A Numerical Study of the Temperature Reduction by Water Spray Systems within Urban Street Canyons
| Autor: | Ying-Chen Lee, 李映辰 |
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| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 Urban heat islands rapidly increase energy demand for air conditioning. To reduce the energy demand for cooling the environment, some possible solutions have been studied and applied. Among these methods, the water spray system is considered most effective and flexible with its dynamic controls. To simulate the cooling effect of water spray system, numerical simulation with Computational Fluid Dynamics (CFD) is used. This simulation was validated with water channel and wind tunnel experiments. The goal of this study is to simulate the cooling effect in the street canyon with different aspect ratio in high relative humidity (70% and 80%) environment, which is often the case in Taipei city. The results showed that if relative humidity is larger than 70%, the air cooled by small water droplets was easily saturated. Large water droplets almost saturated the air just under the nozzles. If the nozzle height was increased from 2.5 m to 3.5 m, the air under the nozzles was completely saturated, and reached wet bulb temperature, which is the lowest bound of temperature. The coolest region is just below the nozzles because the wind in street canyon is too weak to blow the cold air away. However, in a narrow street, people may feel the cooling effect in the middle of the street because the accumulation of the cold air. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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