El modelo actual del sistema eléctrico está cambiando hacia un modelo en el que prevalecen las energías renovables y distribuidas frente a las energías con origen en combustibles fósiles y centralizadas. La reciente modificación de la legislación española sobre energía y en concreto en autoconsumo de energía eléctrica hace que este momento sea un punto de inflexión para la economía, para el cambio climático y sobre todo para reflexionar sobre un nuevo modelo energético basado en el consumo eléctrico cerca del origen del mismo. Por tanto, se propone y se justifica económicamente pasar de un modelo que complemente el actual sistema eléctrico -concentrado en grandes centrales eléctricas- a un modelo basado en la generación de energía eléctrica -distribuida en pequeños generadores- que será íntegramente sostenible y muy eficiente. Groso modo, beneficioso ambiental como reductor del cambio climático, social por la disminución del precio de la electricidad y por ende, de la pobreza energética, y económicamente por el aumento del empleo y de calidad.

Resulta difícil localizar una actividad socialmente útil que no requiera un adecuado aseguramiento energético. Pero al propio tiempo la gestión inadecuada de la energía trae consigo importantes impactos ambientales que afectan negativamente la sostenibilidad de la vida y el agotamiento de valiosos recursos naturales. La investigación pretende reforzar las teorías que explican la estrategia del desarrollo local sostenible y eficiente mediante el aprovechamiento de los recursos endógenos, a partir de la caracterización y revalorización de los potenciales renovables disponibles en el territorio. Para ello se utilizará el método deductivo que permitirá llegar a resultados concretos basados en el examen crítico científicamente argumentado, con diversos datos e informaciones de fuentes primarias y llegar a conclusiones precisas sobre el tema estudiado. Todo ello encaminado a obtener y comparar información, validar datos obtenidos de fuentes primarias y generar conocimientos nuevos vinculados con las posibilidades del medio natural del territorio y su aprovechamiento mediante fórmulas de desarrollo local sostenible. El trabajo de campo como un vehículo que permite realizar un acercamiento a la gestión energética del territorio con el fin de obtener y comparar información, validar datos obtenidos de fuentes primarias y generar conocimientos nuevos vinculados con las posibilidades del medio natural del territorio y su aprovechamiento mediante fórmulas de desarrollo local sostenible. Se partirá de la premisa que el manejo de las fuentes renovables de energía constituye una estrategia para el desarrollo local sostenible y eficiente para aprovechar los recursos endógenos que posee la Provincia de Manabí. Como conclusión de la tesis se puede afirmar que, en el territorio estudiado nunca se ha ejercido un adecuado manejo de las fuentes renovables de energía, a pesar que éstas constituyen el principal motor de desarrollo, especialmente si se contempla el fomento de las capacidades energéticas locales y se promociona el uso adecuado y más sostenible de las mismas. Se logra aportar conocimientos relacionados con los modelos que proponen una adecuada gestión de la energía como palanca para el desarrollo local, en interés de lograr una relocalización de las fuentes que permita articular una matriz energética territorial diversa, eficiente, menos costosa y amigable con el ambiente. Al analizar los diferentes aspectos de la demanda, comparada con la oferta y el análisis de las oportunidades que ofrece el medio natural de Manabí para la generación de energía y se ofrecen sugerencias e indicaciones para fomentar el desarrollo local de base endógena y sostenible para la Provincia.

A detail modelling of railway electrical system with energy storages devices is developed in this thesis in order to analyze most of the implemented railway electrical system. The modelling has been realized from a point of view the design of them as from a point of view of purely energetic efficiency. In this way, after analyzing of the electric railway systems, it has been developed simple element models that have been grouped in four categories: contact line and return circuit, fix elements, mobile elements and energy recovery and storages devices. The complete systems are built from the simple element models linked. The system of equations of the complete system is no linear, and it is solved means of numeric methods. Then, it is shown the structure of Rsim software that has been developed completely as a part of this work, to conclude with two examples of the application of Rsim. The first example belongs an alternative current railway electrification and the second example is a direct current railway electrification. Keywords: DC railway system, AC railway system, railway modeling, energetic efficiency, reverse substations, energy storage devices, unbalance, rail potential, stray currents. A detail modelling of railway electrical system with energy storages devices is developed in this thesis in order to analyze most of the implemented railway electrical system. The modelling has been realized from a point of view the design of them as from a point of view of purely energetic efficiency. In this way, after analyzing of the electric railway systems, it has been developed simple element models that have been grouped in four categories: contact line and return circuit, fix elements, mobile elements and energy recovery and storages devices. The complete systems are built from the simple element models linked. The system of equations of the complete system is no linear, and it is solved means of numeric methods. Then, it is shown the structure of Rsim software that has been developed completely as a part of this work, to conclude with two examples of the application of Rsim. The first example belongs an alternative current railway electrification and the second example is a direct current railway electrification. Keywords: DC railway system, AC railway system, railway modeling, energetic efficiency, reverse substations, energy storage devices, unbalance, rail potential, stray currents.

