Theses for Architecture and Sustainable Built Environment

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    The Environmental and Economic Impacts of the Use of Recycled Asphalt during the Preventive Maintenance of Roadway in the UAE.
    (The British University in Dubai (BUiD), 2023) AL SHEHHI, AISHAH HASSAN OBAID
    Roadways provide the primary means of connection between one area and another. The road network is an essential element of infrastructure development planning, which supports the ability of the citizens to transport goods and services and to travel smoothly. It is, therefore, imperative that an efficient road network is maintained. The significance of a well-maintained efficient roadway network notwithstanding, it is necessary that precious natural resources are saved, and the roadway maintenance practice is geared towards reducing its impacts on the environment. The study assesses the application of cold in-place recycled asphalt in roadway maintenance procedures where the asphalt pavement condition is tested. The options that are provided as a roadway maintenance process in the Dibba-Masafi E89 roadway in the UAE are found by exploring roadway case studies, building software models using RAMS, running different scenarios for the optimum modelling, and studying the priority of undergoing the maintenance among federal roadways. This research attempts to determine the roadway maintenance choices in the UAE federal roadways, by suggesting the use of recycled asphalt in the preventive maintenance of pavements. Financial and environmental advantages are anticipated when using recycled asphalt pavement in roadway maintenance. The study uses combined qualitative and quantitative methodologies to answer research questions to achieve the research aim and objectives. The possible benefits of using recycled asphalt pavement in roadway maintenance have been examined and the disadvantages of using it have been illustrated to understand the effectiveness of the material to be used as an alternative solution. The enhancement to the maintenance system used in the UAE Federal roadways is targeted to reduce the need for maintenance, thus cutting running costs as well as maintenance process costs that comply with sustainability requirements. There are different characteristics and parameters such as rutting, cracking, pavement quality Index, and roughness of pavements that are assessed to get the best solution. To illustrate, the parameters have been explained in detail using RAMS simulation. Depending on that, the maintenance of the roadway performance is done by comparing the roadway to the codes and standards. Furthermore, the economic influences which have been obtained from using recycled asphalt pavement in roadway maintenance are evaluated by the comparison of three scenarios by life cycle cost analysis with consideration of the analysis for 20 years. The scenarios were 50 mm mill and overlay, cold-in-place recycling (CIPR) and reconstruction. The best scenario was chosen (CIPR) with a cost of 174,292 Dhs. Besides that, environmental impact was through waste fill land calculation based on the volume of the case study of the Dibba- Masafi roadway, 13,285 m3 from the conventional pavements, shows that managing this construction area’s waste is a challenge within its given rising volume. However, by using recycled asphalt, 10,488 m3 of waste. Using recycled asphalt saves around 79%. The Future roadway maintenance plans in UAE federal roadways can be more efficient and ensure a better level of service. RAP assists in prioritizing maintenance plans for roadways with the use of RAMS data analysis, which enhances the sustainability and efficiency of the performance.
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    Evaluation of LEED Interior Design Environment to Improve the Indoor Environmental Quality Through Enhancing Lighting Parameters of UAE Campus Buildings
    (The British University in Dubai (BUiD), 2023-11) HASHAYKEH, HANAN A.; Dr Hanan Taleb
    This study investigates the integration of interior artificial lighting, daylight, and quality views, all of which fall under Indoor Environmental Quality (IEQ), a key LEED (ID+C) credit in interior design environments. The research focuses on a campus building in the UAE, specifically the British University in Dubai. Effective design of these variables can enhance visual comfort and improve the building's indoor environment, including lighting quality and user performance. The methodology combines online surveys, field measurements, and computer simulations using DIALux EVO 11. It also considers human factors among students and staff through a mixed-method approach to validate findings and correlate data. The study aims to connect objective and subjective assessments of environmental factors in both daylight and artificial lighting, including lux value, uniformity ratio, glare, and daylight factor, according to EN 12464-1 (2021) standards. Field measurements validate outcomes from the base model in the software. The research offers practical insights into enhancing IEQ in campus buildings through various lighting strategies and scenarios. It analyzes different spaces based on LEED classifications, such as auditoriums, classrooms, libraries, and administration areas. The key findings emphasize the need to balance lighting parameters and conditions to achieve optimal results. The results show improved lighting conditions, enhanced lux values, glare reduction, and balanced light distribution across various spaces, benefiting user experience and performance. For instance, in the corridor areas, the lux value met the target value, ensuring the desired lighting quality. In other locations, such as the auditorium and classroom FF-111, lux values significantly exceeded the target levels, with values reaching 527lx and 602lx, respectively, greatly enhancing overall lighting conditions. The study's actionable insights cater to designers, architects, and stakeholders involved in campus building projects in the UAE. By integrating sustainable standards, this research promotes environmentally sustainable indoor environments that prioritize occupant well-being and enhance the quality of educational spaces.
