Dissertations / Theses on the topic 'Building envelope'

Due to the significant impact of the building sector on greenhouse gas emissions, newer and stricter regulations aimed at reducing total energy use in buildings have appeared in the last few years. In the European context, all the new constructions will thus soon be asked to be nearly Zero Energy Buildings (nZEB). In order to reach this target, new concepts and technologies capable of further improving buildings’ energy efficiency need to be developed. A very promising strategy to overcome current technologylimitations is represented by revisiting the conventional approach that considers the building as a staticobject and moves towards the vision where the building is a responsive and dynamic system. The main feature of this concept is the possibility of continuously changingthe interaction between the building elementsand the outdoor/indoor environment in order to reduce the energy demands and enhance the exploitation of “environmental” and low-exergy energies. In this framework, the building skin isprobably that element of the construction which shows the largest potential, especially if its properties can be continuously tuned so that the best response to different dynamic indoor and outdoor boundary conditions can be achieved. Although it is not possible to state that the dynamic building envelope alone could represent the only solution to achieving the nZEB target, great expectations are placed on advanced integrated façade systems. The aim of this research is therefore to evaluate to what extent dynamic and active building skins can reduce operational energy demand in buildings. In order to find an answer to such a wide (and general) question, the research activity is organized using a multi-level structure. Each segment of the investigation is thus dedicated to assessing the impact of such a vision on different scales: from a whole building skin approach (concept level) to an intermediate scale (system level) and further down to a very detailed and specific class of components (material-technology level). In the concept level, an ideal dynamic building skin is assumed and modelled. The performance of such a theoretical configuration is then numerically assessed and compared with that of a more conventional reference envelope solution. In the system level, an integrated multifunctional façade module, characterized by a high degree of adaptability and responsiveness, is presented, and its energy and thermo-physical behaviour evaluated by means of an experimental analysis. Finally, in the material-technology level, the implication of glazing systems integrating phase change materials on the energy performance and on thermal comfort are evaluated by means of experimental, numerical and laboratory analyses. The findings demonstrate that improvements in energy efficiency and comfort performance can be achieved when dynamic concepts, systems and technologies are applied. In every level, the dynamic component often provides a very good performance and, when compared to a conventional solution, advantages are shown.However, it is important that dynamic components are coherently employed in the framework of an integrated building design vision and properly managed. Further, the simple adoption of such systems without a global approach and optimal control strategies is often not enough to reach a significant improvement in energy efficiency and IEQ. The results also show that, sometimes, the advantages achieved by the investigated configurations may be lower than expected, though an optimization of their performance is probably still possible. Limitations in the analyses and possible solutions for future development of the research activity are also discussed, pointing out that, if from the one hand, considerable efforts are still needed in research and development before a completely adaptable building skin can be effectively employed on a large scale, on the other hand the large potentials that this vision has are worthy of further investigation.

In recent years, the excessive emission of greenhouse gas CO2, it causing globalwarming, already poses a serious threat to human survival. The problem catches theattention all over the world, and promoting the development of building energyefficiency. In order to the sustainable development of human beings, in 1992 theUnited Nations framework convention on climate change (UFCCC) organizationpublished the Kyoto protocol. In the Kyoto protocol, the European countriescommitted that during 2008 and 2012 they would reduce the amount of greenhouseemissions to 8% compare to 1990.[2] Building envelope technologies can helphouseholder reduce the energy consumption use in the building. Building envelopetechnologies used in the project Brogåden – Alingsås which save the energyconsumption from 204 kWh/ m2a to 95 kWh/ m2a in Sweden. While the cost just838SEK/m² or 8% of the total building costs. In China the envelope technologies usedin the project student apartment in Shandong building university save the energyconsumption about 72% compare with the old student apartments.

This is a study about how to improve the building envelope from a group of housing belonging to The Million Programme, a housing programme implanted in the Sweden around 70’s. Massive buildings made of concrete, which were constructed really fast because of the pressing time Schedule and were not developed as they should. This renovation study is explained with examples and drawings and it basically shows how to add thermal insulation on the most conflictive points of the building envelope. It is done in order to improve climatic conditions inside housing, trying to make thermal bridges disappear and reducing energy loss.

The energy demand in the oil- dependent Gulf countries in general and in Saudi Arabia in particular has been increasing sharply in the last decades as a result of the diversification plans. Tall building construction, associated with many environmental and ecological challenges, played an essential role in these plans, as a mean to attract new economies based on global placemaking and international tourism. The significant use of air conditioning to cool indoor spaces, particularly in residential buildings, accounts for more than half of all energy consumption in the country, and despite governmental efforts, the scattered conservation efforts have been largely ineffective due to factors such as lack of awareness and information, in addition to the limitation of the local energy efficiency building regulations. This research aimed to find and prioritise building envelope design solutions that can reduce high energy consumption and cooling loads while maintaining indoor environment for residential tall buildings in Saudi Arabia. In order to achieve that, a hypothesis of integrating the thermal properties and design parameters of the building envelope as a design strategy for tall buildings envelope were proposed, and to test it, a mixed method approach was followed including literature review, data collection, dynamic building simulations and parametric analysis. The main findings emphasised how combining both the thermal properties and design parameters of the building envelope can be an effective way to achieve energy efficiency in residential tall buildings in the hot climate of Jeddah. Especially in relation to solar heat gains, the highest contributor to cooling loads in this building type. The findings highlighted that while the thermal properties of the wall type can reduce up to 10% of the cooling loads, applying external shading devices can achieve a reduction of up to 30% in solar gains. Moreover, effective consideration of building orientation can significantly reduce cooling loads by 25% and solar gains by 60% for the perimeter zones. Based on this, a set of guidelines that incorporate a comparative tool were introduced to help designers to determine the thermal performance and energy use of a typical residential tall building in the early stages of the building’s design. Which also aim to enhance the effectiveness of the local building codes and energy efficiency regulations in relation to this building type.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 126-127).
This thesis investigates the use of a building envelope membrane as fabric-like formwork for exterior cladding systems in buildings. The exterior wall system (i.e., fagade) has evolved to meet the demands of the built environment including protecting occupants and interior space from the environment and, at times, create the building form and provide support for the roofs, floors and ceilings. To accommodate the demanding needs of the industry, integrated exterior wall systems have emerged. This type of panel uses traditional building materials in innovative applications. However, existing products continue to encounter some similar issues associated with traditional building methods. This research aims to propose a concept for an integrated exterior wall system that uses traditional building material in a unique application. Overall, the system will function as the building envelope as well as a load transferring mechanism. The main objective is to study the feasibility and limitations of the design through two experiments. The first experiment assesses the effect of a flexible formwork on the 28-day compressive strength of concrete formed with an array of different types of membranes. The second experiment determines the possibility of implementing an air/water barrier in a physical form-finding application. The desired outcome of the work is to evaluate the practicality of the proposed design and further understand the implications and limitations associated with the system. As a result of the experiments, the application of air/water barriers as tension-like fabrics was found to be applicable. In addition, it was concluded that permeable membrane formwork has a greater impact on the surface properties than the bulk concrete; however, overall the permeable membrane formwork produced a higher strength concrete.
by Chelsea Lynn Sprague.
M. Eng.

A notion exists that the operational savings stemming from Deep Energy Retrofits are not sufficient to justify its capital outlay. This notion has focused property developers' attention on the construction of new green buildings, rather than optimizing existing building stock. Producing new buildings, while many existing properties are utilized on a sub-optimal level, with low rental income and high vacancies is not only resource inefficient, but also contributes to a much greater carbon footprint. The aim of this research is to establish whether retrofitting is a viable means of optimizing energy consumption in buildings based on investment return. The literature reveals that the façade is the most significant variable in energy optimisation in buildings and concluded that over-cladding strategies are generally the most efficient means to reduce heat transfer and control lighting levels. The research have been conducted by means of a two tiered methodology involving a case study approach, along with an experimental design, which was conducted through a simulation. A hypothetical building, representative of Cape Town's building stock was modeled and a number of façade over-clad strategies simulated to derive the most optimal solution. The simulation is conducted in DOE Energy Plus and COMFEN GUI. Capital cost data was collected and compared to energy cost savings in order to determine payback values. It was found that over-clad strategies may be economically feasible, which delivered payback periods of between 5 and 19 years, depending on the strategy. A partial retrofit, involving only the East and West facades was found to be the most feasible from an investment point of view, where woven mesh screens delivered the best results.

Because of the harsh climate of Saudi Arabia, residential buildings on average, consume more than half of the total consumed energy. A substantial share of energy goes to the air-conditioning of buildings. Cooling buildings during summer is a major environmental problem in many Middle Eastern countries, especially since the electricity is highly dependent on fossil fuels. The aim of this study is to obtain a clearer picture of how various measures on the building envelope affects the buildings energy consumption, which can be used as a tool to save energy for buildings in the Middle East. In this study, different energy efficiency measures are evaluated using energy simulations in IDA ICE 4.7 to investigate how much energy can be saved by modifying the building envelope. A two-storey residential building with 247 m2 floor area is used for the simulations. The measures considered are; modifications of the external walls, modification of the roof, window type, window area/distribution, modification of the foundation, shading, exterior surface colour, infiltration rate and thermal bridges. All measures are compared against a base case where the building envelope is set to resemble a typical Saudi Arabian residential. First, all measures are investigated one by one. Thereafter, combinations of the measures are investigated, based on the results from single measure simulations. All simulations are carried out for two cities in Saudi Arabia, both with arid desert climate. Riyadh (midlands) with moderately cold winters and Jeddah (west coast) with mild winter. The results from simulations of single measures show the highest energy savings when changing the window type from single clear glass to double glass with reflective surface saving 27 % energy (heating & cooling) in Riyadh and 21 % in Jeddah. Adding insulation to an uninsulated roof saved up to 23 % and 21 % energy for Riyadh respectively Jeddah. Improvements of the thermal resistance of the exterior walls show 21 % energy savings in Riyadh and only 11 % in Jeddah. Lowering the window to wall ratio from 28 % to 10 % and changing the window distribution results in 19 % (Riyadh) and 17 % (Jeddah) energy savings. Adding fixed shades saves up to 8 % (Riyadh) and 13 % energy (Jeddah) when dimensioned for the peak cooling load. Using bright/reflective surface colour on the roof saves up to 9% (Riyadh) and 17 % (Jeddah) when the roof is uninsulated. For the exterior walls, bright/reflective surface saves up to 5 % (Riyadh) and 10 % (Jeddah) when the walls are uninsulated. The other single measures investigated show less than 7 % energy savings. The results for combined measures show the highest energy savings for two combined measures when improving the thermal resistance of the exterior walls and changing window area/distribution saving up to 52 % (Riyadh) and 39 % (Jeddah). When performing three measures the addition of improved thermal resistance and reflectance of the windows resulted in the highest energy savings, saving up to 62 % (Riyadh) and 48 % (Jeddah). When adding a fourth measure, improving the thermal resistance of the slab shows the highest energy savings, 71 % (Riyadh) and 54 % (Jeddah). Applying all measures on the building envelope results in 78 % (Riyadh) and 62 % (Jeddah) energy savings. Significant energy savings can be achieved with measures on the building envelope. Major savings can be made by adding only 50-100 mm of insulation to the exterior walls and roof. Decreased window area and improvements on the thermal resistance and reflectance on the windows result in significant energy savings. Energy savings achieved with shadings and reflective surface colours decrease significantly when the thermal resistance of the roof and external walls are improved. All measures concerning thermal resistance have a higher impact in Riyadh than in Jeddah due to that a large part of the total heating and cooling is air handling unit (AHU) cooling in Jeddah. AHU cooling is not affected significantly by measures on the building envelope. To optimise energy savings, measures on the building envelope should be considered in combination with measures concerning the AHU.
På grund av det hårda klimatet i Saudiarabien, konsumerar bostadshus mer än hälften av den totala energi som förbrukas. En stor del av den förbrukade energin går till luftkonditionering. Kylningen av byggnader är ett stort miljöproblem i många länder i Mellanöstern, särskilt eftersom elektriciteten till stor del är helt beroende av förbränning av fossila bränslen. Syftet med denna studie är att få en tydligare bild av hur olika åtgärder på klimatskalet påverkar byggnaders energiförbrukning. Tanken är att resultaten ska kunna användas som ett hjälpmedel vid design av mer energieffektiva byggnader i Mellanöstern. I denna studie är olika energieffektivitetsåtgärder utvärderade med hjälp av energisimuleringar i IDA ICE 4.7 för att undersöka hur mycket energi som kan sparas genom att modifiera klimatskalet. Ett bostadshus med 247 m2 golvyta i två våningar används för simuleringarna. De åtgärder som övervägs är; modifieringar av ytterväggar, modifiering av tak, fönstertyp, fönster area/ distribution, modifiering av fundamentet, skuggning, ytskikt, infiltration och köldbryggor. Alla åtgärder jämförs mot ett Base Case där klimatskalet är inställt för att likna en typisk bostad i Saudiarabiens. Först undersöks alla åtgärder en åt gången. Därefter undersöks kombinationer av de studerade åtgärderna, baserat på resultat från simuleringar av enskilda åtgärder. Alla simuleringar utförs för två städer i Saudiarabien, både med torrt ökenklimat. Riyadh (inlandet) med måttligt kalla vintrar och Jeddah (västkusten) med mild vinter. Resultatet från simuleringar av enskilda åtgärder visar högst energibesparing när fönstertypen byts ut från enkelt klarglas till dubbelt reflekterande glas. Med byte av fönstertyp sparas upp till 27 % energi (uppvärmning och kylning) i Riyadh och 21 % i Jeddah. Att isolera taket sparar upp till 23 % och 21 % för Riyadh respektive Jeddah. Förbättrat värmemotstånd i ytterväggarna resulterar i upp till 21 % energibesparing i Riyadh och endast 11 % i Jeddah. Minskning av fönsterarean från 28 % av väggytan till 10 % och omplacering av fönsterna ger19 % (Riyadh) och 17 % (Jeddah) energibesparingar. Solavskärmning med hjälp av fasta skärmtak och fenor sparar 8 % (Riyadh) och 13 % energi (Jeddah) när de är dimensionerad för maximalt kylbehovet. Använda ljus/reflekterande yta på taket sparar upp till 9 % (Riyadh) och 17 % (Jeddah) när taket är oisolerad. För ytterväggar, sparar ljust/reflekterande ytskikt upp till 5 % (Riyadh) och 10 % (Jeddah) när väggarna är oisolerad. De övriga enskilda åtgärderna som undersökts visar mindre än 7 % energibesparing. Resultaten för kombinerade åtgärder visar högst energibesparingar för två kombinerade åtgärder när ytterväggens värmemotstånd förbättras tillsammans med mindre fönsterarea och ändrad fönsterplacering. De två åtgärderna sparar upp till 52 % energi i Riyadh och 39 % i Jeddah. När tre åtgärder utförs, fås den högsta energibesparingen med de två åtgärderna ovan med tillägg av förbättrade fönster med lägre u-värde och högre reflektants. Tillsammans resulterar de tre åtgärderna i en energibesparing upp till 62 % för Riyadh och 48 % för Jeddah. När man lägger till en fjärde åtgärd, fås den högsta besparingen med tillägg av förbättrat u-värde på grunden till de tre tidigare åtgärderna. De fyra åtgärderna sparar upp till 71 % energi i Riyadh och 54 % i Jeddah. Tillämpning av alla åtgärder på klimatskalet resulterar i 78 % (Riyadh) och 62 % (Jeddah) energibesparing. Betydlig reducering av energianvändningen kan uppnås med åtgärder på byggnadens klimatskal. Stora besparingar fås med endast 50 – 100 mm isolering i ytterväggar och tak. Att minska fönsterarean och förbättra fönsternas u-värde och reflektivitet bidrar till stora energibesparingar.  Besparingarna som fås vid solavskärmning och reflektiva ytor på tak och väggar minskar signifikant när taket och ytterväggarna isoleras. Alla åtgärder som förbättrar u-värdet på klimatskalet har en större inverkan i Riyadh än i Jeddah på grund av att en större andel av total uppvärmning och kylning upptas av kylning av inkommande luft i ventilationen. Energin som behövs för att kyla inkommande luft påverkas inte nämnvärt av åtgärderna på klimatskalet. För att optimera energibesparingarna ytterligare, bör åtgärder på klimatskalets övervägas tillsammans med energieffektivitetsåtgärder av ventilationen.