Currently, we can say that the environment is one of the most important topics, being that its incidence is increasingly valued by society.In that sense, in this article we study the figure of sustainable procurement. In this regard, the author believes that it would imply a due balance between wealth creation and social welfare. Therefore, the figure study goes beyond the change of words, but involves a change inperspective that should be analyzed in the light of the principles governing the law. / Actualmente, podemos afirmar que el medio ambiente es uno de los temas más importantes a tratar, siendo que su incidencia es cada vez más valorada por la sociedad. En ese sentido, en el presente artículo se aborda el concepto y función que cumpliría en nuestra sociedad la figura de la contratación sostenible. Al respecto, el autor considera que la misma implicaría un debido balance entre la generación de riqueza y el bienestar social. Por lo tanto, la figura estudiada va más allá de la variación de palabras, sino que implica un cambio en la perspectiva que debe ser analizada a la luz de los principios que rigen el derecho.

El sector de la construcción tiene una gran importancia en el desarrollo sostenible, y la adaptación en España de recientes directivas de la Unión Europea en materia energética, obliga a definir la calificación energética de los edificios, lo cual será un factor importante en la determinación de su valor. A este respecto, la presente Tesis Doctoral analiza la normativa y el software oficial que existe para obtener dicha calificación, en viviendas de nueva construcción y en cada zona climática de España. Partiendo de un proyecto real de viviendas adosadas, se realiza un análisis de los materiales e instalaciones requeridos para cumplir las normativas, así como de los costes de construcción, mantenimiento y consumo energético, y la emisión de CO2, teniendo en cuenta las calificaciones energéticas y las zonas climáticas. Viviendas más sostenibles exigen mayores costes de construcción, que deberían ser compensados con unos menores costes privados de uso. Pero en la práctica esto no ocurre y es necesario definir unos precios del CO2, o tasas medioambientales, para estimar los costes sociales que hagan rentable la elección de viviendas más eficientes energéticamente. La metodología empleada para definir estos precios son el análisis de costes y análisis de inversiones, que integran los costes económicos o privados y los costes sociales o públicos derivados de las emisiones de CO2 durante el uso de la vivienda. Finalmente, se realiza un análisis multicriterio para obtener la composición de viviendas con distintas calificaciones en una promoción inmobiliaria, considerando los objetivos privados y públicos. / Ruá Aguilar, MJ. (2011). MÉTODO DE VALORACIÓN DE VIVIENDAS DESDE LA PERSPECTIVA MEDIOAMBIENTAL Y ANÁLISIS DE COSTES [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/11275 / Palancia

Several studies have shown that the buildings envelope optical properties are important in terms of energy use and thermal comfort level. However, no study has been found in regard of the optimal optical properties for the building envelope. Moreover, developments in the coil-coating industry have made possible to design cost effective optical selective surfaces for the construction sector. Based on the above mentioned, this study pretends to map the envelope optimal optical properties minimizing the energy use for large-open-volume buildings locates in Stockholm, Copenhagen, Liverpool, Amsterdam, Berlin, Vienna, Bern, Rome, and Madrid.A building could be seen as a very complex solar energy conversion system, which is very difficult to describe accurately. Nonetheless, it is possible to use Building Energy Simulation (BES) tools to model, to some extent, its thermal performance under many simplistic assumptions. The simulation tool TRNSYS 17 and the optimization tool GenOpt were selected for this study. Additionally, detailed small-open-volume building thermal performance data, obtained during passive measurements from the steel manufacturer SSAB, in Borlänge-Sweden, were used to assess the methodology for the creation of the large-open-volume simulation models. The variations in large-open-volume building design around Europe are not well documented, which constitutes one of the major impediments for this research. However, detailed European historical building U-value data from the European Union project called iNSPiRe made it possible to achieve the objective of this study.The simulation