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    Analyzing and Simulating Traffic Collision Data to Recommend Policy for Autonomous Taxi Deployment in Dubai
    (The British University in Dubai (BUiD), 2023-12) MAHBOOB, MOHAMED
    The adoption of appropriate and suitable Autonomous vehicles regulations and guidelines is one of the main challenges that governments and transportation decision makers are facing nowadays. Appropriate guidelines to operate autonomous vehicles successfully and to maximize their benefits is crucial for safe and seamless deployment. This research focuses on analyzing the key safety benefits of deploying autonomous taxis for traffic collision avoidance. The research also suggests and recommends policies and guidance to accelerate appropriate and safe autonomous vehicles deployment. The research aims at supporting policy makers and governments with the recommendations for safer deployment of autonomous taxi. The Al Muraqabat area was selected for the simulation model as it had a high frequency of collisions. Statistical analysis of taxi traffic collision data was conducted to identify the human factors that contribute to traffic collisions. The statistical model was developed using the SPSS software. Ten reasons for traffic collisions were studied and 76% of the traffic collisions were due to three reasons that were associated with human factors. Experience, Age and fatigue were identified as main causes of traffic collision which are associated with human drivers. The outcome of the statistical model was used to build a traffic simulation model using the Vissim traffic simulation Software. Seven scenarios were simulated which included a baseline model and three autonomous driving behavior scenarios that were simulated on both 100% and 50% penetration levels. When autonomous scenarios were simulated, the lowest number of traffic collisions occurred for the case of 100% normal driving behavior (367) which was 21% lower than baseline scenario. Policy analysis was used to identify gaps in the current legislations and exploring best practice globally. The interview questions were formulated based on the outcome of statistical analysis, simulation and legislation gaps. The thematic analysis was used to identify the experts’ ideas and thoughts using Nvivo software. Experts suggested focused on engaging the government and providing incentives to the private sector. Restudying urban planning, dedicated autonomous vehicles centers and developing smart infrastructure were the main recommendations. Revising the traffic and developing autonomous vehicles standard are critical for safe deployment.
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    Developing an Urban Resilience Index for Ajman City
    (The British University in Dubai (BUiD), 2023-06) ALSHAMSI, ALYA; Professor Bassam Abu-Hijleh
    Land-use change and worldwide environmental degradation are both accelerated by urbanisation. With global urbanisation accelerating, new regulations are needed to protect urban ecosystems, species, and the services they offer, ensuring more viable, adaptable, and liveable cities. The increase in the research of sustainable development has enhanced the awareness and attention of various global sectors such as developers and policymakers regarding advanced sustainable cities, along with the associated impact of sustainability in terms of the urban transformation. Ajman, one of the seven emirates that make up the UAE, has begun to establish plans, policies, and initiatives for this aim in collaboration with the other governmental agencies. Ajman has faced more obstacles as a result of the Emirate’s growing population, improved social conditions, way of life, and industrial revolution. These difficulties line up with the national and international aims and strategies that focus on pressing environmental, social, and economic problems. As a result, Ajman Municipality has made it a priority to integrate sustainability into all facets of daily life, and considers it to be essential to both its vision and goals. This research is intended to develop an urban resilience index (URI) for Ajman city to support future planning. The primary objective was to develop a tool for measuring and quantifying the resilience of an area, in order to assist policymakers and urban planners in determining whether a development project will be instrumental in enhancing city-level resilience. The proposed URI is based on data collected from a range of indicators spanning a number of key URI component indices. The dimensions over which the indices are distributed were identified through a critical literature review, while keeping Ajman’s local context in mind. The methodology for the current research was the primary qualitative approach, which was collected by conducting interviews. Ajman’s URI, according to the stakeholder feedback, should include institutional, infrastructural, social, and economic factors. The stakeholders also pointed out that the primary urban indicators that should be included in Ajman’s URI are the ecological environment’s quality, environmental policies, land use, public service amenities, disaster response and reduction framework, and critical city infrastructure. One of the issues raised was that the population of urban areas has grown