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Low-energy buildings have, in recent years, gained attention and moved towards a large-scale introduction in the residential sector. During this process, national and international criteria for energy use in buildings have become stricter and the European Union has through the Energy Performance of Buildings Directive imposed on member states to adapt their building regulations for ‘Nearly Zero Energy Buildings’, which by 2021 should be standard for new buildings. With a primary focus on new terraced and detached houses, this thesis analyses how the concept of low-energy buildings may be further developed to reduce the energy use in the residential sector. The main attention is on the technical performance in terms of indoor climate and heat consumption as well as on the market diffusion of low-energy buildings into the housing market. A multidisciplinary approach is applied, which here means that the concept of low-energy buildings is investigated from different perspectives as well as on different system levels. The thesis thus encompasses methods from both engineering and social sciences and approaches the studied areas through literature surveys, interviews, assessments and simulations. The thesis reveals how an increased process integration of the building’s energy system can improve the thermal comfort in low-energy buildings. Moreover, it makes use of learning algorithms – in this case artificial neural networks – to study how the heat consumption can be predicted in a low-energy building in the Swedish climate. The thesis further focuses on the low-energy building as an element in our society and it provides a market diffusion analysis to gain understanding of the contextualisation process. In addition, it suggests possible approaches to increase the market share of low-energy buildings. / <p>QC 20140321</p>

The issue of low energy construction is currently actual and often discussed topic. The main reason is continuously increasing consumption and price of energy. Additionally, projections show this trend is not going to rapidly change in the upcoming years. The construction of buildings in low energy standard should become one of the most significant sources in energy savings in European Union for the upcoming period. Low energy constructions in contrast with standard constructions are distinguished not only because of low energy consumption and lower operating expenses but also for its favorable impact on the environment. The main purpose of this thesis will be the assessment of economical effectiveness of current low energy constructions and underline the importance of energy saving constructions by using LCA method as one of the possibilities in increasing the quality of environment.

Due to desirable emission reductions and population growth, an increasing energy demand isidentified as a dire issue for energy systems. The introduction of low energy building districtsenables an increased energy system efficiency. This study’s aim is twofold. Firstly, an extensive urban building energy model is used to simulatethe yearly use and geographic distribution of the heat demand for residential and commercialbuildings that are to be supplied by a low-temperature district heating system. Two buildingenergy performance cases are studied; one where all buildings are assumed to be of PassiveHouse standard, and one where the building energy performance is in line with conventionalnew-building regulations in Sweden. The study showed that that Passive Houses will generatethe lowest yearly heat demand and that implementation of ventilation heat recovery has a bigimpact. Furthermore, the results showed that a variation of building energy performance mightbe advantageous when planning a new city district with district heating. Secondly, one specific building is in detail modeled as Passive House and according to BBR-standards and simulated in the building energy simulation software IDA ICE to investigate whatbuilding heating system is best suited for low-temperature heat supply. The temperaturedemands for floor heating and low tempered radiators is investigated and compared toconventional water-based radiators. Results showed that floor heating requires lowertemperature’s than low temperature radiators, but both are well suited for low temperaturedistrict heating. The study’s results will be used as an example for future city district planning aswell as presenting relevant heating systems for low-temperature district heating.

The theme of my thesis deals with a winery near to the village Strachotín next to the Protected Landscape Area Pálava. It focuses, in particular, on the design of this object which serves not only to processing and producing of wine but also for degustation followed by the tour of wine production. Another part of my thesis is the design of accommodation, restaurant and wellness center by the means of using low-energy buildings, their various construction systems and natural materials. The whole conception is based on the overall potential of the territory, using the local sources and supporting the economic and social development of the area.