work showed, that the building envelope optimal optical properties are related to the magnitude of the heating and cooling loads. Consequently, GenOpt was used to plot the sensitivity of the building envelope optimal optical properties to the ratio between the heating demand and the total energy demand (Qheat/Qtotal). In regard to the large-open-volume building optimal optical properties in the selected locations, it was found that the allocation of optimal optical properties does not lead to significant energy savings in locations with relatively low solar availability and high thermal insulation levels. Nonetheless, a final envelope optical properties study for a small-open-volume building model based on three existing buildings differing only on their optical properties was made for 243 world-capital cities. The simulations reinforced the results for the large-open-volume building in the European locations, and additionally showed huge energy savings potential for most of the world capital cities. This investigation restates the results obtained by Joudi (2015), “Possible energy savings by the smart choice of optical properties on the interior and exterior surfaces of the building.” / Varios estudios han demostrado que las propiedades ópticas de las envolturas delos edificios son importantes en términos de consumo energético y de nivel deconfort térmico. Sin embargo, no se ha encontrado estudio alguno con respecto alas propiedades ópticas óptimas para las envolturas de los edificios.Conjuntamente, los desarrollos en la industria de bobinas metálicas revestidas hanhecho posible diseñar superficies selectivas rentables para el sector de laconstrucción. Basándose en lo anteriormente expuesto, este estudio pretendemapear las propiedades ópticas óptimas de la envoltura que minimizan el uso deenergía para edificios de gran volumen abierto localizados en Estocolmo,Copenhague, Liverpool, Ámsterdam, Berlín, Viena, Berna, Roma y Madrid.Un edificio podría ser visto como un sistema de conversión de energía solar muycomplejo, que es muy difícil de describir con precisión. No obstante, es posibleutilizar las herramientas de Simulación de Energía de Edificios (BES) para modelar,hasta cierto punto, su rendimiento térmico bajo una considerable cantidad desuposiciones simplistas. El programa de simulación TRNSYS 17 y el programa deoptimización GenOpt fueron seleccionadas para este estudio. Adicionalmente, conel fin de evaluar la metodología utilizada para la creación de los modelos desimulación para edificios de gran volumen abierto, se utilizaron datos detallados derendimiento térmico de edificios de pequeño volumen abierto, obtenidos durantemediciones pasivas del fabricante de acero SSAB, en Borlänge-Suecia. Lasvariaciones en el diseño de edificios de gran volumen abierto en toda Europa noestán bien documentadas, lo que constituye uno de los principales impedimentospara esta investigación. Sin embargo, los datos detallados y en orden cronológicode los niveles de aislamiento térmico (U-value) en la construcción europea,recopilados por el proyecto de la Unión Europea llamado iNSPiRe, permitieronalcanzar el objetivo de este estudio.El trabajo de simulación demostró que las propiedades ópticas óptimas de laenvoltura del edificio están relacionadas con la magnitud de las cargas decalefacción y refrigeración. En consecuencia, GenOpt fue utilizado para graficar lasensibilidad de las propiedades ópticas óptimas de la envolvente del edificio conrespecto a la proporción entre la demanda de calefacción y la demanda total deenergía (Qheat/Qtotal). En cuanto a las propiedades ópticas óptimas del edificio degran volumen abierto en las ubicaciones seleccionadas, se encontró que laasignación de propiedades ópticas óptimas no conduce a ahorros de energíasignificativos en ubicaciones con disponibilidad solar relativamente baja y altosniveles de aislamiento térmico. Sin embargo, un último estudio de propiedadesópticas de envolvente para un modelo de construcción de pequeño volumen abiertobasado en tres edificios existentes que difieren sólo en sus propiedades ópticas serealizó para 243 capitales mundiales. Las simulaciones reforzaron los resultadospara el edificio de gran volumen abierto en las localidades europeas, y ademásmostraron un enorme potencial de ahorro de energía para la mayoría de lascapitales mundiales. Esta investigación reitera los resultados obtenidos por Joudi (2015), "Posibles ahorros de energía por la elección inteligente de propiedadesópticas en las superficies interiores y exteriores del edificio".

