Experimental investigation on cooling load caused by unorganized ventilation in subway station: A case study

Unorganized ventilation significantly increases the energy consumption of subway stations. However, the quantitative description of cooling load caused by the unorganized ventilation in subway stations with platform screen doors (PSDs) still needs to be explored in depth. This study firstly proposed an experiment-based method to determine the airflow rate of unorganized ventilation, and then the corresponding cooling load is determined. Based upon this method, a series of field tests were conducted at a subway station in Shanghai. By analyzing the experimental data, the characteristic of unorganized ventilation at PSDs and entrance/exit passages was obtained. As for PSDs, the volume of unorganized ventilation in a cycle (the period from the upward train entering the station to the next upward train starting to approach the station) from the tunnel to the platform and from the platform to the tunnel is 2112.24 m3 and 4219.31 m3, respectively. With regard to entrance/exit passages, the volume of unorganized ventilation is 2655 m3 in a cycle. Thereafter, the above-mentioned results were used to determine cooling load. Owing to the difference in the departure density of train on weekdays and weekends, two typical summer days were selected for the purpose of cooling load analysis. The overall cumulative value of the cooling load caused by unorganized ventilation was 1416 kWh on a working day and 1718 kWh for the weekend, which accounted for 16.74 % and 19.19 % of the daily cooling load, respectively.