Masters Degree Dissertations

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12504/225

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    Design and simulation of a solar thermal cooling system for national medical stores
    (Kyambogo University(Unpublished work), 2024-10) Mbaga, Martin
    Solar energy is a clean form of energy that is essential for nearly all natural processes. Solar thermal cooling offers multiple advantages compared to conventional electrically powered systems. A study was conducted to design and simulate a solar thermal cooling system for the cold storage facility at the National Medical Stores, to solve the problem of the high electricity cost incurred while running the current cold storage cooling system. The system was designed using assorted calculations and the respective parameters were acquired, it was modeled and simulated, to use flat plate collectors and a LiBr-water absorption chiller. The solar-powered absorption cooling system simulation was carried out using the TRNSYS simulation program, with weather parameters for Kampala, Uganda where the facility is located, and the results indicated that the system is viable and applicable, and can provide the required cooling sufficiently. To ensure continuous system performance and increase reliability, a 119m3 hot water storage tank was included in the system, to ensure that the system can continue running for 48 hours for periods when there is no solar radiation. The system was designed with a capacity of 315kW (89.6 refrigeration tons), a 1,487m2 flat plate solar collector tilted at 100 to the horizontal, and its coefficient of performance (C.O.P) determined as 0.667. The system was successfully designed and simulated and the development is recommended for National Medical Stores in order to control the high costs of electricity that are generated from using grid power. .
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    Utilization of a 3D CFD model to simulate airflow behaviour towards optimization of cooling within data center
    (Kyambogo University (Unpublished work), 2024-10) Ochan, Patrick Awoii
    In recent years, efficient cooling management systems in data centers have been a high priority to ensure that the optimum operating condition is maintained under the current high level of digitalization. However, numerous data centers still encounter cooling inefficiencies due to factors such as CRAC unit arrangement, poorly positioned perforated tiles, and inadequate return air patterns where supply air mixes with return air. Addressing these challenges is essential for enhancing airflow and improving cooling efficiency. Therefore, in this research, the quality of temperature distribution and the airflow pattern in the DFCU data center were analyzed using the computational fluid dynamics (CFD) approach. CFD simulations were used to quantify the facility’s thermal cooling by developing a graphical user interface for component description and viewing. There was a need to compare the flow field and temperature distribution in the data center under different layouts since using CFD models describing solid bodies with thermal mass and energy balance principle makes it possible to visualize temperature and airflow patterns. From the results, the DFCU Bank data center showed temperature variations; hence there was a timely need for efficient cooling management to ensure the temperatures were within the limits recommended by ASHRAE. The simulation results had projections of the high-temperature zones and a comprehensive 3D examination of airflow distribution, and optimization methods established the best airflow arrangement. In addition to that, detailed temperature examinations of the individual racks and three-dimensional thermal mapping would establish the problematic regions and also inform how well the computer room air conditioning units were working. The various conclusions drawn from the research reveal that the cooling capacity would be improved, by adding two additional CRAC units each of 18kw, incorporating a return air duct system for better air distribution, and reducing exhaust air and supply air mixing through arterial blanking. These would result in a streamlined airflow in the data center, and a high cooling efficiency will be noted, which would eventually lead to low levels of energy consumed.