Analysis of factors influencing heat transfer of deep-buried pipe groups

In order to reveal the heat transfer mechanism of deep-buried pipe groups, this paper establishes a numerical model of deep-buried pipe groups based on the superposition principle, and verifies the model through experimental data. By analysing the heat extraction from each buried pipe, the annual minimum inlet temperature of buried pipes and the soil temperature around the buried pipes, the influence of the factors such as the layout method of buried pipes, the spacing between buried pipes, the depth of buried pipes and the operating flow on the heat extraction capacity of buried pipe groups is explored. The results show that when the pipe group is arranged in a single row, the heat extraction capacity is the largest, but its heat influence area is large. With the increase of the spacing between buried pipes, the heat extraction capacity of pipe groups increases. At the end of the 20th year, when the spacing between buried pipes increases from 10 m to 50 m, the inlet temperature increases by 13.76 ℃, and the recommended spacing between buried pipes is 30 m to 40 m. When the depth of buried pipes and the operating flow increase, the heat extraction capacity of pipe groups increases, but the increase rate gradually decreases. When designing the depth of buried pipes and the operating flow, drilling costs and circulating pump power consumption should be considered, and the operating flow should not be less than 7 kg/s.