On roof geometry for urban wind energy exploitation in high-rise buildings

The European program HORIZON2020 aims to have 20% of electricity produced by renewable sources. The building sector represents 40% of the European Union energy consumption. Reducing energy consumption in buildings is therefore a priority for energy efficiency. The present investigation explores the most adequate roof shapes compatible with the placement of different types of small wind energy generators on high-rise buildings for urban wind energy exploitation. The wind flow around traditional state-of-the-art roof shapes is considered. In addition, the influence of the roof edge on the wind flow on high-rise buildings is analyzed. These geometries are investigated, both qualitatively and quantitatively, and the turbulence intensity threshold for horizontal axis wind turbines is considered. The most adequate shapes for wind energy exploitation are identified, studying vertical profiles of velocity, turbulent kinetic energy and turbulence intensity. Curved shapes are the most interesting building roof shapes from the wind energy exploitation point of view, leading to the highest speed-up and the lowest turbulence intensity.

Mejora del comportamiento t��rmico de los morteros de cal aditivados y su empleo en la rehabilitaci��n de inmuebles = Improvement of thermal behaviour of additived lime mortars and their use in rehabilitation of buildings

La envolvente de la edificaci��n es la responsable de equilibrar el intercambio energ��tico entre el interior y el exterior, por lo tanto cualquier actuaci��n encaminada a la reducci��n del consumo energ��tico ha de establecer, como uno de sus objetivos prioritarios, la mejora del comportamiento de la misma. Las edificaciones anteriores a 1940 constituyen la mayor parte de las existentes en ��reas rurales y centros urbanos. En ellas, la repercusi��n de la fachada sobre las transmitancias globales pone de manifiesto la necesidad de intervenci��n. Sin embargo, su elevada inercia t��rmica y los importantes saltos t��rmicos caracter��sticos de gran parte de Espa��a plantean la importancia de que aqu��lla se efect��e por el exterior. A tal respecto, la falta de disponibilidad de espesor suficiente para implantar sistemas tipo SATE deriva en que, frecuentemente, la ��nica soluci��n viable sea la de aislar por el interior perdiendo con ello la capacidad de acumulaci��n t��rmica del muro y con el asociado riesgo de condensaciones. La amplia tradici��n en el empleo de revestimientos, especialmente en base de cal, permiten que ��stos sean utilizados no s��lo como elemento est��tico o de protecci��n de la obra de f��brica antigua sino tambi��n para la mejora del comportamiento t��rmico del soporte, si se aprovecha el mecanismo de transmisi��n t��rmica por radiaci��n. ��ste es el objetivo de la presente Tesis Doctoral en la que se estudia la modificaci��n de las propiedades radiantes de los morteros de revestimiento para la mejora de la eficiencia energ��tica de las construcciones hist��ricas, principalmente las constituidas por muros monol��ticos, aunque podr��a ser de aplicaci��n a otro tipo de construcciones compuestas por diversas capas. Como punto de partida, se estudi�� y revis�� la documentaci��n disponible sobre las investigaciones de las tres ��reas cient��fico-tecnol��gicas que convergen en la Tesis Doctoral: rehabilitaci��n, material y comportamiento t��rmico, a partir de lo cual se comprob�� la inexistencia de estudios similares al objeto de la presente Tesis Doctoral. Complementariamente, se analizaron los revestimientos en lo concerniente a los materiales que los constituyen, la composici��n de las mezclas y caracter��sticas de cada una de las capas as�� como al enfoque que, desde el punto de vista t��rmico, se estimaba m��s adecuado para la obtenci��n de los objetivos propuestos. Bas��ndonos en dichos an��lisis, se preseleccionaron ochenta materiales que fueron ensayados en t��rminos de reflectancia y emisividad para elegir cuatro con los que se continu�� la investigaci��n. ��stos, junto con la cal elegida para la investigaci��n y el ��rido marm��reo caracter��stico de la ��ltima capa de revestimiento, fueron caracterizados t��rmicamente, de forma pormenorizada, as�� como qu��mica y f��sicamente. Los fundamentos te��ricos y los estudios preliminares desarrollados con distintos materiales, en estado fresco y endurecido, fueron empleados en la dosificaci��n de componentes de las mezclas, en dos proporciones distintas, para el estudio del efecto del agregado. ��stas se ensayaron en estado fresco, para comprobar su adecuaci��n de puesta en obra y prever su VI adherencia al soporte, as�� como en estado endurecido a 28 y 90 d��as de curado, para conocer las propiedades que permitieran prever su compatibilidad con aqu��l y estimar el alcance de la reducci��n de transferencias t��rmicas lograda. Adem��s, se estudiaron las