Coupling effect of tunnel ventilation and SSHPS operation strategy on the thermal environment in energy tunnels

• Developed theoretical models and a dynamic simulation system for SSHPS. • Revealed the coupling effect of tunnel ventilation and SSHPS operation. • Given a coupling operation strategy of the tunnel ventilation system and SSHPS. • Provide theoretical support for the stable regulation of tunnel thermal conditions. The subway tunnel source heat pump system (SSHPS) is one of the effective technologies for addressing the thermal pollution problem in subway tunnels. However, existing studies have focused solely on analyzing the system performance of SSHPS, with insufficient attention given to the impact of its coupled operation with the tunnel ventilation system on the thermal environment within the tunnel. This study developed a simulation system for the SSHPS based on a pilot project. The coupling effects of the SSHPS operational strategy and tunnel ventilation rate on the thermal environment within the tunnel were systematically analyzed. The results indicate that increasing tunnel ventilation during the cooling season can partially alleviate the elevated temperatures caused by SSHPS operation, although the cooling effect is limited. Conversely, reducing ventilation during the heating season can effectively prevent tunnel temperatures from exceeding the threshold caused by SSHPS operation. Furthermore, the implementation of a strategy involving the year-round continuous operation of SSHPS, in conjunction with variable air volume control within the tunnel, allows for a more flexible and effective control of the tunnel thermal environment. This study establishes a theoretical foundation and provides technical references for ensuring the long-term thermal stability of the subway energy tunnel's thermal environment.