significantly in recent years, and is expected to grow even further. Therefore, planners cannot find a balance between measures that can be better implemented to make urban systems, cities, and their people more resilient to problems. A 17-item universal resilience indicator composite was developed and found to be effective in assisting policymakers with the planning and assessment of a resilient future Ajman. The proposed URI can provide comprehensive information on urban resilience to climate change for municipal planners in cities. It allows for comprehensive city comparisons, which aids in the qualitative evaluation of areas of strength and weakness. It also allows one to look into the relationships between the total URI and other aspects of urban climate change resistance. Thus, the URI can be used to assess individual components of urban resilience and their associated indicators, as well as broad indicators of urban climate change resilience.
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    Performance Optimization of Photovoltaic Thermal System under UAE Climate Condition: Experimental and Simulation Analysis
    (The British University in Dubai (BUiD), 2021-03) ALSHAAER, SHEIKHA ALI
    One of the worldwide challenges is reducing energy consumption to reduce greenhouse gas (GHG) emissions that are associated with energy production and use. Delay in taking proper action will lead to the catastrophic effect of global warming (Ghoneim, 2016). In general, until today, the majority of energy is produced from fossil fuel sources (Riffat, 2011). There are various reasons for still depending on fossil fuel resources to produce energy. Fossil fuel energy has a lower production cost than renewable energy (Sharma, 2016). In addition, fossil fuel is very efficient in producing energy. On the other hand, generating power from solar energy is considered to be a promising solution. However, the Photovoltaic system has low efficiency resulting from the low conversion factor of Photovoltaic cells (Shaneb & other 2017). Accordingly, various researchers focused on enhancing the PV performance through avoiding shading and, using the sun tracking system. Photovoltaic thermal is considered to be one of the methods used to enhance the electrical performance of PV systems. The main working principle of PVT is passing fluid at the back of the PV panel that removes the excess heat from the PV panel surface and enhances electrical efficiency. The fluid used in PVT is either water, air, or refrigerant (Shaneb et al, 2017). The aim of performing the test was to evaluate and assess both electrical and thermal performance of the PVT system, under UAE climate conditions, in the first phase of the study. Then, enhance the performance of PVT, by optimizing some of the design parameters. To achieve the project aims, the research started with a review of previous studies related to PVT. The literature review focused on data required to be collected during the experimental phase, the capability of TRNSYS software, and optimization parameters. Therefore, the research methodology has been carried out in two parts: experimental and simulation. In the first part, the performance of PVT, in comparison with PV panel, was tested experimentally. The collected data from the experiment were utilized to develop a simulation model to represent PVT by using TRNSYS software. The simulation model was used to optimize the PVT performance by changing some of the design parameters. The design parameters were: number of collector tubes, tubes diameter, and PVT panel area, and water flow rates. Experimental results showed that the enhancement in electrical efficiency of PVT in winter was 0.7%, which is equal to 5% more in comparison with PV. The results in summer were 1.2%, which is equal to 8.9% more in comparison with PV panel. The overall PVT efficiency in winter was 53.8%, and in summer the overall PVT efficiency was 57.1%. A simulation model was developed for the PVT system, based on data collected from the experiment. The model has been validated, comparing the experimental results with simulation results, with a tolerance of 5% error. In the simulation part, some design parameters were optimized by testing a range of values: number of collector tubes, tubes diameter, PVT panel area, and water flow rates. The aim of changing the design parameters was to optimize the performance of PVT during winter and summer. The results showed that the optimum number of collector tubes was 12 tubes; the optimum tube diameter was 0.04 m; and the water flow rate was 2.5 GPM in both winter and summer. In addition, results showed that changing the PVT area was not feasible. There was no enhancement in the overall efficiency. Based on the identified optimum values of design parameters, the optimized model was created. The results from the optimized model showed further enhancement in comparison with the reference model. The percentage of electrical efficiency enhancement of PVT was 7.2% in winter and 7.5% in summer, compared to the reference model. In addition, the research compared the electrical performance of the PV panel with the PVT optimized model. The electrical efficiency of the PVT optimized model provided higher electrical efficiency than the PV panel by 6% during winter and 10% during summer.
