Comparative Analysis of Heat Transfer Performance of Energy Segment Connections

With the rapid advancement of urbanization and societal development, the demand for energy has surged. A significant amount of waste heat is generated during subway operations. Currently, many projects employ subway-source heat pump technology to absorb this waste heat for heating and cooling above-ground buildings. By integrating heat exchangers with tunnel structures, energy shield segments are formed, achieving efficient waste heat utilization. However, the optimal design configuration of these energy segments remains an area requiring further investigation. This study utilizes COMSOL Multiphysics software to simulate and analyze the heat transfer performance of energy segments under various connection modes, considering different inlet water temperatures and velocities during both heating and cooling seasons.

The results indicate that all connection modes exhibit excellent heat transfer performance. Specifically, in the heating season, the tandem segment achieves a CHE (capillary heat exchanger) heat transfer rate of 545.15 W, while the parallel segment reaches 563.18 W. During the cooling season, the respective heat transfer rates are 657.21 W and 711.77 W. The parallel segment demonstrates superior heat transfer performance compared to the tandem segment in both seasons. Simulation outcomes confirm that energy segments possess outstanding heat transfer capabilities and can effectively absorb waste heat within tunnels. For practical applications, parallel segments offer enhanced heat transfer capacity, whereas series segments have minimal impact on the internal tunnel structure. This research provides a theoretical foundation for the implementation of metro-source heat pump systems in engineering projects.