Abstract: Abstract:Taking N315-16.7/538/538 unit as example, the organic working medium cycle was added into thermal circulation system of thermal power unit, and a new power generation model was established. Based on the combination of the water steam circulation module and the organic working medium circulation module, the thermal economic efficiency calculations for different designed conditions were carried out. The result show that the optimal model can reduce the heat loss of the unit cold end and the waste heat pollution, and the unit thermal economic efficiency can be improved.

Key words: Key words:thermal power unit, optimized model, organic working medium, latent heat of vaporization, thermal economic efficiency