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    Fuzzy Techniques in Visual Performance and Illumination Applications
    (The British University in Dubai (BUiD), 2020-08) Alhamad, Issah
    The lighting design calculation has many variables that do not realistically have crisp values and therefore can be considered fuzzy. By fuzzy we mean that a particular variable does not have an exact value. The vagueness of such variables will certainly lead to imprecise outcomes. In fact, many visual performance and luminous variables and metrics are- either by nature or by virtue of their inherent complexity- not precise. To come up with an exact output from input that is, by its very nature, uncertain and imprecise is virtually impossible. We believe that the uncertainty that is inherent in many lighting design variables leads to imprecise lighting design outcomes. Hence, Fuzzy logic technique is suitable for implementation in visual performance and illumination applications. Moreover, Fuzzy logic can solve the problem of complex mathematical formulas and a large number of correction factors currently used in visibility models. This work is exploring the possibility of applying the fuzzy techniques in both indoor lighting and road lighting by demonstrating how lighting variables can be represented in fuzzy sets rather than crisp sets. The first part of this study is related to indoor illuminance selection, three variables (Age, Task characteristics, and task importance) have been considered as an input for the fuzzy model with the target Illuminance as the output. This model allows for the lighting designer to select the precise target illuminance based on the actual conditions and avoid underlit or overlit situations. Moreover, a digital tool has been developed based on the membership functions established in this study that allows the lighting designer to check the state of the uniformity and compare the target illuminance (based on his choice or based on the application) with the achieved illuminance from lighting calculations. The second part of this study (road lighting) models the visual performance based on fuzzy techniques. This allows the proposed visual performance model to include more input variables compared to the current visibility models. The input variables are luminance contrast (positive and negative), age, visual size, retinal illuminance, eccentricity, background complexity, and disability glare, while the output variable is the Fuzzy relative visual performance (FRVP). The results of these models have been compared to the current visual performance model and it was found to be in good conformance. Moreover, the term ‘critical contrast’ is introduced, defined as the minimum contrast required to produce a change in the rating of the visual performance for a particular values of visual age, visual size, retinal illuminance, eccentricity, and background complexity. A digital tool has been developed to calculate the fuzzy relative performance and is available to be used
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    Heating, Ventilation and Air Conditioning Multivariable Control System with Least Energy Dissipation
    (The British University in Dubai (BUiD), 2019-03) Touqan, Basim
    The highest energy consumption in building sector is caused by building's services such as lighting units and thermal comfort systems. Heated Ventilated Air Conditioning (HVAC) system consumes approximately 50% of the total building energy bill. Many measures have been proposed to achieve energy efficient buildings. Accurate HVAC mathematical models, as well as suitable HVAC control system that leads to optimised energy consumption and improved system performance are part of the engineering efforts to achieve greater efficiency. This study is part of such engineering efforts. It concentrates on employing a ready developed reliable HVAC system mathematical model, namely hybrid distributed-lumped parameter model which handles HVAC as spatially and dimensional dispersed systems for specific HVAC components such as ventilated volume. Other components, such as fan motors, inlet and exit impedances, have physical properties that treated as concentrated lumped mass elements without compromising on the accuracy. Applying an appropriate automatic control strategy to achieve improved HVAC system performance associated with least control energy consumption is one of the major research objectives. This objective has been achieved by adopting and applying a multivariable Least Effort (LE) control technique to regulate a multivariable three inputs-three outputs HVAC system model that employs output feedback, passive compensators and proportional gains, avoiding employment of active integrators. Direct Nyquist Array (DNA), as an alternative multivariable control technique, was employed to compare with the LE performance in terms of system performance and proportional control energy cost. Contrasting the straightforward procedure used to decouple the interaction between the outputs in the LE controller, the identification of decoupling matrix in the DNA controller was based on a trial and error approach, which was very time consuming. After decoupling the plant transfer function matrix, the DNA controller was able to regulate and control the HVAC multivariable system based on using PID loop control, but on the price of consuming higher proportional control energy cost which contravenes with global efforts to minimize energy consumption inside buildings. The ratios of proportional control energy cost between LE and DNA at the time 900 seconds following disturbance unity changes on the system outputs are , and for three different disturbance scenarios. LE controller has shown also better system performance than DNA which at the end makes it superior to the DNA control solution based on the consideration of the simplicity of each controller, the system behaviour under closed loop control and the control energy dissipation.
