No description available.

It is widely acknowledged that sustainability principles should be addressed in the housing market to tackle climate change. In this research, particular attention is paid to latent issues (people's knowledge, motives and values) related to energy saving and carbon reductions in the operational phase of house occupation. In this research, design process is described as a transfer between areas of knowledge bearing on a particular project, aiming for consensus of problem solving. Hence better results can be expected if a close consensus on the alternative options could be achieved between different stakeholder groups. However, stakeholders from different groups often have different systems for value judgement in reality and it is difficult to get the message across in the design decision-making process. To provide a deep insight into the given phenomena, this research explores priority variances between four key stakeholder groups in terms of student accommodation design: designers, clients, occupants and legislators. A multi-strategy research framework is designed for the collection and analysis of data. In this hierarchical context, consultation responses from different stakeholder groups are compared against an agreed set of issues (drawn from EcoHomes). Among these four key stakeholder groups, particular attention is paid to the Occupant Group as its members, student residents (both future housing designers and current housing occupants), are supposed to be better educated on sustainability issues and have a positive effect, through changes in their attitudes, social values and inspirations (willingness to change their lifestyles towards greater environmental sensitivity), over the vast campaigns of education, debate and public participation. It is found that current architectural education frequently overlooks that adapting to climate change could involve carbon-intensive actions - though architectural students have had a general awareness of sustainability principles, it has so far made limited impact on their design protocols or lifestyle choices. Other important findings, such as the interrelationship between education and its effect on student residents' environmental awareness and social desirability, can be fed back into the socio-technical research model (e. g. Bayesian Belief Network model) or used to inform current sustainability-related education. The significant priority variances between different stakeholder groups are also specified. It is concluded that a complete consensus across all stakeholders is unlikely to be achieved in the near future. To achieve better design results, therefore, a communication platform is proposed to facilitate knowledge transfer. Two approaches are addressed to introduce the principle of trans-disciplinary communication: a common language and a broader collaborative decision- making process. Furthermore, by criticising the weighting exercise underpinned BRE's EcoHomes, a Code for Sustainable Student Accommodation (CSSA) is proposed. Rather than achieving a broad consensus, it represents opinions from all levels of decision-makers and acknowledges the priority variances within and between them. As an exploratory case study, the weighting method of CSSA needs to be further verified and developed in the future for legitimate purpose. All research findings are explored and interpreted to the degree of an architect's knowledge level, which reflects the researcher's personal values.

Residential buildings are not only a major energy consumer, but also have considerable ecological impact. Quite often, architects can constitute a large part of the problem of tackling climate change. It is notable, however, that architects around the world have recently been encouraged to embrace the principles of sustainable design, which essentially aims to promote a suite of sustainable architectural practices such as those centred on enhancing household energy and water efficiency. Nonetheless, there seems to be a comparatively limited interest in pursuing the sustainability agenda among architects in the Middle East. In addition, there has been a corresponding dearth of academic research on this topic in spite of its apparent importance. This thesis considers the case of Saudi Arabia, and analyses the energy and water consumption of its current residential buildings in the context of two different climatic settings in the country, with the ultimate aim of establishing guidelines towards achieving sustainable architectural practices within the Saudi residential sector . An extensive literature review has been conducted in order to establish a broad understanding of existing sustainable architectural practices around the world. Using available literature, the thesis also examines both the current status of sustainability within the Saudi building sector, and the need for sustainable residential buildings in Saudi Arabia. Current energy and water consumption within two typical Saudi houses (an apartment complex and villa) were analysed using simulation software packages. Next, a number of design-oricntated energy and water conservation measures were suggested, and their serving potential assessed. In addition, especially as for this Ph.D. research, fourteen highly-informed Saudi stakeholders were interviewed in order to both validate the simulation results and to engage in in-depth discussions on ways of making residential buildings within Saudi Arabia more sustainable. Ultimately, a number of barriers that currently impede a transition towards a sustainable residential sector in Saudi Arabia have been identified. The thesis goes further and provides a number of design and non-design related strategies that have the potential to change the status quo with regard to the limited application of sustainable architectural principles within Saudi residential buildings.