caracter��sticas generales de las mezclas que sirvieron para establecer correlaciones entre distintas propiedades y entender los resultados mec��nicos, f��sicos (comportamiento frente al agua) y energ��ticos. Del estudio conjunto de las distintas propiedades analizadas se propusieron dos mezclas, una blanca y otra coloreada, cuyas caracter��sticas permiten garantizar la compatibilidad con la obra de f��brica antigua, desde el punto de vista f��sico y mec��nico, y preservar la autenticidad de los revestimientos, en cuanto a la t��cnica de aplicaci��n tradicional en sistemas multicapa. El comportamiento t��rmico de las mismas, sobre una obra de f��brica de 40 cm de espesor, se estim��, en estado estacionario y pseudo-transitorio, demostr��ndose reducciones del flujo t��rmico entre 16-48%, en condiciones de verano, y entre el 6-11%, en invierno, en funci��n de la coloraci��n y de la rugosidad de la superficie, en comparaci��n con el empleo de la mezcla tradicional. Por lo que, se constata la viabilidad de los materiales compuestos propuestos y su adecuaci��n al objetivo de la investigaci��n. VII ABSTRACT The envelope is responsible for balancing the energy exchange between the inside and outside in buildings. For this reason, any action aimed at reducing energy consumption must establish, as one of its key priorities, its improvement. In rural areas and urban centers, most of the constructions were built before 1940. In them, the impact of the fa��ade on the global transmittance highlights the need for intervention. However, its high thermal inertia and fluctuation of temperatures in the majority of Spain bring up that it should be placed outside the insulation. In this regard, the lack of availability of enough thickness to implement systems such as ETICS results in that often the only viable solution is to isolate the interior, losing thereby the wall���s heat storage capacity with the associated risk of condensation. The tradition in the use of renders, especially lime-based, allows us to use them not only as an aesthetic element or to protect the ancient masonry, but also for improved thermal performance of the support by taking advantage of the heat transfer mechanism by radiation. This is the aim of this Doctoral Thesis in which the modification of the radiative properties of lime mortars for renders to improve the energy efficiency of historic buildings, mainly composed of monolithic walls, is studied, although it could be applied to other structures composed of several layers. As a starting point, the available literature in the three scientific-technological areas that converge at the Doctoral Thesis: rehabilitation, material and thermal behaviour, was reviewed, and confirmed the absence of researches similar to this Doctoral Thesis. Additionally, the renders were studied with regard to the materials that constitute them, the composition of the mixtures and the characteristics of each layer, as well as to the approach which, from a thermal point of view, was deemed the most suitable for achieving the objectives sets. Based on thre aforementioned analysis, eighty materials tested in terms of reflectance and emissivity were pre-selected, to choose four with which the research was continued. Common marble sand, used in the last layer of the renders, together with the appointed materials and hydrated lime were characterized thermally, in detail, as well as chemically and physically. The theoretical bases and preliminary studies with different materials, in fresh and hardened state, were used in the dosage of the composition of the mixtures. In order to study their effect they were used in two different proportions, that is, ten mixtures in total. These were tested in their fresh state to evaluate their setting-up suitability and foresee their adhesion to the support, as well as in their hardened state, at 28 and 90 days of curing, to establish the properties which enabled us to anticipate their compatibility with the old masonry walls and estimate the scope of the reduction of heat transfers achieved. In addition, the general characteristics of the mixtures used to establish correlations and to understand the mechanical, physical and energy results were studied. Two mixtures, one white and one colored, were proposed as the result of the different properties analysed, whose characteristics allow the guarantee of mechanical and physical compatibility VIII with the old masonry and preserve the authenticity of the renders. The thermal behavior of both, applied on a masonry wall 40 cm thick, was estimated at a steady and pseudo-transient state, with heat flow reductions between 16-48% during summertime and 6-11% during wintertime, depending on the color and surface roughness, compared to the use of the traditional mixture. So, the viability of the proposed composite materials and their fitness to the aim of the research are established.