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    Prevalence and risk factors of poor indoor air quality and sick house syndrome symptoms in Dubai
    (The British University in Dubai (BUiD), 2019-04) ALI, MUNA IBRAHIM
    "Housing environment is a key determinant of health and wellbeing for individuals, communities, and public health at large. Recently, an increasing range of diseases related to poor Indoor Environmental Quality (IEQ) commonly referred to as Sick Building Syndrome (SBS) symptoms – or Sick House Syndrome (SHS) in case of housing related symptoms –which are evolving as a global concern. What exacerbate the concern regarding SHS is its’ being a product of intricate interactions between three multivariate factors involving the IEQ factors in addition to building and population characteristics. Due to that complexity; high levels of ambiguity and uncertainty enfold the associations between IEQ and SHS. Globally, previous research focused in investigating the associations between IEQ and health symptoms in offices more than houses. However, housing IEQ and its associated health risks is of growing concern because of the longer exposure to contaminants and its inclusion of vulnerable individuals. In the United Arab Emirates (UAE), poor indoor air quality (IAQ) in housing – which is one of the IEQ factors – is considered as the 2nd environmental health risk. However, few population-based researches were conducted regarding poor housing IEQ and its associations with SHS. None covered a sample including the different nationalities living in UAE. That is important in revealing more realistic results reflecting the present IEQ and SHS in UAE housing. Furthermore, the impact of many building variables on IEQ and SHS is under-researched by previous studies i.e. applied HVAC system, building age and type. Therefore, this research sought to respond to a number of questions aiming to: (1) Explore the IEQ conditions and prevalent SHS in Dubai housing; (2) Identify the risk factors affecting IAQ and SHS; (3) Investigate the impact of the applied heating, ventilation, and air conditioning (HVAC) system on IEQ and SHS; (4) Assess the sufficiency of provided AERs; and (5) Propose appropriate strategies to mitigate poor IEQ and SHS prevalence. The two major methods employed by this study were a cross-sectional survey and a field study. The survey collected data from 770 Dubai residents. The utilized questionnaire was adopted and adapted from the MM 040 NA questionnaire, EPA IEQ in addition to EPA IAQ and work environment questionnaire. A pilot survey covering 120 Dubai households was conducted to examine the reliability and validity of the proposed questionnaire and to develop it accordingly. SPSS Statistics Version 23 software was used for the survey analysis and it encompassed the conduct of principal component analysis (PCA) and multiple linear regression (MLR) models. Regarding the field study; it was conducted in the living hall of 60 Dubai household and it included measurements, questionnaire, and AERs calculations using CO2 steady-state method. Performed measurements were: (1) Continuous measurement of indoor PM2.5, PM10, CO, CO2, TVOC, RH, and T levels for 24 hours; (2) A single sample of indoor HCHO drawn for 30 minutes; and (3) A spot measurement of outdoor CO2, CO, TVOC, RH, and T levels. The survey results revealed that prevalent health symptoms experienced at least 1 – 3 days/week in Dubai households were ergonomic symptoms experienced by about 18% of Dubai households, general (17%), skin (17%), fatigue (17%), nose (17%), neurological (15%), cough (12%), eye (10%), throat (9%), chest symptoms (8%), and fever (5%). Prevalent SHS symptoms – occurred at least once a week and became better outdoors – were about 30%. The most prevalent IEQ conditions at least 1 – 3 days/week was dust and dirt experienced by about 29% then “Too quiet” (22%), “Too hot” (22%), “Too humid” (19%), “Too noisy” (19%), “Too cold” (17%), “Too glary” (13%), “Too dim” (14%), “Little air” (15%), “Too dry” (16%), and “Stuffy bad air” (14%). The most prevalent odors at least 1 – 3 days/week were “Fishy/food odors” reported by approximately 21%, “Body/cosmetics odors” (20%), “Tobacco smoke” (20%), “Incense smoke” (19%), “Chemicals odors” (7%), “Dampness odors” (6%), “Diesel/engine exhaust” (6%), “New carpets’ odors” (4%), and “Paint odors” (4%). Moreover, following is a summary