The work in this thesis examines the land utilisation and simulated thermal performance of a pair of two-storey, three bedroom, semi-detached earth sheltered houses based on an existing residential development in South Wales, UK. When designed as Exposed South Wall type earth sheltered houses, which incorporate a number of passive solar design principles, each house provides a ratio of 0.508 for the internal floor area to the overall plot area, which is more efficient than 0.319 for a non earth sheltered house on the same development site. The simulation study has shown that the temperature of the earth sheltering the ground floor rooms is relatively stable on the coldest and warmest day of the CIBSE test year of 1985, but fluctuates widely on the same days at 1500 mm below ground level. The stable earth temperatures enable the ground floor rooms in twenty computer models to record higher resultant temperatures than the first floor rooms, on both the above days. In addition, the temperature range between models in the ground floor rooms is much smaller than in the first floor rooms where there are three variations of earth cover of 1500, 750 and 250 mm. With 100 mm of externally placed polystyrene insulation and an exposed, insulated and south facing first floor wall, 1500 mm of earth sheltering and family occupancy is required, so that both the ground and first floor rooms record resultant temperatures between 18 and 21 °C. With an insulated first floor buffer wall and Trombe wall or a non-insulated first floor buffer wall and insulated passive solar conservatory higher resultant temperatures are recorded and thinner earth covers become feasible with family occupancy. By increasing the insulation to 300 mm of polystyrene the thickness of earth cover and the inclusion of a first floor passive solar collector becomes less significant in recording comfortable internal resultant temperatures. However, the internal resultant temperatures exceed the upper comfort temperature of 23 °C in most rooms in the family and single adult occupied earth sheltered houses. Three optimum design solutions are given which record comfortable internal temperatures and that provide designers with a choice of earth cover, first floor design configuration and insulation thickness.

The UK is committed to cutting greenhouse gas emissions by 80% from 1990 levels by 2050, with intermediate targets set in the form of 5-year carbon budgets. Residential sector emissions accounted for 26% of UK greenhouse gas emissions in 2009. For the UK to meet its carbon budgets, residential sector emission reductions of 35-40% are required by 2022 from 2009 levels, with further reductions beyond. As shown here, the UK has a range of policies and initiatives to reduce carbon emissions from the residential sector; and there is a range of methods and technologies available to reduce carbon emissions from dwellings. The process of selecting the combination of methods and technologies to reduce carbon emissions from dwellings is here termed the specification of a construction strategy. Energy assessment tools (such as SAP, BREDEM and PHPP) are integral to this process. They are used to predict the energy use of dwellings, to demonstrate compliance with targets and regulations, and to compare and choose between alternative construction strategies. However, current energy assessment tools, and the associated methodologies and data, are insufficient for optimal strategy selection. This is because they do not assist in the systematic comparison of all combinations of options; they do not assist in the evaluation of whole life energy, carbon and cost; they do not always allow sufficient flexibility for key inputs and assumptions characterising the dwelling and its use; and they do not allow sufficient flexibility for the key metrics (weather data, carbon emission factors, and energy costs) or lead users to develop values for these metrics appropriate to the study period. Following detailed analysis of the current processes of construction strategy selection for dwellings, a framework is developed for the rapid identification of the optimal construction strategy (within the constraints of the tools and data used), whilst evaluating the whole life energy, carbon, cost and performance of alternative strategies. Methodologies are developed and implemented in a working tool for the systematic comparison of all combinations of options entered by the user; the evaluation of whole life energy, carbon and cost in an energy assessment tool; the use of flexibility for key inputs and assumptions to test the sensitivity of strategy performance to changes in these values; and the development and application of metrics appropriate to the study period under consideration. The use of the framework, methodologies, and tool are demonstrated in worked examples for a new dwelling constructed to the proposed 2016 ‘Zero Carbon Homes’ standard, and for the renovation of an existing dwelling.