En la historia de la humanidad las comunicaciones siempre han sido de vital importancia, pero es en estos últimos años que la necesidad de la hiperconectividad se ha vuelo una realidad. Diversos dispositivos, ya sean electrónicos o no, cuentan con elementos que les permiten conectarse a internet y ser monitoreados. Es a partir de estos conceptos que nace el paradigma de Internet de las Cosas (Internet of Things, IoT). Esta intrincada red de comunicaciones plantea varios desafíos en términos de conectividad y alimentación, y más aún, cuando se espera que el número de estos dispositivos llegue a los casi 100 mil millones en un futuro muy cercano. Considerando este enorme y acelerado incremento del número de dispositivos de IoT se hace necesaria la implementación de técnicas eficientes para proveerlos de energía para su funcionamiento. Una manera alternativa al uso de las clásicas baterías, tan contaminantes para el medio ambiente, es por medio de la cosecha de energía a través de señales de radio frecuencia (RF). En este sentido, y tratándose de señales RF, pueden aprovecharse las mismas tanto para la transferencia de energía como para la de información. Para poder realizar simultáneamente esta transferencia de energía e información es necesario aplicar ciertas técnicas que permitan separar estos dos tipos de señales, tanto en la transmisión como en la recepción. En la práctica, esta transferencia de energía no es un asunto trivial, debido a las limitaciones que existen en la transmisión y recepción de este tipo de señales, como así también a las grandes pérdidas que provocan los canales inalámbricos. Es por esto que es necesario proveer técnicas que mejoren la eficiencia desde el punto de vista tanto del transmisor como del cosechador de energía, localizado en el receptor. Por otro lado, desde el punto de vista de las pérdidas ocasionadas por el canal, pueden aprovecharse técnicas nuevas que mitiguen esta problemática, extendiendo el rango de trabajo de los sistemas. Como requisito adicional en el camino hacia las tecnologías de Sexta Generación (6G), la provisión de seguridad es una preocupación importante en el contexto de las futuras redes inalámbricas, y aquellas que operan bajo el paradigma de la cosecha de energía no son una excepción. La inherente naturaleza de las comunicaciones inalámbricas de esparcir la señal en todas direcciones (broadcast) las hace vulnerables a amenazas de agentes externos capaces de robar información. Pero, en el contexto de IoT donde los nodos de bajo costo/complejidad, con limitaciones estrictas de energía y recursos, son los componentes principales, las técnicas tradicionales para la transmisión segura de información no son compatibles. Por esto, es necesario proveer técnicas que no necesiten de un costo computacional tan elevado y puedan ser aprovechadas por cualquier dispositivo. / In the history of mankind, communications have always been of vital importance, but it is in recent years that the need for hyperconnectivity has become a reality. Various devices, whether electronic or not, have elements that allow them to connect to the Internet and be monitored. It is from these concepts that the Internet of Things (IoT) paradigm is born. This intricate communications network poses several challenges in terms of connectivity and power, and even more so, when the number of these devices is expected to reach almost 100 billion in the very near future. Considering this huge and accelerated increase in the number of IoT devices, it becomes necessary to implement efficient techniques to provide them with power for their operation. An alternative to the use of classic batteries, so polluting for the environment, is by means of energy harvesting through radio frequency (RF) signals. In this sense, RF signals can be used for both energy and information transfer. In order to carry out this energy and information transfer simultaneously, it is necessary to apply certain techniques that allow separating these two types of signals, both in transmission and reception. In practice, this energy transfer is not a trivial matter, due to the limitations that exist in the transmission and reception of this type of signals, as well as the high losses caused by wireless channels. This is why it is necessary to provide techniques that improve efficiency from the point of view of both the transmitter and the energy harvester, located at the receiver. On the other hand, from the point of view of the losses caused by the channel, new techniques can be used to mitigate this problem, extending the working range of the systems. As an additional requirement on the road to Sixth Generation (6G) technologies, the provision of security is a major concern in the context of future wireless networks, and those operating under the energy harvesting paradigm are no exception. The inherent nature of wireless communications to spread the signal in all directions (broadcast) makes them vulnerable to threats from external agents capable of stealing information. But, in the context of IoT where low-cost/complexity nodes, with strict energy and resource constraints, are the main components, traditional techniques for secure information transmission are not compatible. Therefore, it is necessary to provide techniques that do not require such a high computational cost and can be exploited by any device.

