Introduction  In order to simplify the neutral surface method selection and the calculation method of the area of louvers for the natural ventilation of the steam turbine rooms of the traditional power plants, to further reveal the relationship between the neutral surface and the total area of the air inlet and outlet as well as the economy, a steam turbine room of a waste incineration power plant is analyzed as an engineering case. The different louver heights, the area of the air inlet and outlet and the cost are calculated by the neutral surface method.

  Method  The Python programming was used to calculate the complicated trial calculation process.

  Result  The results demonstrate that under the premise of fully considering the heat dissipation of the mezzanine floor and the operating floor of the steam turbine room, 100% bottom air inlet and 60%-40% air inlet mode are more economical. No matter which air inlet modes, the neutral surface height is selected according to the operating floor +3 ~ 9 m range, and the fluctuation of the total area and cost of air inlet and outlet are small.

  Conclusion  The neutral surface and the area of the air inlet and outlet louvers of actual projects can be selected by using this method.