Le contexte énergétique international impose de nouvelles orientations au secteur du bâtiment neuf ou en rénovation. Toute nouvelle solution doit être techniquement efficace et respectueuse pour l’environnement. Il s'agit dans ce travail de thèse de réaliser une étude numérique et expérimentale de matériaux de construction biosourcés liés au contexte transfrontalier Lorrain (France-Belgique- Luxembourg). En effet, ce travail intègre une partie du projet européen « Ecotransfaire » mené pour le développement d'une filière durable propre aux éco-matériaux. La sélection des matériaux selon une liste de critères à la fois scientifiques, géographiques et environnementaux a permis de répondre à notre problématique en s'orientant vers l'intégration des matériaux biosourcés pour leurs aspects favorables à l'environnement et à l’efficacité énergétique du bâtiment. Intégrés au bâtiment, ces matériaux sont sujets à plusieurs phénomènes de transfert de chaleur et de masse. Dans un premier temps et pour mieux appréhender ces phénomènes, un modèle de transfert couplé de chaleur, d'air, d'humidité (HAM transfers) est utilisé pour simuler le comportement hygrothermique d’un matériau en bois massif à structure supposée homogène. Ce modèle, mis en œuvre et résolu par la méthode des éléments finis, a été validé par des résultats analytiques retenus dans la littérature. L'étude de sensibilité du modèle au couplage, aux dimensions dans l'espace, aux conditions aux limites et aux variabilités des paramètres d'entrée est également présentée. Une des difficultés de l’utilisation de ce modèle réside dans la prise en considération de l'aspect fortement hétérogène de certains matériaux. Ainsi, dans ce travail, nous proposons une approche de caractérisation d'un composite lignocellulosique hétérogène de structure poreuse. En effet ce matériau est composé de deux constituants bien connus dans le domaine de l’industrie de construction: Le bois et le ciment. Le bois est incorporé sous forme de granulats avec des formes et des tailles irrégulières et le ciment est utilisé comme un liant. Le travail réalisé permet de remonter aux propriétés intrinsèques équivalentes de ce matériau (conductivité thermique et perméabilité à la vapeur) à l’aide des techniques de micro-tomographie. La méthodologie suivie consiste à la détermination de la structure d'échantillon par une prise d'images à l'échelle microscopique. Une fois la structure de l’échantillon générée, une reconstruction de la représentation bidimensionnelle précède la génération de la structure tridimensionnelle à l'aide d’un outil numérique qui permet de déterminer les propriétés équivalentes des domaines reconstruits en 3D. La perméabilité et la conductivité thermique équivalentes sont les deux propriétés évaluées dans cette configuration. Ces deux propriétés dépendent fortement de la porosité et de la distribution des pores dans la phase continue (la phase solide). De plus la composition de ce matériau et les fractions volumiques de chacun de ses constituants influent sur la formation de sa microstructure et par conséquent sur ses propriétés de transferts thermiques et hydriques. L'ensemble des connaissances développées dans ce travail permet une piste sérieuse pour l'élaboration d'un éco-matériau à propriétés contrôlées pour des usages spécifiques dans la construction et la rénovation / International energy context requires a new orientation to the building sector as in construction or in renovation. Any new solution must be technically efficient and environmentally acceptable. In this thesis, the object is to achieve a numerical and experimental analysis of a building biobased materials. Some of these materials are included from the study of a transborder project to the Lorraine region (France, Belgium and Luxembourg). Indeed an Ecotransfaire project was included in this work. This project has been oriented to the development of a sustainable eco materials chain. A process of analysis has been established in order to select the materials candidates on the basis of scientific, geographical and environmental criteria. The answers are moving towards the integration of bio-based materials. These materials are subject of several heat and mass transfers phenomena. So understanding these mechanisms within a building material has been achieved firstly. This resulted on a coupled model of heat transfer, air, moisture experienced by the HAM model. This model is applied to a wooden building material whose its structure is assumed homogeneous. Then, this model was implemented and solved by the finite element method. Its numerical solution is validated by analytical results available in the literature. The study of sensitivity of the model coupling, dimensions in space, the boundary conditions and the variability of input parameters is also presented. One of the difficulties of using this model is the case of heterogeneous materials. Thus, in this work, we propose an approach of characterization of a heterogeneous lignocellulosic composite material with a porous structure. In fact, this material is composed of two components: Wood and cement. The wood is presented by a shapes aggregates with irregulars sizes and the cement is considered as the binder in the composition. The object was to predict its equivalent intrinsic properties (thermal conductivity and vapor permeability) by using the micro-tomography techniques.The methodology consists to determine the structure of the sample by taking images at the microscopic scale. Once the structure of the sample is generated, we will conduct from a reconstruction of the two-dimensional representation to a three dimensional structure by using a numerical tool which determines the equivalent properties of the 3D reconstructed domain. The permeability as well as the equivalent thermal conductivity are the two properties evaluated in this configuration. These two properties are strongly depend to the porosity and to pore distribution in the continuous phase (the solid one). Moreover the composition of the material and the volume fractions of each components influence the formation of microstructure and consequently the thermal and hydric transfers