Buildings are considered to be one of the primary contributors to the socioeconomic development of a country. However, they use a large portion of energy and available natural resources. With the industrialization leading to an increase in urban population, the number of urban buildings which has major effects on energy consumption, has significantly increased. Even with the implementation of energy efficient policies, energy consumption in buildings has regularly grown over the last decades affecting the building's operating cost. For this reason, the construction industry seeks to create a model of sustainable development in buildings which has low environmental impact and high economic and social gains. Currently, most of the world population is gathered in buildings mainly placed in urban areas. Unfortunately, a big part of these buildings are badly constructed without or with unsuitable insulation on the building envelope, and without any heating system. After some decades in use, these buildings suffer from an unacceptable interior living environment due to the unappropriated building envelope solution. This practice causes energy losses through the façades and roofs while producing low interior comfort inside the building, as well as health problems to the occupants. Therefore, nowadays the building industry is concerned with designing new construction solutions with novel components and geometries which are able to face the current energy inefficiency in buildings. The TCP is a novel energy efficient building envelope construction solution which is capable of channeling the sunlight through the opaque part of the walls. Its versatility is based on its capacity for concentrating and scattering daylight into the building's interior while achieving energy savings, i.e. reducing dependence on artificial lighting and also improving the occupant's interior comfort. The complexity of this novel construction solution comes from the physical behavior and geometry of its components, i.e. the Compound Parabolic Concentrator (CPC) and the Optical Fiber (OF). Currently, there is no software in the market that can simulate the daylight transmission of the CPCs and the OFs. In addition, there are no daylight metrics able to properly assess the daylight performance of the TCP. In this sense, this research considered this TCP innovative to give answers to the aforementioned problems. In fact, the building case study shows how is possible to energy retrofit existing façades and roofs while improving the interior living environment and also reducing the energy consumption of the heating and/or cooling systems. This confirm the need to urge the construction industry to design and develop novel energy efficient construction solutions, e.g. Translucent Concrete Panel (TCP). The TCP has the capability of daylight permeability in an anidolic way through the opaque parts of the exterior façades and roofs. Due to the nature of traditional building materials blocking the passage of natural light, there is a constant requirement of artificial lighting into the building, even during daytime. On the other side, some of the most commonly used daylight metrics are not precise enough in order to assess the daylight performance of the prototype. For this reason, the research has designed new daylight tests adapted to the TCP daylight features in order to evaluate its daylight performance. In fact, this is the first required step for future research lines that will be based on computer simulations that to rapidly assess influential parameters of the novel building envelope in several building sub-systems and systems.
Els edificis estan considerats els primers contribuïdors del desenvolupament socioeconòmic d’un país. No obstant, utilitzen una gran quantitat d’energia i recursos naturals disponibles. Amb la industrialització, que va donar lloc a un increment de la població urbana, aquest resulta un factor que ha fet augmentar el nombre d’edificis urbans i ha creat un major efecte en el consum energètic. Tot i la implementació de polítiques d’eficiència energètica, el consum energètic ha augmentat durant les ultimes dècades afectant a la despesa operacional de l’edifici. Per aquesta raó, la indústria de la construcció cerca crear models de desenvolupament sostenible en edificis i que tinguin un baix impacte mediambiental i un alt impacte econòmic i guanys socials. Això requereix l’adopció d’un sistema integrat que cobreixi un nombre de característiques tals com reducció energètica, millora de l’ús de materials, la qual cosa inclou l’aigua, reutilització i reciclatge de materials, i emissions de control. Més que mai, a dia d’avui hi ha una creixent preocupació per l’esgotament dels recursos naturals. Per tant, desenvolupament i implementació de noves tecnologies d’energia renovable s’han tornat importants i necessàries per la societat. Des de que la terra rep constantment radiació solar, la qual resulta una font d’energia gratuïta neta i abundant, la utilització de la energia solar en edificis esta agafant força. A dia d’avui, amb les noves tecnologies, la llum solar pot ser emprada per una varietat d’usos, tals com generadora d’electricitat, llum interior natural, escalfadora d’aigua, entre altres. Actualment els nous edificis acostumen a integrar sistemes solars dintre de la part exterior de la envolvent, els quals poden col·lectar grans quantitat d’energia solar. A més a més, els humans hem evolucionat sota la influència de la llum del sol i el cicle llum-foscor mitjançant el desenvolupament d’una varietat d’avantatges psicològics, la qual cosa afecta al caràcter i salut de la gent, així com menor absència del lloc de treball i més alta productivitat. Després de la introducció de la llum elèctrica, la gent va començar a passar més temps dins de l’interior dels edificis. Conseqüentment, el confort tèrmic es va tornar un factor significatiu pels humans amb vistes a desenvolupar una activitat dintre de l’edifici. Així que, una millora en la eficiència energètica dels edificis contribueix al confort interior i la salut dels ocupants. Per aquest motiu, façanes i cobertes multifuncionals estan darrerament guanyant l’atenció del mercat de la construcció a causa de la seva versatilitat en l’estalvi d’energia i la millora en el confort interior de l’edifici. La present recerca pretén cobrir les qüestions comentades amb anterioritat referents a la millora de l’eficiència energètica dels edificis i obtenir, d’aquesta manera, una reducció en consum energètic amb tecnologies innovadores que utilitzen fonts d’energia solar per crear un ambient interior confortable. Per aquest objectiu, la present Tesis s’ha dividit en dos línies de treball. La primera línia de recerca descriu i il·lustra els problemes constructius més habituals durant el cicle de vida de les façanes i cobertes dels edificis construïts amb una solució constructiva de baix rendiment energètic. Per tant, s’ha estudiat un cas real on s’ha rehabilitat energèticament la envolvent exterior d’un edifici plurifamiliar d’habitatge social. Aquesta feina te la intenció entendre la complexitat i els requeriments de la envolvent exterior de l’edifici en termes d’eficiència energètica, juntament amb el confort interior dels ocupants. A través del cas real estudiat, s’ha observat millores significatives en l’estalvi energètic després de la rehabilitació energètica de les façanes i cobertes que dóna lloc a un augment del confort tèrmic interior. El resultat demostra la necessitat que hi ha d’empènyer a la indústria de la construcció de dissenyar i desenvolupar noves envolvents exteriors energèticament eficients tant per noves construccions com per edificis rehabilitats. Una de les solucions novells és el cas del Panell de Formigó Translúcid (Translucent Concrete Panel – TCP). El TCP presenta una nova alternativa passiva el qual redueix el consum energètic tot optimitzant l’entrada de llum solar natural a dintre de l’edifici a través de la tradicional part opaca de les parets exterior de façana i coberta. Això permet la permeabilitat de la llum natural a través de les parets tot millorant el confort tèrmic i lumínic interior. Basada en els resultats obtinguts en la primera línia de recerca, la segona línia només estudia i analitza el comportament de la llum del TCP. Durant les darreres dècades, ciència i indústria han creat diferents sistemes lumínics actius i passius els quals intenten proveir solucions per reduir i alleugerir la ineficiència energètica dels edificis. El TCP es veu com una nova tecnologia constructiva, energèticament eficient, dissenyada per envolvents exteriors, i que té la propietat de resoldre la càrrega energètica de la part opaca de les parets i permetre l’entrada de llum natural. No obstant això, actualment el comportament de la llum dels TCPs no es pot simular per ordinador degut a que no hi ha cap software en el mercat que pugui simular i analitzar les propietats de transmissió de llum dels dos components principals del TCP i que són: Concentrador Solar (Compound Parabolic Concentrator – CPC) i la Fibra Òptica (Optical Fiber – OF). Per tant, nous estudis experimentals han hagut de ser dissenyats amb procediments teòrics. Els tests van tenir lloc a l’exterior sota condicions reals de cel i d’aquesta manera en un futur poder crear i validar programes els quals permetran una fàcil adopció del TCP per part de la indústria. No obstant això, tots els tests van ser dividits en dos categories. El primer buscava demostrar i confirmar que el TCP, amb un disseny apropiat dels seus components i orientació, pot distribuir la llum natural dintre del edifici durant les hores solars. Diferents panells de TCP amb diferents diàmetres i rati de les OF, van ser assajats a l’exterior junt amb panells amb CPCs de diferents geometries. Com els primers resultats van ser òptims, això va ajudar poder moure la recerca a un segon nivell el qual estava principalment centrat en la millora de la quantitat de llum solar capturada amb els CPCs i la quantitat de llum distribuïda amb les OFs dintre de l’edifici. Amb aquest objectiu, la present recerca va proposar modificar els extrems de les OFs amb diferent geometries, i així analitzar-les independentment i alinear-les amb CPCs de diferent geometries. Aquest ha sigut un punt important per l’estudi, degut a que els extrems modificats de la OF són capaços de millorar l’entrada de llum natural a l’interior de l’edifici Per una altra banda, hi ha un gran nombre de diferents sistemes mètrics utilitzats per professionals per avaluar les propietats de la llum dintre d’un espai. Per aquest motiu, tots els tests van ser dissenyat seguint els objectius de la recerca. No obstant això, la present Tesis va decidir dissenyar i construir un Petit Portable Banc de Proves (Small Portable Test Bed – SPTB) per ser utilitzat a l’exterior i el qual té un sistema integrat de control de sensors sense cables i que activament respon als canvis exteriors climàtics durant els tests. El SPTB es una mena de cub el qual vol simular la envolvent exterior de l’edifici amb quatre façanes i coberta. Aquest disseny específic pot permetre analitzar a la vegada les façanes sota les quatre orientacions, juntament amb la coberta. Així que el SPTB va ser concebut com una eina per fer assajos sota condicions reals exteriors. A més a més, gràcies a la versatilitat de la seva estructura, les dimensions del SPTB poden ser canviades en cas necessari. Per la present recerca, el primer objectiu d’aquest banc de proves portable era fer una avaluació justa del comportament de la llum del TCP basat en tests de llum dinàmics. I en segon lloc, el SPTB buscava desenvolupar una eina física per ser utilitzada més enllà de les necessitats de la present recerca, així com en altres projectes i assajos. Pel novell TCP cas d’estudi, el SPTB va ser ubicat a l’exterior i una varietat de petites mostres a escala real de TCPs van ser assajades per analitzar el comportament de la llum sota condicions de cel reals, així com una recopilació de dades les quals eren enviades wireless i emmagatzemades a una base de dades centrals ubicada a internet. Els resultats finals obtinguts en la present Tesis confirmen que utilitzant la tecnologia comentada en aquesta recerca, es demostra que les mesures preses en eficiència energètica, pot millorar el confort interior i la salut dels ocupants. Aquest és el cas de la rehabilitació energètica de la façana utilitzada com a cas d’estudi tot obtenint aproximadament un 12% d’estalvi energètic. Per un altre costat, el TCP equipat amb CPCs, es capaç de dispersar (directa i difusa) llum solar, i d’aquesta manera millorar la distribució lumínica en el interior de l’edifici. La recerca ha millorar la llum capturada i dispersada per les OFs tot modificant la geometria dels extrems de la OF. Amb l’ús del SPTB, ha sigut possible avaluar el comportament de la llum del TCP tot utilitzant sistemes mètrics lumínics dinàmics. No obstant, més recerca experimentals junt amb noves simulacions per ordinador, s’haurien de fer en un futur a fi d’obtenir resultats més concloents en termes d’estalvi energètic i confort tèrmic interior
Los edificios son considerados los primeros contribuyentes al desarrollo socioeconómico de un país. No obstante, utilizan una gran cantidad de la energía y de recursos naturales disponibles. Con la industrialización tuvo lugar un importante incremento de la población urbana y este hecho provocó un aumento del número de edificios urbanos, los cuales provocaron un mayor incremento del consumo energético. A pesar de que se han implementado políticas de eficiencia energética, el consumo energético ha seguido aumentando durante las últimas décadas y ha afectado al gasto operacional del edificio. Por este motivo, la industria de la construcción busca crear modelos de desarrollo sostenible en edificios que tengan un bajo impacto medioambiental, y un alto impacto económico y beneficios sociales. Esto requiere la adopción de un sistema integrado que cubra un número de características, así como reducción energética, mejora del uso de los materiales, incluyendo el agua, reutilización y reciclaje de materiales, y emisiones de control. Más que nunca, a día de hoy, hay una creciente preocupación por el agotamiento de los recursos naturales. Por tanto, desarrollo e implementación de nuevas tecnologías de energía renovable resultan tan importantes y necesarias para la sociedad. Desde que la tierra recibe constantemente radiación solar, la cual es una fuente de energía gratuita, limpia y abundante, el uso de la energía solar en edificios está ganando fuerza. A día de hoy, con las nuevas tecnologías, la luz solar puede ser empleada para una amplia variedad de usos, así como generadora de electricidad, luz interior natural, calentadora de agua, entre otras utilidades. Actualmente, los nuevos edificios acostumbran a integrar sistemas solares dentro de la parte exterior de la envolvente del edificio, los cuales pueden captar gran cantidad de energía solar. Además, los humanos hemos evolucionado bajo la influencia de la luz solar y el ciclo luz-oscuridad. Este hecho ha permitido el desarrollo de una variedad de ventajas psicológicas que afectan al carácter y a la salud de las personas, así como a una menor ausencia del lugar de trabajo y una alta productividad. Tras la aparición de la luz eléctrica, la gente comenzó a pasar más tiempo dentro de los edificios. Consecuentemente, el confort térmico resultó un factor significativo para los humanos en vistas a poder desarrollar una actividad dentro del edificio. Así pues, vemos que una mejora en la eficiencia energética de los edificios contribuye al confort interior y a la salud de los ocupantes. Por este motivo, últimamente, fachadas y cubiertas multifuncionales están ganando la atención del mercado de la construcción debido a su versatilidad en el ahorro de energía y en la mejora del confort interior del edificio. La presente investigación cubre las cuestiones comentadas con anterioridad referentes a la mejora de la eficiencia energética de los edificios, y así obtener una reducción en el consumo energético mediante tecnologías innovadoras que utilizan fuentes de energía solar para crear un ambiente interior confortable. Por este motivo, la presente Tesis está dividida en dos líneas de trabajo. La primera línea de investigación describe e ilustra los problemas constructivos más habituales durante el ciclo de vida de las fachadas y cubiertas de los edificios construidos con una solución constructiva de bajo rendimiento energético. De tal manera, se ha estudiado un caso real en donde se ha rehabilitado energéticamente la envolvente exterior de un edificio plurifamiliar de vivienda social. Este trabajo tiene la intención de ser utilizado como una herramienta para entender la complejidad y los requisitos de la envolvente exterior del edificio en temas de eficiencia energética, junto al confort interior de los ocupantes. A través del caso real estudiado, se han observado mejoras significativas en el ahorro energético después de la rehabilitación energética de las fachadas y cubierta, dando lugar a un aumento del confort térmico interior. El resultado demuestra la necesidad de incitar a la industria de la construcción para que sea capaz de diseñar y desarrollar nuevas envolventes exteriores energéticamente eficientes, tanto en el caso de nuevas construcciones como en el de edificios rehabilitados. Una de las soluciones noveles es el caso del Panel de Hormigón Translucido (Translucent Concrete Panel – TCP). El TCP presenta una nueva alternativa pasiva capaz de reducir el consumo energético del edificio, con la optimización de la entrada de luz solar natural dentro del mismo, a través de la tradicional parte opaca de las paredes exteriores de fachada y cubierta, permitiendo así la permeabilidad de la luz solar a través de las paredes y mejorando el confort térmico y lumínico interior. Basada en los resultados obtenidos en la primera línea de investigación, la segunda línea solamente estudia y analiza el comportamiento de la luz del TCP. Durante las últimas décadas, ciencia e industria han creado diferentes sistemas lumínicos activos y pasivos los cuales intentan proveer soluciones para reducir y aligerar la ineficiencia energética de los edificios. El TCP está considerado como una nueva tecnología constructiva energéticamente eficiente diseñada para envolventes exteriores, y que tiene la propiedad de resolver la carga energética de la parte opaca de las paredes permitiendo así la entrada de luz natural. No obstante, actualmente el comportamiento de la luz de los TCPs no se puede simular por ordenador debido a que no hay ningún software en el mercado que pueda simular y analizar las propiedades de transmisión de luz de los dos componentes principales del TCP que son Concentrador Solar (Compound Parabolic Concentrator – CPC) y la Fibra Óptica (Optical Fiber – OF). Por tanto, los nuevos estudios experimentales han tenido que ser diseñados siguiendo procedimientos teóricos. Los test tuvieron lugar en el exterior bajo condiciones reales de cielo y de esta manera en un futuro poder crear y validar programas los cuales permiten una fácil adopción del TCP por parte de la industria. No obstante, todos los test se dividieron en dos categorías. El primero buscaba demostrar y confirmar que el TCP, con un diseño apropiado de sus componentes y orientación, puede distribuir la luz natural dentro del edificio durante las horas solares. Diferentes paneles de TCP, con diferentes diámetros y ratios de OFs, fueron ensayados en el exterior junto con paneles con CPCs de diferentes geometrías. Dado que los primeros resultados fueron óptimos, se pudo dirigir la investigación a un segundo nivel, principalmente centrado en la mejora de la cantidad de luz solar capturada con los CPCs y la cantidad de luz distribuida con las OFs dentro del edificio. Con este objetivo, la presente investigación propuso modificar geométricamente los extremos de las OFs con diferentes geometrías, y así analizarlas independientemente y alinearlas con CPCs de diferentes geometrías. Este ha sido un punto importante del estudio, debido a que los extremos modificados de las OFs son capaces de mejorar la entrada de luz natural en el interior del edificio. Por otro lado, existe una gran diferencia entre los diferentes sistemas métricos utilizados por los profesionales para evaluar las propiedades de la luz dentro de un espacio. Por este motivo, todos los ensayos fueron diseñados siguiendo los objetivos de la investigación. No obstante, la presente Tesis decidió diseñar y construir un Pequeño Portable Banco de Pruebas (Small Portable Test Bed – SPTB) para ser utilizado en el exterior, el cual tiene un sistema integrado de control de sensores sin cables y que activamente responden a los cambios exteriores climáticos durante los ensayos. El SPTB es una especie de cubo que pretende simular la envolvente exterior del edificio con cuatro fachadas y cubierta. Este diseño específico permite analizar a la vez las fachadas bajo las cuatro orientaciones junto con la cubierta. De hecho, el SPTB fue concebido como una herramienta versátil para realizar ensayos bajo condiciones reales exteriores. Además, gracias a la versatilidad de su estructura, las dimensiones del SPTB pueden ser cambiadas en caso necesario. Para la presente investigación, el primer objetivo de este banco de pruebas era realizar una evaluación justa del comportamiento de la luz del TCP basado en ensayos de luz dinámicos. Y en segundo lugar, el SPTB buscaba desarrollar una herramienta física para ser utilizada más allá de las necesidades de la presente investigación, así como en otros proyectos y ensayos. Para el novel TCP caso de estudio, el SPTB fue ubicado en el exterior y una variedad de pequeñas muestras a escala real de TCPs fueron ensayadas para analizar el comportamiento de la luz bajo condiciones reales del cielo, así como una recopilación de datos los cuales eran enviados Wireless i guardadas a una base de datos centrales ubicado en internet. Los resultados finales obtenidos en la presente Tesis confirman que, utilizando la tecnología comentada en ésta investigación, se demuestra que las medidas tomadas en eficiencia energética pueden mejorar el confort interior y la salud de los ocupantes. Éste es el caso de la rehabilitación energética de la fachada utilizada como casa de estudio donde se obtuvo aproximadamente un 12% de ahorro energético. Por otro lado, el TCP equipado con CPCs, es capaz de dispersar (directa y difusa) luz solar, i de esta manera mejorar la distribución lumínica del interior del edificio. La investigación ha mejorado la luz capturada y dispersada por las OFs gracias a la modificación de los extremos de la OF. Con el uso del SPTB, ha sido posible evaluar el comportamiento de la luz del TCP con la utilización de sistemas métricos lumínicos dinámicos. No obstante, más investigación experimental junto con nuevas simulaciones por ordenador, se tendrían que hacer en un futuro a fin de obtener resultados más concluyentes en términos de ahorro energético y confort térmico interior

