Research On Energy-saving Ventilation Technology For Subway Environmental Control System

Subway environmental control system consumes most power in the metro. There have been some available measures used for saving energy in terms of system designs, equipment selection and subway operations. However most researches are about energy-saving air-conditioning system in the station instead of the energy-saving ventilation system in the tunnel.All the7th line of Chengdu metro uses the system of platform shed door, which causes the tunnel absolutely apart from the station platform, In the meantime that the trackway exhaust system is set in the station tunnel and all the stations adopt the single-piston vent shaft. That is to say, only one vent shaft is assembled at the end of the exit of the station. According to the primary design documents of7th line of Chengdu metro, the paper sets up the metro’s geometric model which is used in the SES program and this paper has study the following questions:(1) This paper analyzes the impacts of changes in different periods of traffic, train operating mode, soil heat storage and other factors. Then it does metro thermal environment hourly simulation by using SES in a variety of air flow conditions and the different operational periods. At last we get energy-saving operational strategies and effects of subway ventilation systems in various conditions.(2) The simulation analyzes the adoption of the middle vent shaft. And it makes the theoretic accounts for the design.The conclusions and the results of this paper are as follows:(1) The most energy-saving method which meets the requirements of the temperature criterion is that:in the initial operational stage, exhaust vent shaft should be closed, In the recent operational stage, exhaust vent shaft should be closed during non-peek times. In the future operational stage, exhaust vent shaft is closed in different hours and opens in different amount of air.(2) The7th line of Chengdu metro is a loop line. Airflow circulates in the circle and exchanges only by ventilation shaft. Piston vent shafts intake fresh air in the initial, recent and future operational stage with exhaust vent shaft open. The amount of air input is equal to the air output in the initial and recent operational stage. And the amount is larger in the future operational stage under the energy-saving operation plan.(3) After the middle vent shaft is cancelled, the temperature of running tunnel which is located in the station will slightly change, the other remains unchanged. In addition, the cancel of middle vent shaft will only increase the air’s quantity of the running tunnel and vent shaft that the middle vent shaft locates. The comprehensive analysis is that the middle vent shaft which is in the7th line of Chengdu metro could be canceled.