Next Generation of Energy Residential Gateways for Demand Response and Dynamic Pricing

Predictions about electric energy needs, based on current electric energy models, forecast that the global energy consumption on Earth for 2050 will double present rates. Using distributed procedures for control and integration, the expected needs can be halved. Therefore implementation of Smart Grids is necessary. Interaction between final consumers and utilities is a key factor of future Smart Grids. This interaction is aimed to reach efficient and responsible energy consumption. Energy Residential Gateways (ERG) are new in-building devices that will govern the communication between user and utility and will control electric loads. Utilities will offer new services empowering residential customers to lower their electric bill. Some of these services are Smart Metering, Demand Response and Dynamic Pricing. This paper presents a practical development of an ERG for residential buildings.

Wind turbine wakes for wind energy

During recent years, wind energy has moved from an emerging technology to a nearly competitive technology. This fact, coupled with an increasing global focus on environmental concern and a political desire of a certain level of diversification in the energy supply, ensures wind energy an important role in the future electricity market. For this challenge to be met in a cost-efficient way, a substantial part of new wind turbine installations is foreseen to be erected in big onshore or offshore wind farms. This fact makes the production, loading and reliability of turbines operating under such conditions of particular interest.

Environmental analysis of residential building facades through energy consumption, GHG emissions and costs

This paper provides some results on the potential to minimize environmental impacts in residential buildings life cycle, through fa��ade design strategies, analyzing also their impact on costs from a lifecycle perspective. On one hand, it assesses the environmental damage produced by the materials of the building envelope, and on the other, the benefits they offer in terms of habitability and liveability in the use phase. The analysis includes several design parameters used both for rehabilitation of existing facades, as for new facades, trying to cover various determinants and proposing project alternatives. With this study we intended to contribute to address the energy challenges for the coming years, trying also to propose pathways for innovative solutions for the building envelope.

Assessing the solar irradiation potential for solar photovoltaic applications in buildings at low latitudes �� Making the case for Brazil

In Brazil, a low-latitude country characterized by its high availability and uniformity of solar radiation, the use of PV solar energy integrated in buildings is still incipient. However, at the moment there are several initiatives which give some hints that lead to think that there will be a change shortly. In countries where this technology is already a daily reality, such as Germany, Japan or Spain, the recommendations and basic criteria to avoid losses due to orientation and tilt are widespread. Extrapolating those measures used in high latitudes to all regions, without a previous deeper analysis, is standard practice. They do not always correspond to reality, what frequently leads to false assumptions and may become an obstacle in a country which is taking the first step in this area. In this paper, the solar potential yield for different surfaces in Brazilian cities (located at latitudes between 0�� and 30��S) are analyzed with the aim of providing the necessary tools to evaluate the suitability of the buildings��� envelopes for photovoltaic use

Mode II fracture energy in the adhesive bonding of dissimilar substrates: carbon fibre composite to aluminium joints

The end-notched flexure (ENF) test calculates the value of mode II fracture energy in adhesive bonding between the substrates of same nature. Traditional methods of calculating fracture energy in the ENF test are not suitable in cases where the thickness of the adhesive is non-negligible compared with adherent thicknesses. To address this issue, a specific methodology for calculating mode II fracture energy has been proposed in this paper. To illustrate the applicability of the proposed method, the fracture energy was calculated by the ENF test for adhesive bonds between aluminium and a composite material, which considered two different types of adhesive (epoxy and polyurethane) and various surface treatments. The proposed calculation model provides higher values of fracture energy than those obtained from the simplified models that consider the adhesive thickness to be zero, supporting the conclusion that the calculation of mode II fracture energy for adhesives with non-negligible thickness relative to their adherents should be based on mathematical models, such as the method proposed in this paper, that incorporate the influence of this thickness.

Reuse of vacant agro-industrial buildings. The case of the public slaughterhouses in Spain

Nearly 3000 slaughterhouses (74% of them public facilities) were built in Spain during the last decades of the nineteenth century and the first half of the twentieth century. The need to comply with new technical requirements and regulations on the hygiene of the meat passed in the 70s and the gradual replacement of public facilities by larger and more modern private slaughterhouses have subsequently led to the closure and abandonment of many of these buildings. Public slaughterhouses generally consisted of several single-storey and open-plan buildings located around a courtyard. Although originally they were preferably located on the outskirts of the towns, many slaughterhouses are now placed inside the built up areas, due to the urban development. The present work aims to contribute to a better understanding of these agro-industrial buildings and to provide ideas for their conservation and reuse. A review on the historical evolution and the architectural features of the public slaughterhouses in Spain is presented and different examples of old vacant slaughterhouses reused to accommodate libraries, offices, community centres, exhibition halls or sports centres, among others, are shown in the paper.

