期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2019
卷号：267
期号：4
页码：1-9
DOI：10.1088/1755-1315/267/4/042010
出版社：IOP Publishing
摘要：Based on the in-site thermal response experiment of a shallow geothermal energy plant in Guiyang, a model characterizing the heat transfer process between well-backfill material-ground material of a buried double vertical U-tube underground heat transfer system is established. Moreover, the influence of the thermal conductivity of the backfill material on the heat exchange efficiency for the summer condition is investigated. Results show that the maximum error between the outlet water temperatures calculated from model and obtained from field testing is less than 1.7%, which verifies the correctness of the model. When the thermal conductivity of the backfill is low, the heat in the buried heat exchanger is basically limited in the domain of the borehole. Furthermore, it is observed that the heat transfer efficiency increases, as the thermal conductivity increases. When the thermal conductivity of the backfill is close to that of the surrounding rock, the heat transfer efficiency increases in a faster rate. However, when the thermal conductivity of the backfill further increases, the heat transfer efficiency insignificantly increases. It is found that higher thermal conductivity of the backfill material has limited improvement on the heat exchange capacity of the buried pipe.
