Abstract: The evolution of underground temperature field of the pumping and injecting wells area with different aquifer structures was investigated experimentally. The transport behavior of the thermal-wet of different aquifer media and their thermal interaction were analyzed under same total water flow rate and well geometric parameters. The experimental results showed that the effect of aquifer rockyness variation on the occurrence time of the thermal breakthrough is significant while relatively small on the later thermal interaction. For the aquifer with larger size of gravel, the thermal breakthrough advances significantly. The effect of aquifer distribution on the thermal breakthrough is less than thermal interaction. For the homogeneous aquifer medium, the water flow rate of each well should be evenly distributed to postpone the thermal breakthrough and weaker the thermal interaction. For the inhomogeneous aquifer medium, each well should have individual flow adjustment to improve the thermal-wet balance and avoid the adverse influence of aquifer in homogeneity.

Key words: thermal energy engineering, underground source heat pump, aquifer structure, temperature evolution, pumping and injecting wells field