Research on Heat Exchange Law and Structural Design Optimization of Deep Buried Pipe Energy Piles

A deeply buried pipe energy pile (DBP-EP) combines the advantages of a ground source heat pump (GSHP) and an inside buried pipe energy pile (IBP-EP) and is an efficient, clean, and energy-saving technology. Based on field tests and numerical simulations, this paper explores the temperature distribution and heat exchange effects of DBP-EP under different influencing factors. The results show that when the pile-to-well ratio is approximately 0.3–0.4, the heat exchange of the energy pile obtains the best benefit; the inlet water temperature is the most significant factor affecting the heat exchange effect of the energy pile, and when combined with a reasonable pile-to-well ratio, the energy pile obtains the best heat exchange effect; the flow rate has a significant impact on the heat exchange effect of the energy pile, but needs to be set reasonably according to the pile-to-well ratio; the influence of inlet water temperature, well depth, flow rate, and pile length on the heat exchange efficiency of the energy pile is gradually weakened. The research results of this paper provide a theoretical basis for the structural design optimization of DBP-EP and promote the popularization and application of energy pile technology.