La región Lambayeque esta entre las principales ciudades que con alto consumo energético ya que tiene un alto porcentaje de uso de energías por sus diversas actividades económicas que están en constante crecimiento. El centro de esparcimiento ‘’LAS PIRKAS’’ ubicado en el distrito de Jayanca, provincia de Lambayeque, departamento de Lambayeque, con el transcurrir de los años ha ido acaparando un gran protagonismo en el sector turismo, lo que ha llevado a generar a una gran ampliación de su demanda energética para poder satisfacer a sus consumidores. En donde no se ha realizado un estudio de consumo energético en sus instalaciones, teniendo como consecuencia un gasto promedio mensual de 11817,2 kW-h/mes, resultando un índice de consumo energético de 1,93 Para poder solucionar este dilema se propuso una auditoria energética comprendiendo únicamente a la parte eléctrica para reducir el consumo de energía sin interrumpir las funciones del centro de esparcimiento donde se identificaron las áreas de mayor consumo como la cocina y restaurante que significan el 50% de uso de la energía total, así mismo presentar propuestas de mejora para el uso eficaz de la energía eléctrica. La práctica de las medidas planteadas aumentará en proporción la reducción aproximada del consumo eléctrico anual de 25 267,224 kW-h y una economización de S/17 472, 30 disminuyendo también el índice de consumo promedio a 1,54. Esto se llevará a cabo con una inversión de S/ 47 811 para mejorar sus equipos e instalaciones, teniendo una relación beneficio/costo de 1,21, logrando recuperar la inversión en aproximadamente 4 años. La auditoría energética demuestra que es posible reducir el consumo de energía, aumentando y mejorando la eficiencia energética del centro de esparcimiento ´´LAS PIRKAS´´ / The Lambayeque region is among the main cities with high energy consumption since it has a high percentage of energy use due to its various economic activities that are constantly growing. The ''LAS PIRKAS'' recreation center located in the district of Jayanca, province of Lambayeque, department of Lambayeque, over the years, has gained great prominence in the tourism sector, which has led to generating a great expansion of its energy demand to be able to satisfy its consumers. Where an energy consumption study has not been carried out in its facilities, resulting in an average monthly expense of 11817.2 kW-h/month, resulting in an energy consumption index of 1.93 To solve this dilemma, an energy audit was proposed, comprising only the electrical part to reduce energy consumption without interrupting the functions of the leisure center where the areas with the highest consumption were identified, such as the kitchen and restaurant, which represented 50 % of use. of total energy, as well as present improvement proposals for the effective use of electrical energy. The practice of the proposed measures will proportionately increase the approximate reduction in annual electricity consumption of 25,267.224 kW-h and a saving of S/17,472, 30 also decreasing the average consumption index to 1.54. This will be carried out with an investment of S/ 47,811 to improve its equipment and facilities, having a benefit/cost ratio of 1.21, recovering the investment in approximately 4 years. The energy audit demonstrates that it is possible to reduce energy consumption, increasing and improving the energy efficiency of the recreation center´´LAS PIRKAS

[ES] Las ciudades representan un papel muy importante en el desarrollo sostenible. En general, es conocido, que el sector residencial representa unos porcentajes elevados en cuanto a consumos totales de energía y emisiones de CO2. El avance en el conocimiento ha demostrado que todo el parque edificado tiene un comportamiento energético poco efectivo y que puede ser mejorable, avanzando así en las nuevas directrices de mejora que se están imponiendo desde las administraciones. Así pues, ante un parque construido abundante y obsoleto, la rehabilitación es el gran potencial que puede contribuir a la mejora del cambio climático, a través de la propuesta de estrategias y escenarios de actuación sostenibles y adecuados a los entornos sociales, económicos y medioambientales correspondientes. La construcción sostenible se fundamenta en optimizar el impacto conjunto en el medio natural de las tres dimensiones fundamentales en cualquier actividad humana: medioambiente, economía y sociedad. Así pues, surge la necesidad de establecer un patrón de medida que permita evaluar y cuantificar la sostenibilidad de un edificio, de forma que sea objetivo y comparable, que reduzcan la complejidad de otros estándares ya existentes. La presente tesis desarrolla una sistemática de análisis del medio urbano en todas sus dimensiones, a partir de una parametrización de las distintas tipologías constructivas y de su evolución. De esta forma, se está en condiciones de conocer la evolución de los sistemas urbanos partiendo de la evolución de las variables constructivas. / [CA] Les ciutats representen un paper molt important en el desenvolupament sostenible. En general, és conegut que el sector residencial representa uns percentatges elevats quant a consums totals d'energia i emissions de CO2. L'avenç en el coneixement ha demostrat que tot el parc edificat té un comportament energètic poc efectiu i que pot ser millorable, avançant així a les noves directrius de millora que s'estan imposant des de les administracions. Així doncs, davant d'un parc construït abundant i obsolet, la rehabilitació és el gran potencial que pot contribuir a millorar el canvi climàtic, a través de la proposta d'estratègies i escenaris d'actuació sostenibles i adequats als entorns socials, econòmics i mediambientals corresponents . La construcció sostenible es fonamenta en optimitzar limpacte conjunt en el medi natural de les tres dimensions fonamentals en qualsevol activitat humana: medi ambient, economia i societat. Sorgeix, doncs, la