mismo no suele estar ligado a la construcci��n modular ligera y/o ligera industrializada; m��s bien se le ve unido a la idea de cerramientos masivos con gran inercia t��rmica propios de est��ndares de dise��o como el Passivhaus; y aunque com��nmente a la construcci��n ligera se le asocian otros conceptos que le restan valor (corta vida ��til; funci��n y formas limitadas, fuera de todo orden est��tico; limitaci��n en los niveles de confort, etc.), los avances que se van alcanzando en materia de tecnolog��as para el aprovechamiento de la energ��a y sistemas de generaci��n renovables, pueden conseguir revertir estas ideas y unificar el criterio de eficiencia + construcci��n modular ligera. Prototipos y proyectos acad��micos��� como el concurso Solar Decathlon que se celebra desde el a��o 2002 promovido por el DOE (Departamento de Energ��a de los Estados Unidos), y que cuenta con ediciones europeas como las de los a��os 2010 y 2012, replantean la idea de la construcci��n industrializada, modular y ligera dentro del contexto de la eficiencia energ��tica, con prototipos de viviendas de �� 60m2, propuestos por las universidades concursantes, y cuyo objetivo es alcanzar y/o desarrollar el concepto de NZEB (Net Zero Energy Building) o edificio de energ��a cero. Esta opci��n constructiva no s��lo representa durabilidad, seguridad y est��tica, sino tambi��n, rapidez en la fabricaci��n y montaje, adem��s de altas prestaciones energ��ticas como se ha podido demostrar en las sucesivas ediciones del Solar Decathlon. Este tipo de iniciativas de desarrollo de tecnolog��as constructivas, no s��lo apuntan a la eficiencia energ��tica sino al concepto global de energ��a neta, Energ��a plus o cero emisiones de CO2. El nivel de emisiones por la fabricaci��n y puesta en obra de los materiales de construcci��n depende, en muchos casos, no solo de la propia naturaleza del material, sino tambi��n de la cantidad de recursos utilizados para producir una unidad de medida determinada (kg, m3, m2, ml, etc). En este sentido podr��a utilizarse, en muchos casos, el argumento v��lido de que a menos peso, y a menos tama��o, menos emisiones globales de gases de efecto invernadero y menos contaminaci��n. Para el trabajo de investigaci��n de esta tesis se han tomado como referencias v��lidas para estudio, prototipos tanto de CML (Modular 3D) como de CIL (panelizado y elementos 2D), dado que para los fines de an��lisis de las prestaciones energ��ticas de los materiales de cerramiento, ambos sistemas son equiparables. Para poder llegar a la conclusi��n fundamental de este trabajo de tesis doctoral - que consiste en demostrar la viabilidad tecnol��gica/ industrial que supone la combinaci��n de la eficiencia energ��tica y la construcci��n modular ligera - se parte del estudio del estado de la t��cnica ( desde la selecci��n de los materiales y los posibles procesos de industrializaci��n en f��brica, hasta su puesta en obra, funcionamiento y uso, bajo los conceptos de consumo cero, cero emisiones de carbono y plus energ��tico). Adem��s -y con un estado de la t��cnica que identifica la situaci��n actual- se llevan a cabo pruebas y ensayos con un prototipo a escala natural y c��lulas de ensayo, para comprobar el comportamiento de los elementos compositivos de los mismos, frente a unas condicionantes clim��ticas determinadas. Este tipo de resultados se contrastan con los obtenidos mediante simulaciones inform��ticas basadas en los mismos par��metros y realizadas en su mayor��a mediante m��todos simplificados de c��lculos, validados por los organismos competentes en materia de eficiencia energ��tica en la edificaci��n en Espa��a y de acuerdo a la normativa vigente. ABSTRACT This thesis discusses lightweight modular construction within the context of energy efficiency in nZEB (near Zero Energy Building) and NZEB (Net Zero Energy Building) both used in Europe and, specifically, within the limits of the regulatory framework of the EU Directive 2010/31. In the European Union the building sector represents 40% of the total energy consumption of the continent. Due to the need to reduce this consumption, European decision-making institutions have proposed aims (20-20-20 aims) to render building equipment more efficient. These aims are bound by law and oblige all member States to endeavour to reduce consumption and GEI emissions before the year 2020. Lightweight modular construction concepts and energy efficiency are not generally associated because this type of building is not normally meant for intensive use and does not have closures with insulation levels which fit the local regulations or building codes of each country. The objective of nZEB or NZEB and even Energy Plus, depending on each case, will necessarily be associated (as established in the guidelines) not only with the improvement of insulation levels in buildings, but also with the implementation of renewable systems of generation, independent of the type of building system used and of the building typology. Although it is true that the levels of industrialisation in the technological society today have reached several of the building process phases - particularly in the composite elements of buildings - it is also true that the quotas of development achieved in the area of construction have not reached the evolutionary levelfound in other fields of engineering, such as aeronautics or the automobile industry. Although there have been models and testimonial projects of lightweight industrialised building since the end of last century, even going back as far as the beginning of the XX century with examples of lightweight modular construction such as the Voisin House, industrialisation in the building industry has not been constant nor is its comercialisation comparable to massive and heavy construction. The terms industrialised building, prefabricated building, modular building and lightweight building, do not always refer to the same thing and they are not always synonymous. A building can be prefabricated