Study on ground temperature response of multilayer stratums under operation of ground-source heat pump. (25th May 2016)

• Record Type: Journal Article
• Authors: Zhou, Shiyu; Cui, Wenzhi; Tao, Jiaxiang; Peng, Qingyuan
• Is Part Of: Applied thermal engineering. Volume 101(2016:May)
• Page Start: 173
• Page End: 182
• Publication Date: 2016-05-25
• Subjects: Ground temperature -- Multilayer -- Stratum -- Ground source heat pump -- Thermal property; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2016.02.130
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: The ground temperature variation caused by the operation of a practical GSHP system is monitored. A numerical model is constructed according to the monitoring borehole and a TRT process is simulated. The temperature variation is different along the vertical direction due to the different thermal properties of the stratums. The relationship between temperature distribution and thermal properties along the depth direction is inferred. The fact that the heat flux along the borehole is proportional to thermal conductivities is demonstrated. Abstract: The operation of the ground source heat pump (GSHP) system in cooling dominated areas will cause heat accumulation under the ground, which results in the increase of the ground temperature. In the previous studies, the change of ground temperature was usually deemed as an average variation. This assumption may be right in the homogenous and isotropic soil. In multilayer ground geology, however, the temperature variation caused by the GSHP system operation is quite different along the vertical direction, which was illustrated in this paper based on the ground temperature monitoring data from a practical GSHP system. A numerical model was constructed according to the monitoring borehole that was located at the ground heat exchanger (GHE) field, and a long term heat injection process was simulated. It has been found that the temperature variation along the vertical direction at a distance from the borehole was in accordance with the monitored temperature variation. The fact that the heat exchange rate is proportional to the value of thermal conductivities was demonstrated with the distribution of the temperature difference between the circulating fluid and borehole wall.