During the summer, buildings in hot dry climates have the inevitable problem of cooling. These climates are characterized by hot summer days with cold nights, a high degree of solar radiation, low humidity and with a nearly fixed seasonal and daily pattern of wind. These natural phenomena could be exploited by nocturnal ventilation to cool the building fabric, thus saving energy during the day and providing comfort at night. The procedures to evaluate thermal performance of buildings with special reference to nocturnal ventilation are studied. Various approaches to building thermal response are first reviewed. Dynamic thermal simulation computer models are developed to predict hourly 'internal temperatures'. These are used to study the various constituents of models. They are based on: -the Admittance Method (as suggested by the CIBSE Guide); -a similar procedure but with higher harmonics; -the Response Factor Method (suggested by ASHRAE); -and the Finite Difference Method. A room surrounded by similar rooms in a multi-storey building, having only one external wall, was simulated in the laboratory. It was subjected to typical variations of a hot climate. Predictions of the computer simulations are compared with laboratory results and it is shown that -the closest agreement was obtained with the Response Factor and Finite Difference methods which are equally good; -for higher rates of ventilation, representation of a room by a simple three nodes model thermal network will give sufficiently accurate results; while for lower rates of ventilation a more detailed model gives more accurate results; -the standard Admittance Method gives adequate results, especially with higher rates of ventilation. It could also be used for hourly temperature-, calculations and variable ventilation without loosing significant accuracy; -a fuller treatment in the Admittance Method of time-lag and time-lead, associated with the dynamic thermal factors, will not greatly improve the results. An increase in the number of harmonics in the procedure did not also result in significant improvements, especially with a high rate of ventilation. Natural ventilation into rooms through open windows in these climates is theoretically investigated. It is shown that the rate of natural air flow obtained may be sufficient to meet the requirements of passive cooling by nocturnal ventilation. A computer program is developed to calculate the rate of air flow in multi-zone buildings, and a new relationship is suggested, which will reduce the complexity of natural air flow calculations in multi-zone buildings subjected to cross ventilation.

Energy demand in the built environment is quite important. China holds a large population and the energy use in the building sector is about 1/3. The rebuilding of old houses and building new low energy houses are becoming more and more popular in China. Low energy building not only consumes less energy, but also provides good indoor environment. An indoor climate software IDA is used in energy and indoor climate simulation. The traditional high isolated low energy house in a hot climate is analyzed, on a typical day in either summer or winter, or during the whole year. Energy consumptions under different parameters are presented. Results show that high isolated house may not always be suitable in a hot climate.

The thermal environment in outdoor spaces can significantly influence users’ thermal perception and thus their use of these spaces. Improving microclimatic conditions in urban spaces will most likely encourage people to spend more time outdoors, with the potential to improve their health and wellbeing, as well as boosting social cohesion. As well as enhancing the environmental quality of cities it should also eventually improve the quality of life of its citizens. This thesis is one of the first attempts to investigate the outdoor thermal comfort and the effect of cultural differences in hot arid climates. Case studies were carefully selected in two different parts of the world (Marrakech in North Africa and Phoenix-Arizona in North America) to represent a variety of users in similar climatic context. Field surveys, carried out during winter and summer, included: structured interviews with a standard questionnaire; observations of the human activities; and microclimatic monitoring. The results revealed that the solely physiological approach is insufficient to assess the outdoor thermal comfort conditions in hot arid climates. Environmental variables such as air temperature and solar radiation, could have a great impact on the use of the outdoor spaces in the hot arid climate, and may determine the number of people and activities in them. The study also shows that participants who usually spend more time outdoors due to their life style, “outdoors individuals”, tend to stay longer in the studied sites compared with the “indoors individuals” who spend more time indoors. This is probably because the “outdoor individuals” have better experience of the outdoor conditions and respective thermal conditions. Experience has a strong link with expectations so that according to their past experience, people prepare themselves for the expected weather by taking adaptive measures. People from different cultures in the hot arid climate are likely to evaluate their thermal conditions differently, have diverse thermal comfort requirements, and use urban public spaces differently as well. Further work needs to be done to cover more geographical areas within the hot arid climate. Such an expansion may generalise the findings of this study or explain any particularity associated with the sites of the current study. More research is also needed to investigate he thermal requirements and use of outdoor spaces by different social groups by using robust classification methods. Emphasis should be on investigating the influence of thermal comfort on the use of outdoor public spaces by young and older people, and how that may affect their health and will being in such climates.