yet not be modular or lightweight. To give an example, this is the case of building with prefabricated concrete panels. What is constant is that, in the case of lightweight modular construction, prefabrication and industrialisation are almost always implicit in many historical and contemporary examples. Energy efficiency (nZEB or even NZEB) is not normally linked to lightweight modular construction and/or industrialised lightweight; rather, it is united to the idea of massive closureswith high thermal inertia typical of design standards such as the Passive House; and although other concepts that subtract value from it are generally associated with lightweight building (short useful life, limited forms and function, inappropriate toany aesthetic pattern; limitation in comfort levels, etc.), the advances being achieved in technology for benefitting from energy and renewable systems of generation may well reverse these ideas and unify the criteria of efficiency + lightweight modular construction. Academic prototypes and projects - such as the Solar Decathlon competition organised by the US Department of Energy and celebrated since 2002, with its corresponding European events such as those held in 2010 and 2012, place a different slant on the idea of industrialised, modular and lightweight building within the context of energy efficiency, with prototypes of homes measuring approximately 60m2, proposed by university competitors, whose aim is to reach and/or develop the NZEB concept, or the zero energy building. This building option does not only signify durability, security and aesthetics, but also fast manufacture and assembly. It also has high energy benefits, as has been demonstrated in successive events of the Solar Decathlon. This type of initiative for the development of building technologies, does not only aim at energy efficiency, but also at the global concept of net energy, Energy Plus and zero CO2 emissions. The level of emissions in the manufacture and introduction of building materials in many cases depends not only on the inherent nature of the material, but also on the quantity of resources used to produce a specific unit of measurement (kg, m3, m2, ml, etc.). Thus in many cases itcould be validly arguedthat with less weight and smaller size, there will be fewer global emissions of greenhouse effect gases and less contamination. For the research carried out in this thesis prototypes such as the CML (3D Module) and CIL (panelled and elements) have been used as valid study references, becauseboth systems are comparablefor the purpose of analysing the energy benefits of closure materials. So as to reach a basic conclusion in this doctoral thesis - that sets out to demonstrate the technological/industrial viability of the combination of energy efficiency and lightweight modular construction - the departure point is the study of the state of the technique (from the selection of materials and the possible processes of industrialisation in manufacture, to their use on site, functioning and use, respecting the concepts of zero consumption, zero emissions of carbon and Energy Plus). Moreover, with the state of the technique identifying the current situation, tests and practices have been carried out with a natural scale prototype and test cells so as to verify the behaviour of the composite elements of these in certain climatic conditions. These types of result are contrasted with those obtained through computer simulation based on the same parameters and done, principally, using simplified methods of calculation, validated by institutions competent in energy efficiency in Spanish building and in line with the rules in force.

Clean Coal Technologies Scenario and Evaluation of Present CO2 Dwindling Initiatives to Approach Zero Emission Power Stations By Coal Combustion. Deployment Situation and Evaluation Study

In the present uncertain global context of reaching an equal social stability and steady thriving economy, power demand expected to grow and global electricity generation could nearly double from 2005 to 2030. Fossil fuels will remain a significant contribution on this energy mix up to 2050, with an expected part of around 70% of global and ca. 60% of European electricity generation. Coal will remain a key player. Hence, a direct effect on the considered CO2 emissions business-as-usual scenario is expected, forecasting three times the present CO2 concentration values up to 1,200ppm by the end of this century. Kyoto protocol was the first approach to take global responsibility onto CO2 emissions monitoring and cap targets by 2012 with reference to 1990. Some of principal CO2emitters did not ratify the reduction targets. Although USA and China spur are taking its own actions and parallel reduction measures. More efficient combustion processes comprising less fuel consuming, a significant contribution from the electricity generation sector to a CO2 dwindling concentration levels, might not be sufficient. Carbon Capture and Storage (CCS) technologies have started to gain more importance from the beginning of the decade, with research and funds coming out to drive its come in useful. After first researching projects and initial scale testing, three principal capture processes came out available today with first figures showing up to 90% CO2 removal by its standard applications in coal fired power stations. Regarding last part of CO2 reduction chain, two options could be considered worthy, reusing (EOR & EGR) and storage. The study evaluates the state of the CO2 capture technology development, availability and investment cost of the different technologies, with few operation cost analysis possible at the time. Main findings and the abatement potential for coal applications are presented. DOE, NETL, MIT, European universities and research institutions, key technology enterprises and utilities, and key technology suppliers are the main sources of this study. A vision of the technology deployment is presented.