EUs direktiv för energiprestanda innebär att alla nya byggnader från och med 2021 ska vara nära-nollenergibyggnader. De stundande kraven innebär att beställare måste skärpa sina energikrav vid upphandling av flerbostadshus. Vidare spelar lågenergibyggnader som koncept en viktig roll för att nå hållbar utveckling och det är av högsta vikt att kommande byggprojekt blir effektiva både i byggprocess och vidare i driftskedet.  Nybyggnation av lågenergibyggnader har visat sig problematisk i många aspekter, där den uppmätta energianvändningen i många fall visat sig väsentligt högre än vad som projekterats. I och med den ny byggpraxis med bättre isolation, lufttäthet och ventilation med återvinning blir tappvarmvatten och hushållsel de största energiposterna i en byggnads energibalans.  Syftet med arbetet är att konkretisera problemen som finns för nyproducerade flerbostadshus med energikrav för lågenergibyggnader. Utifrån det har fokus lagts på två byggnader som AB Bostäder låtit bygga – båda projekterade för att uppnå lågenergikrav.  Likt befarat visar Examensarbetet att det är svårt att härleda problemet till specifika poster. Byggprocessen i sig kan vara en bidragande faktor, där tidsbrist, bristfällig kommunikation och okunskap kring ny byggpraxis är förekommande i en bransch som har svårt att hinna med den efterfrågade volymen av nybyggnation. Vad gäller specifika felkällor till försämrad energiprestanda stödjer vår rapport tidigare publicerade rapporter i ämnet där bristfällig indata vid energiberäkningar, byggprocessens inverkan, oaktsamhet av VVC-förluster och betydelsen av brukare har belysts. / The energy performance of buildings directive means that all new buildings must be nearly zero energy buildings by 31 December 2020. The current requirements mean that constructor companies must tighten their energy requirements when procuring multi-family houses. Lowenergy buildings as concepts play an important role in achieving sustainable development, and it is of the utmost importance that future construction projects become effective both in the construction process and on further operation.  New construction of low-energy buildings has proved to be quite problematic in many aspects, where the measured energy performance in many cases proved to be significantly higher than projected. With the new building practice with better insulation, air tightness and ventilation with recycling – hot water supply and household appliances become the largest energy posts in a building's energy balance.  The purpose of this master thesis is to concretize the problems that exist for newly produced multi-family houses with energy requirements for low-energy buildings. Based on this, focus has been on two building that AB Bostäder Borås recently has built – both built to achieve low energy requirements.  As expected, this master thesis shows the difficulty to deduce the problem to specific aspects. The construction process itself may be the source of error, where time shortages, inadequate communication and lack of knowledge concerning low energy buildings are present in an industry with difficulties catching up with the demanded volume of new construction. Regarding specific sources of vulnerability to energy performance, our report supports previously published reports where the lack of input data for energy calculations, the impact of the construction process, negligence of losses due to recirculation of hot water and the importance of user behaviour have been highlighted.

Les bâtiments à très basse consommation d’énergie bénéficient d’une isolation thermique performante et d’une bonne étanchéité à l’air, souvent couplées à une conception bioclimatique du bâtiment. L’apport d’énergie nécessaire au chauffage et au rafraîchissement de l’ambiance s’en trouve considérablement réduit. Dans ce contexte, il devient possible d’utiliser l’air comme unique vecteur d’énergie, à des débits suffisamment faibles pour permettre son intégration dans le système de ventilation sanitaire, et avec un écart de température réduit entre l’air soufflé et l’ambiance. Une unité terminale de soufflage, ou diffuseur d’air, a alors pour rôle d’assurer un mélange optimal de l’air neuf avec l’air ambiant, de façon à obtenir une répartition homogène de température et de vitesse dans les pièces d’habitation, et un bon renouvellement de l’air intérieur. Ce travail de thèse propose une étude du confort thermique et de l’efficacité de ventilation dans une cellule climatique à échelle 1 en conditions contrôlées, dans le contexte d’utilisation d’un système combiné de ventilation, chauffage et rafraîchissement. Une stratégie de ventilation par mélange est mise en œuvre à l’aide d’un diffuseur d’air composé de douze buses lobées de géométrie complexe, et l’occupation est prise en compte par des mannequins cylindriques, qui constituent des sources de chaleur sensible et de dioxyde de carbone. La vitesse d’air, la concentration en CO2 ainsi que les températures d’air, de globe noir et des parois de la cellule sont suivies expérimentalement pour différentes conditions de soufflage d’air chaud et froid. Les mesures expérimentales sont complétées par des simulations numériques de mécanique des fluides (CFD), qui visent à caractériser l’écoulement dans la cellule. Cette approche fait intervenir une méthode de modélisation en deux temps afin d’intégrer correctement la géométrie complexe du diffuseur d’air dans les simulations. Des études paramétriques sont ensuite proposées pour des conditions non testées expérimentalement. Celles-ci visent à mettre en évidence l’impact des conditions de soufflage et des charges internes sur l’écoulement et sur le confort, pour les conditions spécifiques aux bâtiments à très basse consommation d’énergie. / Low-energy buildings benefit from a good thermal insulation and air tightness, associated with a smart integration of the building in its environment. Consequently, the required power for heating and cooling of the building is reduced to a great extent. This allows the use of conditioned ventilation air as the only energy vector: the air is supplied into the rooms at a low-velocity and with a low temperature difference with the indoor air. Air terminal devices are used, whose aim is to provide a homogeneous distribution of temperature and velocity inside of the rooms, and an efficient disposal of the indoor air pollutants. In this prospect, the thermal comfort and ventilation effectiveness in a test room (scale 1) resulting from an integrated heating, cooling and ventilation system is assessed both experimentally and numerically. The air is supplied close to the ceiling through a wall-mounted diffuser of complex geometry composed of twelve lobed nozzles, and the occupancy is modeled by two cylindrical manikins releasing sensible heat and carbon dioxide. Experimentally, the air velocity, CO2 concentration, indoor air, wall and black globe temperatures are monitored in order to assess the Predicted Mean Vote and draught rate in the occupied zone as well as the ventilation efficiency. Computational Fluid Dynamics (CFD) simulations are then performed in order to provide valuable information on the airflow patterns in the room. The air diffuser’s geometry being too complex for a direct simulation, a two-step modeling approach is adopted in order to take it into account in the simulations and to accurately represent the heat and mass transfers in the room. Furthermore, parametric studies are performed in order to investigate the influence of the supplying conditions and the internal heat gains on the airflow and on the resulting comfort, for particular conditions corresponding to those of low-energy buildings.