Problem description: The buildings consume significant amounts of energy and are therefore major contributors to the overall CO2 emissions at the present time. The reduction of energy consumption in buildings is a major contribution to the overall control of global warming and to the improvement of sustainability. These reductions are essential as the world faces economic and energy crisis. An important key to the world’s energy problem is sustainable development. Taking the island of Cyprus as a case study, this thesis explores the different building categories and types, analyse building energy models and propose guidelines for the success development of Zero energy buildings in hot climates without compromising the comfort levels of the buildings. Purpose: The ultimate target is to be able to design and operate a building which requires no fossil fuel consumption – the so called “zero energy/carbon (emissions)” building. It is important for all countries to set a national goal in order to achieve zero energy consumption in the building sector and reduce the energy demands. Method: Through the theoretical research the project explored the causes of the problem of building energy, the different types of buildings, the definitions of zero energy buildings in various countries, regulations and standards concerning the buildings energy and all the available technology, methods and materials that can be used in the building sector. In this way the analysis presents the needs of the project and the point of focus during the practical part of the research with simulation of building models. The practical part of the project was the simulation of different building models in order to apply and check the theoretical findings and finally reach conclusions on the development of Zero energy buildings in hot climate countries. During the building simulation a variety of parameters such as the weather, the orientation, the shading methods, the insulation methods, the buildings materials, the glazing, the HVAC systems and building operation profiles were checked in order to find the appropriate combination of factors and achieve the zero energy building goals. Conclusions: This new approach to zero energy building, gives a new perspective to the energy consumption of the building and the indoor environment while also taking environmental impact from the building sector into account. This change in approach is a crucial part of the overall problem of how to achieve the ultimate goal of Zero Energy Buildings and how to convert buildings into “producers” of energy and help solve the world energy problem/crisis.

abstract: The use of Reclaimed Asphalt Pavements (RAP) in newly produced asphalt mixtures has been gaining a wide attention from state Departments of Transportations (DOTs) during the past four decades. However, the performance of these mixtures in harsh and hot climate areas such as Phoenix, Arizona has not been carefully addressed. This research focuses on evaluating the laboratory and field performance of Hot Mix Asphalt Mixtures (HMA) produced with two different RAP contents 15%, and 25%. A road section was identified by the City of Phoenix where three test sections were constructed; the first being a control (0% RAP), the second and the third sections with 15% and 25% RAP contents, respectively. The 25% RAP mixture used a lower Performance Grade (PG) asphalt per local practices. During construction, loose HMA mixtures were sampled and transported to the laboratory for advanced material characterization. The testing included Dynamic Modulus (DM) test to characterize the stiffness of the material, Flow Number (FN) test to characterize the rutting resistance of the mixtures, IDEAL CT test to characterize the crack initiation properties, C* Fracture test to investigate the crack propagation properties, Uniaxial Fatigue to evaluate fatigue cracking potential, and Tensile Strength Ratio test (TSR) to evaluate the moisture susceptibility. Field cores were obtained from each test section and were tested for indirect tensile strength characteristics. In addition, asphalt binder testing was done on the extracted and recovered binders. The laboratory results, compared to the control mixture, indicated that adding 15% and 25% RAP to the mix did not have significant effect on the stiffness, improved the rutting potential, had comparable cracking potential, and gave an acceptable passing performance against potential moisture damage. The binder testing that was done on the extracted and recovered binders indicated that the blended RAP binder yields a high stiffness. Based on results obtained from this study, it is recommended that the City of Phoenix should consider incorporating RAP in their asphalt mixtures using these low to moderate RAP contents. In the future implementation process, it is also recommended to include specifications where proper mixture designs are followed and supported with some of the laboratory tests outlined in this research. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2019