Le secteur du bâtiment représente 35% des la consommations énergétiques dans les pays membres de l’agence international de l’énergie en 2010 et 39,8% aux Etats-Unis en 2015. Plus de 50% de cette consommation a été utilisée pour la production de chaleur et de froid. Néanmoins cette consommation peut être réduite par l'amélioration la performance énergétique du bâtiment. La performance thermique de l'enveloppe du bâtiment joue un rôle primordial. Par conséquent, le diagnostic thermique de l'enveloppe du bâtiment est nécessaire pour, par exemple, la réception de nouvelles constructions, l'amélioration de la performance énergétique des anciens bâtiments, ainsi que la vente et la location des logements. Pourtant, il existe très peu de méthodes quantitatives pour la caractérisation des parois épaisses. L'objectif de cette étude est d'explorer des méthodes quantitatives innovantes de diagnostic thermique de l'enveloppe du bâtiment. Des mesures expérimentales ont été réalisées en laboratoire (à l’IFSTTAR à Nantes) et in situ (à l’IUT de Bordeaux). Différents capteurs et méthodes d'instrumentation ont été étudiés pour mesurer la densité de flux et la température de surfaces des parois, afin de procurer des recommandations pour le choix des capteurs ainsi que des protocoles de traitement de données. A partir des données mesurées (température et densité de flux des surfaces de l'enveloppe), trois approches numériques ont été proposées pour estimer des paramètres thermiques des parois multicouches épaisses : par méthode inverse, par réponse à un échelon et par réponse impulsionnelle. En outre, une méthode innovante non-destructive utilisant la rayonnement térahertz a été étudiée. Les mesures ont été effectuées au sein du laboratoire I2M. Cette méthode permet de caractériser le coefficient d'absorption des matériaux constructifs ordinaires comme isolation, plâtre, béton, bois… Elle pourrait postérieurement être combinée avec une méthode thermique pour apporter des informations complémentaires
Buildings represent a large share in terms of energy consumption, such as 35% in the member countries of IEA (2010) and 39.8% in U.S. (2015). Climate controlling (space heating and space cooling) occupies more than half of the consumption. While this consumption can be reduced by improving the building energy efficiency, in which the thermal performance of building envelope plays a critical role. Therefore, the thermal diagnosis of building envelope is of great important, for example, in the case of new building accreditation, retrofitting energy efficiency of old building and the building resale and renting. However, very few diagnostic methods exist for the characterization of thick walls. The present measurement standards that based on steady state heat transfer regime need a long time (several days). The classical transient technologies, such as flash method, are difficult to implement on the walls because of the large thickness of walls and the complex conditions in situ. This thesis aims to explore innovative methodologies for thermal quantitative diagnosis of building envelope. Two experimental cases were carried out: one is in laboratory (IFSTTAR, Nantes) and the other is in situ (IUT, Bordeaux). Different sensors and instruments were studied to measure the wall heat flux and surface temperature, and provided some guidelines for the choice of sensors and data processing protocols as well. Using these measured data, three estimation approaches were proposed to estimate the thermal parameters of the multilayer thick wall: pulse response curve method, step response curve method and inverse method, which can be applied for different diagnostic situations. In addition, an innovative NDE (non-destructive evaluation) method using terahertz (THz) radiation was also investigated. Measurements were carried out in I2M laboratory to characterize the absorption coefficient of standard building materials (insulation, plaster, concrete, wood ...). This THz method can be combined with a previous thermal method to provide some complementary information

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2010.
"June 2010."
Includes bibliographical references (p. 78-86).
This investigation proposes the use of a three-pronged approach to evaluating building envelopes for low-rise affordable housing in urban contexts: construction cost estimating, building performance modeling, and cradle to grave life cycle assessment. Two climate regions were investigated: hot-humid and hot-dry, in two large urban cities: Phoenix and Miami. The envelope systems compared were conventional for the practice area versus best practice and high r-value systems. The results demonstrate that the application of the three-pronged method yields data architects can use to improve energy performance, reduce costs and limit negative environmental impacts.
by Jason W. Tapia.
S.M.