Diploma thesis deals with issue of another possible application of PUR foam in the building, especially during the construction of the masonry structures with the integrated thermal isolator in the low-energy and the passive buildings. The practical part shows the production of the test sample of selected PUR foams and the trials that were performed on the samples. The aim of the thesis was choosing of the PUR foam with the best attributes which would be suitable as an integrated thermal isolator into masonry structures. In the conclusion there was chosen the best foam from which the masonry fragments were made. The static tests were performed on these fragments.

There is an urgency within the building sector to reduce its greenhouse gas emissions and mitigate climate change. An increased proportion of biobased building materials in construction is a potential measure to reduce these emissions. Life cycle assessment (LCA) has often been applied to compare the climate impact from biobased materials with that from e.g. mineral based materials, mostly favouring biobased materials. Contradicting results have however been reported due to differences in methodology, as there is not yet consensus regarding certain aspects. The aim of this thesis is to study the implications from non-traditional practices in climate impact assessment of timber buildings, and to discuss the shortcomings of current practices when assessing such products and comparing them with non-renewable alternatives. The traditional practices for climate impact assessment of biobased materials have been identified, and then applied to a case study of a building with different timber frame designs and an alternative building with a concrete frame. Then, non-traditional practices were explored by calculating climate impact results using alternative methods to handle certain methodological aspects, which have been found relevant for forest products in previous research such as the timing of emissions, biogenic emissions, carbon storage in the products, end-of-life substitution credits, soil carbon disturbances and change in albedo. These alternative practices and their implications were also studied for low-carbon buildings. The use of non-traditional practices can affect the climate impact assessment results of timber buildings, and to some extent the comparison with buildings with lower content of biobased building materials. This effect is especially evident for energy-efficient buildings. Current normal practices tend to account separately for forest-related carbon flows and aspects such as biogenic carbon emissions and sequestration or effects from carbon storage in the products, missing to capture the forest carbon cycle as a whole. Climate neutrality of wood-based construction materials seems like a valid assumption for studies which require methodological simplification, while other aspects such as end-of-life substitution credits, soil carbon disturbances or changes in albedo should be studied carefully due to their potentially high implications and the uncertainties around the methods used to account for them. If forest phenomena are to be included in LCA studies, a robust and complete model of the forest carbon cycle should be used. Another shortcoming is the lack of clear communication of the way some important aspects were handled. / <p>QC 20150310</p>

