Dissertations for Building Services Engineering (BSE)

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    Double Skin Façade for an office building in the extreme UAE climate
    (The British University in Dubai (BUiD), 2021-07) ALI, NIZAM AHMED AKBAR
    Regional climate change scenarios indicate ever-increasing building energy consumption trends which are a serious cause of concern for the built environment sector of the UAE. Mitigating the increasing energy trends is very well understood by employment of active technological changes in the building services systems. This research focuses on the other side of the coin which is the passive technologies in reducing building energy consumption, more specifically technologies related to the skin of the building. A conventional passive skin technology (external shading) is fielded against unconventional passive skin technology (double skin façade - DSF) on key metrics such as annual cooling energy, annual solar gain, temperature and velocity profiles. The course of the research takes a holistic approach starting with a review of existing studies leading all the way to intermodal comparison of the dynamic thermal simulation and CFD results. Promising results are obtained for the building with external shading with 9.2% annual cooling energy savings whereas the study shows an increase of +1.42% jump in annual cooling energy consumption with the DSF building as compared to a generic high rise tower base case. Intermodel comparison reflects upon the under estimation of the dynamic thermal simulations in predicting cooling energy savings as compared to CFD simulation. An additional CFD sensitivity analysis further sheds light into the ability of the k-e turbulence models and constant effective models in determining stable solutions for CFD simulation of large unrestricted vertical volumes in DSF cavities.
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    Studying the impact of an energy retrofit of a UAE-based existing building by adding intelligent valves on the main chilled water risers and reconfigure the chilled water pumps to be on variable water flow loop configuration
    (The British University in Dubai (BUiD), 2021-08) MAHMOUD, ABDALLAH
    Buildings’ retrofit has been evolving throughout the past decades worldwide, aiming to improve the overall efficiency of the buildings and its operations, and many owners on private and public sectors are looking for highly effective systems and systems’ components to operate and manage their building stock due to the excessive energy consumption, thermal comfort, indoor air quality and hygienic requirements. This research is going to provide practical insights in building technologies, what multiple attempts have been evolving to improve HVAC systems, either from the effectiveness of heating and cooling distribution systems designs and retrofits or from the system components and operational strategies and techniques, particularly on the chilled water loops’ configuration retrofit and temperature difference “ΔT”. Such retrofit debates have been going into many experimental methods, on-premises’ solutions, new technologies, and multiple techniques of operations, and many guidelines have been published and shared for the sake of continuous improvement of chilled water systems and the optimum ways of operations and to clear those doubts surrounding those kinds of debates, this dissertation is verifying couple of those retrofit measures. With that being said, this research aims to provide reliable information and outputs on the best practice of operating chilled water network for a UAE-based building by converting the constant primary network to a variable one in addition to solve permanently the building ΔT issues by replacing the conventional pressure dependent control valves and adding intelligent valves on the main risers and the main airside equipment for this selected building, aiming to be quite practical as could as possible and have the outcome of combining both measures together, accordingly, the results show a potential energy saving on the range of 14-21% on the conservative side by applying the suggested retrofit measures, which leads to approximately an energy cost of savings of at least half a million to seven hundred thousands of UAE dirhams along with simple payback of 3-4 years which is considered an attractive SPB period for investors on such fields. Such energy cost savings is derived as a result of the significant reduction on pumping capacity in addition to insignificant but noticeable reduction on the lift of the air-cooled chillers’ compressors. Additionally, the research tries to present to buildings’ retrofit community a methodology to be followed for any future attempts on the same field by utilizing computer-based modeling software “IESVE” to simulate the existing cases and compare multiple scenarios for chilled water loops and ΔT. As a result of this research, it is made proven to any debates that retrofitting a typical UAE building by converting constant primary pumps into variable loop in addition to limiting the ΔT between 6 to 9oC on the risers side should lead to a magnificent energy cost saving.
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    COVID-19 bacteria viability and transmission in a shared ducted air conditioning system in multi residential building
    (The British University in Dubai (BUiD), 2021-09) ARAJI, HIBATALLAH
    The last year of 2020 by all thoughts, had changed the whole world normality. We have woken up on a sudden change of where whatever was granted, is not anymore. It is not granted that you go to work, to school, for grocery shopping or hang out as usual. It is not granted that holidays will be passed with families, and your plan to have the trip you were excited for is frozen till further notice. And above all, you might be in a risk of health issue and you were not aware of, and you might have put your most valuable people in your life in a health risk and you are not aware of. The year of 2020 had started with a hit of a virus of SARS- Cov-2 named after its starting year at end of 2019 “COVID - 19”, that had changed our life and taken us to a phase of pandemic. The pandemic of COVID - 19 has been the hit, the topic, and the change. When things were so granted, we didn’t have the time to appreciate the little but not so little things anymore. We had time to reconnect within our small families, had time to talk and listen without saying later. We had time to sit together and share moments that had been lost in the hectic speed of life. Welcome back to those values! This phase had urged the world to look into two scenarios for COVID - 19; one being the importance of limiting and stopping its spread; and the other scenario was to find the cure. The World Health Organization (WHO) had initiated and supported all studies, researches and experiments on the subject. This study will assist in the first target to look how the transmission of the virus is going into buildings and its services and what can be done to limit it.
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    Resilience of UAE high-rise buildings to climate change: Impacts of projected climate changes on annual energy demands.
    (The British University in Dubai (BUiD), 2020-07) Sallam, Duaa
    The impact of climate change and global warming on buildings energy consumption has been an arguable topic in many studies all around the world. However, there are limited studies on the effect of climate change on UAE buildings and its impact on energy demand. As global warming is hitting all areas in the entire world, designing and retrofitting buildings based on future weather conditions is essential to avoid early deterioration of buildings especially in countries with high air temperatures like UAE. This motivates the research on finding to most energy efficient solutions that would reduce energy consumption of UAE high-rise buildings in present and future weather conditions. To achieve this goal, future weather datasets in hourly time step for UAE were collected from three statistical tools representing stabilization and high emission scenarios. Those datasets were analyzed and compared with present weather files. This study has revealed that the derived future weather files daily dry-bulb temperatures are increasing throughout the years, while the daily relative humidity ratio and global horizontal solar radiation values are marginally decreasing from the present values. Then, energy efficient solutions were selected to test their effect on total system and cooling energy of high-rise buildings in UAE. Those solutions include increasing the insulation of external walls, improving the glazing thermal properties, and adding heat recovery units to the HVAC system. In this study, a high-rise building with 60% WWR which represents a typical UAE high-rise building was used as a base case to test the selected solutions on it. This study has shown that the energy consumption of UAE high-rise building will keep increasing in future and it can reach up to 50% more from the present consumption in period 2090 in high emission scenario. Using glazing with enhanced thermal properties would reduce more energy than applying sensible and latent heat recovery units. However, after 50 years the sensible and latent recovery units would reduce more energy than the enhanced glazing. Applying the three best options in this study was able to reduce total system and cooling energy by 20% to 21% in present and future periods.