New Constructive Solutions to Improve Energy Efficiency in Existing Buildings and their Economic Viability

The improvement of energy efficiency in existing buildings is always a challenge due to their particular, and sometimes protected, constructive solutions. New constructive regulations in Spain leave a big undefined gap when a restoration is considered because they were developed for new buildings. However, rehabilitation is considered as an opportunity for many properties because it allows owners to obtain benefits from the use of the buildings. The current financial and housing crisis has turned society point of view to existing buildings and making them more efficient is one of the Spanish government���s aims. The economic viability of a rehabilitation action should take all factors into account: both construction costs and the future operative costs of the building must be considered. Nevertheless, the application of these regulations in Spain is left to the designer���s opinion and always under a subjective point of view. With the research work described in this paper and with the help of some case-studies, the cost of adapting an existing building to the new constructive regulations will be studied and Energetic Efficiency will be evaluated depending on how the investment is recovered. The interest of the research is based on showing how new constructive solutions can achieve higher levels of efficiency in terms of energy, construction and economy and it will demonstrate that Life Cycle Costing analysis can be a mechanism to find the advantages and disadvantages of using these new constructive solutions. Therefore, this paper has the following objectives: analysing constructive solutions in existing buildings - to establish a process for assessing total life cycle costs (LCC) during the planning stages with consideration of future operating costs - to select the most advantageous operating system ��� To determine the return on investment in terms of construction costs based on new techniques, the achieved energy savings and investment payback periods.

Assessment of expected damage on buildings subjected to Lorca earthquake through an energy-based seismic index method and nonlinear dynamic response analyses

The city of Lorca (Spain) was hit on May 11th, 2011, by two consecutive earth-quakes of magnitudes 4.6 and 5.2 Mw, causing casualties and important damage in buildings. Many of the damaged structures were reinforced concrete frames with wide beams. This study quantifies the expected level of damage on this structural type in the case of the Lorca earth-quake by means of a seismic index Iv that compares the energy input by the earthquake with the energy absorption/dissipation capacity of the structure. The prototype frames investigated represent structures designed in two time periods (1994���2002 and 2003���2008), in which the applicable codes were different. The influence of the masonry infill walls and the proneness of the frames to concentrate damage in a given story were further investigated through nonlinear dynamic response analyses. It is found that (1) the seismic index method predicts levels of damage that range from moderate/severe to complete collapse; this prediction is consistent with the observed damage; (2) the presence of masonry infill walls makes the structure very prone to damage concentration and reduces the overall seismic capacity of the building; and (3) a proper hierarchy of strength between beams and columns that guarantees the formation of a strong column-weak beam mechanism (as prescribed by seismic codes), as well as the adoption of counter-measures to avoid the negative interaction between non-structural infill walls and the main frame, would have reduced the level of damage from Iv=1 (collapse) to about Iv=0.5 (moderate/severe damage)

Energy and Lighting Performance of Buildings in the Neighbourhood Ciudad de los Angeles, Before and After Refurbishing.

The Spanish Ministry of Economy and Competitiveness is funding the SHERIF Research Project, which falls under the INNPACTO pr ogram. This project aims to increase the rate of the existing building refurbishment fro m the energy efficiency point of view by designing a facade system that must be an economica l, flexible and integrated solution 1 . Under this project has been performing several task s regarding the constructive characterization and energy evaluation of the therm al behaviour of facades on existing buildings . In order to perform the latter task, in which this article will focus, has been developing a survey of various buildings in the nei ghbourhood Ciudad de los Angeles, which has as main objective the comparison between the ac tual energy and light behaviour of different buildings, prior and posterior to any ref urbishment works have been undertaken. The evaluation of the actual performance of buildin gs before and after being refurbished is aimed to determine the impact of the work developed as well as learn from the work performed for future interventions.