The objective of the present thesis is to provide a methodological approach for the design of responsive building envelope components through the application of optimisation analyses. In detail, this approach was applied to opaque building envelope components with Phase Change Materials (PCMs). Since multi-objective optimisation problems generally result in a series of trade-off solutions called Pareto-front, the main focus was to investigate which values assumed by the optimisation variables led to the optimal set of solutions. In this way, the optimisation analysis was used as a tool to gain knowledge on specific problems. After an overview on PCMs and on the application of optimisation analyses to the building envelope for improving the energy efficiency of buildings, three levels of analysis were explored; material level, component level and building level. At the material level, the optimisation approach was applied to estimate the temperature-dependent specific heat curve of PCMs through best-fit of experimental data. Given the measured surface temperatures of a sample as boundary conditions and the known thermo-physical properties of the materials to a numerical model, the curve which minimised the difference between measured and simulated heat fluxes on both faces of the sample was found. At the component level, “equivalent” parameters for the dynamic thermal characterisation of opaque building envelope components with PCM were proposed. Starting from the definition of the traditional dynamic thermal properties according to ISO 13786:2007, a monthly equivalent periodic thermal transmittance and the corresponding time shift were defined by imposing steady-periodic conditions with monthly average external air temperature and solar irradiance profiles while keeping a constant air temperature on the internal side. Then, the monthly equivalent values were synthesised in a unique yearly value by means of a simple average. A parametric model was subsequently developed to describe PCM-enhanced multi-layer walls with simultaneous use of at most two PCMs, and an optimisation analysis was carried out for three locations (Palermo, Torino and Oslo) to find wall layout and PCMs' thermo-physical properties (melting temperature, melting temperature range, latent heat of fusion and thermal conductivity) which minimise yearly equivalent periodic thermal transmittance, overall PCM thickness and thickness of the wall. At the building level, the investigations focused on the application of optimisation analyses for the energy retrofit of office buildings. Three retrofit options on the opaque envelope components were considered in the aforementioned locations; intervention either on the external side of the wall, on the internal side of the wall, or on both sides of the wall. Moreover, either the same retrofit solution for all the walls or a different wall solution for each orientation were considered. In both cases, a maximum of two PCM materials could be selected by the optimisation algorithm. With regard to the objective functions, the problem was faced under two points of view. On one side, optimisations were run with three objectives to minimise the building energy need for heating, cooling and the investment cost. On the other side, the optimisations were performed with two objectives to minimise primary energy consumption and global cost. Only for the climate of Oslo, where heating is mostly electric and no cooling system was adopted, the minimisation objectives were primary energy consumption, global cost and thermal discomfort. Even though a proper optimisation of the thermo-physical properties of PCMs was found to be especially advisable when the operation of the HVAC system implies a non-trivial solution, the results of these analyses allowed to propose a few design guidelines for PCM selection and application. However, for the analysed case studies, PCM prices need to be reduced in order to become a cost-effective retrofit option.

Energy is the vital source of life and it plays a key role in development of human society. Any living creature relies on a source of energy to exist. Similarly, machines require power to operate. Starting with Industrial Revolution, the modern life clearly depends on energy. We need energy for almost everything we do in our daily life, including transportation, agriculture, telecommunication, powering industry, heating, cooling and lighting our buildings, powering electric equipment etc. Global energy requirement is set to increase due to many factors such as rapid industrialization, urbanization, population growth, and growing demand for higher living standards. There is a variety of energy resources available on our planet and non-renewable fossil fuels have been the main source of energy ever since the Industrial Revolution. Unfortunately, unsustainable consumption of energy resources and reliance on fossil fuels has led to severe problems such as energy resource scarcity, global climate change and environmental pollution. The building sector compromising homes, public buildings and businesses represent a major share of global energy and resource consumption. Therefore, while buildings provide numerous benefits to society, they also have major environmental impacts. To build and operate buildings, we consume about 40 % of global energy, 25 % of global water, and 40 % of other global resources. Moreover, buildings are involved in producing approximately one third of greenhouse gas emissions. Today, the stress put on the environment by building sector has reached dangerous levels therefore urgent measures are required to approach buildings and to minimize their negative impacts. We can design energy-efficient buildings only when we know where and why energy is needed and how it is used. Most of the energy consumed in buildings is used for heating, cooling, ventilating and lighting the indoor spaces, for sanitary water heating purposes and powering plug-in appliances required for daily life activities. Moreover, on-site renewable energy generation supports building energy efficiency by providing sustainable energy sources for the building energy needs. The production and consumption of energy carriers in buildings occur through the network of interconnected building sub-systems. A change in one energy process affects other energy processes. Thus, the overall building energy efficiency depends on the combined impact of the building with its systems interacting dynamically all among themselves, with building occupants and with outdoor conditions. Therefore, designing buildings for energy efficiency requires paying attention to complex interactions between the exterior environment and the internal conditions separated by building envelope complemented by building systems. In addition to building energy and CO2 emission performance, there are also other criteria for designers to consider for a comprehensive building design. For instance, building energy cost is one of the major cost types during building life span. Therefore, improving building efficiency not only addresses the challenges of global climate change but also high operational costs and consequent economic resource dependency. However, investments in energy efficiency measures can be costly, too. As a result, the economic viability of design options should be analysed carefully during decision-making process and cost-effective design choices needs to be identified. Furthermore, while applying measures to improve building performance, comfort conditions of occupants should not be neglected, as well. Advances in science and technologies introduced many approaches and technological products that can be benefitted in building design. However, it could be rather difficult to select what design strategies to follow and which technologies to implement among many for cost-effective energy efficiency while satisfying equally valued and beneficial objectives including comfort and environmental issues. Even using the state-of-the-art energy technologies can only have limited impact on the overall building performance if the building and system integration is not well explored. Conventional design methods, which are linear and sequential, are inadequate to address the inter-depended nature of buildings. There is a strong need today for new methods that can evaluate the overall building performance from different aspects while treating the building, its systems and surrounding as a whole and provide quantitative insight information for the designers. Therefore, in the current study, we purpose a simulation-based optimization methodology where improving building performance is taken integrally as one-problem and the interactions between building structure, HVAC equipment and building-integrated renewable energy production are simultaneously and dynamically solved through mathematical optimization techniques while looking for a balanced combination of several design options and design objectives for real-life design challenges. The objective of the methodology is to explore cost-effective energy saving options among a considered list of energy efficiency measures, which can provide comfort while limiting harmful environmental impacts in the long term therefore financial, environmental and comfort benefits are considered and assessed together. During the optimization-based search, building architectural features, building envelope features, size and type of HVAC equipment that belong to a pre-designed HVAC system and size and type of considered renewable system alternatives are explored simultaneously together for an optimal combination under given constraints. The developed optimization framework consists of three main modules: the optimizer, the simulator, and a user-created energy efficiency measures database. The responsibility of the optimizer is to control the entire process by implementing the optimization algorithm, to trigger simulation for performance calculation, to assign new values to variables, to calculate objective function, to impose constraints, and to check stopping criteria. The optimizer module is based on GenOpt optimization environment. However, a sub-module was designed, developed and added to optimization structure to enable Genopt to communicate with the user-created database module. Therefore, every time the value of a variable is updated, the technical and financial information of a matching product or system equipment is read from the database, written into simulation model, and fed to the objective formula. The simulator evaluates energy-related performance metrics and functional constraints through dynamic simulation techniques provided by EnergyPlus simulation tool. The database defines and organizes design variables and stores user-collected cost related, technical and non-technical data about the building energy efficiency measures to be tested during the optimization. An updated version of Particle Swarm Optimization with constriction coefficient is used as the optimization algorithm. The study covers multi-dimensional building design aims through a single-objective optimization approach where multi objectives are represented in a ε-Constraint penalty approach. The primary objective is taken as minimization of building global costs due to changes in design variables therefore it includes minimization of costs occur due to operational energy and water consumption together with ownership costs of building materials and building systems. Moreover, a set of penalty functions including equipment capacity, user comfort, CO2 emissions and renewable system payback period are added to the main objective function in the form of constraints to restrict the solution region to user-set design target. Consequently, multi-objective design aims are translated into a single-objective where the penalty functions acts as secondary objectives. The performance of the proposed optimization methodology was evaluated through a case study implementation where different design scenarios were created, optimized and analysed. A hypothetical base-case office building was defined. Three cities located in Turkey namely Istanbul, Ankara and Antalya were selected as building locations. Therefore, the performance of the methodology in different climatic conditions was investigated. An equipment database consists of actual building materials and system equipment commonly used in Turkish construction sector was prepared. In addition, technical and financial data necessary for objective function calculation were collected from the market. The results of the case studies showed that application of the proposed methodology achieved giving climate-appropriate design recommendations, which resulted in major cost reductions and energy savings. One of the most important contributing factors of this thesis is introducing an integrative method where building architectural elements, HVAC system equipment and renewable systems are simultaneously investigated and optimized while interactions between building and systems are being dynamically captured. Moreover, this research is distinctive from previous studies because it makes possible investigating actual market products as energy efficiency design options through its proposed database application and a sub-program that connect optimization engine with the data library. Therefore, application of the methodology can provide support on real-world building design projects and can prevent a mismatch between the optimization recommendations and the available market solutions. Furthermore, another contributing merit of this research is that it achieves formulating competing building design aims in a single objective function, which can still capture multi-dimensions of building design challenge. Global costs are minimized while energy savings are achieved, CO2-equivalent emission is reduced, right-sized equipment are selected, thermal comfort is provided to users and target payback periods of investments are assured. To conclude, the proposed methodology links building energy performance requirements to financial and environmental targets and it provides a promising structure for addressing real life building design challenges through fast and efficient optimization techniques.

La crescente consapevolezza delle problematiche legate alla sostenibilità ambientale e alla riduzione dei consumi energetici del costruito ha recentemente determinato un cambiamento anche nei processi e nei metodi costruttivi, concentrando l’attenzione di utenti e operatori di settore nei confronti dell’involucro edilizio, individuato quale principale responsabile dell’efficienza energetica e del comfort ambientale interno degli edifici. Parallelamente, gli interessi delle varie discipline coinvolte in tali processi sono stati rivolti tanto alla produzione di architetture sostenibili quanto nei confronti di una nuova generazione di edifici, intelligenti ed efficienti, capaci di interagire con la continua variabilità dell’ambiente circostante e con le esigenze sempre in mutamento dei loro utenti finali, i cosiddetti smart buildings. In tale quadro di riferimento, gli infissi, e, più in generale, i componenti trasparenti di involucro, rimangono i principali responsabili del comportamento termo-ambientale dell’edificio nei confronti dell’ambiente esterno (è stato stimato che le finestre sono responsabili di circa il 60% del totale consumo di energia di un edificio). Da queste considerazioni discende dunque la volontà di concentrare l’attenzione della presente ricerca nei confronti dei componenti trasparenti di involucro, in virtù delle opportunità offerte dalla ricerca in questo campo per via di limiti ancora esistenti legati al loro ruolo specifico all’interno dei sistemi di involucro. È evidente infatti come essi costituiscano ancora i componenti che necessitano della maggiore implementazione in termini di prestazioni – presentando criticità che tuttora non riescono ad essere risolte contando unicamente sulle caratteristiche intrinseche del materiale che li compone, il vetro appunto – ma che, allo stesso tempo, presentano un grande potenziale, dovuto alla loro capacità di reagire e interagire con gli stimoli esterni. L’obbiettivo principale del presente lavoro pertanto, è quello di compensare l’assenza di linee orientative per l’integrazione dei suddetti componenti all’interno dei sistemi di involucro, in modo da massimizzarne le prestazioni. A valle di un’analisi nel dominio dei cosiddetti smart buildings, quale ultima frontiera della ricerca architettonica e tecnologica contemporanea – strutturatasi in un database per la loro caratterizzazione sistematica – la tesi esplora il ruolo svolto dai componenti trasparenti di involucro nell’ambito di sistemi edilizi complessi, classificando le tecnologie esistenti e fornendo una metodologia per la valutazione comparata di prodotti differenti, al fine di valutarne la potenziale integrabilità. Scopo finale della ricerca è la messa a punto di uno strumento di supporto decisionale rivolto all’informazione e creazione di nuove possibilità progettuali di sistemi di involucro intelligenti, comprendendo il ruolo e le potenzialità che i componenti trasparenti di involucro rivestono all’interno di questo specifico dominio. Tale strumento si compone in realtà di tre elementi separati: i) una balanced scorecard, ii) una matrice di valutazione (assement matrix) e quello che viene qui definito come iii) “configuratore di smart windows”, vero e proprio risultato applicativo del presente lavoro. Tale configuratore è stato concepito come una sorta di matrice aperta per la compilazione e la quantificazione di diverse opzioni tecniche e prestazionali relative alle diverse tecnologie investigate, al fine di fornire un supporto decisionale verso un’integrazione consapevole ed efficace dei componenti trasparenti all'interno di sistemi di involucro edilizio complessi, colmando il divario rispetto alla pratica corrente e supportando eventuali future attività di ricerca e sviluppo.
The growing awareness about issues related to environmental sustainability and energy consumption reduction of the built environment has led to a shift in building process and technologies. In this framework, the greater attention is addressed towards building envelope as major responsible for building energy efficiency so as for the internal environmental comfort of end-users. Besides, interests of various disciplines have been directed not only to the production of sustainable architectures but even towards a new generation of energy-efficient, interactive buildings, defined smart buildings, capable of reacting to the continuous variability of the surroundings and the ever-changing needs of end-users. In the context here depicted, fenestration systems have been identified as one of the major responsible for buildings’ behaviour towards the external environment (it has been appraised that windows are accountable for about the 60% of the whole building energy consumption). From these considerations descend the choice to deal with glazed components, under the opportunities research offers in this field due to still existing shortcomings related to the specific role they play within building envelope systems. Indeed, it is evident that fact that glass is still the building component that needs of the most implementation in terms of performance – presenting issues that cannot be resolved only resorting to materials’ innovation – but that is, at the same time, a material with great potential, due to its intrinsic ability in reacting to external stimuli. Therefore, the main objective of the present research is to provide a solution to the existing lack of guidance about how existing glazing technologies could be profitably integrated into buildings in a way that maximises their performance. So, after investigating the world of the smart building envelopes, as the latest goal of contemporary architectural and technological research – developing a characterization of them through the creation of a supporting database of smart architecture – the present work exploring the role that transparent building components play in this framework, classifying existing glazing technologies and providing a systematic methodology to assess their building integration potential. The final aim of this research was to design a decision support tool(box) for architects, to inform and create new design possibilities, providing an insight into the application and design of smart building envelope systems and understanding role and potentialities of transparent building components within this specific framework. Such toolbox is composed of three separated tools: i) a balanced scorecard, ii) an assessment matrix and iii) the smart windows configurator, final achievement of the dissertation. It is conceived as a sort of open matrix for compiling and quantify options for decision making support towards the conscious and effective integration of transparent building components within advanced and innovative building envelope systems, bridging the gap from current practice thus supporting further research and development activities.

