Numerical study of geothermal heat transfer characteristics and ground temperature response of shallow pipe group

Abstract

Pipe groups play a critical role in shallow geothermal energy applications, with the ground temperature response significantly influencing their heat transfer efficiency. This study develops three-dimensional numerical models in ANSYS, based on ground thermal response tests, to analyze the heat transfer characteristics and ground temperature response in both a single pipe and a 3 × 3 pipe group. The results showed that during operations involving heat extraction and natural recovery, heat transfer experiences decay across multiple cycles. This decay in the pipe group is 4–6 times greater than that observed in a single pipe. The heat transfer attenuation in a pipe is linear with its distance from other buried pipes. A staggered pipe arrangement slightly outperforms an aligned configuration, though the difference is negligible, less than 0.1 %. The seasonal attenuation in buried pipe heat transfer can be effectively mitigated by incorporating heat extraction, natural recovery, and heat storage. Within the 15-meter calculation domain, the heat transfer in the buried pipe is largely influenced by the ground’s heat storage properties. This study introduces a new perspective on optimizing buried pipe heat transfer by focusing on the ground temperature response.