Output Impedance Correction Circuit (OICC): A New Concept to Improve the Dynamic Response of DC/DC Converters with Additional Energy Path

El desarrollo da las nuevas tecnolog��as permite a los ingenieros llevar al l��mite el funcionamiento de los circuitos integrados (Integrated Circuits, IC). Las nuevas generaciones de procesadores, DSPs o FPGAs son capaces de procesar la informaci��n a una alta velocidad, con un alto consumo de energ��a, o esperar en modo de baja potencia con el m��nimo consumo posible. Esta gran variaci��n en el consumo de potencia y el corto tiempo necesario para cambiar de un nivel al otro, afecta a las especificaciones del M��dulo de Regulador de Tensi��n (Voltage Regulated Module, VRM) que alimenta al IC. Adem��s, las caracter��sticas adicionales obligatorias, tales como adaptaci��n del nivel de tensi��n (Adaptive Voltage Positioning, AVP) y escalado din��mico de la tensi��n (Dynamic Voltage Scaling, DVS), imponen requisitos opuestas en el dise��o de la etapa de potencia del VRM. Para poder soportar las altas variaciones de los escalones de carga, el condensador de filtro de salida del VRM se ha de sobredimensionar, penalizando la densidad de energ��a y el rendimiento durante la operaci��n de DVS. Por tanto, las actuales tendencias de investigaci��n se centran en mejorar la respuesta din��mica del VRM, mientras se reduce el tama��o del condensador de salida. La reducci��n del condensador de salida lleva a menor coste y una prolongaci��n de la vida del sistema ya que se podr��a evitar el uso de condensadores voluminosos, normalmente implementados con condensadores OSCON. Una ventaja adicional es que reduciendo el condensador de salida, el DVS se puede realizar m��s r��pido y con menor estr��s de la etapa de potencia, ya que la cantidad de carga necesaria para cambiar la tensi��n de salida es menor. El comportamiento din��mico del sistema con un control lineal (Control Modo Tensi��n, VMC, o Control Corriente de Pico, Peak Current Mode Control, PCMC,���) est�� limitado por la frecuencia de conmutaci��n del convertidor y por el tama��o del filtro de salida. La reducci��n del condensador de salida se puede lograr incrementando la frecuencia de conmutaci��n, as�� como incrementando el ancho de banda del sistema, y/o aplicando controles avanzados no-lineales. Usando esos controles, las variables del estado se saturan para conseguir el nuevo r��gimen permanente en un tiempo m��nimo, as�� como el filtro de salida, m��s espec��ficamente la pendiente de la corriente de la bobina, define la respuesta de la tensi��n de salida. Por tanto, reduciendo la inductancia de la bobina de salida, la corriente de bobina llega m��s r��pido al nuevo r��gimen permanente, por lo que una menor cantidad de carga es tomada del condensador de salida durante el tr��nsito. El inconveniente de esa propuesta es que el rendimiento del sistema es penalizado debido al incremento de p��rdidas de conmutaci��n y las corrientes RMS. Para conseguir tanto la reducci��n del condensador de salida como el alto rendimiento del sistema, mientras se satisfacen las estrictas especificaciones din��micas, un convertidor multifase es adoptado como est��ndar para aplicaciones VRM. Para asegurar el reparto de las corrientes entre fases, el convertidor multifase se suele implementar con control de modo de corriente. Para superar la limitaci��n impuesta por el filtro de salida, la segunda posibilidad para reducir el condensador de salida es aplicar alguna modificaci��n topol��gica (Topologic modifications) de la etapa b��sica de potencia para incrementar la pendiente de la corriente de bobina y as�� reducir la duraci��n de tr��nsito. Como el transitorio se ha reducido, una menor cantidad de carga es tomada del condensador de salida bajo el mismo escal��n de la corriente de salida, con lo cual, el condensador de salida se puede reducir para lograr la misma desviaci��n de la tensi��n de salida. La tercera posibilidad para reducir el condensador de salida del convertidor es introducir un camino auxiliar de energ��a (additional energy path, AEP) para compensar el desequilibrio de la carga del condensador de salida reduciendo consecuentemente la duraci��n del transitorio y la desviaci��n de la tensi��n de salida. De esta manera, durante el r��gimen permanente, el sistema tiene un alto rendimiento debido a que el convertidor principal con bajo ancho de banda es dise��ado para trabajar con una frecuencia de conmutaci��n moderada para conseguir requisitos est��ticos. Por otro lado, el comportamiento din��mico durante los transitorios es determinado por el AEP con un alto ancho de banda. El AEP puede ser implementado como un camino resistivo, como regulador lineal (Linear regulator, LR) o como un convertidor conmutado. Las dos primeras implementaciones proveen un mayor ancho de banda, acosta del incremento de p��rdidas durante el transitorio. Por otro lado, la implementaci��n del convertidor computado presenta menor ancho de banda, limitado por la frecuencia de conmutaci��n, aunque produce menores p��rdidas comparado con las dos anteriores implementaciones. Dependiendo de la aplicaci��n, la implementaci��n y la estrategia de control del sistema, hay una variedad de soluciones propuestas en el Estado del Arte (State-of-the-Art, SoA), teniendo diferentes propiedades donde una soluci��n ofrece m��s ventajas que las otras, pero tambi��n unas desventajas. En general, un sistema con AEP ideal deber��a tener las siguientes propiedades: 1. El impacto del AEP a las p��rdidas del sistema deber��a ser m��nimo. A lo largo de la operaci��n, el AEP genera p��rdidas adicionales, con lo cual, en el caso ideal, el AEP deber��a trabajar por un peque��o intervalo de tiempo, solo durante los tr��nsitos; la otra opci��n es tener el AEP constantemente activo pero, por la compensaci��n del rizado de la corriente de bobina, se generan p��rdidas innecesarias. 