Entransy analysis optimization of cooling water flow distribution in a dry cooling tower of power plant under summer crosswinds

The performance of natural draft dry cooling tower (NDDCT) of a coal-fired power generating unit is susceptible to ambient conditions, such as natural wind and temperature. An approach was proposed to relieve the adverse effects of ambient wind, which was the optimization of waterside flow re-distribution among heat exchangers of NDDCT under natural wind. With the help of entransy balance equations that described the heat transfer processes in each heat exchanger sector and condenser, all 20 influencing factors were considered to establish the optimization mathematical model of whole system, including both of the steam turbine subsystem and dry cooling system. A practical 660 MW dry cooling super-critical power generating unit was selected as object. The flow and heat transfer of NDDCT by natural wind effect were obtained numerically with verification. The results indicated that the performance of NDDCT could be improved by optimal distribution of waterside flow rate among the heat exchangers at any wind speed, especially at high wind speed. The comprehensive saving of power output coal consumption could be acquired although the pump power would raise by optimal water flow distribution. The decrease of coal consumption could reach 0.74 g/kWh at the natural wind speed of 12 m/s. (C) 2018 Elsevier Ltd. All rights reserved.