Multiprotocol Android Application for Smart Control and Monitoring in Buildings

This paper presents a multiprotocol mobile application for building automation which supports and enables the integration of the most representative control technologies such as KNX, LonWorks and X-10. The application includes a real-time monitoring service. Finally, advanced control functionalities based on gestures recognition and predefined scenes have been implemented. This application has been developed and tested in the Energy Efficiency Research Facility located at CeDInt-UPM, where electrical loads, blinds and HVAC and lighting systems can be controlled.

On the economics of energy consumption in 4G networks: the case of Spain

Reducing energy consumption is one of the main challenges in most countries. For example, European Member States agreed to reduce greenhouse gas (GHG) emissions by 20% in 2020 compared to 1990 levels (EC 2008). Considering each sector separately, ICTs account nowadays for 2% of total carbon emissions. This percentage will increase as the demand of communication services and applications steps up. At the same time, the expected evolution of ICT-based developments - smart buildings, smart grids and smart transportation systems among others - could result in the creation of energy-saving opportunities leading to global emission reductions (Labouze et al. 2008), although the amount of these savings is under debate (Falch 2010). The main development required in telecommunication networks ?one of the three major blocks of energy consumption in ICTs together with data centers and consumer equipment (Sutherland 2009) ? is the evolution of existing infrastructures into ultra-broadband networks, the so-called Next Generation Networks (NGN). Fourth generation (4G) mobile communications are the technology of choice to complete -or supplement- the ubiquitous deployment of NGN. The risk and opportunities involved in NGN roll-out are currently in the forefront of the economic and policy debate. However, the issue of which is the role of energy consumption in 4G networks seems absent, despite the fact that the economic impact of energy consumption arises as a key element in the cost analysis of this type of networks. Precisely, the aim of this research is to provide deeper insight on the energy consumption involved in the usage of a 4G network, its relationship with network main design features, and the general economic impact this would have in the capital and operational expenditures related with network deployment and usage.

Optimizaci��n de la composici��n del hueco de fachada en materia de eficiencia energ��tica. Propuesta de indicador como herramienta para el an��lisis integral del elemento acristalado = Energy performance optimization of window systems. Proposal of an indicator as a tool for an integrated analysis of glazing