2. El AEP deber��a ser activado inmediatamente para minimizar la desviaci��n de la tensi��n de salida. Para conseguir una activaci��n casi instant��nea, el sistema puede ser informado por la carga antes del escal��n o el sistema puede observar la corriente del condensador de salida, debido a que es la primera variable del estado que act��a a la perturbaci��n de la corriente de salida. De esa manera, el AEP es activado con casi cero error de la tensi��n de salida, logrando una menor desviaci��n de la tensi��n de salida. 3. El AEP deber��a ser desactivado una vez que el nuevo r��gimen permanente es detectado para evitar los transitorios adicionales de establecimiento. La mayor��a de las soluciones de SoA estiman la duraci��n del transitorio, que puede provocar un transitorio adicional si la estimaci��n no se ha hecho correctamente (por ejemplo, si la corriente de bobina del convertidor principal tiene un nivel superior o inferior al necesitado, el regulador lento del convertidor principal tiene que compensar esa diferencia una vez que el AEP es desactivado). Otras soluciones de SoA observan las variables de estado, asegurando que el sistema llegue al nuevo r��gimen permanente, o pueden ser informadas por la carga. 4. Durante el transitorio, como m��nimo un subsistema, o bien el convertidor principal o el AEP, deber��a operar en el lazo cerrado. Implementando un sistema en el lazo cerrado, preferiblemente el subsistema AEP por su ancho de banda elevado, se incrementa la robustez del sistema a los par��sitos. Adem��s, el AEP puede operar con cualquier tipo de corriente de carga. Las soluciones que funcionan en el lazo abierto suelen preformar el control de balance de carga con m��nimo tiempo, as�� reducen la duraci��n del transitorio y tienen un impacto menor a las p��rdidas del sistema. Por otro lado, esas soluciones demuestran una alta sensibilidad a las tolerancias y par��sitos de los componentes. 5. El AEP deber��a inyectar la corriente a la salida en una manera controlada, as�� se reduce el riesgo de unas corrientes elevadas y potencialmente peligrosas y se incrementa la robustez del sistema bajo las perturbaciones de la tensi��n de entrada. Ese problema suele ser relacionado con los sistemas donde el AEP es implementado como un convertidor auxiliar. El convertidor auxiliar es dise��ado para una potencia baja, con lo cual, los dispositivos elegidos son de baja corriente/potencia. Si la corriente no es controlada, bajo un pico de tensi��n de entrada provocada por otro parte del sistema (por ejemplo, otro convertidor conectado al mismo bus), se puede llegar a un pico en la corriente auxiliar que puede causar la perturbaci��n de tensi��n de salida e incluso el fallo de los dispositivos del convertidor auxiliar. Sin embargo, cuando la corriente es controlada, usando control del pico de corriente o control con hist��resis, la corriente auxiliar tiene el control con prealimentaci��n (feed-forward) de tensi��n de entrada y la corriente es definida y limitada. Por otro lado, si la soluci��n utiliza el control de balance de carga, el sistema puede actuar de forma deficiente si la tensi��n de entrada tiene un valor diferente del nominal, provocando que el AEP inyecta/toma m��s/menos carga que necesitada. 6. Escalabilidad del sistema a convertidores multifase. Como ya ha sido comentado anteriormente, para las aplicaciones VRM por la corriente de carga elevada, el convertidor principal suele ser implementado como multifase para distribuir las perdidas entre las fases y bajar el estr��s t��rmico de los dispositivos. Para asegurar el reparto de las corrientes, normalmente un control de modo corriente es usado. Las soluciones de SoA que usan VMC son limitadas a la implementaci��n con solo una fase. Esta tesis propone un nuevo m��todo de control del flujo de energ��a por el AEP y el convertidor principal. El concepto propuesto se basa en la inyecci��n controlada de la corriente auxiliar al nodo de salida donde la amplitud de la corriente es n-1 veces mayor que la corriente del condensador de salida con las direcciones apropiadas. De esta manera, el AEP genera un condensador virtual cuya capacidad es n veces mayor que el condensador f��sico y reduce la impedancia de salida. Como el concepto propuesto reduce la impedancia de salida usando el AEP, el concepto es llamado Output Impedance Correction Circuit (OICC) concept. El concepto se desarrolla para un convertidor tipo reductor s��ncrono multifase con control modo de corriente CMC (incluyendo e implementaci��n con una fase) y puede operar con la tensi��n de salida constante o con AVP. Adem��s, el concepto es extendido a un convertidor de una fase con control modo de tensi��n VMC. Durante la operaci��n, el control de tensi��n