A Case Study of Field Thermal Response Test and Laboratory Test Based on Distributed Optical Fiber Temperature Sensor

Yongjie Ma, Yanjun Zhang (), Yuxiang Cheng, Yu Zhang, Xuefeng Gao and Kun Shan
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Yongjie Ma: College of Construction Engineering, Jilin University, Changchun 130026, China
Yanjun Zhang: College of Construction Engineering, Jilin University, Changchun 130026, China
Yuxiang Cheng: Engineering Research Center of Geothermal Resources Development Technology and Equipment, Ministry of Education, Jilin University, Changchun 130026, China
Yu Zhang: State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China
Xuefeng Gao: College of Construction Engineering, Jilin University, Changchun 130026, China
Kun Shan: College of Construction Engineering, Jilin University, Changchun 130026, China

Energies, 2022, vol. 15, issue 21, 1-20

Abstract: To design an efficient ground source heat pump (GSHP) system, it is important to accurately measure the thermophysical parameters of the geotechnical layer. In the current study, a borehole is tested in detail using a combined thermal response test system (CTRTS) based on a distributed optical fiber temperature sensor (DOFTS) and a laboratory test. Real-time monitoring of the stratum temperature according to depth and operation time and the geothermal profile and thermal conductivity of each stratum are obtained. The results show that the undisturbed ground temperature is 10.0 °C, and the formation temperature field within 130 m can be divided into variable temperature formation, constant temperature formation (9.13 °C), and warming formation (geothermal gradient is 3.0 °C/100 m). The comprehensive thermal conductivity of the region is 1.862 W/m·K. From top to bottom, the average thermal conductivity of silty clay, mudstone, argillaceous siltstone, and mudstone is 1.631 W/m·K, 1.888 W/m·K, 1.862 W/m·K, and 2.144 W/m·K, respectively. By comparing the measurement results, the accuracy and effectiveness of the CTRTS are verified. Therefore, it is recommended to use the thermal conductivity obtained by the CTRTS to optimize the design of the borehole heat exchanger (BHE). This study provides a case for establishing a standard distributed thermal response test (DTRT).

Keywords: distributed optical fiber temperature sensor; field test; thermal conductivity; thermal response test (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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