Investigation on thermal environment of subway stations in severe cold region of China: A case study in Harbin

In recent years, numerous subway lines have been under construction with the rapid development of subways in the cold regions of China. Harbin, a typical city in severe cold regions, has harsh winter weather, and the lowest outdoor temperature can reach -37.7 degrees C. Therefore, the thermal environment of the station and the thermal comfort of passengers are facing huge challenges. Owing to the complexity of the subway environment, few field test studies, especially long-term tests, have been conducted. In this study, long-term field test on the thermal environment, questionnaire survey and thermal comfort analysis of two typical subway stations were conducted. A revised comfort temperature was proposed based on the constant changes in passenger metabolism. The field test results showed that the temperature and moisture content of the station were affected by the type of platform door, interval driving, operating time, and piston effect. The results of the questionnaire survey showed that the temperature, humidity, and thermal comfort of the two subway stations were satisfactory for most passengers. Passengers experienced a noticeable draft only in the aisle. After calculation, the lower limits of the comfortable temperature for the aisle, hall, and platform of the Harbin Metro were determined to be 10.6, 11.2, and 13.8 degrees C, respectively. The data obtained in this study provide a valuable reference for the construction and operation of subways in severe cold regions.