necessitat d'establir un patró de mesura que permeti avaluar i quantificar la sostenibilitat d'un edifici, de manera que sigui objectiu i comparable, que redueixin la complexitat d'altres estàndards ja existents. Aquesta tesi desenvolupa una sistemàtica danàlisi del medi urbà en totes les seves dimensions, a partir duna parametrització de les diferents tipologies constructives i de la seva evolució. D'aquesta manera s'està en condicions de conèixer l'evolució dels sistemes urbans partint de l'evolució de les variables constructives. / [EN] Cities play a very important role in sustainable development. In general, it is well known that the residential sector represents a high percentage of total energy consumption and CO2 emissions. Advances in knowledge have shown that the entire building stock has an inefficient energy performance and that it can be improved, thus advancing in the new guidelines for improvement that are being imposed by the administrations. Thus, faced with an abundant and obsolete building stock, refurbishment is the great potential that can contribute to the improvement of climate change, through the proposal of sustainable strategies and action scenarios that are appropriate to the corresponding social, economic and environmental settings. Sustainable construction is based on optimising the joint impact on the natural environment of the three fundamental dimensions of any human activity: environment, economy and society. Thus, the need arises to establish a standard of measurement to evaluate and quantify the sustainability of a building, in a way that is objective and comparable, reducing the complexity of other existing standards. This thesis develops a systematic analysis of the urban environment in all its dimensions, based on a parameterisation of the different building typologies and their evolution. In this way, we are in a position to know the evolution of urban systems in the urban environment in all its dimensions, based on a parameterisation of the different building typologies and their evolution. / La realización de esta tesis ha derivado en la participación en un proyecto de investigación de las Comunidades Europeas: Proyecto: “Grow Green”, Contract Number 730283-2 Proyecto H2020-SCC-2016-2017 titulado GREEN CITIES FOR CLIMATE AND WATER RESILIENCE, SUSTAINABLE ECONOMIC GROWTH, HEALTHY CITIZENS AND ENVIRONMENTS. / Iborra Lucas, M. (2024). Aproximación metodológica al análisis integrado de la sostenibilidad urbana partiendo de las tipologías constructivas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203609

In the international context, this research analyzes the state of the art of scientific discussion, the action exerted by national and local governments through regulations, and the opinion of professionals in the field of construction of buildings in relation to the implementation of energy efficiency measures in buildings. In general, the interest in the different areas has been driven primarily by: 1) the worldwide increased energy consumption in buildings, emphasizes by an increasingly urbanized world and the resource scarcity for power generation, primarily fossil fuels; 2) the increase in greenhouse gas emissions related to the buildings' construction and operation; and 3) the thermal behaviour of the building's envelope, which determines the energy demand for thermal conditioning; mainly for heating in winter and cooling in summer. The foregoing has resulted in the implementation of different types of energy efficiency measures in the building sector around the world. On the one hand, through mandatory measures, driven by national and local governments through building codes; mandatory measures require that when building a new building or refurbishing an existing one, the architects, private developers, or builders must comply with building standards that govern the thermal performance of the different elements of the buildings' thermal envelope. On the other hand, by implementing voluntary measures, such as international certification systems, established by non-governmental institutions, aimed at legitimizing the efforts of building owners, design teams, and builders to design, build, and operate buildings in an environmentally friendly way. The latter has triggered an international trend and an increasing demand for certification of the so-called "green buildings". Such independent certification systems seek to reduce the environmental impact of activities in the construction sector. In the Chilean context, this research analyzes the relationship between two main pillars of the Chilean economy, the energy sector and the private housing sector. Particularly, this research focuses on the implementation of energy efficiency measures in the private housing market in Santiago, the Chilean capital. From the energy perspective, the high vulnerability for power generation by the dependence on the provision of gas from neighbouring countries and periods of drought affecting hydroelectric power generation, has led to the Chilean government intervention. Government intervention is centred on two main lines of action: 1) the diversification of the country's energy matrix, through the implementation of alternative systems for power generation based on non-conventional renewable energy sources; and 2) the implementation of energy efficiency measures. In the construction sector, the latter is expressed by the entry into force of the New Thermal Regulations for new residential buildings in three stages in the building code since 2000. With the implementation of new regulations in the construction sector in the Chilean context and the growing demand for green building in the international context, private real estate companies and construction companies, which are the backbone of the construction sector in Chile, have reacted by offering energy efficient real estate products in Santiago de Chile. Based on the foregoing, arises the main