研究目的
To investigate the application of distributed temperature sensing technology in thermal response tests for borehole heat exchangers, focusing on the acquisition of ground temperature, installation of heat exchange tubes, optimization of monitoring positions, and the difference in thermal conductivity obtained by the ETRT and numerical simulation.
研究成果
The study concluded that DTS technology provides accurate ground temperature profiles, double U-tubes offer more accurate thermal conductivity measurements, installing optical fibers outside the U-tube sidewall is preferable, and numerical simulations must account for interfacial thermal resistance. The findings also suggested a minimum spacing of 16 m between adjacent heat exchange wells to avoid interaction effects.
研究不足
The study acknowledges the limitations in accurately estimating cool power during the cooling process and the need to consider interfacial thermal resistance in numerical simulations for more accurate thermal conductivity estimations.
1:Experimental Design and Method Selection:
The study involved a field trial in Heze, Shandong Province, China, using the enhanced thermal response test (ETRT) method with distributed temperature sensing (DTS) technology. Numerical models were built to compare and analyze the results.
2:Sample Selection and Data Sources:
The field trial was conducted in a 120-m-long borehole passing through 22 strata, divided into four types: fine sand, silty clay, silt, and clay.
3:List of Experimental Equipment and Materials:
The setup included U-tubes with an inner diameter of 2.9 cm, a buffer, valves, a pump, pressure gauge, flow meter, thermal meters, and a DTS interrogator (model NZS-DTS-M06).
4:9 cm, a buffer, valves, a pump, pressure gauge, flow meter, thermal meters, and a DTS interrogator (model NZS-DTS-M06).
Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: The test was divided into five stages, including measuring ground temperature using DTS, heating and cooling the U-tubes at specified powers, and collecting uninterrupted data.
5:Data Analysis Methods:
The thermal conductivities were calculated using the line-source models and compared with numerical simulation results.
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