Les bâtiments à faible consommation d’énergie connaissent, ces dernières années, un grand intérêt étant donné le rôle important qu’ils jouent dans la diminution des émissions de gaz à effet de serre d’une part, et la flambée des prix des combustibles, d’autre part. Néanmoins, dans de nombreux cas la réalisation de ce type de bâtiments n’atteint pas les performances escomptées. Ce problème est dû en grande partie à : 1) la perte d’informations tout au long du cycle de vie du bâtiment, 2) la non évaluation régulière des décisions prises par les acteurs intervenants. Le commissionnement en tant que processus de contrôle qualité joue un rôle important dans le bon déroulement du processus de réalisation de bâtiments à faible consommation d’énergie. Cette recherche vise à développer une méthodologie dont l’objectif est d’assister les personnes responsables de cette mission dans la définition de plans de commissionnement adaptés à leurs projets. Nous avons réalisé en premier, un état de l’art de la réalisation des bâtiments à faible consommation d’énergie, que nous avons par la suite confronté à la réalité à travers une enquête auprès des acteurs du bâtiment et d’étude de cas réels. Cette étape nous a permis de formuler une hypothèse concernant la nécessité d’un commissionnement «évolutif» -adapté aux particularités de chaque projet - et de décrire une méthodologie globale d’assistance à la conception des bâtiments à faible consommation d’énergie, qui intègre une aide à la décision, une gestion de l’information et un commissionnement «évolutif» qui vient vérifier le bon déroulement des deux premiers. Pour mettre en application cette méthodologie, une boîte à outils a été développée. Elle est constituée de : 1) un outil dit «statique» qui permet de définir un premier plan de commissionnent générique qui répond aux caractéristiques d’un projet, à partir d’une base de données exhaustives de tâches de commissionnement, 2) un outil dit «dynamique» basé sur les probabilités, qui permet de mettre à jour le plan de commissionnement initial (générique), en l’adaptant au projet en cours. Cette mise à jour permet de prendre en compte les particularités et imprévus rencontrés lors de la réalisation d’un projet, rendant ainsi le plan de commissionnement plus précis. Une expérimentation, dans un cas réel, du premier outil et des applications du second ont été faites pour montrer leurs possibilités et leurs limites. Les résultats font apparaître deux points importants : 1) l’intérêt d’avoir un plan de commissionnement structuré et évolutif pour vérifier la qualité de la réalisation des bâtiments à faible consommation d’énergie et assurer ainsi l’atteinte des performances souhaitées, 2) l’intérêt d’utiliser un outil probabiliste tel que les réseaux Bayésiens pour anticiper les dérives et prendre en charge les imprévus rencontrés lors de ce processus vivant. Cette méthodologie représente une base pour le développement d’outils d’assistance à la définition de plans de commissionnement «évolutifs» pour le neuf et l’existant, et tous les secteurs du bâtiment / The low energy buildings know, these latest years, a great interest because of the important role that they play in reducing the greenhouse gas emissions on one hand, and the rise of the combustibles prices, on the other hand. Nevertheless, in many cases, low energy consumption buildings do not achieve the expected performances. This problem is largely due to: 1) the loss of information throughout the building life cycle, 2) the non-regular evaluation of the decisions made by the actors intervening in their conception. The commissioning, as a quality control process, plays an important role in the good progress of the realization process of low energy buildings case. This research aims to develop a methodology to assist the persons responsible of the commissioning in the definition of commissioning plans adapted to their projects. Firstly, we performed a state of art of the low energy consumption buildings realisation that we then confronted, to the reality through an investigation with building actors and a study of real cases. This step allowed us to formulate a hypothesis concerning the necessity of a "progressive" commissioning -adapted to project particularities - and to describe a global methodology of assistance to the low energy consumption buildings realisation that integrates a decision making aid, an information management and a "progressive" commissioning that verify the good realisation of the two first functions. To put this methodology into application, a toolbox was developed. It comprises: 1) a tool named "static" that allows defining a first generic commission plan that satisfies the project characteristics, based on an exhaustive data of commissioning tasks, 2) a tool named "dynamic" based on the probabilities, that allows updating the initial (generic) commissioning plan. This update manages the unexpected events met during the project realization; witch permits the commissioning plan to be more precise. An experimentation of the first tool was done in a real case and applications of the second were done to show their possibilities and their limits. The results show two important points: 1) the interest of having a structured and progressive commissioning plan to verify the quality of low energy consumption buildings realisation and guarantee the achievement of the expected performances, 2) the interest of using a probabilistic tool such as the Bayésien networks to anticipate the drifts and to deal with the unexpected events met throughout the building life cycle. This methodology represents a basis for the development of assistance tools for the definition of commissioning "progressive" plans for the new and the existing, and all the building sectors