Against such problems as frozen in air cooled condenser and lag in heat supply extraction parameter adjustment that occurred on cogeneration units in winter

a model was established to conduct thermal dynamic calculation

combining with a 4×220 MW direct air cooled cogeneration uni.The minimum condenser steam flow and heat supply extraction flow under different environmental temperatures were obtained

and the origin software was employed to draw the corresponding performance curves.The results showed that

with an increase in the environmental temperature

the steam amount required by condenser reduced and the variation rate of the steam flow decreased gradually.When the environmental temperature was lower than-5 ℃

the basic heater had reached the maximum heating load

peak-load heater should be started to satisfy the heat users.When the environmental temperature was below-6 ℃

the required total steam amount had exceeded the maximum steam amount

so fuel input should be increased to improve the main steam amount or part of the condenser units should be shut down to reduce power generation.This method can calculate the heat/electricity ratio at different environmental temperatures correctly and regulate the parameters of power generation and heat supply timely to realize the reasonable utilization of energy.