de salida de convertidor principal y control de corriente del subsistema OICC est��n siempre cerrados, incrementando la robustez a las tolerancias de componentes y a los par��sitos del cirquito y permitiendo que el sistema se pueda enfrentar a cualquier tipo de la corriente de carga. Seg��n el m��todo de control propuesto, el sistema se puede encontrar en dos estados: durante el r��gimen permanente, el sistema se encuentra en el estado Idle y el subsistema OICC esta desactivado. Por otro lado, durante el transitorio, el sistema se encuentra en estado Activo y el subsistema OICC est�� activado para reducir la impedancia de salida. El cambio entre los estados se hace de forma aut��noma: el sistema entra en el estado Activo observando la corriente de condensador de salida y vuelve al estado Idle cunado el nuevo r��gimen permanente es detectado, observando las variables del estado. La validaci��n del concepto OICC es hecha aplic��ndolo a un convertidor tipo reductor s��ncrono con dos fases y de 30W cuyo condensador de salida tiene capacidad de 140��F, mientras el factor de multiplicaci��n n es 15, generando en el estado Activo el condensador virtual de 2.1mF. El subsistema OICC es implementado como un convertidor tipo reductor s��ncrono con PCMC. Comparando el funcionamiento del convertidor con y sin el OICC, los resultados demuestran que se ha logrado una reducci��n de la desviaci��n de tensi��n de salida con factor 12, tanto con funcionamiento b��sico como con funcionamiento AVP. Adem��s, los resultados son comparados con un prototipo de referencia que tiene la misma etapa de potencia y un condensador de salida f��sico de 2.1mF. Los resultados demuestran que los dos sistemas tienen el mismo comportamiento din��mico. M��s aun, se ha cuantificado el impacto en las p��rdidas del sistema operando bajo una corriente de carga pulsante y bajo DVS. Se demuestra que el sistema con OICC mejora el rendimiento del sistema, considerando las p��rdidas cuando el sistema trabaja con la carga pulsante y con DVS. Por lo ��ltimo, el condensador de salida de sistema con OICC es mucho m��s peque��o que el condensador de salida del convertidor de referencia, con lo cual, por usar el concepto OICC, la densidad de energ��a se incrementa. En resumen, las contribuciones principales de la tesis son: ��� El concepto propuesto de Output Impedance Correction Circuit (OICC), ��� El control a nivel de sistema basado en el m��todo usado para cambiar los estados de operaci��n, ��� La implementaci��n del subsistema OICC en lazo cerrado conjunto con la implementaci��n del convertidor principal, ��� La cuantificaci��n de las perdidas din��micas bajo la carga pulsante y bajo la operaci��n DVS, y ��� La robustez del sistema bajo la variaci��n del condensador de salida y bajo los escalones de carga consecutiva. ABSTRACT Development of new technologies allows engineers to push the performance of the integrated circuits to its limits. New generations of processors, DSPs or FPGAs are able to process information with high speed and high consumption or to wait in low power mode with minimum possible consumption. This huge variation in power consumption and the short time needed to change from one level to another, affect the specifications of the Voltage Regulated Module (VRM) that supplies the IC. Furthermore, additional mandatory features, such as Adaptive Voltage Positioning (AVP) and Dynamic Voltage Scaling (DVS), impose opposite trends on the design of the VRM power stage. In order to cope with high load-step amplitudes, the output capacitor of the VRM power stage output filter is drastically oversized, penalizing power density and the efficiency during the DVS operation. Therefore, the ongoing research trend is directed to improve the dynamic response of the VRM while reducing the size of the output capacitor. The output capacitor reduction leads to a smaller cost and longer life-time of the system since the big bulk capacitors, usually implemented with OSCON capacitors, may not be needed to achieve the desired dynamic behavior. An additional advantage is that, by reducing the output capacitance, dynamic voltage scaling (DVS) can be performed faster and with smaller stress on the power stage, since the needed amount of charge to change the output voltage is smaller. The dynamic behavior of the system with a linear control (Voltage mode control, VMC, Peak Current Mode Control, PCMC,���) is limited by the converter switching frequency and filter size. The reduction of the output capacitor can be achieved by increasing the switching frequency of the converter, thus increasing the bandwidth of the system, and/or by applying advanced non-linear controls. Applying nonlinear control, the system variables get saturated in order to reach the new steady-state in a minimum time, thus the output filter, more specifically the output inductor current slew-rate, determines the output voltage response. Therefore, by reducing the output inductor value, the inductor current reaches faster the new steady state, so a smaller amount of charge is taken from the output capacitor during the transient. The drawback of this approach is that the system efficiency is penalized due to increased switching losses and RMS currents. In order to achieve both the output capacitor reduction and