Study on Energy-Saving Potential Based on Heat and Moisture Transfer Characteristics During Fresh Air Introduction in Deep Underground Engineering

The goal of this paper is to clarify the heat–moisture coupled regulation mechanism of deep-buried underground air tunnels and to address the research gaps in the heat–moisture coupled transfer between airflow and surrounding rock. This paper established a 560 m deep ventilation shaft with a diameter of 5 m focused on the heat–moisture coupled transfer of “surrounding rock—air tunnel—airflow” to investigate the airflow characteristics; analyze the heat and moisture changes of the tunnel surface and airflow, as well as the energy storage characteristics of the surrounding rock; and compare the induced airflow characteristics across four typical cities in China. The results show the following: there is an “inlet effect” in the deep-buried air tunnel; the wall temperature becomes basically stable after 200 m from the entrance, while a greater depth is required for the stable section of humidity; in summer, the airflow temperature decreases by more than 1 °C and the enthalpy decreases by 3.5 kJ/kg; in addition, the ground temperature in Guangzhou is relatively high, resulting in a limited effect on adjusting the intake airflow. This study aims to provide support for the energy-saving design of fresh air systems in deep-buried underground buildings.