基于ε-NTU方法的干湿联合冷却塔特性分析

Performance Analysis of Hybrid Cooling Tower Based on Effectiveness-NTU Method

本文基于ε-NTU方法建立了热力发电厂干湿联合冷却系统的热力计算模型,系统研究了干湿联合系统在降低机组夏季运行背压和出塔水温等方面的特性。在此基础上,结合我国部分城市气象数据,分析了干湿联合系统在多种气象环境下的适用性问题。结果表明:干湿联合系统可以有效改善空冷机组因夏季环境高温导致的背压升高、机组出力受限的问题,降低冷却塔出塔水温有助于提高发电厂的热经济性;干湿联合系统较适宜应用在低温低湿或者高温适湿的地区,在高温高湿地区则不建议采用。

Based on the effectiveness-NTU （ε-NTU） method, a mathematical model was set up for the hybrid （dry/wet） cooling system that is used in power plants. With this model, the characteristics of the hybrid cooling tower in adjusting outlet water temperature and influencing steam turbine back pressure were studied. Besides, the applicability of hybrid cooling system in different regions of China was analyzed with regional meteorological data. The results indicate that the hybrid cooling system helps to solve the problem of increased back pressure and reduced energy e^ciency of air-cooled power plants in summertime by effectively lowering the temperature of circulation cooling water. Generally the hybrid cooling system is appropriate to be applied in the areas with low temperature and low humidity, or high temperature and intermediate hmnidity. It is not fit for areas with high temperature and high humidity.