Building envelopes are elements with a long lifetime, which provide a barrier between internal and external space and contribute to the internal environmental conditions provision. Their complex role ensures a large impact on the environmental and energy performance of a building and the occupant perception of a space. This study looks at the use of novel materials and processes to help reduce the environmental impact of buildings by improving facade and transparent roof design. There are three main strands to the work. First, novel building components, ETFE foil cushions were examined. Physical testing has shown that ETFE foil cushions compare favourably to double glazing in terms of thermal and daylighting performance which was also noted as one of the most likeable feature by occupants. Environmental impact analysis has indicated that ETFE foils can reduce the environmental impact of a building through reduced environmental burden of both the construction and operation of the building. Secondly, a cradle-to-gate Life Cycle Analysis (LCA) was carried out for float glass, which considered the environmental impacts of glass manufacture. The embodied energy was calculated to be 13.4 ± 0.5 GJ per tonne while the total number of eco-points 243 ± 11 per tonne. It is shown that float glass is comparable to the use of steel, and highly preferable to the use of aluminium as a cladding panel. Finally, a concept design tool (FACADE) was developed by defining a large number of office facade models and employing dynamic thermal, daylighting and environmental impact modelling to create a database which can be accessed through a user friendly interface application. A parametric analysis has indicated that using natural ventilation where possible can reduce the environmental impact of offices by up to 16%. Improving the standard of the facade and reducing the internal heat loads from lighting and equipment can reduce environmental impact up to 22%. This study makes a significant contribution to understanding the environmental impact of building envelope individual and integrated components.

The aim of this study was to investigate the effects of windows and building envelope materials on the thermal performance of residential buildings, for the climatic conditions of Ankara. The effects of the thermal mass of the building envelope, together with the effects of glazing type and shading conditions of south-facing windows on thermal performance were investigated using two computer-based thermal analysis programs called: ECOTECT 5.0 and ENERGY-10. The hypothetical building model used for computer simulations was based on the sample residential building defined in the Turkish Standards on the Regulations for Building Insulation, TSE 825, as prepared by the Tü
rk Standartlari Enstitü
sü
(TSE, Turkish Standards Institute). Simulation studies were first conducted with ECOTECT 5.0, but since the results did not conform to earlier researches and, since this discrepancy could not be explained even by the support forum prepared by the authors of this software, it was decided to continue the simulations with ENERGY-10, which proved to be more consistent. The results of 240 program runs of ENERGY- 10 were explained through graphical and statistical analysis on the basis of annual heating, cooling, and total energy needs of the building model. The study showed that building envelope materials having high thermal storage capacities together with high-performance glazing, in terms of increased thermal resistance, provided significant energy savings, which could be augmented by increasing the size of south-facing windows. The study also revealed that shading devices in the form of fixed overhangs applied to a south-facing window of any size did not provide substantial reductions in the energy demands of residential buildings, when annual total energy demands were considered for the climatic conditions of Ankara.

A study to optimize insulation thickness for stock-, industrial- and office-buildings for external walls and roof in an economical perspective has been conducted on behalf of DynaMate. DynaMate’s role is to maintain all Scania’s buildings. Analysis has also included other parts of the building envelope, such as windows, exterior doors and industrial doors. In this thesis, three different types of exterior wall constructions has been investigated, these are a sandwich design consisting of sheet metal and a another one consisting of concrete, as well as a wall of concrete with a coating of plasters. Furthermore, two types of roof structures have been studied, these are TRP-sheets and a concrete structure, both of which are externally isolated. For all types of building envelopes, different standard thicknesses of insulation have been used and the U-value of the windows has been varied. To calculate the energy needed for the different kinds of buildings, the program IDA Indoor Climate and Energy has been used.  Furthermore, a sensitivity analysis of the air tightness has been implemented for the building envelope. Based on the program results LCC (Life-cycle cost) calculations have been carried out for all combinations, thus be able to form an idea of ​​the combination and what kind of structure that is most economically tenable. A thermograph study was conducted in an existing warehouse at Scania. Observations show that the connection between the sandwich material of sheet metal and the foundation wall is flawed as this has a much lower thermal resistance compared to other parts of the building envelope. An alternative connection was developed which reduces the heat loss to one-fifth of the initial connection. An analysis regarding the companies approach to the vapour barrier in roof structures for industrial buildings has been investigated from a moisture standpoint. The analysis shows that without a functioning vapour barrier the moisture content in the construction increases over time, which leads to increased heating costs. The conclusion of this study shows that a reduction of insulation thickness for all types of studied buildings is more economically tenable than increasing the thickness. This is mainly due to the high cost of capital that the company uses for these investments. This means that any savings on cooling and heating costs very quickly is overthrown by the interest rate of the additional cost of the investment.

Recent studies have shown that the optical properties of building exterior surfaces are important in terms of energy use and thermal comfort. While the majority of the studies are related to exterior surfaces, the radiation properties of interior surfaces are less thoroughly investigated. Development in the coil-coating industries has now made it possible to allocate different optical properties for both exterior and interior surfaces of steel-clad buildings. The aim of this thesis is to investigate the influence of surface radiation properties with the focus on the thermal emittance of the interior surfaces, the modeling approaches and their consequences in the context of the building energy performance and indoor thermal environment. The study consists of both numerical and experimental investigations. The experimental investigations include parallel field measurements on three similar test cabins with different interior and exterior surface radiation properties in Borlänge, Sweden, and two ice rink arenas with normal and low emissive ceiling in Luleå, Sweden. The numerical methods include comparative simulations by the use of dynamic heat flux models, Building Energy Simulation (BES), Computational Fluid Dynamics (CFD) and a coupled model for BES and CFD. Several parametric studies and thermal performance analyses were carried out in combination with the different numerical methods. The parallel field measurements on the test cabins include the air, surface and radiation temperatures and energy use during passive and active (heating and cooling) measurements. Both measurement and comparative simulation results indicate an improvement in the indoor thermal environment when the interior surfaces have low emittance. In the ice rink arenas, surface and radiation temperature measurements indicate a considerable reduction in the ceiling-to-ice radiation by the use of low emittance surfaces, in agreement with a ceiling-toice radiation model using schematic dynamic heat flux calculations. The measurements in the test cabins indicate that the use of low emittance surfaces can increase the vertical indoor air temperature gradients depending on the time of day and outdoor conditions. This is in agreement with the transient CFD simulations having the boundary condition assigned on the exterior surfaces. The sensitivity analyses have been performed under different outdoor conditions and surface thermal radiation properties. The spatially resolved simulations indicate an increase in the air and surface temperature gradients by the use of low emittance coatings. This can allow for lower air temperature at the occupied zone during the summer. The combined effect of interior and exterior reflective coatings in terms of energy use has been investigated by the use of building energy simulation for different climates and internal heat loads. The results indicate possible energy savings by the smart choice of optical properties on interior and exterior surfaces of the building. Overall, it is concluded that the interior reflective coatings can contribute to building energy savings and improvement of the indoor thermal environment. This can be numerically investigated by the choice of appropriate models with respect to the level of detail and computational load. This thesis includes comparative simulations at different levels of detail.

Building management system (BMS) offers a wide range of measurements and historical data about the building but few types of researches use these data to analyze the building performance. This study aims to explore the indoor climate and building insulation by taking advantage of the BMS of the study case, which 767 sensors are installed in the room and wall structures and the signal data are available at the online web application. In addition, during the inspection, several error sensors and meters are detected are discussed as feedback for the system. It is concluded that the building management system is a good tool to study the building performance in different aspects and the measurements from the sensors are helpful but need validation by conducting a further field measurement in the building.

In this study, the energy conservation potential of selected retrofitting interventions on an office building were investigated, on the basis of which some rational strategies for the improvement of building envelopes in terms of energy, environment and comfort design were proposed. Examined were various measures on envelope constructions that can be retrofitted to existing buildings. By using simulation techniques, the effectiveness of such measures in reducing energy consumption and environmental threat were also assessed. Effects of glazing types, effect of insulation and thermal mass were analyzed as energy efficient retrofit measures to the Engineering Building (MM building) situated on Middle East Technical University Campus, Ankara. The Energy-10 computer program was used for the modeling and simulation of the energy flows through the envelope to examine measures for reducing thermal load. Within this framework, the energy conservation potential of single and combined retrofitting actions was investigated. Based on results from the evaluation model, it was found that a saving of 161.20 MWh in the annual heating load could result, depending on the glazing type. The evaluation showed that thermal insulation is the most effective factor in thermal performance when placed as an exterior layer on walls. The study showed thermal mass has significant impact on increasing the duration, where highest temperatures were achieved, under passive mode. The study also revealed that applying a combination of retrofitting measures which responded to the challenges and opportunities presented by different faç
ade orientations, a saving of 52.41% can be achieved in annual heating energy use in case study building.

The lifetime of the built environment depends strongly on the severity of local climatic conditions. A well-functioning and reliable infrastructure is a precondition for economic growth and social development. The climate and topography of Norway puts great demands on the design and localization of buildings. The relationship between materials, structures and climatic impact is highly complex; illustrating the need for new and improved methods for vulnerability assessment of building envelope performance in relation to externally imposed climatic strains. Historically, major variations in climatic impact have led to corresponding large variations in building practice throughout the country - often well suited to local conditions. Today it is fair to say that sound building traditions and practice to some extent are being rejected in the quest for cost-effective solutions. Furthermore, projected changes in climatic conditions due to global warming will enhance the vulnerability within the built environment.

The primary objectives of the present dissertation are to increase the knowledge about possible impacts of climate change on building envelope performance, and to analyse and update methods for the planning and design of external envelopes in relation to climatic impact. This is accomplished through the development of integrated approaches and improved methods for assessing impacts of external climatic parameters on building envelopes, combining knowledge on materials, structures and relevant climate data, applicable for both historical data and scenarios for climate change. The results will contribute to more accurate building physics design guidelines, promoting high-performance building envelopes in harsh climates.

Approaches to assessments of the risks associated with climate change and buildings are suggested, identifying main areas of vulnerability in the construction industry. It is shown that there are benefits to be gained from the introduction of risk management strategies within a greater extent of the construction industry. A way of analysing the building economics of climate change is also proposed

Analyses of building defects are necessary in order to further develop tools, solutions and preventive measures ensuring high-performance building envelopes. To illuminate the vulnerability of different building envelope elements under varying climatic exposure, a comprehensive analysis of empirical data gathered from process induced building defect assignments is carried out. The amount of building defects in Norway clearly illustrates that it is not only the extreme weather events that need to be studied as a foundation for adaptation towards a changing climate. Furthermore, the analyses of defects reveal a fundamental need for climate differentiated design guidelines.

New and improved methods for geographically dependent design of building envelopes are proposed:

- A method for assessing the relative potential of frost decay or frost damage of porous, mineral building materials exposed to a given climate is developed.

- A national map of the potential for decay in wood structures is developed. Detailed scenarios for climate change for selected locations in Norway are used to provide an indication of the possible future development of decay rates.

- A method for assessing driving rain exposures based on multi-year records of synoptic observations of present weather, wind speed and direction is also presented.

These climate indices can be used as a tool for evaluation of changes in performance requirements or decay rates due to climate change under global warming incorporating data from regional- and local-level climate change scenarios. Historical records of climate data have finally been used to illuminate challenges arising when introducing international standards at the national level, without considering the need for adjustments to reflect varying local climatic conditions.

At present, building standards and design guidelines presuppose use of historic weather data. Historically, location-specific climate data have only to a very limited extent been applied systematically for design purposes, life cycle assessments, and climate differentiation of the suitability of a given technical solution in a given climate. The work is a first step towards methods and approaches allowing for geographically dependent climate considerations to be made in the development of design guidelines for high-performance building envelopes, and also approaches to assess the risks associated with the future performance of building envelopes due to climate change.