La hip��tesis de esta tesis es: "La optimizaci��n de la ventana considerando simult��neamente aspectos energ��ticos y aspectos relativos a la calidad ambiental interior (confort higrot��rmico, lum��nico y ac��stico) es compatible, siempre que se conozcan y consideren las sinergias existentes entre ellos desde las primeras fases de dise��o". En la actualidad se desconocen las implicaciones de muchas de las decisiones tomadas en torno a la ventana; para que su eficiencia en relaci��n a todos los aspectos mencionados pueda hacerse efectiva es necesaria una herramienta que aporte m��s informaci��n de la actualmente disponible en el proceso de dise��o, permitiendo as�� la optimizaci��n integral, en funci��n de las circunstancias espec��ficas de cada proyecto. En la fase inicial de esta investigaci��n se realiza un primer acercamiento al tema, a trav��s del estado del arte de la ventana; analizando la normativa existente, los componentes, las prestaciones, los elementos experimentales y la investigaci��n. Se observa que, en ocasiones, altos requisitos de eficiencia energ��tica pueden suponer una disminuci��n de las prestaciones del sistema en relaci��n con la calidad ambiental interior, por lo que surge el inter��s por integrar al an��lisis energ��tico aspectos relativos a la calidad ambiental interior, como son las prestaciones lum��nicas y ac��sticas y la renovaci��n de aire. En este punto se detecta la necesidad de realizar un estudio integral que incorpore los distintos aspectos y evaluar las sinergias que se dan entre las distintas prestaciones que cumple la ventana. Adem��s, del an��lisis de las soluciones innovadoras y experimentales se observa la dificultad de determinar en qu�� medida dichas soluciones son eficientes, ya que son soluciones complejas, no caracterizadas y que no est��n incorporadas en las metodolog��as de c��lculo o en las bases de datos de los programas de simulaci��n. Por lo tanto, se plantea una segunda necesidad, generar una metodolog��a experimental para llevar a cabo la caracterizaci��n y el an��lisis de la eficiencia de sistemas innovadores. Para abordar esta doble necesidad se plantea la optimizaci��n mediante una evaluaci��n del elemento acristalado que integre la eficiencia energ��tica y la calidad ambiental interior, combinando la investigaci��n te��rica y la investigaci��n experimental. En el ��mbito te��rico, se realizan simulaciones, c��lculos y recopilaci��n de informaci��n de distintas tipolog��as de hueco, en relaci��n con cada prestaci��n de forma independiente (ac��stica, iluminaci��n, ventilaci��n). A pesar de haber partido con un enfoque integrador, resulta dif��cil esa integraci��n detect��ndose una carencia de herramientas disponible. En el ��mbito experimental se desarrolla una metodolog��a para la evaluaci��n del rendimiento y de aspectos ambientales de aplicaci��n a elementos innovadores de dif��cil valoraci��n mediante la metodolog��a te��rica. Esta evaluaci��n consiste en el an��lisis comparativo experimental entre el elemento innovador y un elemento est��ndar; para llevar a cabo este an��lisis se han dise��ado dos espacios iguales, que denominamos m��dulos de experimentaci��n, en los que se han incorporado los dos sistemas; estos espacios se han monitorizado, obteni��ndose datos de consumo, temperatura, iluminancia y humedad relativa. Se ha realizado una medici��n durante un periodo de nueve meses y se han analizado y comparado los resultados, obteniendo as�� el comportamiento real del sistema. Tras el an��lisis te��rico y el experimental, y como consecuencia de esa necesidad de integrar el conocimiento existente se propone una herramienta de evaluaci��n integral del elemento acristalado. El desarrollo de esta herramienta se realiza en base al procedimiento de diagn��stico de calidad ambiental interior (CAI) de acuerdo con la norma UNE 171330 ���Calidad ambiental en interiores���, incorporando el factor de eficiencia energ��tica. De la primera parte del proceso, la parte te��rica y el estado del arte, se obtendr��n los par��metros que son determinantes y los valores de referencia de dichos par��metros. En base a los par��metros relevantes obtenidos se da forma a la herramienta, que consiste en un indicador de producto para ventanas que integra todos los factores analizados y que se desarrolla seg��n la Norma UNE 21929 ���Sostenibilidad en construcci��n de edificios. Indicadores de sostenibilidad���. ABSTRACT The hypothesis of this thesis is: "The optimization of windows considering energy and indoor environmental quality issues simultaneously (hydrothermal comfort, lighting comfort, and acoustic comfort) is compatible, provided that the synergies between these issues are known and considered from the early stages of design ". The implications of many of the decisions made on this item are currently unclear. So that savings can be made, an effective tool is needed to provide more information during the design process than the currently available, thus enabling optimization of the system according to the specific circumstances of each project. The initial phase deals with the study from an energy efficiency point of view, performing a qualitative and quantitative analysis of commercial, innovative and experimental windows. It is observed that sometimes, high-energy efficiency requirements may mean a reduction in the system's performance in relation to user comfort and health, that's why there is an interest in performing an integrated analysis of indoor environment aspects and energy efficiency. At this point a need for a comprehensive study incorporating the different aspects is detected, to evaluate the synergies that exist between the various benefits that meet the window. Moreover, from the analysis of experimental and innovative windows, a difficulty in establishing to what extent these solutions are efficient is observed; therefore, there is a need to generate a methodology for performing the analysis of the efficiency of the systems. Therefore, a second need arises, to generate an experimental methodology to perform characterization and analysis of the efficiency of innovative systems. To address this dual need, the optimization of windows by an integrated evaluation arises, considering energy efficiency and indoor environmental quality, combining theoretical and experimental research. In the theoretical field, simulations and calculations are performed; also information about the different aspects of indoor environment (acoustics, lighting, ventilation) is gathered independently. Despite having started with an integrative approach, this integration is difficult detecting lack available tools. In the experimental field, a methodology for evaluating energy efficiency and indoor environment quality is developed, to be implemented in innovative elements which are difficult to evaluate using a theoretical methodology This evaluation is an experimental comparative analysis between an innovative element and a standard element. To carry out this analysis, two equal spaces, called experimental cells, have been designed. These cells have been monitored, obtaining consumption, temperature, luminance and relative humidity data. Measurement has been performed during nine months and results have been analyzed and compared, obtaining results of actual system behavior. To advance this optimization, windows have been studied from the point of view of energy performance and performance in relation to user comfort and health: thermal comfort, acoustic comfort, lighting comfort and air quality; proposing the development of a methodology for an integrated analysis including energy efficiency and indoor environment quality. After theoretical and experimental analysis and as a result of the need to integrate existing knowledge, a comprehensive evaluation procedure for windows is proposed. This evaluation procedure is developed according to the UNE 171330 "Indoor Environmental Quality", also incorporating energy efficiency and cost as factors to evaluate. From the first part of the research process, outstanding parameters are chosen and reference values of these parameters are set. Finally, based on the parameters obtained, an indicator is proposed as windows product indicator. The indicator integrates all factors analyzed and is developed according to ISO 21929-1:2011"Sustainability in building construction. Sustainability indicators. Part 1: Framework for the development of indicators and a core set of indicators for buildings".