question leading this doctoral thesis: How do real estate developers apply energy efficiency in their housing offer in Santiago de Chile? The main research question is further refined by three sub questions: 1) who are the real estate developers that are adopting energy efficiency and why? This is a compound question, first it seeks to identify real estate companies adopting energy efficiency measures in Santiago de Chile’s private housing market; then it looks into the motivations for doing so; 2) what types of energy efficiency measures are real estate companies adopting? This sub-research question seeks to identify the adopted residential energy efficiency strategies; and 3) which barriers to further implementation of energy efficiency exist? It seeks to identify the setbacks found by energy efficiency adopters in the implementation process, in order to understand local issues in the adoption process. The Case Study and Selection of Sub-Cases for the Analysis The research focuses on the voluntary implementation of residential energy efficiency measures in the private housing market; moreover, it analyzes the case of Santiago de Chile. Therefore, the focus is set on real estate companies that offer energy efficient housing in their offer for real estate products in the metropolitan region. The selection of embedded sub-cases for the analysis, or sub-cases, was made by applying a criterion sampling strategy known as purposive sampling. For this, a thorough review of 568 private real estate companies' websites, offering different real estate products in the Metropolitan Region of Santiago de Chile between June and July 2011, was performed. Out of this group, a set of 45 companies that offering energy efficient homes mentioned were selected. Later on, personal interviews mainly with general managers of real estate development companies and other actors considered key informants because of their knowledge in the field, such as scholars, representatives from public institutions, other public and private research centres, and practitioners, were conducted between April and May 2012. Main Methods and Data Analysis Research is conducted under a qualitative approach, as it focuses primarily on the opinion of real estate companies’ CEOs and other key informants considered information rich when helping answering the research questions. The main tool for data analysis was the thematic content analysis. Main Findings The main results of this research are structured on the basis of the answering the secondary research questions or sub-questions. Who are the real estate developers that are adopting energy efficiency and why? As it was mentioned above, the first part of this compound sub-question seeks to identify the real estate companies that are implementing residential energy efficiency measures in their offer in the housing market in Santiago de Chile. A set of 45 real estate companies were identified because they mentioned to be applying some sort of energy efficiency measures. This was a rather small group since, at that time, 568 real estate companies were offering housing products. Based on the empirical findings, a categorization of real estate companies following the Roger’s model was conducted. Thus, real estate companies were categorized depending on when they began adopting residential energy efficiency measures in their housing offer. The three stages of the New Thermal Regulation issued for the housing sector in Chile were selected as time-milestones for defining the adopter categories. Accordingly, three main categories emerged following Roger’s model. 1) Innovators, includes real estate companies who adopted energy efficiency measures for the first time before the entry into force of the first stage of the NRT in 2000; 2) Early Adopters, groups real estate companies who adopted residential energy efficiency measures for the first time between the first and second stage of the New Thermal Regulation, that is to say between 2001 and 2007; and 3) Early Majority, includes real estate companies who began to apply residential energy efficiency measures starting in 2008, meaning after the second stage of New Thermal Regulation came into force. The empirical evidence suggests that the adoption process of energy efficiency measures has started following the normal development described by Rogers' innovation curve. Therefore, it is expected that the rest of the real estate developers operating in the private housing market in Santiago de Chile will eventually follow the Innovators, Early Adopters, and Early Majority categories. This is mainly due to the recent introduction of thermal regulation by the government and because the housing market is a highly competitive market, in which none of the players can risk to be left behind. The second part of the sub-research question, and probably the most important one, seeks to understand the motivations for real estate companies to offer and implement energy-efficient real estate products in Santiago de Chile’s private housing market. This research identifies the motivations of real estate development companies in the opinion of their managers collected in personal semi-structured interviews conducted during fieldwork. Based on the thematic analysis of the abovementioned interviews, four categories of motivations for offering and applying energy efficiency were identified based on the company managers’ opinion. These categories, in order of preference are: 1) Market Differentiation Strategies (Competitiveness and Trending); 2) Company Policies (Client-Oriented Policies, Innovation Policies, and Environmentally-friendly Policies); 3) Resource efficiency (Reduction of Household\'s Expenses and Concerns for Energy Scarcity); and 4) Government Incentive Schemes (Subsidies to the Use of Renewable Energy). Briefly, the main motivations for adopting energy efficiency measures in the private housing offer are related to marketing strategies. In