The dissertation focuses on methods for assessing impacts of external climatic parameters on a local scale, but with the use of daily and monthly averages of climate data. The reliability of climate indices or climate differentiated design guidelines is strongly dependent on the geographical spreading of the observing station network. The Norwegian network is not optimally distributed to fully embrace local variations, but provides a solid platform for the development of methods for geographically dependent design and guidelines on the appropriateness of different solutions in different climates.

Climate indices (using geographic information systems technology)allowing for quantitative assessment of building envelope performance or decay potential may be an important element in the development of adaptation measures to meet the future risks of climate change in different parts of the world. Finally, the work offers a conceptual point of departure for the development of a vintage model of the robustness of the Norwegian building stock.

Paper VII, IX, XI and XII reprinted with kind permission of Elsevier, sciencedirect.com

Co-polymer facade materials have recently become a popular option in the building industry as an alternative to glazing. Ethylene Tetra-Fluoro-Ethylene (ETFE) foil has been successfully used in many projects as an innovative solution to energy-conscious design challenges. In addition, the use of ETFE membrane has resulted in significant savings in cost and structural support requirements, compared with conventional glazing, due to its low weight. There is a lack of detailed published data reporting its thermal behaviour. This study focuses on the examination of heat transfer through the ETFE membrane, and more specifically heat loss and solar gains. The document examines the impact of the material on the energy use of a building, as well as thermal comfort and interior conditions. Through field-testing and computer simulations the research evaluates the material’s thermal properties to obtain results that will assist in estimating the suitability of ETFE foil use in comparison to glass. Field-testing is used to perform a comparison of the thermal and energy behaviour of a fritted double ETFE cushion to a double glazed cover. The two experimental devices under examination present nearly identical energy consumption due to heating requirements. The experimental findings are implemented in Integrated Environmental Solutions (IES) and used to identify the necessary steps to accurately reproduce the thermal and energy behaviour associated with both covering materials. Further simulations were undertaken to provide a comparison of several types of ETFE cushions to various types of double glass. More specifically, the types examined are a clear double ETFE roof cover and a fritted double ETFE roof cover in comparison to a standard double glazed roof and a low-E double glazed roof. The roofs covers are examined in relation to energy requirements for both the heating and cooling of a space. Such an assessment of performance will provide information for further investigation to improve the material’s features and optimise energy performance.

Presently, there are concerns that buildings in the USA under-performs in terms of energy efficiency when compared with the original design specifications. A significant percentage of the energy loss in these buildings is associated with the building’s envelope. This study provides a qualitative and analytical understanding of the R-value, which indicates the thermal performance of the elements that make up a building envelope. Infrared thermography is used as a methodology to assess the thermal performance of envelopes of ten buildings on East Tennessee State University Campus. A Fluke Ti25 infrared hand-held camera and a DJI phantom-2 drone mounted with FLIR Vue Pro infrared camera were used for data collection. Data analyses were carried out using ‘Smartview’ and ‘FLIR Reporter Pro’ software. The data analyses revealed energy loss, insulation deficiencies, the associated energy costs of the inefficiencies and the potential savings that could result from correcting these deficiencies in the evaluated building’s envelopes.

More than 30% of the final energy uses in the European Union are due to the building energy consumptions. In order to reduce their energy impact and improve their efficiency, the design activity has been given a large importance, both for new buildings or refurbishment projects. Moreover, besides these goals, during the last years the indoor comfort conditions have assumed a more and more relevant significance for professionals in the building design. That required the development of properly detailed instruments of analysis, such as building energy simulation tools (BES). Generally, the more complex a tool, the higher the number of required inputs but not all of them are always available in the early design stages. For this reason, BES codes have been used also to elaborate simpler models. This research analyses the possibilities given by an extensive use of the BES for the evaluation of the building envelope energy performance and some of the different issues related to BES. The first topic discussed is related to the external boundary conditions in BES, in particular the definition of a representative weather file for the description of the external environment and of the modelling of the heat transfer through the ground. The second topic analyses the problems of the validation of the results provided by BES tools and the relative accuracy introduced by the choice of a specific code. The comparison between BES software is carried out both considering the outputs of a whole thermal zone, such as heating and cooling energy needs and peak loads and the time of their occurrences, and the response of a single component (i.e., opaque walls and glazings). Finally, the coherence between the energy needs elaborated by means of BES tools and those by the quasi-steady state model presented in the technical Standard EN ISO 13790:2008 is studied and some correction factors are proposed for this simplified method.
Più del 30% degli impieghi finali di energia nell’Unione Europea è dovuto ai consumi energetici degli edifici. Al fine di ridurre il loro impatto energetico e migliorare la loro efficienza, è stata data una sempre maggiore importanza all’attività di progettazione, sia in merito ai nuovi edifici sia per gli interventi di riqualificazione. Inoltre, in aggiunta a questi obiettivi, durante gli ultimi anni le condizioni di comfort nell’ambiente confinato hanno assunto una sempre maggiore significatività per i progettisti edili. Ciò ha richiesto lo sviluppo di strumenti di analisi adeguatamente dettagliati, come i simulatori dinamici dell’edificio. In generale, più è complesso uno strumento, maggiore è il numero di input richiesti ma non tutti sono sempre disponibili nelle fasi iniziali della progettazione. Per questa ragione, i codici di simulazione dinamica sono stati impiegati anche per sviluppare modelli semplificati. Questa ricerca analizza le possibilità date da un uso estensivo della simulazione dinamica per la valutazione delle prestazioni energetiche dell’involucro edilizio e alcune problematiche relative ad essa. Il primo argomento discusso riguarda le condizioni al contorno nella simulazione dinamica, in particolare la definizione di un file climatico rappresentativo per la descrizione dell’ambiente esterno e la modellazione dello scambio di calore attraverso il terreno. Il secondo argomento analizza i problemi della validazione dei risultati forniti dagli strumenti di simulazione dinamica e l’accuratezza introdotta dalla scelta di uno specifico codice. Il confronto tra i software di simulazione dinamica è condotto sia a livello degli output di un’intera zona termica, quali i fabbisogni di riscaldamento e raffrescamento, i carichi di picco e l’istante in cui si verificano, e la risposta di un singolo componente (i.e., le pareti opache e quelle vetrate). Infine, viene studiata la coerenza tra i fabbisogni energetici elaborati dagli strumenti di simulazione dinamica e quelli ottenuti tramite il modello semi-stazionario presentato nella normativa EN ISO 13790:2008 e vengono proposti alcuni fattori correttivi per questo metodo semplificato.

Les emissions de gasos d’efecte hivernacle i el consum energètic dels edificis han incrementat de forma constant durant els últims quaranta anys, representant al 2010 el 25% de les emissions totals i el 32% del consum energètic a nivell global. Les institucions internacionals preveuen que aquestes emissions poden duplicar-se o inclús triplicar-se al 2050. Un dels objectius d’aquesta tesi és estudiar el consum energètic dels edificis a Europa durant els últims vint anys i demostrar la necessitat de reduir el consum energètic dels edificis per mitigar el canvi climàtic. L'Agència Internacional de l’Energia recomana millorar l’envolvent de l’edifici amb materials i sistemes constructius apropiats com a principal acció per reduir el seu consum energètic. Per aquest motiu, aquesta tesi està enfocada principalment en millorar les propietats tèrmiques dels materials que formen l’envolvent mitjançant l’ús de materials de canvi de fase per l’emmagatzematge d’energia tèrmica en sistemes passius i/o materials sostenibles.
constantemente durante las últimas cuatro décadas, representando en 2010 el 25% de las emisiones totales y el 32% del consumo energético a nivel global. Las instituciones internacionales prevén que pueden duplicarse e incluso triplicarse en 2050. Un objetivo de esta tesis es estudiar el consumo energético de los edificios residenciales europeaos en las últimas dos décadas y demostrar la necesidad de reducir el consumo energético de los edificios para mitigar el cambio climático. La Agencia Internacional de la Energía recomienda mejorar la envolvente del edificio con materiales y sistemas constructivos apropiados como principal acción para reducir su consumo energético. Por este motivo, esta tesis está enfocada en mejorar las propiedades térmicas de los materiales que conforman la envolvente incorporando materiales de cambio de fase para el almacenamiento térmico de energía en sistemas pasivos y/o materiales sostenibles.
Greenhouse gases emissions and energy consumption in buildings were constantly increasing the last 4 decades, representing 25% of total emissions and 32% of global final energy consumption in 2010. These emissions are expected to double or even triple by 2050 according to international institutions projections. Therefore, the reduction of greenhouse gases emissions and energy consumption becomes a necessity to encompass pollution and climate change mitigation. One of the objectives of this PhD thesis is to analyse the trends of the energy consumption of European residential buildings. The main action recommended by the International Energy Agency to reduce significantly the energy consumption in buildings is to improve their envelopes with appropriate materials and construction systems. For this reason, this PhD thesis is focused on materials with thermal properties improved using phase change materials (PCM) for latent thermal energy storage in passive systems and/or sustainable materials to be placed in building envelopes.

The internal thermal climatic condition of a house is directly affected by how the building envelope (walls, windows and roof) is designed to suit the environment it is exposed to. The way in which the building envelope is constructed has a great affect on the energy required for heating and cooling to maintain human thermal comfort. Understanding how the internal climatic conditions react to the building envelope construction is therefore of great value. This study investigates how the thermal behaviour inside of a simple house reacts to changes made to the building envelope with the objective to predict how these changes will affect human thermal comfort when optimising the design of the house. A three-dimensional numerical model was created using computational fluid dynamic code (Ansys Fluent) to solve the governing equations that describe the thermal properties inside of a simple house. The geometries and thermophysical properties of the model were altered to simulate changes in the building envelope design to determine how these changes affect the internal thermal climate for both summer and winter environmental conditions. Changes that were made to the building envelope geometry and thermophysical properties include: thickness of the exterior walls, size of the window, and the walls and window glazing constant of emissivity. Results showed that there is a substantial difference in indoor temperatures, and heating and cooling patterns, between summer and winter environmental conditions. The thickness of the walls and size of the windows had a minimal effect on internal climate. It was found that the emissivity of the walls and window glazing had a significant effect on the internal climate conditions, where lowering the constant of emissivity allowed for more stable thermal conditions within the human comfort range.

La demande d'énergie consommée par les habitants a connu une croissance significative au cours des 30 dernières années. Par conséquent, des actions sont menées en vue de développement des énergies renouvelables et en particulier de l'énergie solaire. De nombreuses solutions technologiques ont ensuite été proposées, telles que les capteurs solaires PV/T dont l'objectif est d'améliorer la performance des panneaux PV en récupérant l’énergie thermique qu’ils dissipent à l’aide d’un fluide caloporteur. Les recherches en vue de l'amélioration des productivités thermiques et électriques de ces composants ont conduit à l'intégration progressive à l’enveloppe des bâtiments afin d'améliorer leur surface de captation d’énergie solaire. Face à la problématique énergétique, les solutions envisagées dans le domaine du bâtiment s’orientent sur un mix énergétique favorisant la production locale ainsi que l’autoconsommation. Concernant l’électricité, les systèmes photovoltaïques intégrés au bâtiment (BIPV) représentent l’une des rares technologies capables de produire de l’électricité localement et sans émettre de gaz à effet de serre. Cependant, le niveau de température auquel fonctionnent ces composants et en particulier les composants cristallins, influence sensiblement leur efficacité ainsi que leur durée de vie. Ceci est donc d’autant plus vrai en configuration d’intégration. Ces deux constats mettent en lumière l’importance du refroidissement passif par convection naturelle de ces modules. Ce travail porte sur la simulation numérique d'une façade PV partiellement transparente et ventilée, conçu pour le rafraichissement en été (par convection naturelle) et pour la récupération de chaleur en hiver (par ventilation mécanique). Pour les deux configurations, l'air dans la cavité est chauffé par la transmission du rayonnement solaire à travers des surfaces vitrées, et par les échanges convectif et radiatif. Le système est simulé à l'aide d'un modèle multi-physique réduit adapté à une grande échelle dans des conditions réelles d'exploitation et développé pour l'environnement logiciel TRNSYS. La validation du modèle est ensuite présentée en utilisant des données expérimentales du projet RESSOURCES (ANR-PREBAT 2007). Cette étape a conduit, dans le troisième chapitre du calcul des besoins de chauffage et de refroidissement d'un bâtiment et l'évaluation de l'impact des variations climatiques sur les performances du système. Les résultats ont permis enfin d'effectuer une analyse énergétique et exergo-économique
The demand of energy consumed by human kind has been growing significantly over the past 30 years. Therefore, various actions are taken for the development of renewable energy and in particular solar energy. Many technological solutions have then been proposed, such as solar PV/T collectors whose objective is to improve the PV panels performance by recovering the heat lost with a heat removal fluid. The research for the improvement of the thermal and electrical productivities of these components has led to the gradual integration of the solar components into building in order to improve their absorbing area. Among technologies capable to produce electricity locally without con-tributing to greenhouse gas (GHG) releases is building integrated PV systems (BIPV). However, when exposed to intense solar radiation, the temperature of PV modules increases significantly, leading to a reduction in efficiency so that only about 14% of the incident radiation is converted into electrical energy. The high temperature also decreases the life of the modules, thereby making passive cooling of the PV components through natural convection a desirable and cost-effective means of overcoming both difficulties. A numerical model of heat transfer and fluid flow characteristics of natural convection of air is therefore undertaken so as to provide reliable information for the design of BIPV. A simplified numerical model is used to model the PVT collector so as to gain an understanding of the complex processes involved in cooling of integrated photovoltaic arrays in double-skin building surfaces. This work addresses the numerical simulation of a semi-transparent, ventilated PV façade designed for cooling in summer (by natural convection) and for heat recovery in winter (by mechanical ventilation). For both configurations, air in the cavity between the two building skins (photovoltaic façade and the primary building wall) is heated by transmission through transparent glazed sections, and by convective and radiative exchange. The system is simulated with the aid of a reduced-order multi-physics model adapted to a full scale arrangement operating under real conditions and developed for the TRNSYS software environment. Validation of the model and the subsequent simulation of a building-coupled system are then presented, which were undertaken using experimental data from the RESSOURCES project (ANR-PREBAT 2007). This step led, in the third chapter to the calculation of the heating and cooling needs of a simulated building and the investigation of impact of climatic variations on the system performance. The results have permitted finally to perform the exergy and exergoeconomic analysis