Domestic hot water consumption vs. solar thermal energy storage: the optimum size of the storage tank

Many efforts have been made in order to adequate the production of a solar thermal collector field to the consumption of domestic hot water of the inhabitants of a building. In that sense, much has been achieved in different domains: research agencies, government policies and manufacturers. However, most of the design rules of the solar plants are based on steady state models, whereas solar irradiance, consumption and thermal accumulation are inherently transient processes. As a result of this lack of physical accuracy, thermal storage tanks are sometimes left to be as large as the designer decides without any aforementioned precise recommendation. This can be a problem if solar thermal systems are meant to be implemented in nowadays buildings, where there is a shortage of space. In addition to that, an excessive storage volume could not result more efficient in many residential applications, but costly, extreme in space consumption and in some cases too heavy. A proprietary transient simulation program has been developed and validated with a detailed measurement campaign in an experimental facility. In situ environmental data have been obtained through a whole year of operation. They have been gathered at intervals of 10 min for a solar plant of 50 m2 with a storage tank of 3 m3, including the equipment for domestic hot water production of a typical apartment building. This program has been used to obtain the design and dimensioning criteria of DHW solar plants under daily transient conditions throughout a year and more specifically the size of the storage tank for a multi storey apartment building. Comparison of the simulation results with the current Spanish regulation applicable, ���C��digo T��cnico de la Edificaci��n��� (CTE 2006), offers fruitful details and establishes solar facilities dimensioning criteria.

Thermal response model of free-running buildings = Model toplotnega odziva netermostatiranih stabv

Reducing energy consumption and eliminating wastage are among the main goals of the European Union (EU) [2]. In order to satisfy all challenges arising from the Kyoto protocol, improving energy efficiency is a very important factor to take into account. There is significant potential for reducing consumption with cost-effective measures. Some studies show that 40% of our energy is consumed in buildings, and the EU has introduced legislation that aims to ensure that less energy is consumed in this way in the future.

Improvement of the Dynamic Performance of a Multiphase Current Controlled Buck Converter using an Auxiliary Synchronous Buck Converter as an Additional Energy Path

This work is related to the output impedance improvement of a Multiphase Buck converter with Peak Current Mode Control (PCMC) by means of introducing an additional power path that virtually increases the output capacitance during transients. Various solutions that can be employed to improve the dynamic behavior of the converter system exist, but nearly all solutions are developed for a Single Phase Buck converter with Voltage Mode Control (VMC), while in the VRM applications, due to the high currents, the system is usually implemented as a Multiphase Buck Converter with Current Mode Control. The additional energy path, as presented here, is introduced with the Output Impedance Correction Circuit (OICC) based on the Controlled Current Source (CCS). The OICC is used to inject or extract a current n-1 times larger than the output capacitor current, thus virtually increasing n times the value of the output capacitance during the transients. Furthermore, this work extends the OICC concept to a Multiphase Buck Converter system while comparing proposed solution with the system that has n times bigger output capacitor. In addition, the OICC is implemented as a Synchronous Buck Converter with PCMC, thus reducing its influence on the system efficiency.

Construction cost and energy consumption resulting from energy retrofitting in an apartment building in Madrid (Spain).

This theoretical study analyzes the relation between the measures necessesary for the energy retrofitting of a residential building constructed in Madrid, their cost and the improvement of the energy rating of the dwellings. The aim of this work is to establish an evaluation methodology that allows developers and architects to obtain conclusions and orientates therm in the decisioin-making process. It will allow finding the most suitable cost-effective solutions in each case. This paper describes the methodology and the findings obtained. Energy retrofitting and the improvement of the energy behaviour of the building depend on the selection of the retrofitting solutions and also on the investment. In this case study to achieve the best energy rates it is necessary to improve the thermal performance of the envelope as well as the energy systems. Energy retrofitting means an increase in property value but it can't only be considered in economic terms. It is necessary to take into account unquantifiable aspects as increased comfort, improved sound insulation, livability, health, or the elimination of energy poverty situations.