characterizing measured indoor IEQ parameters and estimated AERs in the 60 Dubai households: • PM2.5 levels exceeded the 35µg/m3 limit (ASHRAE 2016) in all households. • PM10 levels exceeded the 150µg/m3 limit (DM 2016) in 88% of households. • TVOC levels exceeded the 300µg/m3 by DM (2016) in 67% of households. • CO2 levels exceeded the 800ppm limit (DM 2016) in 45% of households. • T range was not complying with DM (2016) requirements in all households while RH range was not complying with DM (2016) requirements in 60%. • Estimated AER insufficient as per (ASHRAE 2016) in 38% of households. • CO and HCHO levels were acceptable as per national and international standards. According to survey results; perceived IAQ discomfort was significantly associated with: perceived odors, Thermal, Lighting, and Noise comfort, dust allergy, age, migraine, other Africans, in addition to new wall covering. IAQ discomfort was positively associated with all above parameters except the new wall covering. Regarding the signicant associations with prevalent SHS symptoms; the population variables identified as risk factors that had positive association with prevalent SHS symptoms were: dust allergy, migraine, asthma, females, eczema, and other Arabs or MENA Nationals. The following list shows the building and IEQ variables identified as risk factors positively associated with prevalent SHS symptoms. Notably that no significant association was found between any of the three HVAC systems studied by this research with SHS symptoms as per the adjusted MLR models. • Dimness with all SHS symptoms. • Stuffy air, dust, dirt, paint odors, dampness odors, in addition to attached kitchen with Eye, Nose, Throat, and Chest symptoms. • High humidity, incense smoke, water leakage, in addition to Dubai Sector 1 with General, Ergonomic, Nervous, and Skin symptoms. The above results revealed the great opportunities in mitigating prevalent SHS symptoms in Dubai housing when controlling the identified risk factors. To achieve that, collaborative efforts are required from all related bodies i.e. governmental and academic institutions, building industry, and even occupants. Following are the major practical implications and recommendations that can be derived from findings of this research: • Developing related regulations by: o Mandating an appropriate exposure limit for indoor PM2.5 concentration. o Establishing rigorous policies to enforce compliance with mandated limits. o Establishing convenient policies to manage probable environmental risk of incense burning and new paints. o Incorporating the needs of atopic individuals and females in related policies. • Increasing public awareness about below risk factors and how to manage them: o The risk of having unacceptable indoor levels of PM2.5, PM10, TVOC, CO2, T, RH, and AERs that threatens a substantial number of Dubai housing. o The identified IEQ and building risk factors associated with SHS symptoms which were: indoor dimness, dust and dirt, stuffy air, paint odors, high humidity, water leakage, dampness odors, incense smoke, attached kitchens, and Dubai Sector 1. While population risk factors were: dust allergy, migraine, asthma, gender, eczema, and other Arabs or MENA Nationals. • Employing efficient management methods for the above identified risk factors i.e. indoor lighting solutions, moisture control methods, dust prevention strategies … etc. • Conducting further research to fill available theoretical gaps i.e. in-depth researches regarding identified risk factors exploring their sources and management methods. "
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    Courtyards as passive design solution for school buildings in hot areas: UAE as a case study
    (The British University in Dubai (BUiD), 2018-06) SALAMEH, MUNA MAHMOUD
