Research on frequency conversion technology of metro station's ventilation and air-conditioning system

Ventilation and air-conditioning system (VAC) is the most energy-saving potential system in the metro. This paper analyzes the passenger traffic, air-conditioning load and station air supply on the initial, recent and long-term phase of metro station. And it proposes that it is necessary to run chilled-water pumps, air handing unit (AHU) fans and back/exhaust fans with frequency conversion technology (FCT). Then it uses the thermodynamic method to analyze the impact of running chilled-water pumps with FCT. The results show that running chilled-water pumps with FCT can reduce the total power consumption of system, although increases chiller energy consumption. Then the temperature and velocity fields of the platform and station hall are simulated by CFD software according to the variable air volume. And the results show that under the condition of running the VAC system with FCT, temperature and velocity fields distribution are both in the comfortable range. Finally, by taking a typical summer day for example, this paper analyzes the energy savings of chilled-water pumps, AHU fans and back/exhaust fans on the initial, recent and long-term phase, and the calculation results show that the respective total energy savings are 1103.4 kWh, 1064.3 kWh and 926.2 kWh, and the respective total power saving ratio is 73.4%, 71.2% and 59.5%.