For the damp and direct air cooling units constructed during different periods in the same power plant in northern areas of China

the unit system operation mode was changed

and a kind of cold end joint operation system was put forward.This system was applied in a power plant owning two subcritical600 MW coal-fired damp units and two subcritical 600 MW coal-fied direct air cooling units.The results show that

after the unit cold end joint operation

the units can save standard coal of 3.49g/(kW·h)in summer

so the high back pressure and decreasing output problems of the direct air cooling unit in summer was effectively solved.Under rated conditions

the units can save standard coal of 2.97g/(kW·h)

and under any operation conditions

the heat consumption rate of both air cooling units and damp units can be decreased and the thermal efficiency of the units can be enhanced.The investment recovery period of this method is about 2years.