    The global concentration on green efficient schools is growing as schools represent a considerable sector in the built environment, which consumes a lot of energy to provide a standard level of thermal comfort for students. In the UAE, both private and public-school buildings are assumed to be a high energy consumption sector, in addition to universities, banks and shopping malls. Moreover, the energy consumption in schools seems to be encouraged rather than controlled, thus there is the potential for reducing the sector’s energy consumption. Traditional architecture adopted the courtyard design as a distinct form to create the core of houses and moderate the thermal conditions for the surrounding spaces, especially in hot climates. In most of the previous studies on the subject, courtyards were found to be related to houses or buildings in general, rather than educational institutions specifically, such as schools. This research aims to investigate the integration of a well-designed courtyard as a passive design strategy in buildings in the UAE to reduce the energy consumption required for cooling. In addition, the improvements in the thermal comfort conditions within the courtyards should translate to a more comfortable outdoor space for the students. This research adopted a qualitative approach based on case studies and computer simulations. The case studies were five present public schools’ buildings with different plan templates and different courtyard configurations; the schools are models 586, 596, KAT, UPA1 and finally UPA-fin. The computer analysis in this research was based on two software programs: ENVI-met software to evaluate changes in the schools’ microclimates due to the presence of courtyards and IESve software to calculate the energy consumption of the school buildings due to the changes of the microclimates affected by the courtyards. The thermal effect of the courtyards on the school buildings was investigated through two stages. The first stage discussed the orientation of the courtyard. The second stage investigated a range of courtyard configurations and designs through five phases, each focused on one of five relevant parameters which are: courtyard’s shape factor ratio (W/L ratio), courtyard’s area to built-up area (CA/BA ratio), courtyard’s outline shape, courtyard’s height (number of floors) and finally courtyard’s vegetation. There was third stage in this research that investigated the cooling loads for schools (case studies) in relation to the orientation and the design strategies. The cooling plant sensible load was investigated the beginning on specific dates and then it was investigated for the whole academic year. The outcomes of the research investigations concluded that the design and the properties of the courtyards can affect the indoor temperature of the school building, thus the cooling load. Moreover, the results of the computer simulation revealed that the school UPA-fin was the best school case with the optimum courtyards after adopting the following strategies 1- orientation to the north , 2-CA/BA ratio 20%, 3-square outline for the courtyards, 4-additional third floor on the east mass mainly 5- integrating vegetation in the courtyards, succeeded in reducing the Tin to 1.9 ˚C on 21st of September and 1.7 ˚C on 21st of March and that managed to reduce the cooling load by 19% on 21st of September and 27% on 21st of March compared to the basic UPA-fin to the north in phase one . The investigation of the annual cooling load after adopting only four strategies that included 1- orientation, 2-CA/BA ratio 20%, 3-square outline for the courtyards, 4-additional third floor on the east mass mainly and excluding the integration of vegetation, succeeded in reducing the cooling load by 16.5%compared to phase one UPA-fin basic to the north. The results showed that the optimum courtyard had the best predicted mean vote (PMV) performance also, as on 21st of September the max PMV reading for the poorest case of stage two equaled 4.35, which covered 48% of the courtyard’s area, while the max PMV reading for the best case of stage two (phase five) equaled 3.15 and covered 1.5% of the courtyard’s area with a reduction of about 1.2 on the PMV scale. On the other hand, on the 21st of March the max PMV reading for the poorest case of stage two equaled 3.0 and covered 48% of the courtyard’s area; while the max PMV reading for the best case equaled 1.9 and covered 1.5% of the courtyard’s area, with a reduction of about 1.1 according to the PMV scale. The research results revealed that the optimal design of the courtyard can reduce the temperature of the inner spaces of the school, thus it can reduce the cooling load for the school building in general. Moreover, it can improve the thermal comfort for the outdoor areas. The findings of this study will be important for architects, sustainable developers, educational developers, economic consultants and green buildings designers in UAE and in areas with similar climate to help them in designing green schools.