high system efficiency, while satisfying strict dynamic specifications, a Multiphase converter system is adopted as a standard for VRM applications. In order to ensure the current sharing among the phases, the multiphase converter is usually implemented with current mode control. In order to overcome the limitation imposed by the output filter, the second possibility to reduce the output capacitor is to apply Topologic modifications of the basic power stage topology in order to increase the slew-rate of the inductor current and, therefore, reduce the transient duration. Since the transient is reduced, smaller amount of charge is taken from the output capacitor under the same load current, thus, the output capacitor can be reduced to achieve the same output voltage deviation. The third possibility to reduce the output capacitor of the converter is to introduce an additional energy path (AEP) to compensate the charge unbalance of the output capacitor, consequently reducing the transient time and output voltage deviation. Doing so, during the steady-state operation the system has high efficiency because the main low-bandwidth converter is designed to operate at moderate switching frequency, to meet the static requirements, whereas the dynamic behavior during the transients is determined by the high-bandwidth auxiliary energy path. The auxiliary energy path can be implemented as a resistive path, as a Linear regulator, LR, or as a switching converter. The first two implementations provide higher bandwidth, at the expense of increasing losses during the transient. On the other hand, the switching converter implementation presents lower bandwidth, limited by the auxiliary converter switching frequency, though it produces smaller losses compared to the two previous implementations. Depending on the application, the implementation and the control strategy of the system, there is a variety of proposed solutions in the State-of-the-Art (SoA), having different features where one solution offers some advantages over the others, but also some disadvantages. In general, an ideal additional energy path system should have the following features: 1. The impact on the system losses should be minimal. During its operation, the AEP generates additional losses, thus ideally, the AEP should operate for a short period of time, only when the transient is occurring; the other option is to have the AEP constantly on, but due to the inductor current ripple compensation at the output, unnecessary losses are generated. 2. The AEP should be activated nearly instantaneously to prevent bigger output voltage deviation. To achieve near instantaneous activation, the converter system can be informed by the load prior to the load-step or the system can observe the output capacitor current, which is the first system state variable that reacts on the load current perturbation. In this manner, the AEP is turned on with near zero output voltage error, providing smaller output voltage deviation. 3. The AEP should be deactivated once the new steady state is reached to avoid additional settling transients. Most of the SoA solutions estimate duration of the transient which may cause additional transient if the estimation is not performed correctly (e.g. if the main converter inductor current has higher or lower value than needed, the slow regulator of the main converter needs to compensate the difference after the AEP is deactivated). Other SoA solutions are observing state variables, ensuring that the system reaches the new steady state or they are informed by the load. 4. During the transient, at least one subsystem, either the main converter or the AEP, should be in closed-loop. Implementing a closed loop system, preferably the AEP subsystem, due its higher bandwidth, increases the robustness under system tolerances and circuit parasitic. In addition, the AEP can operate with any type of load. The solutions that operate in open loop usually perform minimum time charge balance control, thus reducing the transient length and minimizing the impact on the losses, however they are very sensitive to tolerances and parasitics. 5. The AEP should inject current at the output in a controlled manner, thus reducing the risk of high and potentially damaging currents and increasing robustness on the input voltage deviation. This issue is mainly related to the systems where AEP is implemented as auxiliary converter. The auxiliary converter is designed for small power and, as such, the MOSFETs are rated for small power/currents. If the current is not controlled, due to the some unpredicted spike in input voltage caused by some other part of the system (e.g. different converter), it may lead to a current spike in auxiliary current which will cause the perturbation of the output voltage and even failure of the switching components of auxiliary converter. In the case when the current is controlled, using peak CMC or Hysteretic Window CMC, the auxiliary converter has inherent feed-forwarding of the input voltage in current control and the current is defined and limited. Furthermore, if the solution employs charge balance control, the system may perform poorly if the input voltage has different value than the nominal, causing that AEP injects/extracts more/less charge than needed. 