general, real estate companies operating in Santiago de Chile are looking to distinguish themselves from their competitors by offering energy-efficient housing products. This is mainly because real estate companies are following a trend that is driven by several factors such as: local energy shortage periods, the international influence of green buildings in the real estate market, and the growing demand for international certifications in the Chilean context. What types of energy efficiency measures are real estate companies adopting? As mentioned earlier, this research identifies real estate companies offering energy-efficient housing in the private real estate market of Santiago de Chile who implemented a diversity of energy efficiency strategies in their housing supply, as the empirical evidence shows. Although the motivations for implementing energy efficiency measures are diverse (as described previously), energy efficiency measures are mainly implemented in order to reach a comfort temperature inside the dwelling, making all possible efforts to ensure that energy is used efficiently. In the case of the residential buildings, this means looking for the optimal use of energy for space heating or cooling, lighting, hot sanitary water, and ventilation. In general, depending on whether there is the need to make an additional energy effort in order to achieve optimum indoor comfort conditions, the energy efficiency measures implemented in the private housing sector in Santiago de Chile can be grouped into two main categories of energy efficiency strategies: passive design strategies and active design strategies. On the one hand, passive design strategies refer to what real estate developers are doing to reduce the energy consumption of their housing buildings. Such strategies include: 1) improving the overall thermal performance of the building envelope; 2) the use of renewable energy, mainly solar thermal and photovoltaic technology, for hot sanitary water and energy conversion respectively; and 3) bioclimatic design and construction principles. As it was mentioned in Section 6.1, a basic characteristic of passive design strategies, distinguishing them from active design strategies, is that in order to operate they rely on the building site and the inherited thermal properties of the building materials used in the different housing building typologies. On the other hand, active design strategies refer to the technological innovations implemented in order to maintain an optimal indoor thermal conditioning and to reduce the energy used in the different buildings’ systems; namely, 1) illumination systems; 2) heating systems; 3) centralized control systems; and 4) air conditioning systems. In general, real estate developers adopted active design strategies as a complement to the use of passive design strategies. Not surprisingly, real estate developers have mentioned the improvement of the thermal envelope as the most commonly used residential energy efficiency strategy. This results from the fact that internationally and in Chile, regulations in the housing sector were implemented in order to improve the thermal behaviour of dwellings, and therefore, their energy efficiency. Finally, a third type of energy efficiency strategy adopted by real estate developers in Santiago de Chile is the result of a public-private partnership between the Chilean Government and the Chilectra, the local electricity utility. The initiative is called “Chilectra – Full Electric Buildings” and it offers an optional electrical energy tariff for residential consumers. This strategy is further explained in Section 6.3. Which barriers to further implementation of energy efficiency exist? Based on the opinion of the various key stakeholder involved in this research, this research shows that most barriers to energy efficiency in the private housing sector in Santiago de Chile interact and strengthen each other. The classification of barriers to further implementation of energy efficiency is not straightforward. Nonetheless, in the opinion of real estate companies’ managers, the barriers to adopting energy efficiency measures in the private housing market in Santiago de Chile revolve around the specific characteristics of the local social system. These barriers are: 1) market barriers; 2) organizational barriers; 3) institutional barriers; and 4) behavioural barriers. In relation to the categorization of energy efficiency adopters identified in the first sub-question, the empirical evidence seems to indicate that, not all the barriers play the same role for all adopter categories. In general, market barriers are most relevant to the innovators group. Although most of the real estate developers mentioned that even today the local market and the local construction industry are not ready to provide adequate support (both in the availability of products and services) for further development of the market for energy efficient construction, the deficiency was greater 20 years ago, when the innovators first started to implement residential energy efficiency measures in the private housing sector. Moreover, the other barriers encountered (namely organizational and institutional barriers) are transversal to the adopter categories. This seems to drawn from the organizational and institutional characteristics of the context in which private real estate companies operate. The context remains constant over time and their internal relationships are also maintained, homogeneously affecting all adopter categories. Finally, barriers related to end users and/or clients’ behaviour are mainly listed by early majority adopters, which comprises developers who implement residential energy efficiency measures recently (after 2000). Apparently, this results mainly from the fact that end user are lacking information about the benefits (general and local) to be gained from implementing residential energy efficiency measures.