Research on optimization of ground heat exchanger depth under soil layered and non-layered in the loess plateau region
WU Jinshun
SUN Qihui
CUI Ying
GAO Xuhui
PAN Song
Abstract：In order to study the optimal buried depth of layered and non-layered soil ground heat exchanger in the Loess Plateau.In this paper,a three-dimensional model of a single U-shaped gronnd heat exchanger is es-tablished by Fluent simulation software,and the variation laws of outlet temperature and heat exchange of the buried pipe with depth of 60m,70m,80m,90m and 100m are analyzed under the conditions of layered soil and non-layered soil,respectively,so as to determine the optimal buried depth of the ground heat exchanger.The results show that the buried depth of the ground heat exchanger has a significant influence on the outlet tem-perature and heat exchange capacity of the whole system.The deeper the buried pipe is,the better the heat ex-change performance is,but with the increase of the buried depth of the ground heat exchanger,the growth rate of the two gradually decreases.The temperature difference between the inlet and outlet of the ground heat ex-changer and the heat exchange capacity per well depth in the case of layered soil are larger than those in the case of non-layered soil,and the difference is obvious.In the case of soil stratification,when the burial depth ranges from 60 m to 70 m,the maxium temperature difference between the inlet and outlet is 0.17℃and heat transfer rate is 0.12,respectively;When the burial depth increases from 70m to 80m without soil stratification,the maximum temperature difference between the inlet and outlet is 0.15℃,and the heat transfer rate is 0.13.Taking into account the outlet temperature difference and total heat change rate of the buried pipe,the optimal burial depth for a single U26 pipe and a soil layered buried pipe is 60～70 m,while the optimal burial depth for an ungraded soil buried pipe is 70～80 m.The research conclusion can provide data support and theoretical reference for the burial depth of single U-shaped buried pipes in ground source heat pumps in the Loess Plat-eau region or similar landforms.
Keywords：depth of ground heatexchangersingle U-tube ground heat exchangernumerical simulationoutlet temperature
Publication Date：2024-12-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：12( 45-56 )