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    Urban Geometry: The Effect of Height Diversity and Buildings Configuration on Thermal Performance and Cooling Load at Urban Scale. A Case Study in Dubai / UAE
    (The British University in Dubai (BUiD), 2018-05) SHAREEF, SUNDUS LUAY
    Urban geometry and buildings morphology are important factors that affect both thermal behaviour of the spatial environment as well as a building’s energy performance. This research aims to explore the effect of the urban block with different building configurations on energy performance at the urban level. For this aim, a literature review was conducted to identify the previous and recent studies relevant to this research topic. It has been proven that the compactness element is a key urban geometry variable that controls the desired thermal performance of the built environment in hot climates. However, the previous studies have primarily focused on traditional methods of increasing the shading effect, such as by increasing buildings height / canyon width H/W ratio to provide the required compactness for desired solar access and energy saving target. This research attempts to provide alternative methods to achieving the required compactness and increase the shading effect by adapting building height variations and configurations in urban block design. As observed in the previous literature, the energy consumption assessment and the strategies that can be adopted to reduce this consumption are generally implemented and evaluated on the scale of individual buildings. Therefore, further investigation of both the diversity in building heights and the effect of this on the energy performance, and the evaluation of the energy consumption at the urban scale is required to fill the gap identified in previous literatures. This study utilised two software packages to simulate a base case urban configuration and evaluate this case against the proposed suggested scenarios of different configurations. The proposed scenarios depending on the urban configuration sustainable strategies were implemented and simulated to find the effect of adopting these strategies on the building’s total energy performance within the case study area, i.e., the Dubai / UAE local context and weather characteristics. Three groups with 56 proposed scenarios were simulated, where in different ratios of building height variation were implemented in the first two groups, and different building configurations were adopted for the third group. The research found that a significant variation in building height reduces the cooling load more than a gradual height variation, and consequently offers more energy saving. The variation along the short direction of the urban block has a greater positive effect and the saving in cooling energy consumption reaches 4.6 %. The significant variation in building height along the short axis of the urban block provides more shading to the canyons and the adjacent buildings compared to the base case. This over shading reduces the air temperature by 1.1 ͦ C within the canyon and directly reduces the conduction heat gain through the buildings envelop. This is in addition to the other effect represented by reducing the direct solar access to the building surfaces and decreases the solar energy gained by the buildings envelop through direct radiation. Furthermore, building orientation plays a significant role in the thermal performance of the urban block, and it contributes to the total cooling load energy saving of the urban block by 6.6 % at the peak time of cooling demand. Moreover, the research found that the variation in building heights will increase the wind velocity by up to 23 %, and this improvement in air flow affects the outdoor air temperature positively. This positive effect of the height variation on the outdoor air temperature of the urban canyons reduces the conduction heat gain through the buildings envelop by 4 %, and consequently reduces the energy required for cooling purpose. In addition, the alternative arrangement of the buildings within the block is another geometrical variable that affects the thermal performance of the built environment. It has been found that the alternative, or stagger arrangement, provides more shading effect on both canyon and building surfaces. However, this arrangement reduces the wind speed due to the obstruction created by the buildings mass and decreases the air velocity in the canyons. On the other hand, this type of configuration improves the distribution of the air around the buildings block and consequently enhances the outdoor thermal comfort around most of the buildings within the urban block. The reduction of 1.9 ͦ C in outdoor air temperature, and 4.9 % in cooling load is achieved by increasing the H/W ratio of the main canyons from 0.96 to 1.2. Therefore, designing the urban block with a significant diversity in building heights, or gradual height variation will have the potential of a shading effect and wind speed increase to enhance the thermal performance of the urban block. Finally, adopting the rectangular shape of the urban block, creating diversity in building heights and alternative building morphology are some of passive urban design strategies that can be followed for the optimised urban block configuration, with high efficient morphology and less environmental impact. This prototype is recommended for the new urban development in the UAE and other areas of the same climate zone.