Sustainability study of medium-deep geothermal buried pipe for heat supply
Vol 5, Issue 1, 2022
VIEWS - 301 (Abstract) 223 (pdf)
Abstract
In order to study the temperature change trend of the surrounding geotechnical soil during the operation and thermal recovery of the medium-deep geothermal buried pipe and the influence of the geotechnical soil on the operational stability of the vertical buried pipe after thermal recovery. Based on the data of geological stratum in Guanzhong area and the actual engineering application of medium-deep geothermal buried pipe heating system in Xi’an New Area, the influence law of medium-deep geothermal buried pipe heat exchanger on surrounding geotechnical soil is simulated and analyzed by FLUENT software. The results show that: after four months of heating operation, in the upper layer of the geotechnical soil, the reverse heat exchange zone appears due to the higher fluid temperature; in the lower layer of the geotechnical soil, the temperature decreases more with the increase of depth and shows a linear increase in the depth direction; without considering the groundwater seepage, after eight months of thermal recovery of the geotechnical soil after heating, the maximum temperature difference after recovery is 3.02 ℃, and the average temperature difference after recovery is 1.30 ℃ The maximum temperature difference after recovery was 3.02 ℃ and the average temperature difference after recovery was 1.30 ℃. The geotechnical thermal recovery temperature difference has no significant effect on the long-term operation of the buried pipe, and it can be operated continuously and stably for a long time. Practice shows that due to the influence of various factors such as stratigraphic structure, stratigraphic pressure, radioactive decay and stratigraphic thermal conductivity, the actual stratigraphic temperature below 2000m recovers rapidly without significant temperature decay, fully reflecting the characteristics of the Earth’s constant temperature body.
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1. Omer AM. Ground-source heat pumps systems and applications. Renewable and Sustainable Energy Reviews 2006; 12(2): 344–371.
2. National Development and Reform Commission (NDRC) of People’s Republic of China: Catalogue of green technology promotion 2020. Beijing: National Development and Reform Commission (NDRC) of People’s Republic of China; 2021.
3. Du T, Man Y, Jiang G, et al, Transfer modeling and heat extraction analysis of coaxial tubes deep borehole heat exchanger. Renewable Energy Resources 2020; 38(7): 887–892.
4. Liu J, Cai W, Wang F, et al. Experimental study and tube structure optimization of deep borehole ground source heat pump. Journal of Engineering Thermophysics 2019; 40(9): 2143–2150.
5. Deng J, Wei Q, Zhang H, et al. On-site measurement and analysis on energy consumption and energy efficiency ratio of medium depth geothermal heat pump systems for space heating. Heating Ventilating & Air Conditioning 2017; 47(8): 150–154.
6. Fang L, Diao N, Shao Z, et al. Study on thermal resistance of coaxial tube boreholes in ground-coupled heat pump systems. Procedia Engineering 2017; 205: 3735–3742.
7. Fang L, Diao N, Shao Z, et al. A computationally efficient numerical model for heat transfer simulation of deep borehole heat exchangers. Energy & Buildings 2018; 167: 79–88.
8. Jia L, Cui P, Fang L, et al. Thermal effect of heat transfer process of deep borehole heat exchangers on surrounding rock and soil. Heating Ventilating & Air Conditioning 2021; 51(1): 101–107.
9. Renaud T, Verdin P, Falcone G. Numerical simulation of a deep borehole heat exchanger in the Krafla geothermal system. International Journal of Heat and Mass Transfer 2019; 143: 118496.
10. Lv P, Sun Y, Li Q. ANSYS simulation of soil temperature field around U-tube in geothermal well. Global Geology 2011; 30(2): 301–306.
11. Zhou Y, Zhang H, Jiang X, et al. Influencing factors of constant-temperature layer depth and its estimation in Shaanxi province. Geological Survey of China 2019; (3): 81–86.
DOI: https://doi.org/10.24294/tse.v5i1.1527
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