Study on the Effect of Heat Transfer Characteristics of Energy Piles

Abstract

The thermal performance of energy piles equipped with new metal fins to improve heat transmission is examined in this research. The solid heat transfer module of COMSOL Multiphysics was used to create a 2D numerical model of the energy pile, utilizing the energy pile at a field test site in Nanjing as an example. By contrasting the experimental data, the COMSOL Multiphysics model’s correctness was confirmed. After that, a new kind of energy pile fin was created to improve the heat transfer of the pile. The impact of the new fin type on the energy pile’s heat transfer efficiency was assessed, and the temperature change within the soil surrounding the pile before and after the fin was set was examined by contrasting the parameters of pipe configuration, buried pipe depth, and concrete thermal conductivity. The results indicate that after setting the fins to run for 336 h, the temperature of the concrete area increases by 10.8% to 12.3%, and the temperature of the region surrounding the pile increases by 5.3% to 8.7% when the tube diameter is chosen to be between 20 and 40 mm; The fins maximize the heat transfer temperature between the surrounding soil and the concrete, and as the tube diameter increases, the temperature drops. For 336 h of pile operation, the temperature of the concrete may be raised by 10.8% to 12.3% after the fins are set, and the temperature around the pile can be raised by 5.3% to 8.7%. The heat transmission efficiency of the energy pile can be improved by raising the temperature of the soil surrounding the pile through an increase in the concrete’s thermal conductivity; however, the degree of improvement diminishes as the conductivity rises. It is intended that this study will offer insightful information on the best way to design energy pile heat transfer efficiency.