Dans un cadre de rénovation de bâtiment existant, on propose de baser le diagnostic énergétique et aéraulique sur des mesures in-situ non intrusives. Les données issues des mesures alimentent une méthode inverse qui permettra de déterminer les caractéristiques du bâtiment. La spécificité de la thèse consiste à utiliser l'inférence bayésienne comme approche pour la résolution du problème inverse, ce qui permet de travailler en approche probabiliste et d'obtenir intrinsèquement une estimation des incertitudes
The purpose of the thesis is to develop a building energy performance assessment based on in situ non intrusive measurements. An inverse method using the acquired data allows us to determine the building's characteristics, with more or less accuracy. What is particular in this work is the use of a Bayesian approach, which allows on one hand handling data even if scarce and on the other hand obtaining inherently uncertainty assessment

This research investigates the bio-products/phase change material (PCM) composites for the building envelope application. Bio-products, such as wood and herb, are porous medium, which can be applied in the building envelope for thermal insulation purpose. PCM is infiltrated into the bio-product (porous medium) to form a composite material. The PCM can absorb/release large amount of latent heat of fusion from/to the building environment during the melting/solidification process. Hence, the PCM-based composite material in the building envelope can efficiently adjust the building interior temperature by utilizing the phase change process, which improves the thermal insulation, and therefore, reduces the load on the HVAC system. Paraffin wax was considered as the PCM in the current studies. The building energy savings were investigated by comparing the composite building envelope material with the conventional material in a unique Zero-Energy (ZØE) Research Lab building at University of North Texas (UNT) through building energy simulation programs (i.e., eQUEST and EnergyPlus). The exact climatic conditions of the local area (Denton, Texas) were used as the input values in the simulations. It was found that the EnergyPlus building simulation program was more suitable for the PCM based building envelope using the latent heat property. Therefore, based on the EnergyPlus simulations, when the conventional structure insulated panel (SIP) in the roof and wall structures were replaced by the herb panel or herb/PCM composite, it was found that around 16.0% of energy savings in heating load and 11.0% in cooling load were obtained by using PCM in the bio-product porous medium.

This research investigates the bio-products/phase change material (PCM) composites for the building envelope application. Bio-products, such as wood and herb, are porous medium, which can be applied in the building envelope for thermal insulation purpose. PCM is infiltrated into the bio-product (porous medium) to form a composite material. The PCM can absorb/release large amount of latent heat of fusion from/to the building environment during the melting/solidification process. Hence, the PCM-based composite material in the building envelope can efficiently adjust the building interior temperature by utilizing the phase change process, which improves the thermal insulation, and therefore, reduces the load on the HVAC system. Paraffin wax was considered as the PCM in the current studies. The building energy savings were investigated by comparing the composite building envelope material with the conventional material in a unique Zero-Energy (ZØE) Research Lab building at University of North Texas (UNT) through building energy simulation programs (i.e., eQUEST and EnergyPlus). The exact climatic conditions of the local area (Denton, Texas) were used as the input values in the simulations. It was found that the EnergyPlus building simulation program was more suitable for the PCM based building envelope using the latent heat property. Therefore, based on the EnergyPlus simulations, when the conventional structure insulated panel (SIP) in the roof and wall structures were replaced by the herb panel or herb/PCM composite, it was found that around 16.0% of energy savings in heating load and 11.0% in cooling load were obtained by using PCM in the bio-product porous medium.

The overall heat transfer coefficient of a building wall, the U value, is an interesting parameter to deduce the heat loss rate through the wall. The current method to determine this U value is well known, but is requires a lot of time to be performed. In this work a new idea of methodology is presented to get an accurate idea of the U value in a really smaller time, using an IR camera. IR thermography is a non destructive method that is mainly used today to carry out qualitative observations. In this work it is used as a quantitative tool to determine the conductivity of a wall knowing the external heat transfer coefficient. The error obtained on homogeneous and heterogeneous walls are smaller than 10 %, which is accurate enough for a fast measurement. The thermal mass of the wall can also be estimated with errors between 5 and 20 %, but only if the user has a good first guess of the real value. Finally some ideas are proposed when the heat transfer coefficient is not known, leading to less reliable results. More work is necessary to transform it as a usable method in everyday life. A part of the report concerns some attempts done with a simulation of the experiment, leading to no concrete results but it is still presented as it took some time to be studied.

The concept of adaptability in architecture is one that very often bears technical rather than social connotations. What are the mechanisms and systems that allow buildings to adapt to fluctuating environmental and climatic conditions? These responses are often the driving force behind design considerations, placing emphasis on the manner in which the technical resolutions facilitate appropriate adaptability and environmental response. This adaptability is generally addressed through the building envelope, which acts as the mediator between the interior conditions of a building, and the exterior conditions of its environment (Lovell, 2010). However, beyond addressing these environmental conditions, there are greater urban and social conditions that bear equal weight within any design inquiry. Building adjacencies, ethnographics, social development and imageability of spatial ordering are all fundamental factors that need to be addressed within building envelope design (Lovell, 2010). The design dissertation inquiry explores the multi-faceted nature of building envelopes as well as an architecture of internal and external thresholds. The inquiry examines ways in which building envelopes respond to both the environmental and social complexities of a context, as well as how internal and external threshold and edge conditions can be design generative and communicative; expressing spatial organisations, conditions of privacy and mechanisms of adaptability. This topic of adaptive envelopes and defining thresholds in relation to social complexities has been explored in an architectural design project, which aims to practically address social and environmental issues. This exploration yields a set of key findings into an architecture of thresholds and adaptability in response to the sociotechnical conditions of a context where the lines between the formal and informal are blurred.

The thesis attempts to investigate the issues pertaining to design, fabrication and application of real-time adaptive systems for building envelopes, and to answer questions raised by the idea of motion in architecture. The thesis uses the Solar Decathlon Competition as a platform to base all the research and consequently to verify their applications. Photo-voltaic (PV) panels and shading devices are two different components of Georgia Institute of Technology s the Solar Decathlon House, located above the roof, that are based on the concept of Homeostasis or self-regulated optimization. For the PV panels, the objective is to optimize energy production, by controlling their movement to track the changing position of Sun, whereas, the objective for the shading devices is to reduce heating or cooling loads by controlling the position of shading devices, thus controlling direct and diffused heat gains through the roof. To achieve this adaptive feature, it required three layers of operations. First was the design of the mechanics of movement, which tried to achieve the required motion for the PV panels and shading devices by using minimum components and parameters. Second was the design of the individual parts that are consistent with the overall concept of the House. And finally, the third layer is the design of controls that automates the motion of the PV panels and Shading Devices, using a set of sensors that actuate the attached motors. As a final product, there is an attempt to integrate the precision and material efficiency of digital fabrication with the self-regulated optimization of the roof components.

Dans un contexte de durcissement des règlementations thermiques, la maîtrise de l'étanchéité à l'air des bâtiments est essentielle pour atteindre les objectifs de consommation énergétique. Les fuites d'air parasites à travers l'enveloppe, dues aux défauts de conception ou à une mauvaise mise en oeuvre, mènent à une surconsommation énergétique, mais aussi à des pathologies liées à l'humidité, mettant en péril la durabilité du bâti et la santé des occupants. Le risque lié à l'humidité est particulièrement présent dans les cas des enveloppes légères à ossature bois, sensibles aux transferts d'air.Il est donc nécessaire de mieux comprendre et de quantifier l'impact de ces transferts d'air sur le champ hygrothermique et sur le flux de chaleur au niveau d'un défaut d'étanchéité. Dans ce but, deux modèles numériques traitant les transferts couplés 'air-chaleur' et couplés 'air-chaleur-humidité' sont développés. Le second modèle est d'abord validé en 1D à l'aide de benchmarks numériques. Ensuite, des mesures de température dans un isolant en ouate de cellulose traversé par un flux d'air humide sont comparées avec les sorties des modèles. Une bonne concordance mesures-modèles est obtenue. Le modèle 'air-chaleur-humidité' s'avère plus précis pour prédire le champ de température que le modèle 'air-chaleur'.Suite à cette validation 2D du modèle couplé 'air-chaleur-humidité', celui-ci est appliqué à une géométrie de défaut complexe, mettant en jeu des isolants poreux perméables à l'air en contact avec des fines lames d'air. Ce défaut se veut réaliste, puisqu'il est issu de campagnes de mesures nationales qui ont permis d'identifier les points sensibles des enveloppes à ossature bois vis à vis des fuites d'air parasites. Des simulations sont réalisées avec des conditions aux limites variables en température et humidité sur des temps longs (quatre ans), en exfiltration et en infiltration d'air. Ces études permettent de dégager certaines tendances vis-à-vis des risques liés à l'humidité. Ainsi, l'exfiltration provoque une humidification significative de l'assemblage tandis que l'infiltration mène à un séchage. Une méthodologie pour évaluer les flux thermiques à l'échelle du défaut est également proposée.Dans une dernière partie, une approche simplifiée est proposée pour prendre en compte l'impact des défauts d'étanchéité à l'air sur la déperdition thermique à l'échelle bâtiment. La perte thermique supplémentaire générée par un défaut d'étanchéité peut être caractérisée par un coefficient de perte thermique propre au défaut, et le couplage du flux d'air avec l'enveloppe a une influence significative sur l'évaluation du flux déperditif total. Enfin, l'influence des transferts d'humidité sur les tendances observées est discutée
Within the context of more stringent buildings codes, mastering airtightness is of importance to achieve energy efficient buildings. Unintended air leakage through the building envelope, which is due to bad design and poor workmanship, not only increases energy consumption, but also leads to moisture disorders, affecting building durability and occupants health. This moisture risk is present in particular for lightweight structures such as timber frame buildings, which are sensitive to air leakage.It is therefore necessary to better understand and to assess the impact of unintented air transfers on the hygrothermal field and the heat flux in the vicinity of an airtightness defect. To this end, two numerical models are developped, dealing with Heat-Air (HA) and Heat-Air-Moisture (HAM) transfer respectively. The HAM model is firstly validated in 1D using numerical benchmarks from literature. Then, temperature measurements in a cellulose insulation layer subjected to moist air flow are compared with the models outputs, and good agreement is obtained. The HAM model provides a better prediction of the temperature field compared to the HA model.Following this 2D experimental validation of the HAM model, it is applied to a complex defect geometry, including porous insulation materials and thin air gaps. This defect is meant to be realistic, as it is drawn from a measurement campaign aiming to identify typical envelope leakage points encountered in timber frame buildings.Long term simulations are performed under transient temperature and humidity conditions, in case of air exfiltration and air infiltration. This study helps identifying tendencies towards moisture risk: infiltrating air flow dries the assembly whereas exfiltrating air flow humidifies it. A methodology to assess heat fluxes through the defect is presented.Finally, a simplified approach is derived from the detailed HAM-model, to take into account the contribution of airtightness defects on the total heat loss on the building scale. It is shown that the additional heat loss induced by an airtightness defect may be described by a specific heat loss coefficient. In addition, the coupling between air flow and envelope has a significant impact on total heat flux calculations. The influence of moisture transfers on observed tendencies is also discussed

Ethylene-tetra-fluoro-ethylene (ETFE) is a synthetic fluoropolymer. In the form of ETFE-foil it is applied in building envelopes in a single layer or more commonly, as inflatable cushions composed of multiple layers. ETFE-foils are widely used as a lightweight building envelope where high translucency, low structural weight, and complex shape is essential. However, limited research in the field of thermal performance of ETFE-foil panels and spaces enclosed with it instigated this study. Therefore, this study investigated (I) the thermal behaviour of ETFE-foil materials and the thermal performance of spaces enclosed with ETFE cushion roofs, (II) used commercially available thermal simulation software to predict the thermal performance of spaces enclosed with ETFE cushion and glass roofs and compared this with actual monitored behaviour (III) identified strategies to improve the thermal performance of spaces enclosed with ETFE cushion roofs in current and projected climate scenarios; and finally (IV) proposed design recommendations of ETFE-foil panels/cushions as a building fabric components. Material properties were investigated in laboratory based experiments. Further data were collected from two custom built outdoor test-rigs equipped with single-, two- and three-layer ETFE-foil panels. Environmental data were collected from two case study buildings to evaluate the thermal performance of the spaces enclosed with ETFE-foil cushion roofs. In addition, building simulation was conducted using EDSL TAS version 9.3.3.b to further analyse the indoor thermal environment and compare with monitored behaviour. The study identified variable thermal-optical properties of ETFE foils caused by various percentages of fritted area and its pigment density. The results also identified that the thermal environment of the test-rigs was affected by the variations in the surface temperatures of ETFE-foils and the temperature of air volume between multiple ETFE-foils (in case of two and three layer panels) by convective and radiative heat transfer mechanisms. The results from the case study buildings identified that during hot summer days, indoor air temperature and temperature stratification was higher in the atrium space enclosed with three-layer ETFE-foil cushions compared to the space enclosed with two-layer ETFE-foil cushion covered with rain mesh. However, both of the spaces were overheated during the summer of 2015. To develop an accurate simulation model for ETFE cushion roofs, a novel approach of modelling was developed. The simulation model was validated and calibrated by comparing with measured data from test-rigs and case study buildings. A comparison of predicted results of the spaces enclosed with a multi-layer ETFE-foil cushion roof and a glass roof showed that the extent of overheating was high when spaces were enclosed with glass roofs. Among two-and three-layer ETFE-foil cushion and glass roofs, two-layer ETFE-foil cushions with 75% fritting and rain mesh effectively reduced air temperature and cooling load during the peak summer period. The findings of this study will enable designers to select and develop design strategies for applying ETFE-foils in building envelopes on the basis of thermal and optical requirements. The study also suggested to change the view of current design practice that only focused on current conditions; such as the use of ETFE-foils may require more adaptive approach to mitigate overheating problems in projected climate.

