Because of large temperature difference between summer and winter

as well as in day and night

in north China

the volume flow rate of air-steam mixture

that should be extracted out from the air-cooled condenser

is variating considerably.If the said mixture isn't drawn out by the vacuum-extracting system

the effect of heat transfer in air-cooled condenser will decrease sharply.For this

a reasonable scheme has been put forward as follows:in the case of ambient temperature being above 2 ℃

the operation of water-ring pump can be optimized by using Δt=5 ℃;in the event of ambient temperature being below 2 ℃

the operation of water-ring pump can be optimized by using Δt=3 ℃.Furthermore

the pressure in air-cooled condenser during operation in summer is comparatively higher

the temperature of circulatory cooling water for the water-ring pump has to be always monitored

preventing the working water in said pump from vapourization

so as not to affect the effectiveness of heat transfer in the air-cooled condenser.