Academic literature on the topic 'Building envelope'

The building envelope has a direct impact on the overall energy consumption of a building. Thus, an improvement in the building envelope using energy-efficient material can yield the desired energy performance. This study is based on the materials and compositions used in building envelopes in compliance with the building energy code of Thailand. The building under study is an educational building located in Bangkok, Thailand. Both the energy and the economic aspects of retrofitted building envelopes are discussed in this study. The energy performance was evaluated by calculating the thermal transfer value and whole building energy consumption using the building energy code (BEC) software. The simulation was done under the assumption that the building envelope in the case study building was retrofitted with different materials and compositions. The study determines the feasibility of retrofitting buildings using energy-efficient material by utilizing the discounted payback period and internal rate of return (IRR) as indicators. The results show that retrofitted building envelopes in every case can reduce the whole building energy consumption. In the best envelope configuration, energy consumption can decrease by 65%. In addition, the economic potential is also high, with an IRR value of approximately 15% and a payback period of 23 less than nine years. These finding indicate that a building envelope made with energy-efficient material can achieve good results for both energy performance and economic feasibility.

This paper aims to solve one of the energy issues using specific new building designs using the building-integrated photovoltaic (BIPV) panels as a double skin envelope. The BIPV system can be an innovative material for the building envelope during the design process as a: frame component, curtain wall or shading device. In addition to its power generation, the use of the BIPV can be an integrated part of the design of future envelopes and in the energy renovation of old buildings; these systems can producerenewable energy, minimize energy consumption, provide adequate indoor comfort and have less impact on the environment. As an external envelope of the buildings and a source of energy, the BIPV systems can represent the architectural appearance and aesthetic arrangements of the future building. Our investigation is based on an Energy report in many existing office buildings in a hot arid region of Algeria in order to assess their energy consumption, thereafter; calculate the energy yield after the BIPV hypothetical use in building architecture. The important result shows that the BIPV system enhances energy consumption with different percentages of the total energy consumption per year (Building sample 1: 50%, Building sample 2: 30% and Building sample 3: 65%) this is due to many architectural elements; such as: envelop form, shading devices, opening ratio, and environment masks. The major conclusion of the research reveals that The BIPV systems can preserve the architectural aesthetic appearance as well as enhancement of energy consumption.

This study aims to propose building envelope retrofit packages for existing naturally ventilated school buildings in the hot–humid climatic region of Chennai, India. Indoor thermal parameters were collected through field studies from nine sample classrooms of a selected school building in May 2019, between 9.00 am and 4.00 pm. The thermal performance assessment of the existing building was performed by examining the discomfort hours using the CBE thermal comfort tool. Envelope retrofit strategies gathered from the literature and building standards were applied and studied through simulation. The findings reveal the enormous potential to increase the thermal comfort of existing school buildings through envelope retrofit measures. The results demonstrate that the whole-building temperature can be reduced up to 3.2 °C in summer and up to 3.4 °C in winter. Implementing retrofit measures to the building envelopes of existing buildings will help school owners to increase the comfortable hours of whole buildings by up to 17%. In comparison, annual energy savings of up to 13% for the whole building can be made by enhancing the thermal performance of the building envelope. The findings will also help architects to optimise thermal performance and energy usage with minimal interventions.

The thermal performance of the envelope structure is one of the important components of the performance design of near-zero energy buildings. Minimizing envelope heat loss is the key to improving building energy efficiency. A necessary first step in the building envelope optimization process is the assessment of its actual thermal performance. This paper summarizes the application status of infrared thermography in thermal defect detection of building envelopes and common forms of thermal defects in near-zero energy buildings. Taking a near zero energy building in Shenyang area as the target object, an efficient and non-destructive infrared thermal image measurement method is applied to determine the thermal defect rating of the building from both qualitative and quantitative aspects. The results show that the building has high thermal performance. The temperature field distribution of the building envelope could be quickly obtained by using the infrared thermal imaging instrument. In this way, it can accurately identify the location of thermal bridges and air tightness defects, and provide an efficient and accurate detection method for building energy-saving diagnosis and evaluation.

Purpose of reseach is determining the category of technical condition of building structures to assess the residual resource and service life of industrial facilities and urban infrastructure. Development of a fundamental technical solution to the problem of comprehensive restoration of a workable technical condition of building envelopes, including the provision of mechanical and heat engineering requirements.Methods. According to the current regulatory requirements for buildings put into operation, it is necessary to conduct an engineering survey at least once every 10 years. During the engineering survey of the building located at Kursk region, Kurchatovsky district, K. Libknekhta village, ul. Mira 1, significant defects and damages affecting the technical condition of the building envelope were revealed.Results. According to the results of studies, some factors were identified that need to be eliminated. The ways of solving the identified problems and defects associated with the building envelope are given and described in detail to restore the building to its proper position.Conclusion. When conducting surveys of building structures of buildings and structures, it is necessary to pay attention not only to strengthening building structures, but also to restoring the thermal characteristics of building envelopes and bringing them into line with the requirements of current regulatory documents. To accomplish this task, a reinforcement design has been developed that creates the necessary reinforcement and brings the thermal characteristics of the building envelope in line with modern requirements to ensure the necessary energy efficiency of the building envelope.

