Energy Saving Effect Of The Environment Control System For Subway Air-Conditioning Based On The Variable Frequency Techology

In the operation of subway, the electric consumption of the enviromental control system in the subway always accounts for a quite great proportion, specially those with airconditioning. Although the electric investment only accounts for 8%～10% in the total investment of a station, the consumption actually occupied 40%～50% of the entire subway power,while the energy consumption of the fans has achieved about 50% in the entire air conditioning energy consumption proportion, therefore it is significant to find out how to optimize the design and the operation of the enviromental control system furtherly, and the feasible energy conservation measure specially which aims at the energy saving of fans.In the subway enviromental control system, because the capacity of the air conditioning ventilation system(small system) of the station installations management room is smaller which mainly contains the equipment and the illumination load whose variation is extremely small, it is not significant to use the frequency conversion control. Moreover the TVF system naomally does not move, when the fire happens it moves at the full speed to discharge fume, so the energy conservation potential is smaller, and the TVF system is not taken into account as well. (Water system)At present the freezer has the ability to adjust the load automatically with a high efficiency, so there is no need to adjust the water system. The energy consumption of the big system is extremely great which changes a lot along with personnel change, outside environmental fluctuation and so on, therefore the potential of frequency conversion to save energy is very huge.The frequency conversion velocity modulation controls already has achieved a successful experience in other domains, but it is still in an exploration in subway. This article takes a Chengdu subway station as the example to study on the effect of the frequency conversion control for VAV system. First, the basic model is established which contains a dynamic hot load model of a subway station with PSD, the frequency changer fuzzy control rule and its model, outside and the tunnel meteorology model, the fans and its the energy consumption model and so on. Then the winter stands control temperature, the summer air conditioning season stands control temperature and the controltemperature schedul based on the are determined. Finally it controls the station on the constant temperature based separately on the each air conditioning stage, and it controls RWI on an disadvartageous day in summer.Through the emulations of frequency conversion control for VAV system of the big system under different controls, it is discovered that frequency conversion control may achieve the higher control precision (the control precision between [-1, +1]) and a better energy conservation effect (in summer double fans conserves energy up to 29. 1%, in transition season fans conserves energy up to 31.9%, in winter fans conserves energy upto 70% (two crosswinds machine open)).