The present work deals with the study and analysis of the simultaneous optimization of time, cost and quality by using artificial intelligence technique; The approach is based on the use of genetic algorithms implemented in Matlab applied to a case study, the construction of a new University Campus in Cesena, focusing on the external walls of the building itself. The objective is to find a set of optimal solutions, equally valid, for the realization of stratigraphies of the different types of external masonry; It will then be the task of the designer to choose among possible solutions which he believes to be most appropriate, based on the requirements of the project, which may be in terms of quality, cost, time or a combination of two or more of these evaluation parameters. It will thus illustrate how different solutions provided by the program can be used and collected in a three-dimensional graph.

This thesis tests the use of Welsh-grown timber in the building envelope, through the prototyping of a series of live design projects with a focus on species, technology and tectonic form. Projects are clustered under 4 headings identified as significant to the Welsh timber industry: hardwoods, engineered timber, timber board products and the complete timber envelope. The Welsh timber industry relies heavily on the importation of sawnwood, timber board products and innovative, engineered timber systems to meet an increasing demand to improve construction efficiency and the environmental performance of the building envelope. Compared to Northern and Central Europe and regions such as the Vorarlberg, Austria, Wales is perceived as having an underdeveloped and underperforming timber construction industry with only 15% forest cover to supply a variety of timber sectors. This thesis analyses the properties of Welsh-grown soft and hardwoods, the technical and skill limitations and opportunities of the industry and highlights the impact of the use of timber on the tectonic form of the building envelope. These evaluations inform the observations and reflections of 12 architectural prototype projects to demonstrate potential to exploit the Welsh-grown timber crop in the design and construction of the architectural building envelope. The research demonstrates that it is possible to use Welsh-grown timber for a variety of modular superstructure, cladding and external joinery systems. The conclusions identify limitations, such as a lack of research and development investment, from government and business, and a lack of knowledge and focused direction across the industry. However, the prototype projects show that the unique properties of timber, sustainably grown, managed and processed in Wales can be innovatively manufactured and assembled into prefabricated, components for the design and construction of the low-energy architectural building envelope. Furthermore, the properties, technology and skills available have informed an additive tectonic approach that is specific to Welsh-grown timber.

In this thesis project, a building in Vegagatan 12, Gävle has been analysed. The main objective has been to find why it consumes more energy than it was expected and to solve theoretically the problems.This building is a low energy building certified by Miljöbyggnad which should use less than 55kWh/m2 year and nowadays it is using 62.23 kWh/m2. In order to find why the building is using more energy than the expected several different things has been measured and analyzed.First of all, the heat exchanger of the ventilation unit has been theoretically examined to see if it works as it should and it does. This has been done using the definition of the heat exchangers.Secondly, the heating system has been analysed by measuring the internal temperature of the building and high temperatures have been found (around 22°C) in the apartments and in the corridors. This leads to 5-10% more use of energy per degree.Thirdly, the position and the necessity of all the heaters have been checked. One of the heaters may not make sense, at least in the way the building has been constructed. This leads to bigger heating needs than the expected.Fourthly, the taps and shower heads have been checked to see if they were efficient. Efficient taps and shower heads, reduce the hot water use up to 40%. The result of this analysis has been that all taps and shower heads are efficient.Fifthly, the hot water system has been studied and some heat losses have been found because the lack of insulation of several pipes. Because of this fact 8.37kWh/m2 are lost per year. This analysis has been carried out with the help of an infra red camera and a TA SCOPE.Sixthly, the theoretical and real U values of the different walls have been obtained and compared (concrete and brick walls). As a conclusion, the concrete wall has been well constructed but, the brick wall has not been well constructed. Because of this fact 1 kWh/m2 of heat are lost every year. Apart from that, windows and thermal bridges have also been checked.

This thesis investigates the design of domestic glazed spaces in the United Kingdom, by studying the effect of a range of variables on the thermal properties of glazed spaces, in order to achieve a thermally comfortable environment while minimising the use of energy for heating and cooling. Earlier research work on domestic glazed spaces has concentrated on optimising the design of the space as a mechanism for reducing the space heating load of the parent house. Computer based dynamic thermal simulation is used in this study as the method of assessment and the variables tested are; glazing type, orientation and the degree of integration of the glazed space with the parent building. Unshaded, unventilated, and unheated, glazed spaces were found to be thermally comfortable for only a quarter to a third of the hours of possible use whatever the form, orientation or glazing type. Generally the higher the insulating value of the glazing the fewer the number of comfortable hours for all orientations and arrangements, due to discomfort being caused by high temperatures, even though the weather data used for the simulations only rose above 27'C for 25 hours during the course of the year. Further studies showed that significant reductions in the number of hours experiencing high temperatures could be achieved by the use of buoyancy driven ventilation. The studies indicated that glazed spaces integrated into the house plan tended to experience high temperatures for long periods but that the peak temperatures were much lower than those experienced for shorter periods in the exposed spaces. The effect of ventilation on overheating was therefore more marked in the integral than in the exposed glazed spaces. A study of the effects of roof shading blinds indicated that internal blinds had minimal effect in reducing high temperatures. External blinds had a greater effect than ventilation and a combination of external roof blinds and ventilation appears to provide the best strategy for the control of high temperatures. Studies on space heating loads for the houses and glazed spaces indicated wide variations in the heating loads of the glazed spaces depending predominantly on the insulating properties of the glazing. In terms of the reduction in the space heating load for the parent house, the thermal simulation results predict very little change due to the presence of the glazed space. A study on the effect of increasing the thermal storage properties of the floor construction of the glazed spaces, by substituting a clay tile finish for the original thin carpet layer, in order to reduce high temperatures proved inconclusive with minimal changes in the number of comfortable hours experienced. An investigation of thermal comfort during the Winter indicated that low surface temperatures did not reduce resultant temperatures below the lower limit of the comfortable range in the glazed spaces, during the heated period.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 1998.
Includes bibliographical references (p. 85).
Dynamic Building Enclosures is a system of prefabricated, lightweight, kit-of-parts wall and/or roof elements. This system has the unique capability of dynamically altering, or mutating its shape in reaction to changing user requirements or site climate conditions through the manipulation of a mechanically-driven, computer-controlled frame. The system's ability to actively accommodate multiple functions (potentially with high-performance specifications) within a single space would make it appropriate and desirable for application to a broad spectrum of building typologies. It is postulated that industrial fabrication of standardized elements will increase its economic viability-especially when compared to the multitude of expensive, static, specialized building components it would replace. Since it reacts to optimize environmental performance (temperature, humidity, acoustics, ventilation, and lighting) in changing site conditions it will also be more environmentally responsive and energy-efficient than conventional systems. The objective of this research is to explore the potential gains to users and the building industry of developing an industrially produced building system without the generally associated drawbacks of monotonous, repetitive layouts; inflexibility to changes of use, and the inability to adapt to varying site conditions. The prefabricated kit-of-parts which comprise the system will overlay the complementary structural behavior of form-active structures (cable, tent and arch systems), and vectoractive structures (trusses and space trusses) . The building system design will include: a strut; a node, which will allow the rotation of the struts to accommodate non-regular geometries, and an enclosure system which maintains the desired separation of interior and exterior environments for the various spatial configurations.
by Eric Nelson.
S.M.

There is interest concerning the energy performance of buildings in the United States. Buildings, whether residential, commercial or institutional, generally underperform in terms of energy efficiency when compared to buildings that are constructed following sustainably and energy efficiency standards. A substantial percentage of energy loss in these buildings is associated with the thermal efficiency of its envelope (exterior walls, windows roof, floors and doors). The objective of this study will evaluate the results of three energy modeling techniques developed to investigate the energy transfer through the envelope of existing campus buildings. The techniques employed are solving the heat transfer calculations using spreadsheets, using a stand-alone modeling software (OpenStudio) and using an integrated building energy modeling software (eQuest) employed in Autodesk Revit. The first technique is somewhat different from the other two because it does not require a 3D representation of the building to be generated as the first step in the modeling process. It is the application of a mathematical methodology employing heat transfer algorithms entered into the spreadsheet’s cells to estimate the heat transfer through the building envelope. Data needed for this technique are weather data of the buildings location, surface area of the building envelope, and the overall heat transfer coefficient (U-value) of each component of the building envelope. The OpenStudio technique involves a 3D representation of the building. The building is drawn on a 3D modeling computer program called SketchupPro, which communicates directly to the OpenStudio energy modelling interface. The building operations as well as the building characteristics, such as the composition and type of the elements that made up the building envelop, the thermal zone, occupancy schedule and the space type was inputted in the OpenStudio engine. The OpenStudio engine runs the simulation and generates a detail result about the energy usage and energy transfer in the building. The third method that employs AutoCAD Revit software is a standalone technique that does not require an external software for sketching the building model. Revit the ability to draw the model as well as perform the energy analysis at the same time with the aid of inbuilt eQuest modeling engine. The model in Revit is generated with the right building envelope characteristics as the existing building and the weather file. The process is somewhat similar to the OpenStudio technique; the main difference is the level of detail and limitation provided by both the energy modeling engine (eQuest and EnergyPlus). At the end of the simulation, the building energy modeling using Autodesk Revit presents a detailed result of the energy usage and energy flow in the building. The underlying reason of the comparison of three techniques is to understand the simplest, most efficient, accurate method to quantify heat transfer through the building envelope. By the end of this study, the most efficient technique for investigating the building envelope will be expected to be the EnergyPlus technique because of the usage simplicity, ability to take in a lot of details required for simulation and the periodical software updates.

The thesis explores the technical feasibility of an alternative method of decoupling air-conditioning systems function within the context of ecological issues. The system is a variant of dedicated outdoor air systems to separate dehumidification and cooling in air conditioning equipment. The project specifically investigates locating these components within the building envelope. Placement in the envelope moves the systems closer to fresh air and offers architectural expression for components that are normally out of sight. Designers, engineers, building science, mechanical, structural, biologist, and architectural engineers ideally as agents offer beneficial improvement to the system. The reduction in size of components into the building envelope offers risk. The thesis design space uses historical works, biological analogues, and past work to ground the technical understanding of the topic. Specific use of biological inspired design realizes translation from other systems to improve the alternative decoupled air conditioning system. The thesis develops prototype models for lighting analysis and for sensible and latent heat calculations. Psychrometric charts serve as tools to understand the thermodynamic air-conditioning process in conventional direct expansion vapor compression and solar liquid desiccant air conditioning systems. Data, models, and sketches provide tools for improvements to the 'thick' building envelope. Finally, the diagrams translate into functional decompositions for modifications to improve the system. The thesis probes the constraints in the areas of cost, fabrication, and technology that may not yet exist for selective improvement rather than a barrier to development of the thesis.

This thesis investigates the performance of varied control systems in a office building in the southern parts of Sweden. The control system is designed according to standard EN15232 with three levels of building automation and control systems with a multi-zone approach. Highest standard, class A, is a demand control system with VAV controlled by temperature and CO2-levels in each zone. The lighting in class A is controlled by user demand and dimmers with regard to daylight to meet lighting regulations. The ventilation in the middle system, class B, is VAV controlled by temperature and demand in a zone. lighting is only on when a zone is used but no opportunity to dimmer. The reference object, class C, uses constant air volume CAV based on Swedish regulation and has lighting as in class B. The building envelope is varied between an existing model with 70Às building standard, according to todayÀs standard, and passive house standard in Sweden. All simulations is evaluated through energy performance and indoor climate in terms of temperature, PMV, PPD and CO2-levels. Simulations showed that the class A system has the highest possibility to decrease the energy use compared to the other systems. The reduction in total energy use differs from about 9-27% compared to class C and about 29-34% in electric energy use. Simulations also showed that class A and B are more advantageous to apply in a passive house rather than in the existing building if the total energy is evaluated. With regards to electric energy use, the difference between the building envelopes is too small to state that any difference exists. Neither one of the systems corresponds to ”good” indoor climate in the critical zones, all three is between the range ”good” and ”acceptable” according to standard SE-EN15251. Class A and B show an overall improvement of PMV and PPD compared to class C system. The class B system is closest to fulfill a ”good” indoor climate, especially in the passive house model. Evaluation with respect to CO2-levels class A and C showed acceptable levels.