6. Scalability of the system to multiphase converters. As commented previously, in VRM applications, due to the high load currents, the main converters are implemented as multiphase to redistribute losses among the modules, lowering temperature stress of the components. To ensure the current sharing, usually a Current Mode Control (CMC) is employed. The SoA solutions that are implemented with VMC are limited to a single stage implementation. This thesis proposes a novel control method of the energy flow through the AEP and the main converter system. The proposed concept relays on a controlled injection of the auxiliary current at the output node where the instantaneous current value is n-1 times bigger than the output capacitor current with appropriate directions. Doing so, the AEP creates an equivalent n times bigger virtual capacitor at the output, thus reducing the output impedance. Due to the fact that the proposed concept reduces the output impedance using the AEP, it has been named the Output Impedance Correction Circuit (OICC) concept. The concept is developed for a multiphase CMC synchronous buck converter (including a single phase implementation), operating with a constant output voltage and with AVP feature. Further, it is extended to a single phase VMC synchronous buck converter. During the operation, the main converter voltage loop and the OICC subsystem capacitor current loop is constantly closed, increasing the robustness under system tolerances and circuit parasitic and allowing the system to operate with any load-current shape or pattern. According to the proposed control method, the system operates in two states: during the steady-state the system is in the Idle state and the OICC subsystem is deactivated, while during the load-step transient the system is in the Active state and the OICC subsystem is activated in order to reduce the output impedance. The state changes are performed autonomously: the system enters in the Active state by observing the output capacitor current and it returns back to the Idle state when the steady-state operation is detected by observing the state variables. The validation of the OICC concept has been done by applying it to a 30W two phase synchronous buck converter with 140��F output capacitor and with the multiplication factor n equal to 15, generating during the Active state equivalent output capacitor of 2.1mF. The OICC subsystem is implemented as single phase PCMC synchronous buck converter. Comparing the converter operation with and without the OICC the results demonstrate that the 12 times reduction of the output voltage deviation is achieved, for both basic operation and for the AVP operation. Furthermore, the results have been compared to a reference prototype which has the same power stage and a fiscal output capacitor of 2.1mF. The results show that the two systems have the same dynamic behavior. Moreover, an impact on the system losses under the pulsating load and DVS operation has been quantified and it has been demonstrated that the OICC system has improved the system efficiency, considering the losses when the system operates with the pulsating load and the DVS operation. Lastly, the output capacitor of the OICC system is much smaller than the reference design output capacitor, therefore, by applying the OICC concept the power density can be increased. In summary, the main contributions of the thesis are: ��� The proposed Output Impedance Correction Circuit (OICC) concept, ��� The system level control based on the used approach to change the states of operation, ��� The OICC subsystem closed-loop implementation, together with the main converter implementation, ��� The dynamic losses under the pulsating load and the DVS operation quantification, and ��� The system robustness on the capacitor impedance variation and consecutive load-steps.

Sustainability assessment of energy saving measures: A multi-criteria approach for residential buildings retrofitting���A case study of the Spanish housing stock

The building sector is well known to be one of the key energy consumers worldwide. The renovation of existing buildings provides excellent opportunities for an effective reduction of energy consumption and greenhouse gas emissions but it is essential to identify the optimal strategies. In this paper a multi-criteria methodology is proposed for the comparative analysis of retrofitting solutions. Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) are combined by expressing environmental impacts in monetary values. A Pareto optimization is used to select the preferred strategies. The methodology is exemplified by a case study: the renovation of a representative housing block from the 1960s located in Madrid. Eight scenarios have been proposed, from the Business as Usual scenario (BAU), through Spanish Building Regulation requirements (for new buildings) up to the Passive House standard. Results show how current renovation strategies that are being applied in Madrid are far from being optimal solutions. The required additional investment, which is needed to obtain an overall performance improvement of the envelope compared with the common practice to date, is relatively low (8%) considering the obtained life cycle environmental and financial savings (43% and 45%, respectively).