Air-cooling power units have high back pressures in summer due to high environment temperatures

reducing the power output

thermal efficiency and operation safety. In this study

a wet-dry hybrid cooling system is analyzed with part of exhaust steam cooling by circulating water to decrease the unit back pressure in summer. A mathematic model is established for the effect of wet-dry hybrid cooling system on the thermal economy. Variations of back pressure and net power output with the live steam flow rate

exhaust steam distribution and environmental temperatures are analyzed for a 330 MW direct air cooling power unit. The results show that the power output increases from 326.266 MW to 330 MW and the back pressure drops from 46.8 kPa to 31.9 kPa as the live steam flow rate increases to1120 t·h-1 and the distribution steam flow rate with wet cooling increases to 175 t·h-1. The heat consumption rate decreases 110.9 kJ·(kW·h)-1 and generation standard coal consumption rate decreases 4 g·(kW·h)-1.