Pipe Distance Optimization of Geothermal Resource Heat Pump in Cold Region

Abstract:

In order to prevent freezing damage to tunnels in cold regions, tunnel heating system with geothermal resource heat pump was introduced for the first time at Linchang tunnel in Inner Mongolia Autonomous Region of China. Finite element method （FEM）was employed to analyze the process of heat exchange. First, the thermal properties of rock mass was inverted by calculating initial temperature field. Then, a heat flow function was obtained which is fitted with the heat flow calculated by the experiment data, and a transient heating analysis was made. A comparison between the numerical and experiment temperature proves that the accuracy requirement can be met. Finally, the distance between pipes was optimized by this method, and the most economic distance between pipes ranges from 0.5 to 0.8 m.

Key words:tunnel in cold region; geothermal resource heat pump; finite element method; optimization of distance between pipes