Reduction of energy use in buildings is an important measure to achieve climate change mitigation. It is essential to minimize heat losses when designing and building energy efficient buildings. For an energy-efficient building in a cold climate, a large part of the space heating demand is caused by transmission losses through the building envelope. To achieve this, it is necessary to have processed a detailed design of buildings. Thermal bridges have to be eliminated in the design of buildings. Thermal bridges occur as point ones or linear. One of the specific details that create thermal leakage is located in balcony slabs. The balcony is one of the main reasons of the increased heat loss of buildings. The presence of thermal bridge in constructions of balcony envelopes influences the energy consumption, durability of the building envelopes, and also the thermal comfort of occupants. This paper is focused on advanced analysis of thermal performance of thermal break element applied in balcony slab with parametric correlation to the thermal properties of wall building envelope.

There has been a plea for sustainable use of resources since the twentieth century. Buildings are known to consume forty percent of the world’s resources. Resources such as gas, oil, coal and electrical energy used in heating, cooling and ventilation of buildings are limited, as well as causing air pollution and climate change. For this reason, the energy resources used in the buildings should be used effectively, considering environmental concerns. The aim of this study is to describe the shift in efficient use of energy in buildings using a biomimetic approach in thermoregulative building envelope strategies that support internal thermal comfort. In this study, passive systems integrated into buildings which use solar energy, one of the renewable energy sources for heating, cooling and ventilation purposes have been examined. The methods followed by nature in using solar energy are discussed with the biomimetic approach and suggestions have been made to support the increase of energy efficiency by applying the obtained teachings to passive building envelopes. Keywords: biomimetics; building envelope; kinetic building envelope; passive strategies; Thermal comfort

Modular prefabricated buildings effectively improve the efficiency and quality of building design and construction and represent an important trend in the development of building industrialization. However, there are still many deficiencies in the design and technology of existing systems, especially in terms of the integration of architectural performance defects that cannot respond to occupants’ comfort, flexibility, and energy-saving requirements throughout the building’s life cycle. This research takes modular prefabricated steel structural systems as its research object and sets the detailed design of an integrated modular envelope system as the core content. First, the researcher chose two types of thermal insulation materials, high insulation panels and aerogel blankets, in order to study the construction details of integrated building envelopes for modular prefabricated buildings. Focusing on the weakest heat point, the thermal bridge at the modular connection point, this work used construction design and research to build an experimental building and full-scale model; the goal was to explore and verify the feasibility of the climate-responsive construction technique called “reverse install.” Second, as a response to climate change, building facades were dynamically adjusted by employing different modular building envelope units such as sunshades, preheaters, ventilation, air filtration, pest control, and other functional requirements in order to improve the building’s climate adaptability. Finally, based on the above structural design and research, this study verified the actual measurements and simulation, as well as the sustainability performance of the structure during the operational phase, and provided feedback on the design. The results highlight the environmental performance of each construction detail and optimized possibilities for an integrated envelope design for modular prefabricated buildings during both the design and renovation phases.

This study concerns an overall evaluation of building envelopes, for what concerns the energy, acoustic and lighting performances. It combines different topics of energy and indoor comfort, with the aim to improve the livability of an existing building (a social housing) by means of a comprehensive retrofit of their envelopes. The novel contribution of this study is to apply some methods for energy retrofit of a building envelope in such a way that objectives are achieved within the state-of-the-art combination simulation, optimization approaches, and equations describing the calculations of sound insulation in buildings. The results showed that properties of building envelope like the value of transmittance of the glass window and thermal properties of materials have an impact on indoor environmental quality and energy performance.

Setting standards of thermal resistance of building envelopes is a current task related with energy saving and energy efficiency of building envelopes. The problem of choosing the factor determining the standard thermal resistance also stays current even after updating of the Construction Norms. The author consider the concept of norming the thermal resistance of building envelope, in which the temperature of the inner surface of a building envelope providing comfortable temperature conditions in premises. The main task of an architect, who is designing an energy efficient building envelope is providing comfortable conditions in premises both in cold and warm periods of the year. The temperature of the inner surface of building envelopes should be included into the construction norms as the main criterion providing comfortable air temperature in premises.

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