Si un concepteur, architecte ou ingénieur, veut concevoir un logement de basse consommation et le site du projet se trouve dans une région au climat froid, les réponses sont nombreuses et la littérature scientifique très abondante. Si le site de notre projet se situe en climat chaud, voir très chaud, le nombre de méthodes simples pour concevoir une maison de basse consommation diminue drastiquement. La solution la plus habituelle des concepteurs non initiés à la basse consommation est de faire appel à un ingénieur d’un bureau d’études énergétiques, qui saura proposer des simulations à partir d’un modèle thermique-dynamique et anticiper la consommation du modèle. La mission d’un bureau d’études a un certain coût, et ses services ne peuvent pas être accessibles à tous les projets. Ainsi, des milliers d’architectes en climat chaud proposent des projets inspirés des références lointaines ou des réalisations non adaptées sans les conseils d’un spécialiste de l’énergie du bâtiment. Ces projets, très énergivores, continuent à croître sans cesse. Pour tous ces concepteurs des projets de taille modeste nous proposons dans cette étude une méthode facile, efficace et accessible à tous permettant de prendre conscience des enjeux bioclimatiques et les options architecturales qui existent pour réussir un projet de basse consommation, puis de le défendre auprès de ses commanditaires. En nous appuyant sur les informations en ligne accessibles à tous, nous proposons une méthode basée sur l’utilisation des degrés-jour de refroidissement et de chauffage. Une série de simulations robustes sur un modèle thermique dynamique générique fourni des résultats qui pourront être interprétables par les concepteurs et projetés sur leurs propres conceptions.La première partie de ce document analyse la construction et la culture en climat chaud: méthodes de classification climatique, les phénomènes physiques les plus significatifs en lien avec la basse consommation,et les notions de confort et température ressentie. En suite, nous proposons un outil d’aide à la conception : la Méthode des Saisons Climatiques, une méthode basée sur un concept très simple : l’ouverture ou fermeture de la maison à l’extérieur en fonction des conditions extérieures quantifiée par les degrés-jour du site. Elle permet de faire une classification climatique du site très orientée vers la conception bioclimatique. Elle base le classement d’un site selon des journées types, S1 à S6, selon jour/nuit froid/froide, tempéré/froide, tempéré/tempérée, chaud/froide, chaud/tempérée et chaud/chaude respectivement. Cette nouvelle classification peu ts’appliquer à tous les climats de la Planète. Une période de l’année continue avec une même journée type donne lieu a une Saison Climatique. Chaque Saison climatique aura des spécificités architecturales propres,et parfois contradictoires entre deux saisons climatiques différentes. L’objectif est de trouver la combinaison architecturale la plus efficace pour une période annuelle complète.Des modélisations Energy+ seront faites pour ces 6 journées types ainsi que pour une période annuelle dans une ville au climat très chaud : Dubaï. Des actions architecturales sont évaluées avec un modèle thermique dynamique.Les actions architecturales seront classées par efficacité énergétique et par temps de retour surinvestissement . Deux maisons idéales par journée type seront proposées : la maison la plus performante et la maison la plus rentable. Une méthode de combinaison d’actions architecturales permettra de trouver une combinaison cohérente d’actions en fonction du climat annuel d’un site. Ensuite nous proposerons les caractéristiques communes, un socle commun, de la maison en climat très chaud de la région du Moyen Orient. / The last 25 years have been ground-breaking in architectural design on low energy consumption in cold climate, mainly in north-western cultures. For an architect today, the method to design a passive house in cold weather and the choice of the Architectural Actions (AA), are clearly established. When the question comes to how to build a passive house in warmer, hot, and very hot climates, the strategies arepoor and often results of a combination of western strategies with a local relook. From several visits in MiddleEast countries, Saudi Arabia, UAE, Oman, Palestine, Qatar, we concluded that the strategy for low consumption houses is not established yet and poorly grasped. The lack of training on low energy consumption in hot climate and the low price of energy, force designers and owners to rely on over usage of air-conditioning systems as measures to catch up on poor bioclimatic design. This method proposes a new approach on bioclimatic designfor hot climates from an architect point of view. It is based on a Cooling Degrees Days (CDD) and Heating Degrees Days (HDD) approach, a state of art of contemporary architecture and professional experience. Localclimates are classified according to the energy-hunger of six situations of the exterior temperature during night/day : cold/cold, cold/cool, cool/warm, cold/hot, cool/hot, and hot/hot as CDD and HDD of the twelve month ofthe year. A group of days on one of those situations will be called “climatic season”. In parallel we will create two main “climatic situations”: people keep the house closed to the exterior or opened to the exterior. We will associate passive strategies to these two differents ways to live in the house: “cold” and “hot” to a closed houseand “cool” and “warm” to a house opened up to the exterior. This method allows classifying any climate in theworld under these six climatic seasons. Our climate classification can now be associated to different strategies that we will call “architectural actions” as house is closed or opened. We could already start to design a house from here, but to better understand the influence of each action we have created an Energy+ model to analyze individually the effect of a single AA. The performance of each action is evaluated under the situations of six representative journeys as well as a year round on a very hot city: Dubai. The result of the effect good or badof action during each different season situation allows us to create the best combination of AA that are best fora year round climate resulting of the combination of several climatic seasons. This low-tech method will help usto find the common features of the houses of different hot climates of a big region and find the best typology. We have carried in parallel a cost study of the base house and the financial incidence of each single action to evaluate also the payback period by action.