Adaptive thermal comfort of underground railway coach travelers in cold zone in spring

Carries out a thermal comfort field investigation in the coaches of Metro Line 4 in spring in Xi’an, a representative city of the cold zone, and explores the subjective feelings and adapting characteristics of the thermal environment of underground railway coaches. Selects the travelers, tests the environmental parameters including air temperature, black ball temperature, relative humidity and wind speed, and makes the subjective questionnaires. The results show that the thermal neutral temperature of Xi’an underground railway coaches is 18.9 ℃, the moderate relative humidity and wind speed is 67% and 0.66 m/s, respectively, while the expected temperature, relative humidity and wind speed of the travelers is 20.1 ℃, 68.9% and 0.72 m/s, respectively. The travelers expect the temperature of the coaches to decrease, and the relative humidity and wind speed to increase in spring. Compared with the natural ventilation buildings in Xi’an in spring, their temperature sensitivities are close. Compared with the underground railway coaches in Changchun in spring, there are differences in temperature sensitivity and thermal neutral temperature of the travelers, which may be related to the regional outdoor climate. The neutral temperature in underground railway coaches is lower than that in naturally ventilated buildings in Xi’an, indicating that people have a higher temperature tolerance in short-term heat exposure locations.