Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Mechanical Power Engineering

For cases when it is difficult to introduce sufficient amounts of natural ventilation air to air-cooled chillers, mechanical ventilation is required. A typical example is mechanical/chiller rooms. Due to the confined space, part of the chillers{u2019} exhaust air is expected to be circulated back as part of the total intake air, eventually decreasing the coefficient of performance (COP) of the chillers. The objective of this study is to simulate the airflow distribution around chillers in such mechanical-rooms and to analyze the impact of room height, locations of the intake and exhaust louvers, number of chillers, and intake air velocity on the COP of chillers. This is achieved by developing a computational fluid dynamics (CFD) model in ANSYS® 19.0. The study shows that the locations of the intake and exhaust air-louvers and the intake louver air velocity are the most influential parameters that can significantly affect the performance of the chiller, and the lower this velocity is, the higher the chiller{u2019}s intake air temperature,the best results were achieved at an intake air velocity of 2 m/s. The best configuration for the air-louvers is to introduce the air from two side inlets and to locate the exhaust louver at the top of the room. Finally, the room{u2019}s clear height also affects the recirculation process, but it has a lower impact when compared to other parameters, the best results were achieved at a mechanical-room height of 6 m.

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